06 Anatomy

Question 1 of 263

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A 56 year old man is left impotent following an abdomino-perineal excision of the colon and rectum. What is the most likely

explanation?

A. Psychosexual issues related to an end colostomy

B. Damage to the sacral venous plexus during total mesorectal excision

C. Damage to the left ureter during sigmoid mobilisation

D. Damage to the hypogastric plexus during mobilisation of the inferior

mesenteric artery

E. Damage to the internal iliac artery during total mesorectal excision

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Autonomic nerve injury is the most common cause.

Nerve lesions during surgery

A variety of different procedures carry the risk of iatrogenic nerve injury. These are important not only from the patients

perspective but also from a medicolegal standpoint.

The following operations and their associated nerve lesions are listed here:

• Posterior triangle lymph node biopsy and accessory nerve lesion.

• Lloyd Davies stirrups and common peroneal nerve.

• Thyroidectomy and laryngeal nerve.

• Anterior resection of rectum and hypogastric autonomic nerves.

• Axillary node clearance; long thoracic nerve, thoracodorsal nerve and intercostobrachial nerve.

• Inguinal hernia surgery and ilioinguinal nerve.

• Varicose vein surgery- sural and saphenous nerves.

• Posterior approach to the hip and sciatic nerve.

• Carotid endarterectomy and hypoglossal nerve.

There are many more, with sound anatomical understanding of the commonly performed procedures the incidence of nerve

lesions can be minimised. They commonly occur when surgeons operate in an unfamiliar tissue plane or by blind placement of

haemostats (not recommended).

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Question 2 of 263

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A 73 year old man is due to undergo a radical prostatectomy for carcinoma of the prostate gland. To which of the following lymph nodes will the tumour drain primarily?

A. Para aortic

B. Internal iliac

C. Superficial inguinal

D. Meso rectal

E. None of the above

Next question The prostate lymphatic drainage is primarily to the internal iliac nodes and also the sacral nodes. Although internal iliac is the first site.

Prostate gland The prostate gland is approximately the shape and size of a walnut and is located inferior to the bladder. It is separated from the rectum by Denonvilliers fascia and its blood supply is derived from the internal iliac vessels. The internal sphincter lies at the apex of the gland and may be damaged during prostatic surgery, affected individuals may complain of retrograde ejaculation. Summary of prostate gland

Arterial supply Inferior vesical artery (from internal iliac)

Venous drainage Prostatic venous plexus (to paravertebral veins)

Lymphatic drainage Internal iliac nodes

Innervation Inferior hypogastric plexus

Dimensions • Transverse diameter (4cm) • AP diameter (2cm) • Height (3cm)

Lobes • Posterior lobe: posterior to urethra • Median lobe: posterior to urethra, in between ejaculatory ducts • Lateral lobes x 2 • Isthmus

Zones • Peripheral zone: subcapsular portion of posterior prostate. Most prostate cancers are here • Central zone • Transition zone • Stroma

Relations

Anterior Pubic symphysis Prostatic venous plexus

Posterior Denonvilliers fascia Rectum Ejaculatory ducts

Lateral Venous plexus (lies on prostate) Levator ani (immediately below the puboprostatic ligaments)

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Question 3 of 263

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Which of the following statements relating to the vertebral column is false?

A. There are 7 cervical vertebrae

B. The cervical and lumbar lordosis are secondary curves developing after birth

due to change in shape of the intervertebral discs

C. The lumbar vertebrae do not have a transverse process foramina

D. The lumbar vertebrae receive blood directly from the aorta

E. The spinous process is formed by the junction of the pedicles posteriorly

Next question

The spinous process is formed by 2 laminae posteriorly.

Vertebral column

• There are 7 cervical, 12 thoracic, 5 lumbar, and 5 sacral vertebrae.

• The spinal cord segmental levels do not necessarily correspond to the vertebral segments. For example, while the C1

cord is located at the C1 vertebra, the C8 cord is situated at the C7 vertebra. While the T1 cord is situated at the T1

vertebra, the T12 cord is situated at the T8 vertebra. The lumbar cord is situated between T9 and T11 vertebrae. The

sacral cord is situated between the T12 to L2 vertebrae.

Cervical vertebrae

The interface between the first and second vertebra is called the atlanto-axis junction. The C3 cord contains the phrenic nucleus.

The cervical cord innervates the deltoids (C4), biceps (C4-5), wrist extensors (C6-8), triceps (C7), wrist flexors (C8-T1), and

hand muscles (C8-T1).

Thoracic vertebrae

The thoracic vertebral segments are defined by those that have a rib. The spinal roots form the intercostal nerves that run on the

bottom side of the ribs and these nerves control the intercostal muscles and associated dermatomes.

Lumbosacral vertebrae

Form the remainder of the segments below the vertebrae of the thorax. The lumbosacral spinal cord, however, starts at about T9

and continues only to L2. It contains most of the segments that innervate the hip and legs, as well as the buttocks and anal

regions.

Cauda Equina

The spinal cord ends at L2 vertebral level. The tip of the spinal cord is called the conus. Below the conus, there is a spray of

spinal roots that is called the cauda equina. Injuries below L2 represent injuries to spinal roots rather than the spinal cord proper.

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Question 4 of 263

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The cephalic vein pierces the clavipectoral fascia to terminate in which of the veins listed below?

A. External jugular

B. Axillary

C. Internal jugular

D. Azygos

E. Brachial

Next question

Cephalic vein

Path

• Dorsal venous arch drains laterally into the cephalic vein

• Crosses the anatomical snuffbox and travels laterally up the arm

• At the antecubital fossa connected to the basilic vein by the median cubital vein

• Pierces deep fascia of deltopectoral groove to join axillary vein

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Question 5 of 263

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A 78 year old lady falls over in her nursing home and sustains a displaced intracapsular fracture of the femoral neck. A decision

is made to perform a hemi arthroplasty through a lateral approach. Which of these vessels will be divided to facilitate access?

A. Saphenous vein

B. Superior gluteal artery

C. Superficial circumflex iliac artery

D. Profunda femoris artery

E. Transverse branch of the lateral circumflex artery

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During the Hardinge style lateral approach the transverse branch of the lateral circumflex artery is divided to gain access. The

vessels and its branches are illustrated below:

Image sourced from Wikipedia

Hip joint

• Head of femur articulates with acetabulum of the pelvis

• Both covered by articular hyaline cartilage

• The acetabulum forms at the union of the ilium, pubis, and ischium

• The triradiate cartilage (Y-shaped growth plate) separates the pelvic bones

• The acetabulum holds the femoral head by the acetabular labrum

• Normal angle between femoral head and femoral shaft is 130o

Ligaments

• Transverse ligament: joints anterior and posterior ends of the articular cartilage

• Head of femur ligament (ligamentum teres): acetabular notch to the fovea. Contains arterial supply to head of femur in

children.



Extracapsular ligaments

• Iliofemoral ligament: inverted Y shape. Anterior iliac spine to the trochanteric line

• Pubofemoral ligament: acetabulum to lesser trochanter

• Ischiofemoral ligament: posterior support. Ischium to greater trochanter.

Blood supply

Medial circumflex femoral and lateral circumflex femoral arteries (Branches of profunda femoris)

2 anastomoses: Cruciate and the trochanteric anastomoses (provides most of the blood to the head of the femur) Hence the need

for hemiarthroplasty when there is a displaced femoral head fracture. These anastomoses exist between the femoral artery or

profunda femoris and the gluteal vessels.

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Question 6 of 263

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A 73 year old man undergoes a sub total oesophagectomy with anastomosis of the stomach to the cervical oesophagus. Which

vessel will be primarily responsible for the arterial supply to the oesophageal portion of the anastomosis?

A. Superior thyroid artery

B. Internal carotid artery

C. Direct branches from the thoracic aorta

D. Inferior thyroid artery

E. Subclavian artery

Next question

The cervical oesophagus is supplied by the inferior thyroid artery. The thoracic oesophagus (removed in this case) is supplied

by direct branches from the thoracic aorta.

