USMLE Anatomy Review

7/28/2019 USMLE Anatomy Review

1/19

1. What dermatome overlies

the umbilicus?T10

1. What features demarcate

the boundaries of the lesser or

true pelvis?

Answer: the pelvic brim,

sacrum, and coccyx.

1. What is the sternal angle of

Louis, and why is it

important?

Answer: It is the articulation of the manubrium and

body of the

sternum, and it marks the dividing point of the

superior mediastinum

from the inferior mediastinum. It also overlies the

tracheal bifurcation

and aortic arch and is useful for counting intercostal

spaces.

(Second ribs articulate here.)

1. What underlying bony

feature does the point of the

hip demarcate?

Answer: The greater

trochanter of the femur

2. What abdominal viscera lie

in the left upper

hypochondriac region?

Answer: Spleen, splenic

flexure of the transverse colon,

pancreatic tail, stomach

(variable), and part of the left

kidney.


2/19

2. What is primary site for

lymphatic drainage from the

breast?

Answer: Axillary lymph nodes

(75% of all lymph).

2. When comparing the female

to the male pubic arch, what

difference is

apparent?

Answer: The female pubic

arch is larger and wider.

2. Which three bones fuse to

form the coxal (hip) bone?

Answer: Ilium, ischium, and

pubis. All come together in the

acetabulum.

3. What are the layers of the

abdominal wall?

-Skin;

-Subcutaneous tissue (fatty Camper's fascia and

membranous Scarpa's

-Fascia in the lower abdomen);

-External oblique;

-Internal oblique; and

-Transversus abdominis muscles;

-Tranversalis fascia;

-Extraperitoneal fascia (preperitoneal fat);

-and peritoneum.

3. What important spaces are

created by the sacrospinous

ligament?

Answer: The greater and lesser sciatic foramina.

They provide an

avenue for structures to pass from the pelvis to the

gluteal region

and posterior thigh, and for the pudendal vessels

and nerves to

enter the pudendal canal and pass to the

perineum.


3/19

3. Which hip joint ligament is

the strongest?

Answer: The iliofemoral

ligament, which forms an

inverted "Y"

ligament (of Bigelow) that

limits hyperextension.

4. What is the major blood

supply to the femoral head?

Answer: Primarily the retinacular arteries

of the medial and Lateral femoral

circumflex, and acetabular branch of the

obturator artery, which runs in the

ligament of the femoral head (less

important In adults).

4. What muscles make up the

pelvic diaphragm?

Answer: Levator ani and

coccygeus.

4. What nerve is in the

spermatic cord, and what does

it innervate?

Answer: Genital branch of the

genitofemoral nerve. It

innervates the cremaster

muscle?

5. What are the descriptive

subdivisions of the uterus?

Answer: The body (fundus and

isthmus) and cervix


4/19

5. What nerve innervates the

major hip adductor muscles?

Answer: Superior gluteal nerve. Weakness

of abductors (gluteus

medius and minimus) on the weight-

bearing limb can lead to gluteal

lurch during walking; this is known as a

positive Trendelenburg

sign.

5b. What is a indirect inguinal

hernia?

Answer: A hernia that occurs lateral

to the inferior epigastric vessels,

passes through the deep inguinal

ring and inguinal canal, and may

appear at the superficial inguinal

ring.

6. What is the access point of

the lesser sac?

Answer: The epiploic foramen

(Winslow), just posterior to

the hepatoduodenal ligament

and anterior to the IVC.

6. What is the inferior extent

of the lung and parietal pleura

in quiet respiration at the

midaxillary line?

Lung extends to the eighth rib

and the pleura to the tenth rib.

6. What nerves contribute to

the formation of the lumbar

plexus?

Answer: Ventral primary rami

of L1-L4.


5/19

6. Why is the rectouterine

pouch (of Douglas) important?

Answer: It is the lowest point in the

female pelvis (where

peritoneal fluids may collect), and

access to drain these

fluids is possible via the posterior

vaginal fornix.


subdivisions of the broad

ligament?

Answer: Mesovarium (surrounds

and suspends ovary),

Mesopsalpinx (surrounds and

suspends the uterine tubes),

And mesometrium (surrounds and

supports the uterus).

7. What are two components

of the sciatic nerve?

Answer: Tibial and common

fibular nerves.

7. Where does the

hepatopancreatic ampulla

terminate?

Answer: In the lumen of the

second, or descending, part of

the duodenum.

8. What are the three major

branches of the celiac artery

(trunk), and what

do they supply?

Answer: Left gastric, common hepatic, and splenic.

They supply

the spleen and the foregut derivatives of the GI tract.

