upper limb Flashcards
A 45-year-old woman is being examined as a candidate
for cosmetic breast surgery. The surgeon notes
that both of her breasts sag considerably. Which structure
has most likely become stretched to result in this
condition?
⃣ A. Scarpa’s fascia
⃣ B. Pectoralis major muscle
⃣ C. Pectoralis minor muscle
⃣ D. Suspensory (Cooper’s) ligaments
⃣ E. Serratus anterior muscle
D. The suspensory ligaments of the breast, also
known as Cooper’s ligaments, are fi brous bands that
run from the dermis of the skin to the deep layer of
superfi cial fascia and are primary supports for the
breasts against gravity. Ptosis of the breast is usually
due to the stretching of these ligaments and can be
repaired with plastic surgery. Scarpa’s fascia is the
deep membranous layer of superfi cial fascia of the
anterior abdominal wall. The pectoralis major and
pectoralis minor are muscles that move the upper
limb and lie deep to the breast but do not provide any
direct support structure to the breast. The serratus
anterior muscle is involved in the movements of the
scapula.
GAS 131, 137-138; GA 62
A 27-year-old man was admitted to the emergency
department after an automobile collision in which he
suffered a fracture of the lateral border of the scapula.
Six weeks after the accident, physical examination reveals
weakness in medial rotation and adduction of the
humerus. Which nerve was most likely injured?
⃣ A. Lower subscapular
⃣ B. Axillary
⃣ C. Radial
⃣ D. Spinal accessory
⃣ E. Ulnar
A. Lower subscapular nerves arise from the cervical
spinal nerves 5 and 6. It innervates the subscapularis
and teres major muscles. The subscapularis and
teres major are both responsible for adducting and
medially rotating the arm. A lesion of this nerve
would result in weakness in these motions. The axillary
nerve also arises from cervical spinal nerves 5
and 6 and innervates the deltoid and teres minor
muscles. The deltoid muscle is large and covers the
entire surface of the shoulder, and contributes to arm
movement in any plane. The teres minor is a lateral
rotator and a member of the rotator cuff group of
muscles. The radial nerve arises from the posterior
cord of the brachial plexus. It is the largest branch,
and it innervates the triceps brachii and anconeus in
the arm. The spinal accessory nerve is cranial nerve
XI, and it innervates the trapezius muscle, which elevates
and depresses the scapula. The ulnar nerve
arises from the medial cord of the brachial plexus and
runs down the medial aspect of the arm. It innervates
muscles of the forearm and hand.
GAS 676-682; GA 366, 369
A 48-year-old female court stenographer is admitted
to the orthopedic clinic with symptoms of carpal
tunnel syndrome, with which she has suffered for almost
a year. Which muscles most typically become
weakened in this condition?
⃣ A. Dorsal interossei
⃣ B. Lumbricals III and IV
⃣ C. Thenar
⃣ D. Palmar interossei
⃣ E. Hypothenar
C. The thenar muscles (and lumbricals I and II) are
innervated by the median nerve, which runs through
the carpal tunnel. The carpal tunnel is formed anteriorly
by the fl exor retinaculum and posteriorly by the
carpal bones. Carpal tunnel syndrome is caused by a
compression of the median nerve, due to reduced
space in the carpal tunnel. The carpal tunnel contains
the tendons of fl exor pollicis longus, fl exor digitorum
profundus, and fl exor digitorum superfi cialis muscles.
The dorsal interossei, lumbricals III and IV, palmar interossei,
and hypothenar muscles are all innervated by
the ulnar nerve.
GAS 756-758, 764-765, 788; GA 8, 400
A 45-year-old male arrived at the emergency department
with injuries to his left elbow after he fell in
a bicycle race. Radiographic and MRI examinations
show a fracture of the medial epicondyle and a torn
ulnar nerve. Which of the following muscles would be
most likely to be paralyzed?
⃣ A. Flexor digitorum superfi cialis
⃣ B. Biceps brachii
⃣ C. Brachioradialis
⃣ D. Flexor carpi ulnaris
⃣ E. Supinator
D. Fracture of the medial epicondyle often causes
damage to the ulnar nerve due to its position in the
groove behind the epicondyle. The ulnar nerve innervates
one and a half muscles in the forearm—the
fl exor carpi ulnaris and the medial half of the fl exor
digitorum profundus. The nerve continues on to innervate
muscles in the hand. The fl exor digitorum
superfi cialis is innervated by the median nerve and
the biceps brachii by the musculocutaneous. The radial
nerve innervates both the brachioradialis and
supinator muscles.
GAS 724-730; GA 378, 390, 397-398
While walking to his classroom building, a fi rstyear
medical student slipped on the wet pavement and
fell against the curb, injuring his right arm. Radiographic
images showed a midshaft fracture of the humerus.
Which pair of structures was most likely injured
at the fracture site?