Oesophagus

• 25cm long

• Starts at C6 vertebra, pierces diaphragm at T10 and ends at T11

• Squamous epithelium

Constrictions of the oesophagus

Structure Distance from incisors

Cricoid cartilage 15cm

Arch of the Aorta 22.5cm

Left principal bronchus 27cm

Diaphragmatic hiatus 40cm

Relations

Anteriorly • Trachea to T4 • Recurrent laryngeal nerve • Left bronchus, Left atrium • Diaphragm

Posteriorly • Thoracic duct to left at T5 • Hemiazygos to the left T8 • Descending aorta • First 2 intercostal branches of aorta

Left • Thoracic duct • Left subclavian artery

Right • Azygos vein

Arterial, venous and lymphatic drainage of the oesophagus

Artery Vein Lymphatics Muscularis externa

Upper third Inferior thyroid Inferior thyroid Deep cervical Striated muscle

Mid third Aortic branches Azygos branches Mediastinal Smooth & striated muscle

Lower third Left gastric Posterior mediastinal and coeliac Gastric Smooth muscle

Nerve supply

• Upper half is supplied by recurrent laryngeal nerve

• Lower half by oesophageal plexus (vagus)

Histology

• Mucosa :Nonkeratinized stratified squamous epithelium

• Submucosa: glandular tissue

• Muscularis externa (muscularis): composition varies. See table

• Adventitia

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Question 7 of 263

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Which of the following structures is not closely related to the brachial artery?

A. Ulnar nerve

B. Median nerve

C. Cephalic vein

D. Long head of triceps

E. Median cubital vein

Next question

The cephalic vein lies superficially and on the contralateral side of the arm to the brachial artery. The relation of the ulnar

nerves and others are demonstrated in the image below:


Brachial artery

The brachial artery begins at the lower border of teres major as a continuation of the axillary artery. It terminates in the cubital

fossa at the level of the neck of the radius by dividing into the radial and ulnar arteries.

Relations

Posterior relations include the long head of triceps with the radial nerve and profunda vessels intervening. Anteriorly it is

overlapped by the medial border of biceps.

It is crossed by the median nerve in the middle of the arm.

In the cubital fossa it is separated from the median cubital vein by the bicipital aponeurosis.

The basilic vein is in contact at the most proximal aspect of the cubital fossa and lies medially.

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Question 8 of 263

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The following statements relating to the musculocutaneous nerve are true except?

A. It arises from the lateral cord of the brachial plexus

B. It provides cutaneous innervation to the lateral side of the forearm

C. If damaged then extension of the elbow joint will be impaired

D. It supplies the biceps muscle

E. It runs beneath biceps

Next question

It supplies biceps, brachialis and coracobrachialis so if damaged then elbow flexion will be impaired.

Musculocutaneous nerve

• Branch of lateral cord of brachial plexus

Path

• It penetrates the Coracobrachialis muscle

• Passes obliquely between the Biceps brachii and the Brachialis to the lateral side of the arm

• Above the elbow it pierces the deep fascia lateral to the tendon of the Biceps brachii

• Continues into the forearm as the lateral cutaneous nerve of the forearm

Innervates

• Coracobrachialis

• Biceps brachii

• Brachialis

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Question 9 of 263

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Which ligament keeps the head of the radius connected to the radial notch of the ulna?

A. Annular (orbicular) ligament

B. Quadrate ligament

C. Radial collateral ligament of the elbow

D. Ulnar collateral ligament

E. Radial collateral ligament

Next question

The annular ligament connects the radial head to the radial notch of the ulna. This is illustrated below:


Radius

• Bone of the forearm extending from the lateral side of the elbow to the thumb side of the wrist

Upper end

• Articular cartilage- covers medial > lateral side

• Articulates with radial notch of the ulna by the annular ligament

• Muscle attachment- biceps brachii at the tuberosity

Shaft

• Muscle attachment-

Upper third of the body Supinator, Flexor digitorum superficialis, Flexor pollicis longus

Middle third of the body Pronator teres

Lower quarter of the body Pronator quadratus , tendon of supinator longus

Lower end

• Quadrilateral

• Anterior surface- capsule of wrist joint

• Medial surface- head of ulna

• Lateral surface- ends in the styloid process

• Posterior surface: 3 grooves containing:

1. Tendons of extensor carpi radialis longus and brevis

2. Tendon of extensor pollicis longus

3. Tendon of extensor indicis


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Question 10 of 263

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A 38 year old man presents to the clinic with shoulder weakness. On examination he has an inability to initiate shoulder

abduction. Which of the nerves listed below is least likely to be functioning normally?

A. Suprascapular nerve

B. Medial pectoral nerve

C. Axillary nerve

D. Median nerve

E. Radial nerve

Next question

Theme from April 2012 Exam

Suprascapular nerve

The suprascapular nerve arises from the upper trunk of the brachial plexus. It lies superior to the trunks of the brachial plexus

and passes inferolaterally parallel to them. It passes through the scapular notch, deep to trapezius. It innervates both

supraspinatus and infraspinatus and initiates abduction of the shoulder. If damaged, patients may be able to abduct the shoulder

by leaning over the affected side and deltoid can then continue to abduct the shoulder.

I

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Question 11 of 263

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Which of the following statements relating to the Cavernous Sinus is false?

A. The pituitary gland lies medially

B. The internal carotid artery passes through it

C. The temporal lobe of the brain is a lateral relation

D. The mandibular branch of the trigeminal and optic nerve lie on the lateral wall

E. The ophthalmic veins drain into the anterior aspect of the sinus

Next question

The veins that drain into the sinus are important as sepsis can cause cavernous sinus thrombosis. The maxillary branch of the

trigeminal and not the mandibular branches pass through the sinus

Cavernous sinus

The cavernous sinuses are paired and are situated on the body of the sphenoid bone. It runs from the superior orbital fissure to

the petrous temporal bone.

Relations

Medial Lateral

Pituitary fossa Sphenoid sinus

Temporal lobe

Contents

Lateral wall components (from top to bottom:) Oculomotor nerve Trochlear nerve Ophthalmic nerve Maxillary nerve

Contents of the sinus (from medial to lateral:) Internal carotid artery (and sympathetic plexus) Abducens nerve

Blood supply

Ophthalmic vein, superficial cortical veins, basilar plexus of veins posteriorly.

Drains into the internal jugular vein via: the superior and inferior petrosal sinuses


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Question 12 of 263

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Which of the following is not a branch of the subclavian artery?

A. Superior thyroid artery

B. Vertebral artery

C. Thyrocervical trunk

D. Internal thoracic artery

E. Dorsal scapular artery

Next question

Mnemonic for the branches of the subclavian artery: VIT C & D

V ertebral artery

I nternal thoracic

T hyrocervical trunk

C ostalcervical trunk

D orsal scapular

Superior thyroid artery is a branch of the external carotid artery.

Subclavian artery

Path

• The left subclavian comes directly off the arch of aorta

• The right subclavian arises from the brachiocephalic artery (trunk) when it bifurcates into the subclavian and the right

common carotid artery.

• From its origin, the subclavian artery travels laterally, passing between anterior and middle scalene muscles, deep to

scalenus anterior and anterior to scalenus medius. As the subclavian artery crosses the lateral border of the first rib, it

becomes the axillary artery. At this point it is superficial and within the subclavian triangle.


Branches

• Vertebral artery

• Internal thoracic artery

• Thyrocervical trunk

• Costocervical trunk

• Dorsal scapular artery

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Question 13 of 263

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During the repair of an atrial septal defect the surgeons note that blood starts to leak from the coronary sinus. Which structure

forms the largest tributary of the coronary sinus?

A. Thesbian veins

B. Great cardiac vein

C. Oblique vein

D. Small cardiac veins


Next question

The great cardiac vein runs in the anterior interventricular groove, and is the largest tributary of the coronary sinus. The

Thesbian veins drain into the heart directly.

Heart anatomy

The walls of each cardiac chamber comprise:

• Epicardium

• Myocardium

• Endocardium

Cardiac muscle is attached to the cardiac fibrous skeleton.

