Upper Limb

PREPARED BY MICHAEL C. DAVID ON 23/08/08. PAGE 1 OF 28

T H E U P P E R L I M B. TABLE OF CONTENTS

Anterior Wall. ........................................................................................................... 2 Posterior Wall. .......................................................................................................... 2 Medial Wall. .............................................................................................................. 3 Lateral Wall. .............................................................................................................. 3 Contents Of Axilla. .................................................................................................. 4 Brachial Plexus ......................................................................................................... 5 Superficial Muscles. ................................................................................................. 8 Deep Muscles. .......................................................................................................... 8 Rotator Cuff Muscles (extensile ligaments). ........................................................ 9 Scapular Muscles. ................................................................................................... 10 Posterior Spaces. .................................................................................................... 11 Muscles Of Anterior Compartment Of Arm. ................................................... 13 Cubital Fossa. ......................................................................................................... 13 Muscles of Posterior Compartment Of Arm. ................................................... 14 Superficial Muscles of Anterior Compartment of Forearm. ........................... 15

Intermediate muscles of anterior compartment of forearm. .......................... 15 Deep Muscles Of Anterior Compartment Of Forearm. ................................. 16 Superficial Muscles of Posterior Compartment Of Forearm. ........................ 16 Deep Muscles of Posterior Compartment Of Forearm. ................................. 17 The Anatomical SnuffBox. ................................................................................... 19 Posterior Arterial Supply of Forearm. ................................................................ 19 Nerves of Posterior Compartment Of Forearm. .............................................. 20 A special note on Extensor Digitorum Muscle. ................................................ 20 Carpal TunneL & Palm. ........................................................................................ 21 Thenar Muscles. ..................................................................................................... 24 Hypothenar Muscles. ............................................................................................. 24 Intinisic Muscles of The Hand............................................................................. 25 20 Muscles of The Hand. ...................................................................................... 26 Arteries Of Hand. .................................................................................................. 27 Nerves Of The Hand. ........................................................................................... 28


AXILLA .

ANTERIOR WALL.

NAME. ORIGIN. INSERTION INNERVATION ACTION

Pectoralis Major. Sternocostal Head = 1st six costal cartilages. Clavicular Head = medial half of clavicle.

Lateral lip of bicipital groove. Lateral and Medial Pectoral Nerve. Clavicular Head = C5, C6 Sternocostal Head = C7, C8, T1

1. Adduction & medial rotation of Humerus.

2. Flexion (Clavicular) & extension (sternocostal) of shoulder joint.

Pectoralis Minor. Ribs 3, 4, 5. Coracoid process. Medial Pectoral Nerve (C8, T1) Depresses (and brings forward) Scapula.

Subclavius. 1st Rib. Inferior surface of Clavicle. Nerve to Subclavius (C5, C6) Stabilises clavicle.

Clavipectoral Fascia Clavicle Laterally = coracoid process Medially = sternum. Suspensory Ligaments hold it to skin of armpit.

1. Protection. 2. Forms a sleeve around

Pectoralis Minor. 3. Suspensory ligaments make

armpit wall concave.

POSTERIOR WALL.


Subscapularis Subscapular fossa. Lesser tubercle of humerus. Upper & lower subscapular nerves. (C5, C6)

1. Adduction of arm. 2. Stabilises Glenohumoral joint.

Teres Major Lateral border of Scapula Medial lip of bicipital groove. Lower subscapular Nerve (C5, C6) 1. Adduction of arm. 2. Medial rotation of arm.

Latissimus Dorsi From back Ribbon-like tendon on floor of bicipital groove

Thoraco dorsal nerve (C6, C7, C8) Adduction of arm (climbers muscle)


MEDIAL WALL.


Ribs 1-6

Serratus Anterior Digitations from ribs 1-8. Medial border of Scapula (lower five digitations insert at inferior angle)

Long Thoracic Nerve (C5, C6, C7) 1. Protraction of Scapula (holds it in place).

2. Lower 5 digitations = superior rotation of scapula.

LATERAL WALL.

This is the bicipital groove. The skin and fascia form the base of the axilla.


CONTENTS OF AXILLA.

Axillary artery, Begins at outer border of 1st rib (superior to this = subclavian artery). Ends at inferior border of Teres Major (inferior to this = brachial artery). 1st part above Pectoralis minor muscle. Superior thoracic artery supplies 1st & 2nd intercostal spaces + superior serratus anterior muscle.