⃣ A. Median nerve and brachial artery
⃣ B. Axillary nerve and posterior humeral circum-
fl ex artery
⃣ C. Radial nerve and deep brachial artery
⃣ D. Suprascapular nerve and artery
⃣ E. Long thoracic nerve and lateral thoracic artery
C. A midshaft humeral fracture can result in injury
to the radial nerve and deep brachial artery because
they lie in the spiral groove located in the
midshaft. Injury to the median nerve and brachial
artery can be caused by a supracondylar fracture
that occurs by falling on an outstretched hand and
partially fl exed elbow. A fracture of the surgical neck
of the humerus can injure the axillary nerve and
posterior humeral circumfl ex artery. The suprascapular
artery and nerve can be injured in a shoulder
dislocation. The long thoracic nerve and lateral thoracic
artery may be damaged during a mastectomy
procedure.
GAS 713, 724; GA 361
An 18-year-old male is brought to the emergency
department after an injury while playing rugby. Imaging
reveals a transverse fracture of the humerus about
1 inch proximal to the epicondyles. Which nerve is
most frequently injured by the jagged edges of the broken
bone at this location?
⃣ A. Axillary
⃣ B. Median
⃣ C. Musculocutaneous
⃣ D. Radial
⃣ E. Ulnar
B. A supracondylar fracture often results in injury
to the median nerve. The course of the median nerve
is anterolateral, and at the elbow it lies medial to the
brachial artery on the brachialis muscle. The axillary
nerve passes posteriorly through the quadrangular
space, accompanied by the posterior circumfl ex humeral
artery, and winds around the surgical neck of
the humerus. Injury to the surgical neck may damage
the axillary nerve. The musculocutaneous nerve
pierces the coracobrachialis muscle and descends between
the biceps and brachialis muscle. It continues
into the forearm as the lateral antebrachial cutaneous
nerve. The ulnar nerve descends behind the medial
epicondyle in its groove and is easily injured and produces
“funny bone” symptoms.
GAS 724-731; GA 361
A 52-year-old band director suffered problems in
her right arm several days after strenuous fi eld exercises
for a major athletic tournament. Examination in
the orthopedic clinic reveals wrist drop and weakness
of grasp but normal extension of the elbow joint. There
is no loss of sensation in the affected limb. Which
nerve was most likely affected?
⃣ A. Ulnar
⃣ B. Anterior interosseous
⃣ C. Posterior interosseous
⃣ D. Median
⃣ E. Superfi cial radial
C. The radial nerve descends posteriorly between
the long and lateral heads of the triceps and passes
inferolaterally on the back of the humerus between
the medial and lateral heads of the triceps. It eventually
enters the anterior compartment and descends to
enter the cubital fossa, where it divides into superfi -
cial and deep branches. The deep branch of the radial
nerve winds laterally around the radius and runs
between the two heads of the supinator and continues
as the posterior interosseous nerve, innervating
extensor muscles of the forearm. Because this injury
does not result in loss of sensation over the skin of
the upper limb, it is likely that the superfi cial branch
of the radial nerve is not injured. If the radial nerve
were injured very proximally, the woman would not
have extension of her elbow. The branches of the
radial nerve to the triceps arise proximal to where the
nerve runs in the spiral groove. The anterior interosseous
nerve arises from the median nerve and supplies
the fl exor digitorum profundus, fl exor pollicis
longus, and pronator quadratus, none of which seem
to be injured in this example. Injury to the median
nerve causes a characteristic fl attening (atrophy) of
the thenar eminence.
GAS 750; GA 403
A 32-year-old woman is admitted to the emergency
department after an automobile collision. Radiographic
examination reveals multiple fractures of the
humerus. Flexion and supination of the forearm are
severely weakened. She also has loss of sensation on
the lateral surface of the forearm. Which of the following
nerves has most likely been injured?
⃣ A. Radial
⃣ B. Musculocutaneous
⃣ C. Median
⃣ D. Lateral cord of brachial plexus
⃣ E. Lateral cutaneous nerve of the forearm
B. The musculocutaneous nerve supplies the biceps
brachii and brachialis, which are the fl exors of the
forearm at the elbow. The musculocutaneous nerve
continues as the lateral antebrachial cutaneous nerve,
which supplies sensation to the lateral side of the forearm
(with the forearm in the anatomic position). The
biceps brachii is the most powerful supinator muscle.
Injury to this nerve would result in weakness of supination
and forearm fl exion and lateral forearm sensory
loss. Injury to the radial nerve would result in weakened
extension and a characteristic wrist drop. Injury to
the median nerve causes paralysis of fl exor digitorum
superfi cialis and other fl exors in the forearm and results
in a characteristic fl attening of the thenar eminence.
The lateral cord of the brachial plexus gives origin both
to the musculocutaneous and lateral pectoral nerves.
There is no indication of pectoral paralysis or weakness.
Injury to the lateral cord can result in weakened fl exion
and supination in the forearm, and weakened adduction
and medial rotation of the arm. The lateral cutaneous
nerve of the forearm is a branch of the musculocutaneous
nerve and does not supply any motor
innervation. Injury to the musculocutaneous nerve
alone is unusual but can follow penetrating injuries.