Relations

The heart and roots of the great vessels within the pericardial sac are related anteriorly to the sternum, medial ends of the 3rd to

5th ribs on the left and their associated costal cartilages. The heart and pericardial sac are situated obliquely two thirds to the left

and one third to the right of the median plane.

The pulmonary valve lies at the level of the left third costal cartilage.

The mitral valve lies at the level of the fourth costal cartilage.

Coronary sinus

This lies in the posterior part of the coronary groove and receives blood from the cardiac veins. The great cardiac vein lies at its

left and the middle and small cardiac veins lie on its right. The smallest cardiac veins drain into the atria directly.

Aortic sinus

Right coronary artery arises from the right aortic sinus, the left is derived from the left aortic sinus and no vessel emerges from

the posterior sinus.

Right and left ventricles

Structure Left Ventricle

A-V Valve Mitral (double leaflet)

Walls Twice as thick as right

Trabeculae carnae Much thicker and more numerous

Right coronary artery

The RCA supplies:

• Right atrium

• Diaphragmatic part of the left ventricle

• Usually the posterior third of the interventricular septum

• The sino atrial node (60% cases)

• The atrio ventricular node (80% cases)

Left coronary artery

The LCA supplies:

• Left atrium

• Most of left ventricle

• Part of the right ventricle

• Anterior two thirds of the inter ventricular septum

• The sino atrial node (remaining 40% cases)

Innervation of the heart

Autonomic nerve fibres from the superficial and deep cardiac plexus. These lie anterior to the bifurcation of the trachea,

posterior to the ascending aorta and superior to the bifurcation of the pulmonary trunk. The parasympathetic supply to the heart

is from presynaptic fibres of the vagus nerves.

Valves of the heart

Mitral valve Aortic valve Pulmonary valve Tricuspid valve

2 cusps 3 cusps 3 cusps 3 cusps

First heart sound Second heart sound Second heart sound First heart sound

1 anterior cusp 1 anterior cusp 2 anterior cusps 2 anterior cusps

Attached to chordae tendinae No chordae No chordae Attached to chordae tendinae

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Question 14 of 263

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Which of the following vessels provides the greatest contribution to the arterial supply of the breast?

A. External mammary artery

B. Thoracoacromial artery

C. Internal mammary artery

D. Lateral thoracic artery

E. Subclavian artery

Next question

60% of the arterial supply to the breast is derived from the internal mammary artery. The external mammary and lateral thoracic

arteries also make a significant (but lesser) contribution. This is of importance clinically in performing reduction mammoplasty

procedures.

Breast

The breast itself lies on a layer of pectoral fascia and the following muscles:

1. Pectoralis major

2. Serratus anterior

3. External oblique

Image showing the topography of the female breast


Breast anatomy

Nerve supply Branches of intercostal nerves from T4-T6.

Arterial supply • Internal mammary (thoracic) artery • External mammary artery (laterally) • Anterior intercostal arteries • Thoraco-acromial artery

Venous drainage Superficial venous plexus to sub clavian, axillary and intercostal veins.

Lymphatic drainage • 70% Axillary nodes • Internal mammary chain • Other lymphatic sites such as deep cervical and supraclavicular fossa (later in disease)

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Question 15 of 263

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Which of the following muscles is supplied by the external laryngeal nerve?

A. Transverse arytenoid

B. Cricothyroid

C. Thyro-arytenoid

D. Posterior crico-arytenoid

E. Oblique arytenoid

Next question

The others are all supplied by the recurrent laryngeal nerve.

Larynx

The larynx lies in the anterior part of the neck at the levels of C3 to C6 vertebral bodies. The laryngeal skeleton consists of a

number of cartilagenous segments. Three of these are paired; arytenoid, corniculate and cuneiform. Three are single; thyroid,

cricoid and epiglottic. The cricoid cartilage forms a complete ring (the only one to do so).

The laryngeal cavity extends from the laryngeal inlet to the level of the inferior border of the cricoid cartilage.

Divisions of the laryngeal cavity

Laryngeal vestibule Superior to the vestibular folds

Laryngeal ventricle Lies between vestibular folds and superior to the vocal cords

Infraglottic cavity Extends from vocal cords to inferior border of the cricoid cartilage

The vocal folds (true vocal cords) control sound production. The apex of each fold projects medially into the laryngeal cavity.

Each vocal fold includes:

• Vocal ligament

• Vocalis muscle (most medial part of thyroarytenoid muscle)

The glottis is composed of the vocal folds, processes and rima glottidis. The rima glottidis is the narrowest potential site within

the larynx, as the vocal cords may be completely opposed, forming a complete barrier.

Muscles of the larynx

Muscle Origin Insertion Innervation Action

Posterior cricoarytenoid

Posterior aspect of lamina of cricoid

Muscular process of arytenoid

Recurrent Laryngeal

Abducts vocal fold

Lateral cricoarytenoid

Arch of cricoid Muscular process of arytenoid

Recurrent laryngeal

Adducts vocal fold

Thyroarytenoid Posterior aspect of thyroid cartilage

Muscular process of arytenoid

Recurrent laryngeal

Relaxes vocal fold

Transverse and oblique arytenoids

Arytenoid cartilage Contralateral arytenoid Recurrent laryngeal

Closure of intercartilagenous part of the rima glottidis

Vocalis Depression between lamina of thyroid cartilage

Vocal ligament and vocal process of arytenoid cartilage

Recurrent laryngeal

Relaxes posterior vocal ligament, tenses anterior part

Cricothyroid Anterolateral part of cricoid

Inferior margin and horn of thyroid cartilage

External laryngeal

Tenses vocal fold

Blood supply

Arterial supply is via the laryngeal arteries, branches of the superior and inferior thyroid arteries. The superior laryngeal artery

is closely related to the internal laryngeal nerve. The inferior laryngeal artery is related to the inferior laryngeal nerve. Venous

drainage is via superior and inferior laryngeal veins, the former draining into the superior thyroid vein and the latter draining

into the middle thyroid vein, or thyroid venous plexus.

Lymphatic drainage

The vocal cords have no lymphatic drainage and this site acts as a lymphatic watershed.

Supraglottic part Upper deep cervical nodes

Subglottic part Prelaryngeal and pretracheal nodes and inferior deep cervical nodes

The aryepiglottic fold and vestibular folds have a dense plexus of lymphatics associated with them and malignancies at these

sites have a greater propensity for nodal metastasis.

Topography of the larynx


Question 1 of 248

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A 28 year old man has sustained a non salvageable testicular injury to his left testicle. The surgeon decides to perform an

orchidectomy and divides the left testicular artery. From which of the following does this vessel originate?

A. Abdominal aorta

B. Internal iliac artery

C. Inferior epigastric artery

D. Inferior vesical artery

E. External iliac artery

Next question

The testicular artery is a branch of the abdominal aorta.

Scrotal and testicular anatomy

Spermatic cord

Formed by the vas deferens and is covered by the following structures:

Layer Origin

Internal spermatic fascia Transversalis fascia

Cremasteric fascia From the fascial coverings of internal oblique

External spermatic fascia External oblique aponeurosis

Contents of the cord

Vas deferens Transmits sperm and accessory gland secretions

Testicular artery Branch of abdominal aorta supplies testis and epididymis

Artery of vas deferens Arises from inferior vesical artery

Cremasteric artery Arises from inferior epigastric artery

Pampiniform plexus Venous plexus, drains into right or left testicular vein

Sympathetic nerve fibres Lie on arteries, the parasympathetic fibres lie on the vas

Genital branch of the genitofemoral nerve Supplies cremaster

Lymphatic vessels Drain to lumbar and para-aortic nodes

Scrotum

• Composed of skin and closely attached dartos fascia.

• Arterial supply from the anterior and posterior scrotal arteries

• Lymphatic drainage to the inguinal lymph nodes

• Parietal layer of the tunica vaginalis is the innermost layer

Testes

• The testes are surrounded by the tunica vaginalis (closed peritoneal sac). The parietal layer of the tunica vaginalis

adjacent to the internal spermatic fascia.

• The testicular arteries arise from the aorta immediately inferiorly to the renal arteries.