2nd part behind Pectoralis Major muscle. Thoracoacromial artery supplies deltoid muscle, pectoral muscles, clavicle & acromion. Lateral Thoracic artery runs along Pectoralis minor, and supplies lateral part of mammary area.

3rd part below Pectoralis minor muscle. Subscapular Artery

Circumflex scapular artery to muscle on back of scapular, to form collateral circulation at infraspinous fossa.

Thoraco dorsal artery supplies Latissimus dorsi muscle. Anterior Circumflex Humoral artery. Posterior Circumflex Humoral artery winds around surgical neck of humerus to anastomose with Anterior Circumflex Humoral.

Axillary Vein. Is the continuation of the basilic vein after it pierces the deep fascia at the inferior border of the teres major muscle. Ends at outer border of 1st rib continues subclavian. Cephalic vein joins it as it passes into deep fascia. (Other tributaries accompanying arterial branches, to empty out into axillary vein)

Lymphatic System. Lateral group (associated with axillary artery), Posterior group, and Anterior/Pectoral group (drains 75% of lymph from breast) all three groups of nodes

drain into Central group.

Central group and Infraclavicular Node (drains lateral side of hand) Apical group. Apical group drains: On right subclavian lymph trunk. On left thoracic duct.


BRACHIAL PLEXUS

NERVE. ROOT. SUPPLIES NOTES.

Musculocutaneous nerve C5, C6, C7 1. Biceps brachii muscle 2. Brachialis muscle 3. Coracobrachialis muscle

1. Pierces coracobrachialis muscle. 2. On piercing clavipectoral fascia, it becomes

Lateral antebrachial cutaneous nerve.

Lateral Root of Median nerve C5, C6, C7 1. Flexors of forearm 2. 5muscles in hand

Radial nerve C5, C6, C7, C8, T1 1. Triceps muscle 2. Anconeous muscle 3. Brachioradialis muscle 4. Cutaneous sensation to skin around

extensors + hand.

1. Travels posteriorly, inferiorly and laterally between long & medial heads of triceps enters radial groove on posterior surface of humerus.

2. Travels with Profunda brachii artery.

Axillary nerve C5, C6 1. Deltoid muscle 2. Teres Minor muscle

1. Passes through quadrilateral space, around surgical neck of humerus.

2. Travels with posterior circumflex humoral artery.

3. Becomes Upper lateral brachial cutaneous nerve.

Ulnar nerve C8, T1 1. Hand 2. Little of forearm

Medial to artery.

Median nerve C5, C6, C7, C8, T1 1. Forearm flexors 2. Little of hand muscles of thumb.

Travels with brachial artery.

Dorsal Scapular nerve C5 1. Rhomboid Major & Minor muscle 2. Levator Scapulae muscle.

Pierces Scalenus medius muscle.

Long Thoracic nerve C5, C6, C7 Serratus Anterior muscle. 1. Roots form C5 & C6 pierce Scalenus medius muscle.

2. Root from C7 passes anterior to Scalenus medius muscle.


Suprascapular nerve C5, C6 1. Supraspinatus muscle 2. Infraspinatus muscle

Nerve to Subclavius C5, C6 Subclavius muscle.

Lateral Pectoral nerve C5, C6, C7 Pectoralis Major muscle. 1. Passes through deltopectoral triangle, and pierces clavipectoral fascia.

2. From Lateral cord.

Medial Pectoral nerve C8, T1 1. Pectoralis Major muscle 2. Pectoralis Minor muscle

1. Lies lateral to Lateral Pectoral nerve. 2. Originated from Medial Cord.

Medial Brachial Cutaneous nerve C8, T1 1. Medial skin of arm (sensory) 2. Skin of distal medial forearm

Medial Antebrachial Cutaneous nerve C8, T1 Sensory supplies to skin of medial forearm. Communicates with Intercostobrachial nerve supplies skin on floor of axilla.

Upper Subscapular nerve C5, C6 Subscapularis muscle.

Thoraco dorsal nerve C6, C7, C8 Latissimus dorsi muscle.

Lower Subscapular nerve C5, C6 1. Subscapularis muscle 2. Teres Major muscle


BACK & SCAPULAR REGION.