GAS 720; GA 361, 369-371, 376, 390
A 24-year-old medical student was bitten at the
base of her thumb by her dog. The wound became
infected and the infection spread into the radial
bursa. The tendon(s) of which muscle will most
likely be affected?
⃣ A. Flexor digitorum profundus
⃣ B. Flexor digitorum superfi cialis
⃣ C. Flexor pollicis longus
⃣ D. Flexor carpi radialis
⃣ E. Flexor pollicis brevis
C. Tenosynovitis can be due to an infection of the
synovial sheaths of the digits. Tenosynovitis in the
thumb may spread through the synovial sheath of
the fl exor pollicis longus tendon, also known as the
radial bursa. The tendons of the fl exor digitorum superfi
cialis and profundus muscles are enveloped in
the common synovial fl exor sheath, or ulnar bursa.
Neither the fl exor carpi radialis nor fl exor pollicis brevis
tendons are contained in synovial fl exor sheaths.
GAS 759-761; GA 397-399
Laboratory studies in the outpatient clinic on a
24-year-old female included assessment of circulating
blood chemistry. Which of the following arteries is
most likely at risk during venipuncture at the cubital
fossa?
⃣ A. Brachial
⃣ B. Common interosseous
⃣ C. Ulnar
⃣ D. Anterior interosseous
⃣ E. Radial
A. The three chief contents of the cubital fossa are
the biceps brachii tendon, brachial artery, and median
nerve (lateral to medial). The common and anterior
interosseous arteries arise distal to the cubital fossa; the
ulnar and radial arteries are the result of the bifurcation
of the brachial artery distal to the cubital fossa.
GAS 729; GA 361, 366-368, 380
A 22-year-old male is diagnosed with metastatic
malignant melanoma of the skin over the xiphoid process.
Which nodes receive most of the lymph from this
area and are therefore most likely to be involved in
metastasis of the tumor?
⃣ A. Deep inguinal
⃣ B. Vertical group of superfi cial inguinal
⃣ C. Horizontal group of superfi cial inguinal
⃣ D. Axillary
⃣ E. Deep and superfi cial inguinal
D. Lymph from the skin of the anterior chest
wall primarily drains to the axillary lymph nodes.
GAS 709; GA 12, 133
A 49-year-old female who had suffered a myocardial
infarction must undergo a bypass graft procedure
using the internal thoracic artery. Which vessels will
most likely continue to supply blood to the anterior
part of the upper intercostal spaces?
⃣ A. Musculophrenic
⃣ B. Superior epigastric
⃣ C. Posterior intercostal
⃣ D. Lateral thoracic
⃣ E. Thoracodorsal
C. The anterior intercostal arteries are 12 small
arteries, two in each of the upper six intercostal
spaces at the upper and lower borders. The upper
artery lying in each space anastomoses with the posterior
intercostal arteries, whereas the lower one usually
joins the collateral branch of the posterior intercostal
artery. The musculophrenic artery supplies the
pericardium, diaphragm, and muscles of the abdominal
wall. It anastomoses with the deep circumfl ex iliac
artery. The superior epigastric artery supplies the diaphragm,
peritoneum, and the anterior abdominal wall
and anastomoses with the inferior epigastric artery.
The lateral thoracic artery runs along the lateral border
of the pectoralis minor muscle and supplies the
pectoralis major, pectoralis minor, and serratus anterior.
The thoracodorsal artery accompanies the thoracodorsal
nerve in supplying the latissimus dorsi
muscle and lateral thoracic wall.
GAS 151-155; GA 68
A 22-year-old woman is admitted to the emergency
department in an unconscious state. The nurse
takes a radial pulse to determine the heart rate of the
patient. This pulse is felt lateral to which tendon?
⃣ A. Palmaris longus
⃣ B. Flexor pollicis longus
⃣ C. Flexor digitorum profundus
⃣ D. Flexor carpi radialis
⃣ E. Flexor digitorum superfi cialis
D. The location for palpation of the radial pulse is
lateral to the tendon of the fl exor carpi radialis, where
the radial artery can be compressed against the distal
radius. The radial pulse can also be felt in the anatomic
snuffbox between the tendons of the extensor pollicis
brevis and extensor pollicis longus muscles, where the
radial artery can be compressed against the scaphoid.
GAS 349-377; GA 374, 390, 397-398
A 45-year-old male is admitted to the hospital
after accidentally walking through a plate glass door
in a bar while intoxicated. Physical examination
shows multiple lacerations to the upper limb, with inability
to fl ex the distal interphalangeal joints of the
fourth and fi fth digits. Which of the following muscles
is most likely affected?
⃣ A. Flexor digitorum profundus
⃣ B. Flexor digitorum superfi cialis
⃣ C. Lumbricals
⃣ D. Flexor digitorum profundus and fl exor digitorum
superfi cialis
⃣ E. Interossei
A. The fl exor digitorum profundus is dually innervated
by the ulnar nerve to the medial phalanges
and the median nerve for the lateral phalanges. Because
of the superfi cial course of the ulnar nerve, it is
vulnerable to laceration. Such an injury would result
in an inability to fl ex the distal interphalangeal joints
of the fourth and fi fth digits. The fl exor digitorum
superfi cialis is innervated by the median nerve only,
and the course of this nerve runs too deep to be affected
by lacerations. The lumbricals function to fl ex
the MP joints and assist in extending the IP joints.