• The pampiniform plexus drains into the testicular veins, the left drains into the left renal vein and the right into the

inferior vena cava.

• Lymphatic drainage is to the para-aortic nodes.

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Question 2 of 248

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During a carotid endarterectomy the internal carotid artery is cross clamped. Assuming that no shunt is inserted, which of the

following vessels will not have diminished or absent flow as a result?

A. Anterior cerebral artery

B. Ophthalmic artery

C. Middle cerebral artery

D. Maxillary artery


Next question

Mnemonic for branches of the cerebral portion of the internal carotid artery 'Only Press Carotid Arteries Momentarily'

Only = Opthalmic

Press = Posterior communicating

Carotid = Choroidal

Arteries = Anterior cerebral

Momentarily = Middle cerebral

The maxillary artery is a branch of the external carotid artery.

Internal carotid artery

The internal carotid artery is formed from the common carotid opposite the upper border of the thyroid cartilage. It extends

superiorly to enter the skull via the carotid canal. From the carotid canal it then passes through the cavernous sinus, above

which it divides into the anterior and middle cerebral arteries.

Relations in the neck

Posterior • Longus capitis • Pre-vertebral fascia • Sympathetic chain • Superior laryngeal nerve

Medially • External carotid (near origin) • Wall of pharynx • Ascending pharyngeal artery

Laterally • Internal jugular vein (moves posteriorly at entrance to skull) • Vagus nerve (most posterolaterally)

Anteriorly • Sternocleidomastoid • Lingual and facial veins • Hypoglossal nerve

Relations in the carotid canal

• Internal carotid plexus

• Cochlea and middle ear cavity

• Trigeminal ganglion (superiorly)

• Leaves canal lies above the foramen lacerum

Path and relations in the cranial cavity

The artery bends sharply forwards in the cavernous sinus, the aducens nerve lies close to its inferolateral aspect. The

oculomotor, trochlear, opthalmic and, usually, the maxillary nerves lie in the lateral wall of the sinus. Near the superior orbital

fissure it turns posteriorly and passes postero-medially to pierce the roof of the cavernous sinus inferior to the optic nerve. It

then passes between the optic and oculomotor nerves to terminate below the anterior perforated substance by dividing into the

anterior and middle cerebral arteries.

Branches

• Anterior and middle cerebral artery

• Ophthalmic artery

• Posterior communicating artery

• Anterior choroid artery

• Meningeal arteries

• Hypophyseal arteries

Image demonstrating the internal carotid artery and its relationship to the external carotid artery


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Question 3 of 248

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A 72 year old lady with osteoporosis falls and sustains an intracapsular femoral neck fracture. The fracture is completely

displaced. Which of the following vessels is the main contributor to the arterial supply of the femoral head?

A. Deep external pudendal artery

B. Superficial femoral artery

C. External iliac artery

D. Circumflex femoral arteries

E. Superficial external pudendal artery

Next question

Theme from 2010 Exam

The vessels which form the anastomoses around the femoral head are derived from the medial and lateral circumflex femoral

arteries. These are usually derived from the profunda femoris artery.

Hip joint

• Head of femur articulates with acetabulum of the pelvis

• Both covered by articular hyaline cartilage

• The acetabulum forms at the union of the ilium, pubis, and ischium

• The triradiate cartilage (Y-shaped growth plate) separates the pelvic bones

• The acetabulum holds the femoral head by the acetabular labrum

• Normal angle between femoral head and femoral shaft is 130o

Ligaments

• Transverse ligament: joints anterior and posterior ends of the articular cartilage

• Head of femur ligament (ligamentum teres): acetabular notch to the fovea. Contains arterial supply to head of femur in

children.



Extracapsular ligaments

• Iliofemoral ligament: inverted Y shape. Anterior iliac spine to the trochanteric line

• Pubofemoral ligament: acetabulum to lesser trochanter

• Ischiofemoral ligament: posterior support. Ischium to greater trochanter.

Blood supply

Medial circumflex femoral and lateral circumflex femoral arteries (Branches of profunda femoris)

2 anastomoses: Cruciate and the trochanteric anastomoses (provides most of the blood to the head of the femur) Hence the need

for hemiarthroplasty when there is a displaced femoral head fracture. These anastomoses exist between the femoral artery or

profunda femoris and the gluteal vessels.

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Question 4 of 248

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A 21 year old man is hit with a hammer and sustains a depressed skull fracture at the vertex. Which of the following sinuses is

at risk in this injury?

A. Superior sagittal sinus

B. Inferior petrosal sinus

C. Transverse sinus

D. Inferior sagittal sinus

E. Straight sinus

Next question

Theme in September 2011 Exam

The superior sagittal sinus is at greatest risk in this pattern of injury. This sinus begins at the front of the crista galli and courses

backwards along the falx cerebri. It becomes continuous with the right transverse sinus near the internal occipital protuberance.

Cranial venous sinuses

The cranial venous sinuses are located within the dura mater. They have no valves which is important in the potential for

spreading sepsis. They eventually drain into the internal jugular vein.

They are:

Superior sagittal sinus

Inferior sagittal sinus

Straight sinus

Transverse sinus

Sigmoid sinus

Confluence of sinuses

Occipital sinus

Cavernous sinus

Topography of cranial venous sinuses

Image s

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Question 5 of 248

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A 44 year old man is stabbed in the back and the left kidney is injured. A haematoma forms, which of the following fascial

structures will contain the haematoma?

A. Waldeyers fascia

B. Sibsons fascia

C. Bucks fascia

D. Gerotas fascia

E. Denonvilliers fascia

Next question

Waldeyers fascia- Posterior ano-rectum

Sibsons fascia- Lung apex

Bucks fascia- Base of penis

Gerotas fascia- Surrounding kidney

Denonvilliers fascia- Between rectum and prostate

Renal anatomy

Each kidney is about 11cm long, 5cm wide and 3cm thick. They are located in a deep gutter alongside the projecting verterbral

bodies, on the anterior surface of psoas major. In most cases the left kidney lies approximately 1.5cm higher than the right. The

upper pole of both kidneys approximates with the 11th rib (beware pneumothorax during nephrectomy). On the left hand side

the hilum is located at the L1 vertebral level and the right kidney at level L1-2. The lower border of the kidneys is usually

alongside L3.

The table below shows the anatomical relations of the kidneys:

Relations

Relations Right Kidney Left Kidney

Posterior Quadratus lumborum, diaphragm, psoas major, transversus abdominis

Quadratus lumborum, diaphragm, psoas major, transversus abdominis

Anterior Hepatic flexure of colon Stomach, Pancreatic tail

Superior Liver, adrenal gland Spleen, adrenal gland

Fascial covering

Each kidney and suprarenal gland is enclosed within a common and layer of investing fascia that is derived from the

transversalis fascia into anterior and posterior layers (Gerotas fascia).

Renal structure

Kidneys are surrounded by an outer cortex and an inner medulla which usually contains between 6 and 10 pyramidal structures.

The papilla marks the innermost apex of these. They terminate at the renal pelvis, into the ureter.

Lying in a hollow within the kidney is the renal sinus. This contains:

1. Branches of the renal artery

2. Tributaries of the renal vein

3. Major and minor calyces's

4. Fat

Structures at the renal hilum

The renal vein lies most anteriorly, then renal artery (it is an end artery) and the ureter lies most posterior.

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Question 6 of 248

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A baby is found to have a Klumpke's palsy post delivery. Which of the following is most likely to be present?

A. Loss of flexors of the wrist

B. Weak elbow flexion

C. Pronation of the forearm

D. Adducted shoulder

E. Shoulder medially rotated

Next question

Features of Klumpkes Paralysis

• Claw hand (MCP joints extended and IP joints flexed)

• Loss of sensation over medial aspect of forearm and hand

• Horner's syndrome

• Loss of flexors of the wrist

A C8, T1 root lesion is called Klumpke's paralysis and is caused by delivery with the arm extended.