SUPERFICIAL MUSCLES.


Trapezius 1. External occipital protuberance on skull.

2. Ligamentum nuchae. 3. Spinous processes of C7-

T12

1. Superior fibres @ lateral third of clavicle.

2. Middle fibres @ spine of scapula.

3. Inferior fibres @ base of spine of scapula.

Spinal part of accessory nerve (Cranial nerve XI)

Sensory: C3, C4

1. Superior elevate scapula. 2. Middle retract scapula. 3. Inferior depress scapula. 4. Superior & Inferior

superiorly rotate scapula. 5. Prevents drooping shoulders

Latissimus dorsi 1. Inferior 3 or 4 ribs 2. Spinous processes of T7-

T12 3. Thoracolumbar fascia 4. Iliac crest

Floor of bicipital groove of humerus.

Thoraco dorsal nerve (C6, C7, and C8).

1. Extends humerus at shoulder joint.

2. Adduct humerus at shoulder joint.

3. Medially rotates humerus. 4. Pulls trunk up to arms

(during chin-ups)

DEEP MUSCLES.


Levator Scapulae Posterior tubercles of transverse processes of C1 C4.

Superior part of medial border of scapula.

1. Dorsal Scapular nerve (C5) 2. Cervical Nerve (C3, C4)

1. Elevates scapula 2. Tilts glenoid cavity inferiorly

by rotating scapula 3. Retracts scapula 4. Flexes neck laterally

Rhomboid Major Spinous processes of T2-T5 Medial border of scapula (from Dorsal Scapular muscles (C5). 1. Retracts scapula


level of spine to inferior angle) 2. Rotates scapula to depress glenoid cavity

3. Fixes scapula to thoracic wall.

Rhomboid Minor 1. Ligamentum nuchae 2. Spinal processes of C7 & T1

Medial border of scapula (around level of spine)

Dorsal Scapular muscles (C5). 1. Retracts scapula 2. Rotates scapula to depress

glenoid cavity 3. Fixes scapula to thoracic

wall.

ROTATOR CUFF MUSCLES (EXTENSILE LIGAMENTS).


Subscapularis Subscapular fossa. Lesser tubercle of humerus. Upper and lower subscapular nerves (C5, C6).

1. Medially rotates arm 2. Adducts arm 3. Holds head of humerus into

glenoid cavity stabilises glenoid cavity during shoulder movement.

Supraspinatus Supraspinous fossa of scapula. Superior facet on greater tubercle of humerus.

Suprascapular nerve (C5, C6). 1. Helps Deltoid m., abduct

arm. Initiates 1st 15 of movement.

2. Holds head of humerus into glenoid cavity stabilises glenoid cavity during shoulder movement.

Infraspinatus Infraspinous fossa of scapula Middle facet on greater tubercle of humerus.

Suprascapular nerve (C5, C6). 1. Laterally rotates arm 2. Holds head of humerus into

glenoid cavity stabilises glenoid cavity during


shoulder movement.

Teres Minor Superior part of lateral border of scapula.

Inferior facet on greater tubercle of humerus.

Axillary nerve (C5, C6). 1. Laterally rotates arm 2. Assists adduction of arm 3. Holds head of humerus into

glenoid cavity stabilises glenoid cavity during shoulder movement.

SCAPULAR MUSCLES.


Deltoid 1. Anterior fibres lateral third of clavicle

2. Middle fibres acromion (protected by subacromial bursa)

3. Posterior fibres spine of scapula.

Deltoid tuberosity of humerus. Axillary nerve (C5, C6) 1. Anterior fibres strong flexor (works with Pectoralis major muscle & Coracobrachialis muscle.

2. Middle fibres chief abductor of arm (aided by Supraspinatus muscle.)

3. Posterior fibres strong extensor & laterally rotates humerus.

4. Generally holds arm & stabilises arm.

Teres Major Dorsal surface of inferior angle of Scapula. (forms Posterior Axillary Fold, with tendon of Latissimus dorsi muscle)

Medial lip of bicipital groove of humerus.

Lower Subscapular nerve (C5, C6)

1. Adducts arm 2. Medially rotates arm 3. Helps extend arm from flexed

position. 4. Helps stabilise head of humerus in

Glenoid cavity, during abduction of arm.


POSTERIOR SPACES.