The interossei adduct and abduct the fi ngers.
GAS 736; GA 399, 402
A 24-year-old man is admitted with a wound to
the palm of his hand. He cannot touch the pads of his
fi ngers with his thumb but can grip a sheet of paper
between all fi ngers and has no loss of sensation on the
skin of his hand. Which of the following nerves has
most likely been injured?
⃣ A. Deep branch of ulnar
⃣ B. Anterior interosseous
⃣ C. Median
⃣ D. Recurrent branch of median
⃣ E. Deep branch of radial
D. The recurrent branch of the median nerve is
motor to the muscles of the thenar eminence, which
is an elevation caused by the abductor pollicis brevis,
fl exor pollicis brevis, and opponens pollicis. If the opponens
pollicis is paralyzed, one cannot oppose the
pad of the thumb to the pads of the other digits. The
recurrent branch does not have a cutaneous distribution.
Holding a piece of paper between the fi ngers is
a simple test of adduction of the fi ngers. These movements
are controlled by the deep branch of the ulnar
nerve, which is not injured in this patient.
GAS 770, 773; GA 414, 417
A 55-year-old male is examined in a neighborhood
clinic after receiving blunt trauma to his right
axilla in a fall. He has diffi culty elevating the right arm
above the level of his shoulder. Physical examination
shows the inferior angle of his right scapula protrudes
more than the lower part of the left scapula. The right
scapula protrudes far more when the patient pushes
against resistance. Which of the following neural structures
has most likely been injured?
⃣ A. The posterior cord of the brachial plexus
⃣ B. The long thoracic nerve
⃣ C. The upper trunk of the brachial plexus
⃣ D. The site of origin of the middle and lower
subscapular nerves
⃣ E. Spinal nerve roots C7, C8, and T1
B. “Winging” of the scapula occurs when the medial
border of the scapula lifts off the chest wall when
the patient pushes against resistance, such as a wall.
The serratus anterior muscle holds the medial border of
the scapula against the chest wall and is innervated by
the long thoracic nerve. The serratus anterior assists in
abduction of the arm above the horizontal plane.
GAS 690; GA 361
A mother tugs violently on her male child’s hand
to pull him out of the way of an oncoming car and the
child screams in pain. Thereafter, it becomes obvious
that the child cannot straighten his forearm at the elbow.
When the child is seen in the emergency department,
radiographic examination reveals a dislocation of the
head of the radius. Which of the following ligaments is
most likely directly associated with this injury?
⃣ A. Anular
⃣ B. Joint capsular
⃣ C. Interosseous
⃣ D. Radial collateral
⃣ E. Ulnar collateral
A. The anular ligament is a fi brous band that
encircles the head of the radius, forming a collar that
fuses with the radial collateral ligament and articular
capsule of the elbow. The anular ligament functions
to prevent displacement of the head of the radius
from its socket. The joint capsule functions to allow
free rotation of the joint and does not function in its
stabilization. The interosseous membrane is a fi brous
layer between the radius and ulna helping to hold
these two bones together. The radial collateral ligament
extends from the lateral epicondyle to the margins
of the radial notch of the ulnar and the anular
ligament of the radius. The ulnar collateral ligament
is triangular ligament and extends from the medial
epicondyle to the olecranon of the ulna.
GAS 724-729; GA 388
After a forceps delivery of a male infant, the baby
presents with his left upper limb adducted, internally
rotated, and fl exed at the wrist. The startle refl ex is absent
on the ipsilateral side. Which part of the brachial
plexus was most likely injured during this delivery?
⃣ A. Lateral cord
⃣ B. Medial cord
⃣ C. Roots of the lower trunk
⃣ D. Root of the middle trunk
⃣ E. Roots of the upper trunk
E. The injury being described is also known as
Erb-Duchenne paralysis or “waiter’s tip-hand.” This
usually results from an injury to the upper trunk of the
brachial plexus, presenting with loss of abduction,
fl exion, and lateral rotation of the arm. The superior
trunk of the brachial plexus consists of spinal nerve
roots C5-6.
GAS 700-709; GA 361, 369-371
A 35-year-old patient has a small but painful tumor
under the nail of the little fi nger. Which of the
following nerves would have to be anesthetized for a
painless removal of the tumor?