Brachial plexus

Origin Anterior rami of C5 to T1

Sections of the plexus • Roots, trunks, divisions, cords, branches

• Mnemonic:Real Teenagers Drink Cold Beer

Roots • Located in the posterior triangle • Pass between scalenus anterior and medius

Trunks • Located posterior to middle third of clavicle • Upper and middle trunks related superiorly to the subclavian artery • Lower trunk passes over 1st rib posterior to the subclavian artery

Divisions Apex of axilla

Cords Related to axillary artery

Diagram illustrating the branches of the brachial plexus


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Question 7 of 248

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A 22 year old man undergoes a superficial parotidectomy for a pleomorphic adenoma. The operation does not proceed well and

a diathermy malfunction results in division of the buccal branch of the facial nerve. Which of the following muscles will not

demonstrate impaired function as a result?

A. Zygomaticus minor

B. Mentalis

C. Buccinator

D. Levator anguli oris

E. Risorius

Next question

Buccal branch supplies

Zygomaticus minor Elevates upper lip

Risorius Aids smile

Buccinator

Pulls corner of mouth backward and compresses cheek

Levator anguli oris Pulls angles of mouth upward and toward midline

Orbicularis Closes and tightens lips together

Nasalis Flares nostrils and compresses nostrils

Facial nerve

The facial nerve is the main nerve supplying the structures of the second embryonic branchial arch. It is predominantly an

efferent nerve to the muscles of facial expression, digastric muscle and also to many glandular structures. It contains a few

afferent fibres which originate in the cells of its genicular ganglion and are concerned with taste.

Supply - 'face, ear, taste, tear'

• Face: muscles of facial expression

• Ear: nerve to stapedius

• Taste: supplies anterior two-thirds of tongue

• Tear: parasympathetic fibres to lacrimal glands, also salivary glands

Path

Subarachnoid path

• Origin: motor- pons, sensory- nervus intermedius

• Pass through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. Here they

combine to become the facial nerve.

Facial canal path

• The canal passes superior to the vestibule of the inner ear

• At the medial aspect of the middle ear, it becomes wider and contains the geniculate ganglion.

- 3 branches:

1. greater petrosal nerve

2. nerve to stapedius

3. chorda tympani

Stylomastoid foramen

• Passes through the stylomastoid foramen (tympanic cavity anterior and mastoid antrum posteriorly)

• Posterior auricular nerve and branch to Posterior belly of Digastric and Stylohyoid muscle

Face

Enters parotid gland and divides into 5 branches:

• Temporal branch

• Zygomatic branch

• Buccal branch

• Marginal mandibular branch

• Cervical branch

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Question 8 of 248

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At which of the following vertebral body levels does the common carotid artery typically bifurcate into the external and internal

carotid arteries?

A. C4

B. C2

C. C1

D. C6

E. C7

Next question

It terminates at the upper border of the thyroid cartilege, Which is usually located at C4.

Common carotid artery

The right common carotid artery arises at the bifurcation of the brachiocephalic trunk, the left common carotid arises from the

arch of the aorta. Both terminate at the level of the upper border of the thyroid cartilage (the lower border of the third cervical

vertebra) by dividing into the internal and external carotid arteries.

Left common carotid artery

This vessel arises immediately to the left and slightly behind the origin of the brachiocephalic trunk. Its thoracic portion is 2.5-

3.5 cm in length and runs superolaterally to the sternoclavicular joint.

In the thorax

The vessel is in contact, from below upwards, with the trachea, left recurrent laryngeal nerve, left margin of the oesophagus.

Anteriorly the left brachiocephalic vein runs across the artery, and the cardiac branches from the left vagus descend in front of

it. These structures together with the thymus and the anterior margins of the left lung and pleura separate the artery from the

manubrium.

In the neck

The artery runs superiorly deep to sternocleidomastoid and then enters the anterior triangle. At this point it lies within the

carotid sheath with the vagus nerve and the internal jugular vein. Posteriorly the sympathetic trunk lies between the vessel and

the prevertebral fascia. At the level of C7 the vertebral artery and thoracic duct lie behind it. The anterior tubercle of C6

transverse process is prominent and the artery can be compressed against this structure (it corresponds to the level of the

cricoid).

Anteriorly at C6 the omohyoid muscle passes superficial to the artery.

Within the carotid sheath the jugular vein lies lateral to the artery.

Right common carotid artery

The right common carotid arises from the brachiocephalic artery. The right common carotid artery corresponds with the cervical

portion of the left common carotid, except that there is no thoracic duct on the right. The oesophagus is less closely related to

the right carotid than the left.

Summary points about the carotid anatomy

Path

Passes behind the sternoclavicular joint (12% patients above this level) to the upper border of the thyroid cartilage, to divide

into the external (ECA) and internal carotid arteries (ICA).

Relations

• Level of 6th cervical vertebra crossed by omohyoid

• Then passes deep to the thyrohyoid, sternohyoid, sternomastoid muscles.

• Passes anterior to the carotid tubercle (transverse process 6th cervical vertebra)-NB compression here stops

haemorrhage.

• The inferior thyroid artery passes posterior to the common carotid artery.

• Then : Left common carotid artery crossed by thoracic duct, Right common carotid artery crossed by recurrent

laryngeal nerve

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Question 9 of 248

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A man is stabbed in the chest to the right of the manubriosternal angle. Which structure is least likely to be injured in this case?

A. Aortic arch

B. The trachea

C. Right phrenic nerve

D. Right recurrent laryngeal nerve

E. Brachiocephalic vein

Next question

The right recurrent laryngeal nerve branches off the right vagus more proximally and arches posteriorly round the subclavian

artery. So of the structures given it is the least likely to be injured.

Mediastinum

Region between the pulmonary cavities.

It is covered by the mediastinal pleura. It does not contain the lungs.

It extends from the thoracic inlet superiorly to the diaphragm inferiorly.

Mediastinal regions

• Superior mediastinum

• Inferior mediastinum

• Posterior mediastinum

• Anterior mediastinum

Region Contents

Superior mediastinum • Superior vena cava • Brachiocephalic veins • Arch of aorta • Thoracic duct • Trachea • Oesophagus • Thymus • Vagus nerve • Left recurrent laryngeal nerve • Phrenic nerve

Anterior mediastinum • Thymic remnants • Lymph nodes • Fat

Middle mediastinum • Pericardium • Heart • Aortic root • Arch of azygos vein • Main bronchi

Posterior mediastinum • Oesophagus • Thoracic aorta • Azygos vein • Thoracic duct • Vagus nerve • Sympathetic nerve trunks • Splanchnic nerves

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Question 10 of 248

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An 18 year old man is stabbed in the neck and has to undergo repair of a laceration to the internal carotid artery. Post

operatively he is noted to have a Horners syndrome. Which of the following will not be present?

A. Apparent enopthalmos

B. Loss of sweating on the entire ipsilateral side of the face

C. Constricted pupil

D. Mild ptosis

E. Normal sympathetic activity in the torso

Next question

The anhidrosis will be mild as this is a distal lesion and at worst only a very limited area of the ipsilateral face will be

anhidrotic.

Horners syndrome

Horners syndrome, clinical features:

• Ptosis

• Miosis

• Enopthalmos

• Anhydrosis

Primarily a disorder of the sympathetic nervous system. Extent of symptoms depends upon the anatomical site of the lesion.

Proximal lesions occur along the hypothalamospinal tract

Distal lesions are usually post ganglionic e.g. at level of internal carotid artery or beyond.

In contrast to a 3rd nerve palsy the ptosis is more mild and the pupil constricted rather than dilated.

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Question 11 of 248

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Which of the following types of epithelium lines the lumenal surface of the normal oesophagus?

A. Non keratinised stratified squamous epithelium

B. Ciliated columnar epithelium

C. Keratinised stratified squamous epithelium

D. Non ciliated columnar epithelium


Next question

The oesphagus is lined by non keratinised stratified squamous epithelium. Changes to glandular type epithelium occur as part of

metaplastic processes in reflux.