Quadrilateral Space. Superior boundary = Teres minor muscle. Inferior boundary = Teres major muscle. Medial boundary = long head of Triceps muscle. Lateral boundary = humerus. Posterior circumflex humoral artery & axillary nerve pass through (in direct contact with surgical neck of humerus)

Upper Triangular Space. Superior boundary = Teres minor muscle. Inferior boundary = Teres major muscle. Lateral boundary = long head of Triceps muscle. Circumflex scapular artery passes through.

Lower Triangular Space. Superior boundary = Teres major muscle. Medial boundary = long head of Triceps muscle. Lateral boundary = shaft of humerus. Radial nerve and Profunda brachii artery passes through.


THE SHOULDER JOINTS.

JOINT INTRINSIC LIGAMENTS EXTRINSIC LIGAMENTS MOVEMENTS BLOOD SUPPLY NERVE SUPPLY NOTES.

Sternoclavicular 1. Sternoclavicular ligaments strong. Anteriorly and posteriorly.

2. Interclavicular ligaments weak superior support.

Costoclavicular ligaments from costal cartilage of 1st rib, to inferior margin of medial clavicle. Provides lateral support, and limits any movement of clavicle except inferior movement.

Many directions like a ball and socket joint.

1. Branches of internal thoracic artery.

2. Branches of suprascapular artery.

1. Branches of medial supraclavicular nerve.

2. Branches of Nerve to Subclavius.

Fibro-cartilaginous articular disc. Prevents medial displacement of clavicle, and acts as a shock absorber.

Acromioclavicular Acromioclavicular ligaments provides weak superior support.

Coracoclavicular ligaments from coracoid process to clavicle. Strong support, and provides axis for rotation of Scapula. (conoid and trapezoid)

1. Rotation of acromion on clavicle.

2. Anterior & posterior movement.

1. Branches of Suprascapular artery.

2. Branches of Thoracoacromial artery.

1. Supraclavicular nerve branches.

2. Lateral pectoral nerve branches.

3. Axillary nerve branches.

An incomplete articular disc is present within articular capsule.

Glenohumoral 1. Glenohumoral ligaments anterior support from supraglenoid tubercle to lesser tubercle of humerus.

2. Transverse humoral ligaments across bicipital groove.

3. Coracohumoral ligaments from coracoid process, across capsule, to the anatomical neck of humerus (adjacent to greater tubercle.

Coracoacromial ligaments forms Coracoacromial arch, with coracoid process and acromion. Prevents superior dislocation.

1. Flexion-extension.

2. Abduction-adduction.

3. Circumduction. 4. Rotation.

1. Branches of anterior and posterior circumflex humoral artery.

2. Branches of Suprascapular artery (from Subclavian)

1. Suprascapular nerve.

2. Axillary nerve. 3. Lateral pectoral

nerve.

1. Subacromial bursa between deltoid muscle over fibrous capsule & supraspinatus tendon.

2. Subscapular bursa between subscapularis & neck of scapula.

3. Rotator cuff muscles stabilise joint.


ARM .

MUSCLES OF ANTERIOR COMPARTMENT OF ARM.


Biceps brachii 1. Short head = coracoid process.

2. Long head = supraglenoid tubercle.

1. Radial tuberosity on radius. Protected by a bursa.

2. Bicipital aponeurosis.

Musculocutaneous nerve (C5, C6)

1. Supinates arm. 2. Flexes arm.

Brachialis Distal half of anterior surface of humerus.

Coranoid process. Musculocutaneous nerve (C5, C6)

Flexion of arm.

Coracobrachialis Coracoid process. Halfway down medial side of humerus.

Musculocutaneous nerve (C5, C6)

1. Aids flexion of arm 2. Aids adduction of arm

CUBITAL FOSSA.

Superior boundary = imaginary line between medial & lateral epicondyle of humerus. Medial boundary = lateral edge of Pronator Teres muscle. Lateral boundary = medial edge of Brachioradialis muscle. Floor = Brachialis muscle (superiorly), and Supinator muscle (inferiorly). Roof = Bicipital Aponeurosis. protects the contents from damage during venepuncture. Contents (medial lateral): Median nerve Brachial artery Biceps tendon Radial nerve

Superior to bicipital aponeurosis, lies the Median Cubital Vein. This links the cephalic (lateral) and the basilic (medial) vein, and is the site for venepuncture.