Esophagus (distal end)

Stomach

Duodenum (proximal end)

Liver, gallbladder, pancreas


6/19

8. What powerful flexor of the

thigh at the hip attaches to the

lesser trochanter?

Answer: Iliopsoas muscle.

8. What structures may be

involved in stress

incontinence?

Answer: Stress incontinence may result

from a loss of

functional integrity of the pubovesical

ligaments,

vesicocervical fascia, levator ani, and / or

urethral

sphincter.

9. Identify several easy ways

to differentiate the jejunum

from the ileum.

Answer: The jejunum compared to

the ileum is larger in diameter;

its mesentery contains less fat; its

arterial arcades are fewer; and

it has a longer vasa recta.

9. Uterine prolapse may occur

with the loss of support of

which important structures?

Answer: The transverse

cervical (cardinal) and

uterosacral

ligaments, and the levator ani

muscle,

9. What nerve innervates the

anterior compartment of the

thigh?

Answer: Femoral nerve (L2-

L4). The muscles are largely

extensors

of the leg at the knee.


7/19

10. What are the hamstrings

muscles?

Answer: Semitendinosus,

semimembranosus, and the long head of

the biceps femoris. They extend the thigh

at the hip and flex the leg at the knee. They

are supplied by the tibial nerve and attach

to the ischial tuberosity.

10. What structures are

supplied by the superior

mesenteric artery?

Answer: Midgut derivatives of

the GI tract.

Distal portion of duodenum to

the left colic flexure.

10. Which branches of the

internal iliac

artery arise from the posterior

division?

Answer: iliolumbar, lateral

sacral, and superior gluteal

arteries

11. How does the urinary

bladder empty itself?

Answer: Appropriate central nervous system reflexes

initiate voiding via stimulation of pelvic splanchnic nerves

to the bladder;this causes contraction of the detrusor

smooth muscle of the bladder wall. Voluntary relaxation

of external sphincter urethrae muscle tone occurs in

conjunction with the detrusor contraction,

but it is mediated by the somatic nervous system. In

males, sympathetic relaxation of the internal sphincter

(females lack internal sphincter) also occurs with

detrusor contraction.

11. Where is McBurney's

point?

Answer: One third of the way along a line

connecting the anterior

superior iliac spine to the umbilicus. It is a

good landmark for locating

an inflamed appendix (point of

tenderness).


8/19

11. Why are gluteal

intramuscular injections given

in the upper outer quadrant?

Answer: To avoid injury to the

large sciatic nerve, which runs

through the lower half of the

gluteal region.


subdivisions of the male

urethra?

Answer: Prostatic,

membranous, and spongy

(penile).

12. What is the pes anserinus?

Answer: An attachment arrangement of

tendons of the semitendinosus

gracilis, and sartorius muscles to the

medial tibial condyle (looks like a

goose's foot).

12. What portions of the large

bowel are retroperitoneal?

Answer: Ascending colon,

descending colon, and rectum

*.

13. How does one test for an

ACL injury?

Answer: Anterior drawer sign, where the

tibia moves anterioly in relation

to the femur. The ACL normally prevents

hyperextension of the knee and

is injured more than the posterior cruciate

ligament.


9/19

13. Where do sperm and

seminal fluids empty into the

urethra?

Answer: Into the prostatic

urethra via the ejaculatory

ducts.

13. Where is the bare area of

the liver?

Answer: The portion that is pressed

against the diaphragm and is not

covered with visceral peritoneum. It

will have a dull appearance rather

than glistening appearance.

14. What are the four

important sites of portocaval

anastomoses?

Answer: Esophageal,

paraumbilical, rectal, and

retroperitoneal.

14. What is the innervation of

the external anal sphincter?

Answer: Inferior anal (rectal)

nerves from the pudendal

nerve

(S2-S4).

14. What is the unhappy triad?

Answer: Injury to the ACL,

tibial collateral ligament, and

medial

meniscus.


10/19

15. Trace bile from the liver to

the gallbladder and then

duodenum, naming every

duct traversed in correct

order.

Answer: Right and left hepatic ducts to the

common hepatic duct

to the cystic duct to the gallbladder. From

the gallbladder to the cystic

duct to the common bile duct to the

hepatopancreatic ampulla (of

Vater) to the second part of the duodenum.

15. What is the arterial blood

supply to the muscles of the

anterior compartment

of the leg?

Answer: anterior tibial artery.

15. Which rectal veins are

involved in portocaval

anastomoses?

Answer: The inferior and middle rectal

veins (tributaries

of the internal iliac vein - caval system)

anastomose with

the superior rectal vein from the inferior

mesenteric vein,

a tributary of the portal venous system.

16. What is the

parasympathetic innervation

of the pelvic viscera?