⃣ A. Superfi cial radial
⃣ B. Common palmar digital of median
⃣ C. Common palmar digital of ulnar
⃣ D. Deep radial
⃣ E. Recurrent branch of median
C. The common palmar digital branch comes off
the superfi cial branch of the ulnar nerve and supplies
the skin of the little fi nger and the medial side of the
ring fi nger. The superfi cial branch of the radial nerve
provides cutaneous innervation to the radial (lateral)
dorsum of the hand and the radial two and a half
digits over the proximal phalanx. The common palmar
digital branch of the median nerve innervates
most of the lateral aspect of the palmar hand and the
dorsal aspect of the second and third fi nger as well as
the lateral part of the fourth digit. The deep radial
nerve supplies the extensor carpi radialis brevis and
supinator muscles and continues as the posterior interosseous
nerve. The recurrent branch of the median
nerve supplies the abductor pollicis brevis, fl exor pollicis
brevis, and opponens pollicis muscles.
GAS 744; GA 414
A 25-year-old male athlete is admitted to the
emergency department after a bad landing in the pole
vault. Radiographic examination of his hand reveals a
fractured carpal bone in the fl oor of the anatomic
snuffbox ( Fig. 6-1 ). Which bone has most likely been
fractured?
⃣ A. Triquetral
⃣ B. Scaphoid
⃣ C. Capitate
⃣ D. Hamate
⃣ E. Trapezoid
B. The anatomic snuffbox is formed by the tendons
of the extensor pollicis brevis, the abductor pollicis
longus, and the extensor pollicis longus. The fl oor
is formed by the scaphoid bone, and it is here that one
can palpate for a possible fractured scaphoid.
GAS 752-754; GA 392, 394, 422
A 36-year-old man is brought to the emergency
department because of a deep knife wound on the medial
side of his distal forearm. He is unable to hold a
piece of paper between his fi ngers and has sensory loss
on the medial side of his hand and little fi nger. Which
nerve is most likely injured?
⃣ A. Axillary
⃣ B. Median
⃣ C. Musculocutaneous
⃣ D. Radial
⃣ E. Ulnar
E. The ulnar nerve innervates the palmar interossei,
which adduct the fi ngers. This is the movement
that would maintain the paper between the fi ngers.
The axillary nerve does not innervate muscles of the
hand. The median nerve supplies the fi rst and second
lumbricals, the opponens pollicis, abductor pollicis
brevis, and the fl exor pollicis brevis. None of these
muscles would affect the ability to hold a piece of paper
between the fi ngers. The musculocutaneous and
radial nerves do not supply muscles of the hand.
GAS 661, 706, 720; GA 369-371, 390, 400, 417
A 19-year-old man is brought to the emergency
department after dislocating his shoulder while playing
soccer. Following reduction of the dislocation, he has
pain over the dorsal region of the shoulder and cannot
abduct the arm normally. An MRI of the shoulder
shows a torn muscle. Which of the following muscles
is most likely to have been damaged by this injury?
⃣ A. Coracobrachialis
⃣ B. Long head of the triceps
⃣ C. Pectoralis minor
⃣ D. Supraspinatus
⃣ E. Teres major
D. The supraspinatus is one of the rotator cuff
muscles. Its tendon is relatively avascular and is often
injured when the shoulder is dislocated. This muscle
initiates abduction of the arm, and damage would
impair this movement. The coracobrachialis muscle,
which runs from the coracoid process to the humerus,
functions in adduction and fl exion of the arm. The
triceps’ main function is to extend the elbow, and
damage to its long head would not affect abduction.
The pectoralis minor functions as an accessory respiratory
muscle and to stabilize the scapula and is not
involved in abduction. The teres major functions to
adduct and medially rotate the arm.
GAS 678-680; GA 38-39, 361, 364
A 47-year-old female tennis professional is informed
by her physician that she has a rotator cuff injury
that will require surgery. Her physician explains
that over the years of play a shoulder ligament has
gradually caused severe damage to the underlying
muscle. To which of the following ligaments is the physician
most likely referring?
⃣ A. Acromioclavicular ligament
⃣ B. Coracohumeral ligament
⃣ C. Transverse scapular ligament
⃣ D. Glenohumeral ligament
⃣ E. Coracoacromial ligament
E. The coracoacromial ligament contributes to
the coracoacromial arch, preventing superior displacement
of the head of the humerus. Because this ligament
is very strong, it will rarely be damaged; instead,
the ligament can cause infl ammation or erosion of the
tendon of the supraspinatus muscle as the tendon
passes back and forth under the ligament. The acromioclavicular
ligament, connecting the acromion with
the lateral end of the clavicle, is not in contact with the
supraspinatus tendon. The coracohumeral ligament is
located too far anteriorly to impinge upon the supraspinatus
tendon. The glenohumeral ligament is located
deep to the rotator cuff muscles and would not contribute
to injury of the supraspinatus muscle. The transverse
scapular ligament crosses the scapular notch and
is not in contact with the supraspinatus tendon.
GAS 665; GA 354, 356
A 69-year-old man has numbness in the middle
three digits of his right hand and fi nds it diffi cult to
grasp objects with that hand. He states that he retired
9 years earlier, after working as a carpenter for
50 years. He has atrophy of the thenar eminence ( Fig.
6-2 ). Which of the following conditions is the most
likely cause of the problems in his hand?