Oesophagus

• 25cm long

• Starts at C6 vertebra, pierces diaphragm at T10 and ends at T11

• Squamous epithelium

Constrictions of the oesophagus

Structure Distance from incisors

Cricoid cartilage 15cm

Arch of the Aorta 22.5cm

Left principal bronchus 27cm

Diaphragmatic hiatus 40cm

Relations

Anteriorly • Trachea to T4 • Recurrent laryngeal nerve • Left bronchus, Left atrium • Diaphragm

Posteriorly • Thoracic duct to left at T5 • Hemiazygos to the left T8 • Descending aorta • First 2 intercostal branches of aorta

Left • Thoracic duct • Left subclavian artery

Right • Azygos vein

Arterial, venous and lymphatic drainage of the oesophagus

Artery Vein Lymphatics Muscularis externa

Upper third Inferior thyroid Inferior thyroid Deep cervical Striated muscle

Mid third Aortic branches Azygos branches Mediastinal Smooth & striated muscle

Lower third Left gastric Posterior mediastinal and coeliac Gastric Smooth muscle

Nerve supply

• Upper half is supplied by recurrent laryngeal nerve

• Lower half by oesophageal plexus (vagus)

Histology

• Mucosa :Nonkeratinized stratified squamous epithelium

• Submucosa: glandular tissue

• Muscularis externa (muscularis): composition varies. See table

• Adventitia

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Question 12 of 248

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A 23 year old man is stabbed in the neck, in the region between the omohyoid and digastric muscles, the injury is explored

surgically. At operation a nerve injury is identified immediately superior to the lingual artery as is branches off the external

carotid artery. Which of the following is the most likely result of this injury?

A. Paralysis of the ipsilateral side of the tongue

B. Abduction of the ipsilateral vocal cord

C. Winging of the scapula

D. Paralysis of the ipsilateral hemi diaphragm

E. Inability to abduct the shoulder

Next question

The hypoglossal nerve runs anterior to the external carotid, above the lingual arterial branch. If damaged then ipsilateral

paralysis of the genioglossus, hyoglossus and styloglossus muscles will occur. If the patient is asked to protrude their tongue

then it will tend to point to the affected side.

Anterior triangle of the neck

Boundaries

Anterior border of the Sternocleidomastoid Lower border of mandible Anterior midline

Sub triangles (divided by Digastric above and Omohyoid)

• Muscular triangle: Neck strap muscles

• Carotid triangle: Carotid sheath

• Submandibular Triangle (digastric)

Contents of the anterior triangle

Digastric triangle Submandibular gland Submandibular nodes Facial vessels Hypoglossal nerve

Muscular triangle Strap muscles External jugular vein

Carotid triangle Carotid sheath (Common carotid, vagus and internal jugular vein)

Ansa cervicalis

Nerve supply to digastric muscle

• Anterior: Mylohyoid nerve

• Posterior: Facial nerve


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Question 13 of 248

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Which of the following structures is not directly related to the right adrenal gland?

A. Diaphragm posteriorly

B. Bare area of the liver anteriorly

C. Right renal vein

D. Inferior vena cava

E. Hepato-renal pouch

Next question

The right renal vein is very short and lies more inferiorly.

Adrenal gland anatomy

Anatomy

Location Superomedially to the upper pole of each kidney

Relationships of the right adrenal

Diaphragm-Posteriorly, Kidney-Inferiorly, Vena Cava-Medially, Hepato-renal pouch and bare area of the liver-Anteriorly

Relationships of the left adrenal

Crus of the diaphragm-Postero- medially, Pancreas and splenic vessels-Inferiorly, Lesser sac and stomach-Anteriorly

Arterial supply

Superior adrenal arteries- from inferior phrenic artery, Middle adrenal arteries - from aorta, Inferior adrenal arteries -from renal arteries

Venous drainage of the right adrenal

Via one central vein directly into the IVC

Venous drainage of the left adrenal

Via one central vein into the left renal vein

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Question 14 of 248

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With respect to the basilic vein, which statement is false?

A. Its deep anatomical location makes it unsuitable for use as an arteriovenous

access site in fistula surgery

B. It originates from the dorsal venous network on the hand

C. It travels up the medial aspect of the forearm

D. Halfway between the shoulder and the elbow it lies deep to muscle

E. It joins the brachial vein to form the axillary vein

Next question

It is used in arteriovenous fistula surgery during a procedure known as a basilic vein transposition.

Basilic vein

The basilic and cephalic veins both provide the main pathways of venous drainage for the arm and hand. It is continuous with

the palmar venous arch distally and the axillary vein proximally.

Path

• Originates on the medial side of the dorsal venous network of the hand, and passes up the forearm and arm.

• Most of its course is superficial.

• Near the region anterior to the cubital fossa the vein joins the cephalic vein.

• Midway up the humerus the basilic vein passes deep under the muscles.

• At the lower border of the teres major muscle, the anterior and posterior circumflex humeral veins feed into it.

• Joins the brachial veins to form the axillary vein.

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Question 15 of 248

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Mobilisation of the left lobe of the liver will facilitate surgical access to which of the following?

A. Abdominal oesophagus

B. Duodenum

C. Right colic flexure

D. Right kidney

E. Pylorus of stomach

Next question

The fundus of the stomach is a posterior relation. The pylorus lies more inferolaterally. During a total gastrectomy division of

the ligaments holding the left lobe of the liver will facilitate access to the proximal stomach and abdominal oesophagus. This

manoeuvre is seldom beneficial during a distal gastrectomy.

Liver

Structure of the liver

Right lobe • Supplied by right hepatic artery • Contains Couinard segments V to VIII (-/+Sg I)

Left lobe • Supplied by the left hepatic artery • Contains Couinard segments II to IV (+/- Sg1)

Quadrate lobe • Part of the right lobe anatomically, functionally is part of the left • Couinard segment IV • Porta hepatis lies behind • On the right lies the gallbladder fossa • On the left lies the fossa for the umbilical vein

Caudate lobe • Supplied by both right and left hepatic arteries • Couinard segment I • Lies behind the plane of the porta hepatis • Anterior and lateral to the inferior vena cava • Bile from the caudate lobe drains into both right and left hepatic ducts

Detailed knowledge of Couinard segments is not required for MRCS Part A

• Between the liver lobules are portal canals which contain the portal triad: Hepatic Artery, Portal Vein, tributary of Bile

Duct.

Relations of the liver

Anterior Postero inferiorly

Diaphragm Oesophagus

Xiphoid process Stomach

Duodenum

Hepatic flexure of colon

Right kidney

Gallbladder

Inferior vena cava

Porta hepatis

Location Postero inferior surface, it joins nearly at right angles with the left sagittal fossa, and separates the caudate lobe behind from the quadrate lobe in front

Transmits • Common hepatic duct • Hepatic artery • Portal vein • Sympathetic and parasympathetic nerve fibres • Lymphatic drainage of the liver (and nodes)

Ligaments

Falciform ligament • 2 layer fold peritoneum from the umbilicus to anterior liver surface • Contains ligamentum teres (remnant umbilical vein) • On superior liver surface it splits into the coronary and left triangular ligaments

Ligamentum teres Joins the left branch of the portal vein in the porta hepatis

Ligamentum venosum Remnant of ductus venosus

Arterial supply

• Hepatic artery

Venous

• Hepatic veins

• Portal vein

Nervous supply

• Sympathetic and parasympathetic trunks of coeliac plexus

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Question 16 of 248

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The following statements relating to the ankle joint are true except?

A. Three groups of ligaments provide mechanical stability

B. The sural nerve lies medial to the Achilles tendon at its point of insertion

C. Eversion of the foot occurs at the sub talar joint

D. The flexor hallucis longus tendon is the most posterior structure at the medial malleolus

E. The saphenous nerve crosses the ankle joint.

Next question

The sural nerve lies behind the distal fibula. Inversion and eversion are sub talar movements. The structures passing behind the

medial malleolus from anterior to posterior include: tibialis posterior, flexor digitorum longus, posterior tibia vein, posterior

tibial artery, nerve, flexor hallucis longus.

Ankle joint

The ankle joint is a synovial joint composed of the tibia and fibula superiorly and the talus inferiorly.