Answer: Parasympathetic preganglionic

fibers arise from S2-S4

via pelvic splanchnic nerves that course to

the inferior

hypogastric plexus (pelvic), synapse there,

and then innervate

pelvic viscera (smooth muscle and glands)

16. What nerve innervates the following muscles?

Gastrocnemius

Fibularis longus

Tibialis anterior

Plantaris

Flexor hallucis longus

Flexor digitorum brevis

Soleus

Abductor digiti minimi

Plantar and dorsal interossei

Gastrocnemius - Tibial

Fibularis longus - Superficial fibular

Tibialis anterior - Deep fibular

Plantaris - Tibial

Flexor hallucis longus - Tibial

Flexor digitorum brevis - Medial plantar (from tibial)

Soleus - Tibial

Abductor digiti minimi - Lateral plantar (from tibial)

Plantar and dorsal interossei - Lateral plantar (from

tibial)


11/19

16. Where does the lymphatic

duct begin?

Answer: In the abdomen at the

cisterna chyli, which is the dilated

beginning of the duct that receives

lymph from the lumbar and

interstitial lymphatic glands.

17. Footdrop may indicate an

injury to which nerve?

Answer: Deep fibular nerve ( if

weakened eversion is also

present, then it is the common

fibular nerve).

17. Identify three common

anatomical sites where a renal

calculus (stone)

may become lodged and

obstruct urine flow.

1. Ureteropelvic junction

2. Pelvic brim

- Crossing the bifurcation of common iliac

a or beginning of external iliac a

3. Ureterovesicular junction: Passage

through the wall of the urinary bladder

17. Lymphatic spread of

cancer cells from a malignant

ovarian tumor may

involve the aortic (lumbar)

lymph nodes directly. Why?

Answer: The lymphatic vessels of

the ovary follow the

ovarian artery directly back to the

abdominal aorta and

infiltrate aortic nodes in this region.

18. How is the joint between

the talus and tibia classified?

Answer: Talocrural joint, a

uniaxial synovial hinge

(ginglymus) joint.


12/19

18. Into which veins do the

gonadal veins empty?

Answer: The right vein

empties into the IVC and the

left vein empties into the left

renal vein.

18. What the boundaries of the

diamond-shaped perineum?

Answer: The pubic symphysis

anteriorly, the ischial

tuberosity laterally, and the

coccyx posteriorly.

19. How are thoracic

splanchnic nerves distributed

to the abdominal GI tract?

Answer: They distribute to the foregut and

midgut derivatives of the GI tract by

synapsing in the celiac and superior

mesenteric ganglia and sending

postganglionic fibers to the viscera on the

vessels of the celiac and SMA.

19. What are the two bony

arches of the foot?

Answer: the longitudinal and

transverse arches.

19. Why is the central tendon

of the perineum important?

Answer: It anchors the perineum

because it provides

for attachment of many skeletal

muscles of the perineum

as well as fascial layers.


13/19

20. What is the common cause

of erectile dysfunction?

Answer: Loss of functionality in the nerves that relax

the

smooth muscle tone of the corpus cavernosum, which

impedes blood flow into cavernous erectile tissue.

Current

medications facilitate smooth muscle relaxation and

increase

blood flow.

20. What is the spring

ligament, and why is it

important?

Answer: Plantar calcaneonavicular

ligament, which supports the head

of the talus and medial longitudinal

arch of the foot. It is fairly elastic,

hence its name.

20. Where do the pain

afferents from the abdominal

viscera terminate in the

central nervous system?

Answer: Afferents axons conveying pain

pass via thoracicand lumbar splanchnic

nerves to the dorsal root ganglia (site of

the afferent neurons) and into the spinal

cord between the T5 and L2 levels, where

they synapse in the dorsal horn (gray

matter).

21. What is the female

homologue of the male corpus

spongiosum penis?

Answer: The bulb of the

vestibule.

21. Which nerves of the

lumbar plexus arise from L2-

L4 ventral rami, and what

do they innervate?

Answer: Femoral nerve, which innervates the anteriorcompartment muscles of the thigh (largely kneeextensors), and obturator, which innervates medialcompartment muscles of the thigh (la rgely hip a dductors).

1) Il iohypogastric (L1/T12-L1)

2) Ilio inguinal (L1/T12-L1)

3) Genitofemoral (L1-2)

4) Lateral femora l cutaneous (L2-3)

5) Femoral nerve (L2- 4)

6) Obturator nerve (L2- 4)


14/19

21. Which tarsal bone is

fractured most often?

Answer: Calcaneus. Most are intra-

articular fractures in which

the talus is driven down on the

calcaneus, as in a fall from a

great height, with a landing on the

heel.