⃣ A. Compression of the median nerve in the carpal
tunnel
⃣ B. Formation of the osteophytes that compress
the ulnar nerve at the medial epicondyle
⃣ C. Hypertrophy of the triceps muscle compressing
the brachial plexus
⃣ D. Osteoarthritis of the cervical spine
⃣ E. Repeated trauma to the ulnar nerve
A. The median nerve supplies sensory innervation
to the thumb, index, and middle fi ngers and also
to the lateral half of the ring fi nger. The median nerve
also provides motor innervation to muscles of the thenar
eminence. Compression of the median nerve in the
carpal tunnel explains these defi cits in conjunction
with normal functioning of the fl exor compartment of
the forearm because these muscles are innervated by
the median nerve proximal to the carpal tunnel. The
ulnar nerve is not implicated in these symptoms. It
does not provide sensation to digits 1 to 3. Compression
of the brachial plexus could not be attributed to
pressure from the triceps because this muscle is located
distal to the plexus. In addition, brachial plexus
symptoms would include other upper limb defi cits,
rather than the focal symptoms described in this case.
Osteoarthritis of the cervical spine would also lead to
increasing complexity of symptoms.
GAS 764, 788; GA 406
A 13-year-old boy is brought to the emergency
department after losing control during a motorbike race
in which he was run over by several of the other racers.
Physical examination reveals several cuts and bruises.
He is unable to extend the left wrist, fi ngers, and
thumb, although he can extend the elbow. Sensation is
lost in the lateral half of the dorsum of the left hand.
Which of the following nerves has most likely been
injured to result in these signs, and in what part of the
arm is the injury located?
⃣ A. Median nerve, anterior wrist
⃣ B. Median nerve, arm
⃣ C. Radial nerve, midhumerus
⃣ D. Ulnar nerve, midlateral forearm
⃣ E. Ulnar nerve, midpalmar region
C. The radial nerve innervates the extensor compartments
of the arm and the forearm. It supplies the
triceps brachii proximal to the spiral groove, so elbow
extension is intact here. It also provides sensory innervation to much of the posterior arm and forearm
as well as the dorsal thumb, index, and middle fi ngers
up to the level of the fi ngernails. Symptoms are described
only in the distal limb due to the midhumeral
location of the lesion. The median nerve innervates
fl exors of the forearm and thenar muscles and provides
sensory innervation to the lateral palmar hand.
The ulnar nerve supplies only the fl exor carpi ulnaris
and the medial half of the fl exor digitorum profundus
in the forearm. Additionally, its sensory distribution is
to both the palmar and dorsal aspects of the medial
hand. It does not supply extensor muscles.
GAS 713, 724; GA 361
A 17-year-old male has weakness of elbow fl exion
and supination of the left hand after sustaining a knife
wound in that arm in a street fi ght. Examination in the
emergency department indicates that a nerve has been
severed. Which of the following conditions will also
most likely be seen during physical examination?
⃣ A. Inability to adduct and abduct his fi ngers
⃣ B. Inability to fl ex his fi ngers
⃣ C. Inability to fl ex his thumb
⃣ D. Sensory loss over the lateral surface of his
forearm
⃣ E. Sensory loss over the medial surface of his
forearm
D. The musculocutaneous nerve innervates the
brachialis and biceps brachii muscles, which are the
main fl exors at the elbow. The biceps inserts on
the radius and is an important supinator. Because the
musculocutaneous nerve is damaged in this case, it
leads to loss of sensory perception to the lateral forearm,
which is supplied by the distal portion of the
musculocutaneous nerve (known as the lateral antebrachial
cutaneous nerve). Adduction and abduction of
the fi ngers are mediated by the ulnar nerve and would
not be affected in this instance. The fl exor pollicis brevis
fl exes the thumb and is mainly innervated by the
recurrent branch of the median nerve. Flexion of the
fi ngers is performed by the long fl exors of the fi ngers
and lumbrical muscles, innervated by the median and
ulnar nerves. Sensory innervation of the medial forearm
is provided by the medial antebrachial cutaneous nerve,
a branch of the medial cord of the brachial plexus.
GAS 744; GA 424-425
Following several days of 12-hour daily rehearsals
of the symphony orchestra for a performance of a Wagnerian
opera, the 52-year-old male conductor experienced
such excruciating pain in the posterior aspect of
his right forearm that he could no longer direct the
musicians. When the maestro’s forearm was palpated
2 cm distal to, and posteromedial to, the lateral epicondyle,
the resulting excruciating pain caused the conductor
to weep. Injections of steroids and rest were
recommended to ease the pain. Which of the following
injuries is most likely?
⃣ A. Compression of the ulnar nerve by the fl exor
carpi ulnaris
⃣ B. Compression of the median nerve by the pronator
teres
⃣ C. Compression of the median nerve by the
fl exor digitorum superfi cialis
⃣ D. Compression of the superfi cial radial nerve by
the brachioradialis
⃣ E. Compression of the deep radial nerve by the
supinator
E. The deep radial nerve courses between the two
heads of the supinator and is located just medial and
distal to the lateral epicondyle. It can be irritated by
hypertrophy of the supinator, which compresses the
nerve, causing pain and weakness. The ulnar nerve
courses laterally behind the medial epicondyle and continues
anterior to the fl exor carpi ulnaris. The median
nerve passes into the forearm fl exor compartment; the
superfi cial radial nerve courses down the lateral aspect
of the posterior forearm and would not cause pain due
to pressure applied to the posterior forearm.