MUSCLES OF POSTERIOR COMPARTMENT OF ARM.


Triceps 1. Long head = infraglenoid tubercle of scapula.

2. Lateral head = posterior surface of humerus, superior to radial groove.

3. Medial head = posterior surface of humerus, inferior to radial groove.

Olecranon process protected by Olecranon bursa.

Bursa lie between skin & tendon, and tendon & bone.

Inflammation of bursa Students Elbow.

Radial nerve (C6, C7, C8) 1. Extends arm. 2. Long head steadies the head

of the abducted humerus.

Anconeus Lateral epicondyle of humerus. 1. Lateral surface of olecranon process.

2. Posterior surface of superior ulna.

Radial nerve (C7, C8, T1) 1. Assists triceps in extension of arm.

2. Abducts ulna during pronation.

3. Stabilises elbow joint.


FOREARM .

SUPERFICIAL MUSCLES OF ANTERIOR COMPARTM ENT OF FOREARM.


Pronator Teres Medial epicondyle of humerus & coranoid process of ulna.

Middle of lateral surface of radius.

Median nerve (C6, C7) 1. Pronates forearm 2. Flexes forearm

Flexor Carpi Radialis Medial epicondyle Base of 2nd metacarpal Median nerve (C6, C7) 1. Pronates forearm 2. Flexes forearm

Palmaris Longus Medial epicondyle Distal half of Flexor Retinaculum (forms palmar aponeurosis)

Median nerve (C7, C8) 1. Flexes hand 2. Tightens palmar

aponeurosis.

Flexor Carpi Ulnaris 1. Humoral head medial epicondyle.

2. Ulnar head olecranon & posterior border of Ulna

1. Pisiform 2. Hook of Hamate 3. 5th Metacarpal

Ulnar nerve (C7, C8) 1. Flexes hand 2. Adducts hand

INTERMEDIATE MUSCLES OF ANTE RIOR COMPARTMENT OF FOREARM.


Flexor Digitorum Superficialis

Humero-ulnar head 1. Medial epicondyle. 2. Ulnar collateral

ligament 3. Coranoid process

Radial head superior half of anterior border of radius.

Bodies of the middle phalanges of medial 4 digits.

Median nerve (C7, C8, T1) 1. Flexes middle phalanges of medial 4 digits.

2. Acting more strongly flexes proximal phalanges and hand.


DEEP MUSCLES OF ANTERIOR COMPARTMENT OF FOREARM.


Flexor Digitorum Profundus

Proximal 3/4 of medial and anterior surfaces of Ulna & Interosseous membrane.

Base of distal phalanges of medial 4 digits.

Medial half Ulna nerve (C8, T1) Lateral half Median nerve (C8, T1)

Flexes distal phalanges of medial 4 digits (fingers).

Flexor Pollicis Longus

1. Anterior surface of Radius. 2. Adjacent Interosseous

membrane

Base of distal phalanx of thumb. Anterior interosseous nerve (from median nerve) C8, T1

Flexes phalanges of thumb (1st digit)

Pronator Quadratus Distal quarter of anterior surface of Ulna.

Distal quarter of anterior surface of Radius.

Anterior interosseous nerve (from median nerve) C8, T1

1. Pronates forearm. 2. Deep fibres bind Ulna &

Radius together.

SUPERFICIAL MUSCLES OF POSTE RIOR COMPARTMENT OF FOREARM.

LATERAL.


Brachioradialis Proximal of Lateral Supracondylar ridge of Humerus

Lateral surface of distal end of Radius

Radial nerve (C5, C6, C7) Flexes forearm

Extensor Carpi Radialis Longus

Lateral Supracondylar ridge of Humerus

Base of 2nd Metacarpal Radial nerve (C5, C6) 1. Extends hand at wrist. 2. Abducts hand at wrist

Extensor Carpi Radialis Brevis

Lateral Epicondyle of Humerus Base of 3rd Metacarpal Deep branch of Radial nerve (C7,C8)

1. Extends hand at wrist. 2. Abducts hand at wrist


POSTERIOR.


