usmle anatomy review
TRANSCRIPT
-
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.
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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.
7. What are the descriptive
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
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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).
-
7/28/2019 USMLE Anatomy Review
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.
12. What are the descriptive
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.
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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)
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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)
-
7/28/2019 USMLE Anatomy Review
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
-
7/28/2019 USMLE Anatomy Review
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
-
7/28/2019 USMLE Anatomy Review
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
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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.
-
7/28/2019 USMLE Anatomy Review
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.