GAS 747; GA 390
A 54-year-old female marathon runner presents
with pain in her right wrist that resulted when she fell
with force on her outstretched hand. Radiographic
studies indicate an anterior dislocation of a carpal bone
( Fig. 6-3 ). Which of the following bones is most likely
dislocated?
⃣ A. Capitate
⃣ B. Lunate
⃣ C. Scaphoid
⃣ D. Trapezoid
⃣ E. Triquetrum
B. The lunate is the most commonly dislocated
carpal bone because of its shape and relatively weak
ligaments anteriorly. Dislocations of the scaphoid and
triquetrum are relatively rare. The trapezoid and capitate
bones are located in the distal row of the carpal
bones.
GAS 752-754; GA 392, 394, 422
A 45-year-old man is admitted to the hospital after
a car crash. Radiographic examination reveals mild
disk herniations of C7, C8, and T1. The patient presents
with a sensory defi cit of the C8 and T1 spinal
nerve dermatomes. The dorsal root ganglia of C8 and
T1 would contain cell bodies of sensory fi bers carried
by which of the following nerves?
⃣ A. Medial antebrachial cutaneous nerve
⃣ B. Long thoracic nerve
⃣ C. Lateral antebrachial cutaneous nerve
⃣ D. Deep branch of ulnar nerve
⃣ E. Anterior interosseous nerve
A. The medial antebrachial cutaneous nerve
carries sensory fi bers derived from the C8 and T1
levels. The lateral antebrachial cutaneous nerve is the
distal continuation of the musculocutaneous nerve,
carrying fi bers from the C5, C6, and C7 levels. The
deep branch of the ulnar nerve and the anterior interosseous
nerves carry predominantly motor fi bers. The
sensory fi bers coursing in the radial nerve are derived
from the C5 to C8 levels.
GAS 700-709; GA 361, 369-371
A 23-year-old female maid was making a bed in a
hotel bedroom. As she straightened the sheet by running
her right hand over the surface with her fi ngers
extended, she caught the end of the index fi nger in a
fold. She experienced a sudden, severe pain over the
base of the terminal phalanx. Several hours later when
the pain had diminished, she noted that the end of her
right index fi nger was swollen and she could not completely
extend the terminal interphalangeal joint. Which
one of the following structures within the digit was
most likely injured?
⃣ A. The proper palmar digital branch of the median
nerve
⃣ B. The vinculum longa
⃣ C. The insertion of the tendon of the extensor
digitorum onto the base of the distal phalanx
⃣ D. The insertion of the fl exor digitorum profundus
tendon
⃣ E. The insertion of the fl exor digitorum superfi -
cialis tendon
C. The contraction of the extensor mechanism
produces extension of the distal interphalangeal joint.
When it is torn from the distal phalanx, the digit is
pulled into fl exion by the fl exor digitorum profundus.
The proper palmar digital branches of the median
nerve supply lumbrical muscles and carry sensation
from their respective digits. Vincula longa are slender,
bandlike connections from the deep fl exor tendons to
the phalanx that can carry blood supply to the tendons.
The insertions of the fl exor digitorum superfi -
cialis and profundus are on the fl exor surface of the
middle and distal phalanges, respectively, and act to
fl ex the interphalangeal joints.
GAS 745-747; GA 378, 401
A 45-year-old patient had fallen upon his outstretched
hand, resulting in a Smith fracture of the
distal end of the radius. The fractured bone displaced a
carpal bone in the palmar direction, resulting in nerve
compression within the carpal tunnel. Which of the
following carpal bones will most likely be dislocated?
⃣ A. Scaphoid
⃣ B. Trapezium
⃣ C. Capitate
⃣ D. Hamate
⃣ E. Lunate
E. In a Smith fracture, the distal fragment of the
radius deviates palmarward, often displacing the lunate
bone. The other listed bones are unlikely to be
displaced in a palmar direction by a Smith fracture.
GAS 752-754; GA 392, 394, 422
A 15-year-old girl was brought to the emergency
department with a tear of the tendons in the fi rst dorsal
compartment of the wrist from a severe bite by a pit
bull dog. The injured tendons in this compartment
would include which of the following muscles?
⃣ A. Extensor carpi radialis longus and brevis
⃣ B. Abductor pollicis longus and extensor pollicis
brevis
⃣ C. Extensor digitorum
⃣ D. Extensor indicis proprius
⃣ E. Extensor carpi ulnaris
B. The abductor pollicis longus and extensor
pollicis brevis are the occupants of the fi rst dorsal
compartment of the wrist. The extensor carpi radialis
longus and brevis are in the second compartment.
The extensor digitorum is in the third compartment,
as is the extensor indicis proprius. The extensor carpi
ulnaris is located in the sixth dorsal compartment.