Extensor Digitorum Lateral Epicondyle of Humerus Extensor expansions of medial 4 digits

Posterior Interosseous nerve (C7,C8)

1. Extends medial 4 digits at Metacarpal-phalangeal joint

2. Extends hand at wrist

Extensor Digiti Minimi

Lateral Epicondyle of Humerus Extensor expansion of 5th digit Posterior Interosseous nerve (C7,C8)

Extends 5th digit at the Metacarpal-phalangeal joint, and the Interphalangeal joint

Extensor Carpi Radialis Ulnaris

1. Lateral Epicondyle of Humerus

2. Posterior border of Ulna

Base of 5th Metacarpal Posterior Interosseous nerve (C7,C8)

1. Extends hand at wrist 2. Adducts hand at wrist

Anconeus Lateral Epicondyle of Humerus 1. Lateral surface of olecranon 2. Superior part of posterior

surface of Ulna

Radial nerve (C7, C8, T1) 1. Assists Triceps in extending elbow joint

2. Stabilises elbow joint 3. Abducts Ulna during

pronation

DEEP MUSCLES OF POST ERIOR COMPARTMENT OF FOREARM.


Abductor Pollicis Longus

1. Posterior surfaces of Ulna, Radius

2. Interosseous membrane

Base of 1st Metacarpal Posterior Interosseous nerve (C7, C8)

1. Abducts thumb 2. Extends thumb at Carpal-

metacarpal joint

Extensor Pollicis Brevis

1. Posterior surface of Radius 2. Interosseous membrane

Base of proximal phalanx of thumb

Posterior Interosseous nerve (C7, C8)

Extends proximal phalanx of thumb at Metacarpal-phalangeal joint.

Extensor Pollicis Longus

1. Posterior surface of middle third of Ulna

2. Interosseous membrane

Base of distal phalanx of thumb Posterior Interosseous nerve (C7, C8)

Extends distal phalanx of thumb at Metacarpal-phalangeal joint, and Interphalangeal joint.


Extensor Indicis 1. Posterior surface of Ulna 2. Interosseous membrane

Extensor expansion of 2nd digit Posterior Interosseous nerve (C7, C8)

1. Extends index finger 2. Helps extend hand

Extensor Retinaculum

Distal end of Radius 1. Styloid process of Ulna 2. Triquetrum 3. Pisiform

Prevents bow-stringing of the long extensor tendons, when the hand is hyper-extended at the wrist joint.


THE ANATOMICAL SNUFF BOX.

Lateral boundary = Abductor Pollicis Longus and Extensor Pollicis Brevis.

Medial boundary = Extensor Pollicis Longus. Contents of Anatomical Snuffbox are: Cephalic vein superficial to tendons Superficial branch of radial nerve superior to tendons Radial artery deep to tendons, forming floor of snuffbox. Pierces 1st Dorsal Interosseous to form Deep Palmer Arch,

Princeps Pollicis artery, and Radialis Indicis artery.

Scaphoid forms floor. It is narrow in the middle, and frequently fractured

Pain in snuffbox.

Blood supply enters distally, and leaves proximally through nutrient

foramen risk of Avascular Necrosis.

POSTERIOR ARTERIAL S UPPLY OF FOREARM.

The posterior interosseous artery (arising from the common interosseous artery branch of the ulnar artery) supplies all the muscles of the posterior compartment of the forearm.

Posterior Interosseous passes posteriorly between the Radius and Ulna, just proximal to the interosseous membrane.

It enters the posterior compartment, between Supinator muscle and Abductor Pollicis Longus.

Terminates by anastomosis with Anterior Interosseous artery, and the Dorsal Carpal Arch.


NERVES OF POSTERIOR COMPARTMENT OF FOREA RM.

Radial nerve supplies Extensor Carpi Radialis Longus before splitting into a superficial branch and a deep branch, just superior to the elbow.

The deep branch supplies the Extensor Carpi Radialis Brevis, and the Supinator muscle. It then pierces the Supinator, and enters the posterior compartment.

Henceforth, it is called the Posterior Interosseous nerve, and supplies the remaining forearm extensors.

It lies on the interosseous membrane, with the Posterior Interosseous artery. The superficial branch runs down the forearm with the Radial artery, to be the most lateral

structure at the wrist. It divides into digital branches, to give cutaneous supply to the lateral 3 digits, and the dorsal surface of the palm.

A SPECIAL NOTE ON EX TENSOR DIGITORUM MUSCLE.