Ligaments of the ankle joint

• Deltoid ligament (medially)

• Lateral collateral ligament

• Talofibular ligaments (both anteriorly and posteriorly)

The calcaneofibular ligament is separate from the fibrous capsule of the joint. The two talofibular ligaments are fused with it.

The components of the syndesmosis are

• Antero-inferior talofibular ligament

• Postero-inferior talofibular ligament

• Inferior transverse talofibular ligament

• Interosseous ligament

Movements at the ankle joint

• Plantar flexion (55 degrees)

• Dorsiflexion (35 degrees)

• Inversion and eversion movements occur at the level of the sub talar joint

Nerve supply

Branches of deep peroneal and tibial nerves.

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Question 17 of 248

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A 78 year old man is lifting a heavy object when a feels a pain in his forearm and is unable to continue. He has a swelling over

his upper forearm. An MRI scan shows a small cuff of tendon still attached to the radial tuberosity consistent with a recent tear.

Which of the following muscles has been injured?

A. Pronator teres

B. Supinator

C. Aconeus

D. Brachioradialis

E. Biceps brachii

Next question

Biceps inserts into the radial tuberosity. Distal injuries of this muscle are rare but are reported and are clinically more important

than more proximal ruptures.

Radius

• Bone of the forearm extending from the lateral side of the elbow to the thumb side of the wrist

Upper end

• Articular cartilage- covers medial > lateral side

• Articulates with radial notch of the ulna by the annular ligament

• Muscle attachment- biceps brachii at the tuberosity

Shaft

• Muscle attachment-

Upper third of the body Supinator, Flexor digitorum superficialis, Flexor pollicis longus

Middle third of the body Pronator teres

Lower quarter of the body Pronator quadratus , tendon of supinator longus

Lower end

• Quadrilateral

• Anterior surface- capsule of wrist joint

• Medial surface- head of ulna

• Lateral surface- ends in the styloid process

• Posterior surface: 3 grooves containing:

1. Tendons of extensor carpi radialis longus and brevis

2. Tendon of extensor pollicis longus

3. Tendon of extensor indicis


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Question 18 of 248

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The oesophagus is constricted at the following levels apart from:

A. Cricoid cartilage

B. Arch of the aorta

C. Lower oesophageal sphincter

D. Left main stem bronchus

E. Diaphragmatic hiatus

Next question

The oesophagus is not constricted at the level of the lower oesophageal sphincter.

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Question 19 of 248

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A 19 year old man is playing rugby when he suddenly notices a severe pain at the posterolateral aspect of his right thigh. Which of the following muscle groups is most likely to have been injured?

A. Semimembranosus

B. Semitendinosus

C. Long head of biceps femoris

D. Gastrocnemius

E. Soleus

Next question Theme from April 2012 Exam The biceps femoris is the laterally located hamstring muscle. The semitendinosus and semimembranosus are located medially. Rupture of gastrocnemius and soleus may occur but is less common.

Biceps femoris The biceps femoris is one of the hamstring group of muscles located in the posterior upper thigh. It has two heads. Long head

Origin Ischial tuberosity

Insertion Fibular head

Action Knee flexion, lateral rotation tibia, extension hip

Innervation Tibial nerve (L5, S1, S2)

Arterial supply Profunda femoris artery, inferior gluteal artery, and the superior muscular branches of popliteal artery

Image demonstrating the biceps femoris muscle, with the long head outlined


Short head

Origin Lateral lip of linea aspera, lateral supracondylar ridge of femur

Insertion Fibular head

Action Knee flexion, lateral rotation tibia

Innervation Common peroneal nerve (L5, S1, S2)

Arterial supply Profunda femoris artery, inferior gluteal artery, and the superior muscular branches of popliteal artery

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Question 20 of 248

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Which of the following is a branch of the third part of the axillary artery?

A. Superior thoracic

B. Lateral thoracic

C. Dorsal scapular

D. Thoracoacromial

E. Posterior circumflex humeral

Next question

The other branches include:

• Subscapular

• Anterior circumflex humeral

Axilla

Boundaries of the axilla

Medially Chest wall and Serratus anterior

Laterally Humeral head

Floor Subscapularis

Anterior aspect Lateral border of Pectoralis major

Fascia Clavipectoral fascia

Content:

Long thoracic nerve (of Bell)

Derived from C5-C7 and passes behind the brachial plexus to enter the axilla. It lies on the medial chest wall and supplies serratus anterior. Its location puts it at risk during axillary surgery and damage will lead to winging of the scapula.

Thoracodorsal nerve and thoracodorsal trunk

Innervate and vascularise latissimus dorsi.

Axillary vein Lies at the apex of the axilla, it is the continuation of the basilic vein. Becomes the subclavian vein at the outer border of the first rib.

Intercostobrachial nerves Traverse the axillary lymph nodes and are often divided during axillary surgery. They provide cutaneous sensation to the axillary skin.

Lymph nodes The axilla is the main site of lymphatic drainage for the breast.

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Question 21 of 248

Next

Which of the following structures separates the intervertebral disks from the spinal cord?

A. Anterior longitudinal ligament

B. Posterior longitudinal ligament

C. Supraspinous ligament

D. Interspinous ligament

E. Ligamentum flavum

Next question

The posterior longitudinal ligament overlies the posterior aspect of the vertebral bodies. It also overlies the posterior aspect of

the intervertebral disks.

Intervertebral discs

• Consist of an outer annulus fibrosus and an inner nucleus pulposus.

• The anulus fibrosus consists of several layers of fibrocartilage.

• The nucleus pulposus contains loose fibres suspended in a mucoprotein gel with the consistency of jelly. The nucleus

of the disc acts as a shock absorber.

• Pressure on the disc causes posterior protrusion of the nucleus pulposus. Most commonly in the lumbrosacral and lower

cervical areas.

• The discs are separated by hyaline cartilage.

• There is one disc between each pair of vertebrae, except for C1/2 and the sacrococcygeal vertebrae.

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Question 22 of 248

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At what level does the aorta bifurcate into the left and right common iliac arteries?

A. L1

B. L2

C. L3

D. L4

E. L5

Next question

The aorta typically bifurcates at L4. This level is usually fairly constant and is often tested in the exam.

Levels

Transpyloric plane

Level of the body of L1

• Pylorus stomach

• Left kidney hilum (L1- left one!)

• Right hilum of the kidney (1.5cm lower than the left)

• Fundus of the gallbladder

• Neck of pancreas

• Duodenojejunal flexure

• Superior mesenteric artery

• Portal vein

• Left and right colic flexure

• Root of the transverse mesocolon

• 2nd part of the duodenum

• Upper part of conus medullaris

• Spleen

Can be identified by asking the supine patient to sit up without using their arms. The plane is located where the lateral border of

the rectus muscle crosses the costal margin.

Anatomical planes

Subcostal plane Lowest margin of 10th costal cartilage

Intercristal plane Level of body L4 (highest point of iliac crest)

Intertubercular plane Level of body L5

Common level landmarks

Inferior mesenteric artery L3

Bifurcation of aorta into common iliac arteries L4

Formation of IVC L5 (union of common iliac veins)

Diaphragm apertures • Vena cava T8 • Oesophagus T10 • Aortic hiatus T12

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Question 23 of 248

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A 23 year old man is due to undergo a mitral valve repair for mitral regurgitation. Which of the following is a feature of the

mitral valve?

A. Its closure is marked by the first heart sound

B. It has two anterior cusps

C. The chordae tendinae attach to the anterior cusps only

D. The chordae tendinae anchor the valve directly to the wall of the left ventricle

E. It is best auscultated in the left third interspace

Next question

The mitral valve is best auscultated over the cardiac apex, where its closure marks the first heart sound. It has only two cusps.

These are attached to chordae tendinae which themselves are linked to the wall of the ventricle by the papillary muscles.

Heart anatomy

The walls of each cardiac chamber comprise:

• Epicardium

• Myocardium

• Endocardium

Cardiac muscle is attached to the cardiac fibrous skeleton.

Relations

The heart and roots of the great vessels within the pericardial sac are related anteriorly to the sternum, medial ends of the 3rd to

5th ribs on the left and their associated costal cartilages. The heart and pericardial sac are situated obliquely two thirds to the left

and one third to the right of the median plane.