22. In the lower limb, what

are the two deep tendon

reflexes?

Answer: The patellar tendon

reflex (L3-L4) and the

calcaneal

tendon reflex (S1-S2).

22. What is the

parasympathetic innervation

to the GI tract?

Answer: Foregut and midgut

derivatives are innervated by

the vagus nerve; the hindgut is

innervated by the pelvic

splanchnic nerves (S2-S4).

23. What is the blood supply

to the sole of the foot?

Answer: Medial and lateral

plantar arteries derived from

the posterior tibial artery.

25. What dermatomes are associated with

each of the following regions?

Inguinal region

Knee

Second toe

Posterior leg and thigh

L1

L4

L5

S1-S2


15/19

32. What is the axis around

which the gut tube rotates

during development?

Answer: The superior

mesenteric artery (SMA).

Esophageal tributaries anastomoses

with those tributaries to azygos

system > SVC

Complication:

ESOPHAGEAL VARICOSE

VEINS

Esophageal tributaries

anastomoses with those

tributaries to azygos system >

SVC

Complication: ?

Esophageal varices

Indirect vs Direct Inguinal Hernia

Leaves lateral to the inferior epigastric vessels

Enters through the deep inguinal ring

Mainly congenital

Most common (75%)

Hernial sac by persistent processus vaginalis and the

covering of the spermatic cord

Lies within the cord, covered by processus vaginalis

Indirect

Indirect vs Direct Inguinal Hernia

Leaves medial to inferior epigastric vessels

Protrudes through the inguinal (Hesselbach's) triangle

Always acquired, but seems like genetic factors predispose

Hernial sac by fascia transversalis & peritoneum

Lies outside of the processus vaginalis, parallel to

spermatic cord and its coverings.

Direct Inguinal Hernia


16/19

Paraumbilical veins

anastomoses with

subcutaneous veins of anterior

abdominal wall > SVC & IVC

Complication: ?

CAPUT MEDUSAE

stopped at slide 119..... will

continue later...

Superior rectal vein

anastomoses with middle and

inferior rectal veins to the IVC

Complication: ?

Internal HEMORRHOIDS

Trace the conduction pathway

through the heart.

SA node to AV node to

common AV bundle (of His) to

right and left bundle branches

and subendocardial Purkinje

system.

Veins of Retzius - anastomose

of small colic veins with veins

in the posterior abdominal

wall

Complication: ?

SILENT VARICES


17/19

What are semilunar valves?

The pulmonary and aortic

valves. Each has three

semilunar cusps or leaflets.

(They share a common

embryologic origin.)

What are the hallmarks of

tetralogy of Fallot?

Pulmonary stenosis or

narrowing of the right

ventricular outflow, transposed

aorta, right ventricular

hypertrophy and VSD.

What does the fourth pair of

aortic arches become in the

adult?

Answer: On the right side, the

right subclavian artery; on the

left side, the aortic arch.

What is the most common

congenital heart defect?

Answer: VSD (ventricular

septal defect), which usually

occurs in

the membranous portion of

the ventricular septum.

What is thoracic outlet

syndrome?

Compression of one or more of the

structures passing

out of the thoracic outlet. The

subclavian artery or vein or lower

portion of the brachial plexus is

often involved.


18/19

What structure of the

embryonic foregut region

gives rise to the lung buds?

Laryngotracheal diverticulum.

What types of nerve fibers

travel in the thoracic cardiac

nerves?

Postganglionic sympathetic

fibers (to the heart) and

visceral afferents from the

heart.

What veins drain the posterior

thoracic wall?

Drainage is largely by

tributaries of the azygos

system of veins (intercostal

veins).

Which coronary artery

supplies the SA node?

Right coronary artery, usually

its SA nodal branch

Why do most lung abscesses

occur in the right lung?

The right main bronchus is wider,

shorter, and more vertical than the

left bronchus, and aspirated

infective agents can gain easier

access to the right lung.


19/19

Why is angina pectoris an

example of referred pain?

Visceral afferents from the ischemic heart are

conveyed to the upper thoracic spinal cord levels,

which also receive somatic afferents from the T1-

T4 dermatomes. Both groups of afferents converge

in the dorsal horn of the spinal cord, and angina

may be perceived as localized to the somatic

distribution

(T1-T4) rather than identified with the heart.

Why is the azygos system of

veins important clinically?

Answer: It has important connections with

tributaries of the inferior vena cava and portal

system, which normally drains most of the venous

blood from below the diaphragm back to the

heart. If this drainage is compromised, the

connections with the azygos system provide

alternative routes of venous return to the heart.

USMLE Anatomy Review

Documents

Transcript of USMLE Anatomy Review