At Metacarpal-phalangeal joint, there is a diamond shaped aponeurosis wrapped around the joint = Dorsal Digital Expansion.

Extensor Digitorum passes through the Dorsal Digital Expansion, and partially attaches to proximal phalanges.

The central band attaches to the middle phalanx. The marginal bands (medial & lateral) go around the middle phalanx, and then merge and

attach to the distal phalanx.

To make a fist, the extensor tendons have to be longer than the flexor tendons. When the Metacarpal-phalangeal joint is extended by Extensor Digitorum, there is too

much slack in the tendon to further extend the Interphalangeal joints.

The Lumbricals and Interossei attach onto the margins of the Dorsal Digital Expansions, and contract to re-tension the Extensor Digitorum, by pulling on its hood.

Thus the Extensor Digitorum and its collateral reinforcements extend the interphalangeal joints.


THE HAND.

CARPAL TUNNEL & PALM .

Bones of wrist are Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, and Hamate. Roof of carpal tunnel is the Flexor Retinaculum. Contents of the Carpal Tunnel are: Median nerve Flexor Digitorum Superficialis tendons (4) Flexor Digitorum Profundus tendons (4) Flexor Carpi Radialis tendon in its own sleeve Flexor Pollicis Longus tendon.

Superficial to roof of Carpal Tunnel are: Ulnar artery Ulnar nerve Palmar branch of ulnar nerve Palmar branch of median nerve Palmaris Longus tendon Superficial branch of Radial artery.

Palmar Aponeurosis (= deep fascia) originates at border of Flexor Retinaculum, and attaches to base of proximal phalanges of fingers. Where it attaches to skin, are visible skin creases. It extends Palmaris Longus. Medially attached to 5th Metacarpal. Laterally attached to 1st Metacarpal. Divides palm into: Lateral (Thenar) compartment. Central (Mid-palmar) compartment.

Further split by a Septa from lateral edge of aponeurosis to 3rd Metacarpal.


Medial (Hypothenar) compartment. Dupuytren's Contracture = a tight fibrous band developing in palm, that pulls digits into a flexed position. Fibrous flexor sheaths bind down tendons of digits, and prevents them from bow-stringing, when digits are flexed. Pass from metacarpals to the distal phalanges. At Interphalangeal joints, they are composed of cruciate fibres, to allow flexion.

Attachments of Flexor Digitorum Superficialis and Flexor Digitorum Profundus.

Synovial sheaths lie deep to the fibrous sheaths over tendons. They have occasional vincula, for a blood supply.


Each digit has a neurovascular bundle on either side of it. From posterior to anterior: Digital vein Digital artery Digital nerve.


THENAR MUSCLES.


Abductor Pollicis Brevis

1. Flexor Retinaculum 2. Scaphoid & trapezium

tubercles

Lateral side of base of proximal phalanx of thumb.

Recurrent branch of Median nerve (C8, T1)

1. Abduction 2. Aids opposition

Flexor Pollicis Brevis 1. Flexor Retinaculum 2. Trapezium tubercle

Lateral side of base of proximal phalanx of thumb.

Recurrent branch of Median nerve (C8, T1)

1. Flexes thumb

Opponens Pollicis 1. Flexor Retinaculum 3. Trapezium tubercle

Lateral side of 1st Metacarpal. Recurrent branch of Median nerve (C8, T1)

1. Opposition of thumb. 2. Medial rotation

Adductor Pollicis 1. Oblique head bases of 2nd & 3rd metacarpals + Capitate & adjacent carpal bones.

2. Transverse head anterior surface of body of 3rd metacarpal

Medial side of base of proximal phalanx of thumb

Deep branch of Ulnar nerve. (C8, T1)

Adducts thumb towards middle digit.

HYPOTHENAR MUSCLES.


Abductor Digiti Minimi

Pisiform Medial side of base of proximal phalanx of 5th digit.

Deep branch of Ulnar nerve (C8, T1)

Abduction.

Flexor Digit Minimi Brevis

Hook of Hamate and Flexor Retinaculum.

Medial side of base of proximal phalanx of 5th digit.


Flexion.

Opponens Digit Minimi

Hook of Hamate and Flexor Retinaculum.

Medial border of 5th metacarpal Deep branch of Ulnar nerve (C8, T1)

Draws 5th metacarpal anteriorly, and laterally rotates it, bringing 5th digit into opposition with thumb.