The pulmonary valve lies at the level of the left third costal cartilage.

The mitral valve lies at the level of the fourth costal cartilage.

Coronary sinus

This lies in the posterior part of the coronary groove and receives blood from the cardiac veins. The great cardiac vein lies at its

left and the middle and small cardiac veins lie on its right. The smallest cardiac veins drain into the atria directly.

Aortic sinus

Right coronary artery arises from the right aortic sinus, the left is derived from the left aortic sinus and no vessel emerges from

the posterior sinus.

Right and left ventricles

Structure Left Ventricle

A-V Valve Mitral (double leaflet)

Walls Twice as thick as right

Trabeculae carnae Much thicker and more numerous

Right coronary artery

The RCA supplies:

• Right atrium

• Diaphragmatic part of the left ventricle

• Usually the posterior third of the interventricular septum

• The sino atrial node (60% cases)

• The atrio ventricular node (80% cases)

Left coronary artery

The LCA supplies:

• Left atrium

• Most of left ventricle

• Part of the right ventricle

• Anterior two thirds of the inter ventricular septum

• The sino atrial node (remaining 40% cases)

Innervation of the heart

Autonomic nerve fibres from the superficial and deep cardiac plexus. These lie anterior to the bifurcation of the trachea,

posterior to the ascending aorta and superior to the bifurcation of the pulmonary trunk. The parasympathetic supply to the heart

is from presynaptic fibres of the vagus nerves.

Valves of the heart

Mitral valve Aortic valve Pulmonary valve Tricuspid valve

2 cusps 3 cusps 3 cusps 3 cusps

First heart sound Second heart sound Second heart sound First heart sound

1 anterior cusp 1 anterior cusp 2 anterior cusps 2 anterior cusps

Attached to chordae tendinae No chordae No chordae Attached to chordae tendinae

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Theme: Nerve lesions

A. Intercostobrachial

B. Median

C. Axillary

D. Radial

E. Ulnar

F. Musculocutaneous

G. Brachial plexus upper cord

H. Brachial plexus lower cord

Please select the most likely nerve injury for the scenarios given. Each option may be used once, more than once or not at all.

24. A 23 year old rugby player sustains a Smiths Fracture. On examination opposition of the thumb is markedly weakened.

Median This high velocity injury can often produce significant angulation and displacement. Both of these may impair the function of the median nerve with loss of function of the muscles of the thenar eminence

25. A 45 year old lady recovering from a mastectomy and axillary node clearance notices that sensation in her armpit is impaired.

Intercostobrachial The intercostobrachial nerves are frequently injured during axillary dissection. These nerves traverse the axilla and supply cutaneous sensation.

26. An 8 year old boy falls onto an outstretched hand and sustains a supracondylar fracture. In addition to a weak radial pulse the child is noted to have loss of pronation of the affected hand.

You answered Ulnar The correct answer is Median This is a common injury in children. In this case the angulation and displacement have resulted in median nerve injury.

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Question 27 of 248

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A 23 year old lady with sialolithiasis of the submandibular gland is undergoing excision of the gland. Which of the following

nerves is at risk as the duct is mobilised?

A. Lingual nerve

B. Buccal nerve

C. Facial nerve

D. Glossopharyngeal

E. Vagus

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The lingual nerve wraps around Whartons duct. The lingual nerve provides sensory supply to the anterior 2/3 of the tongue.

Submandibular gland

Relations of the submandibular gland

Superficial Platysma, deep fascia and mandible Submandibular lymph nodes Facial vein (facial artery near mandible) Marginal mandibular nerve Cervical branch of the facial nerve

Deep Facial artery (inferior to the mandible) Mylohoid muscle Sub mandibular duct Hyoglossus muscle Lingual nerve Submandibular ganglion Hypoglossal nerve

Submandibular duct (Wharton's duct)

• Opens lateral to the lingual frenulum on the anterior floor of mouth.

• 5 cm length

• Lingual nerve wraps around Wharton's duct. As the duct passes forwards it crosses medial to the nerve to lie above it

and then crosses back, lateral to it, to reach a position below the nerve.

Innervation

• Sympathetic innervation- Superior Cervical ganglion via the Lingual nerve

• Parasympathetic innervation- Submandibular ganglion

Arterial supply

Branch of the Facial artery. The facial artery passes through the gland to groove its deep surface. It then emerges onto the face

by passing between the gland and the mandible.

Venous drainage

Anterior Facial vein (lies deep to the Marginal Mandibular nerve)

Lymphatic drainage

Deep cervical and jugular chains of nodes

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Question 28 of 248

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Which of the following is true in connection with the phrenic nerves?

A. They both lie anterior to the hilum of the lungs

B. They are derived from spinal roots C 2,3,4

C. They pierce the diaphragm at the level of T7

D. They consist of motor fibres only


Next question

C3,4,5

Keeps the diaphragm alive!

They both lie anterior to the hilum of the lung. The phrenic nerves have both motor and sensory functions. For this reason sub

diaphragmatic pathology may cause referred pain to the shoulder.

Phrenic nerve

Origin

• C3,4,5

Supplies

• Diaphragm, sensation central diaphragm and pericardium

Path

• The phrenic nerve passes with the internal jugular vein across scalenus anterior. It passes deep to prevertebral fascia of

deep cervical fascia.

• Left: crosses anterior to the 1st part of the subclavian artery.

• Right: Anterior to scalenus anterior and crosses anterior to the 2nd part of the subclavian artery.

• On both sides, the phrenic nerve runs posterior to the subclavian vein and posterior to the internal thoracic artery as it

enters the thorax.

Right phrenic nerve

• In the superior mediastinum: anterior to right vagus and laterally to superior vena cava

• Middle mediastinum: right of pericardium

• It passes over the right atrium to exit the diaphragm at T8

Left phrenic nerve

• Passes lateral to the left subclavian artery, aortic arch and left ventricle

• Passes anterior to the root of the lung

• Pierces the diaphragm alone

Image showing the passage of the phrenic nerve in the neck


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Question 29 of 248

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A 32 year old man presents with an inguinal hernia and undergoes an open surgical repair. The surgeons decide to place a mesh

on the posterior wall of the inguinal canal to complete the repair, which of the following structures will lie posterior to the

mesh?

A. Transversalis fascia

B. External oblique

C. Rectus abdominis

D. Obturator nerve


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Inguinal canal walls: 'MALT: 2M, 2A, 2L, 2T':

Starting from superior, moving around in order to posterior:

Superior wall (roof): 2 Muscles:Internal oblique, transversus abdominis

Anterior wall: 2 Aponeuroses: Aponeurosis of external oblique, Aponeurosis of internal oblique

Lower wall (floor): 2 Ligaments: Inguinal Ligament, Lacunar Ligament Posterior wall: 2Ts: Transversalis fascia, Conjoint

Tendon

This is actually quite a straightforward question. It is simply asking for the structure that forms the posterior wall of the inguinal

canal. This is composed of the transversalis fascia, the conjoint tendon and more laterally the deep inguinal ring.

Inguinal canal

Location

• Above the inguinal ligament

• The inguinal canal is 4cm long

Boundaries of the inguinal canal

Floor • External oblique aponeurosis • Inguinal ligament • Lacunar ligament

Roof • Internal oblique • Transversus abdominis

Anterior wall External oblique aponeurosis

Posterior wall • Transversalis fascia • Conjoint tendon

Laterally • Internal ring • Fibres of internal oblique

Medially • External ring • Conjoint tendon

Contents

Males Spermatic cord and ilioinguinal nerve As it passes through the canal the spermatic cord has 3 coverings:

• External spermatic fascia from external oblique aponeurosis

• Cremasteric fascia • Internal spermatic fascia

Females Round ligament of uterus and ilioinguinal nerve

Related anatomy of the inguinal region

The boundaries of Hesselbachs triangle are commonly tested and illustrated below:


The image below demonstrates the close relationship of the vessels to the lower limb with the inguinal canal. A fact to be borne

in mind when repairing hernial defects in this region.

06 Anatomy

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