INTINISIC MUSCLES OF THE HAND.


1st & 2nd Lumbricals Each from one of the two lateral tendons of Flexor Digitorum Profundus.

Unipennate

Lateral sides of extensor expansions of 2nd to 5th digit.

Median nerve (C8, T1) Flexes digits at Metacarpal-phalangeal joints, and extends Interphalangeal joints. (Salute position) 3rd & 4th Lumbricals Each from two of the three

medial tendons of Flexor Digitorum Profundus.

Bipennate


Palmar Interossei Palmar surfaces of 1st, 2nd, 4th & 5th metacarpals.

Unipennate

Extensor expansions, and bases of proximal phalanges of 1st, 2nd, 4th & 5th digits.


Adduction.

Dorsal Interossei Adjacent sides of metacarpal bones.

Bipennate

Extensor expansion and bases of proximal phalanges of 2nd, 3rd & 4th digits.


Abduction.



Palmaris Brevis Flexor Retinaculum & palmar aponeurosis.

Skin on medial side of palm (therefore lies in fascia, deep to skin and hypothenar eminence)

Superficial branch of Ulnar nerve (C8, T1)

1. Wrinkles skin on medial side of palm.

2. Deepens hollow of palm, to aid grip.

20 MUSCLES OF THE HA ND.

Palmaris Brevis 1 Thenar Muscles 3 Adductor Pollicis 1 Hypothenar Muscles 3 Lumbricals 4 Interossei 8

20


ARTERIES OF HAND.

Ulnar artery

Main branch

Supplies medial side of little finger, and web spaces of fingers. From the web spaces, the arterial supply divides to run along the medial and lateral sides of the fingers, up to medial side of index finger.

Superficial Palmar branch

Radial artery

Deep branch

Main branch

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Superficial Palmar Arch

Gives branches to the thumb (Princeps Pollicis artery), and to the lateral side of the index finger (Radialis Indicis artery).

Deep Palmar Arch


NERVES OF THE HAND.

MEDIAN NERVE.

Lies at wrist, between Flexor Carpi Radialis & Flexor Digitorum Superficialis tendons. Palmar branch originates proximal to Carpal tunnel, and supplies lateral skin of palm

sensation of palm is unaffected by Carpal Tunnel Syndrome.

Cutaneous supply to lateral 3 fingers, and nail beds. Muscular supply to: 3 Thenar muscles (recurrent branch) Lateral two Lumbricals.

ULNAR NERVE.

Lies at wrist in between Flexor Digitorum Superficialis & Flexor Carpi Ulnaris tendons. Palmar branch originates proximal to Flexor Retinaculum, and supplies medial skin of

palm.

Main branch runs superficially to Flexor Retinaculum, and laterally to the Pisiform, and Hook of Hamate.

Superficial branch gives a cutaneous supply to medial 1 fingers. Deep branch give a muscular supply to: 3 Hypothenar muscles Two medial Lumbricals 8 Interossei Adductor Pollicis muscle.

RADIAL NERVE.

Supplies no muscles in hand. Cutaneous supply to dorsal surface of hand
Anterior Wall.Posterior Wall.Medial Wall.Lateral Wall.Contents Of Axilla.Brachial PlexusSuperficial Muscles.Deep Muscles.Rotator Cuff Muscles (extensile ligaments).Scapular Muscles.Posterior Spaces.Muscles Of Anterior Compartment Of Arm.Cubital Fossa.Muscles of Posterior Compartment Of Arm.Superficial Muscles of Anterior Compartment of Forearm.Intermediate muscles of anterior compartment of forearm.Deep Muscles Of Anterior Compartment Of Forearm.Superficial Muscles of Posterior Compartment Of Forearm.Lateral.Posterior.Deep Muscles of Posterior Compartment Of Forearm.The Anatomical SnuffBox.Posterior Arterial Supply of Forearm.Nerves of Posterior Compartment Of Forearm.A special note on Extensor Digitorum Muscle.Carpal TunneL & Palm.Thenar Muscles.Hypothenar Muscles.Intinisic Muscles of The Hand.20 Muscles of The Hand.Arteries Of Hand.Nerves Of The Hand.Median Nerve.Ulnar Nerve.Radial Nerve.

Upper Limb

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