GAS 748-749; GA 401-402, 412-413
As she fell from the uneven parallel bars, the 17-
year-old female gymnast grasped the lower bar briefl y
with one hand but then fell painfully to the fl oor. An
MRI examination reveals an injury to the medial cord
of the brachial plexus. Which of the following spinal
nerve levels would most likely be affected?
⃣ A. C5, C6
⃣ B. C6, C7
⃣ C. C7, C8
⃣ D. C7, C8, T1
⃣ E. C8, T1
E. The medial cord has been injured by traction
on the lower trunk of the brachial plexus. The medial
cord is the continuation of the inferior (lower) trunk
of the brachial plexus, which is formed by C8 and T1.
C5 and C6 are typically associated with the superior
(upper) trunk level and thus the lateral cord. C7 forms
the middle trunk. An injury to the posterior cord
would usually involve the C7 spinal nerve. This is a
typical Klumpke paralysis.
GAS 700-709; GA 361, 369-371
A 21-year-old female softball pitcher is examined
in the emergency department after she was struck in
the arm by a line drive (a ball hit very hard and low).
Radiographic and MRI studies show soft tissue injury
to the region of the spiral groove, with trauma to the
radial nerve. Which of the following muscles would be
intact after this injury?
⃣ A. Flexor carpi ulnaris
⃣ B. Extensor indicis
⃣ C. Brachioradialis
⃣ D. Extensor carpi radialis
⃣ E. Supinator
A. The fl exor carpi ulnaris muscle is not innervated
by the radial nerve but rather by the ulnar
UPPER LIMB
195
nerve. The brachioradialis, extensor carpi radialis,
and supinator muscles are all innervated by the radial
nerve distal to the spiral groove.
GAS 737-739; GA 378, 390, 397, 398
Examination of a 21-year-old female athlete with
an injury of the radial nerve in the spiral groove would
typically demonstrate which of the following physical
signs?
⃣ A. Weakness of thumb abduction and thumb
extension
⃣ B. Weakness of thumb opposition
⃣ C. Inability to extend the elbow
⃣ D. Paralysis of pronation of the hand
⃣ E. Paralysis of abduction and adduction of
the arm
A. Injury to the radial nerve in the spiral groove
will paralyze the abductor pollicis longus and both
extensors of the thumb. This injury will also lead to
wrist drop (inability to extend the wrist). Weakness of
grip would also occur, although this is not mentioned
in the question. If the wrist is fl exed, fi nger fl exion
and grip strength are weakened because the long
fl exor tendons are not under tension. Note how much
your strength of grip is increased when your wrist is
extended versus when it is fl exed.
GAS 661, 709, 722-724; GA 366, 371
The 58-year-old convenience store operator had
received a superfi cial bullet wound to the soft tissues on
the medial side of the elbow in an attempted robbery. A
major nerve was repaired at the site where it passed
behind the medial epicondyle. Bleeding was stopped
from an artery that accompanied the nerve in its path
toward the epicondyle. Vascular repair was performed
on this small artery because of its important role in supplying
blood to the nerve. Which of the following arteries
was most likely repaired?
⃣ A. The profunda brachii
⃣ B. The radial collateral artery
⃣ C. The superior ulnar collateral artery
⃣ D. The inferior ulnar collateral artery
⃣ E. The anterior ulnar recurrent artery
C. The superior ulnar collateral branch of the
brachial artery accompanies the ulnar nerve in its path
posterior to the medial epicondyle and is important in
the blood supply of the nerve. The profunda brachii
passes down the arm with the radial nerve. The radial
collateral artery arises from the profunda brachii and
anastomoses with the radial recurrent branch of the
radial artery proximal to the elbow laterally. The inferior
ulnar collateral artery arises from the brachial artery
and accompanies the median nerve into the forearm.
The anterior ulnar recurrent artery arises from the
ulnar artery and anastomoses with the inferior ulnar
collateral anterior to the elbow.
GAS 743, 767-769; GA 368
A 60-year-old male butcher accidentally slashed
his wrist with his butcher knife, partially dividing the
ulnar nerve. Which of the following actions would
most likely be lost as a result of this injury?
⃣ A. Flexion of the proximal interphalangeal joint
of the fi fth digit (little fi nger)
⃣ B. Extension of the thumb
⃣ C. Adduction of the fi fth digit
⃣ D. Abduction of the thumb
⃣ E. Opposition of the thumb
C. Adduction of the fi fth digit is produced by
contraction of the third palmar interosseous muscle.
All of the interossei are innervated by the deep branch
of the ulnar nerve. Flexion of the proximal interphalangeal
joint is a function of the fl exor digitorum superfi
cialis, supplied by the median nerve. Opposition
of the thumb is a function of the opponens pollicis,
supplied by the recurrent branch of the median
nerve.
GAS 729, 772-774; GA 414
A 23-year-old male medical student fell asleep in
his chair with Netter’s Atlas wedged into his axilla.
When he awoke in the morning, he was unable to extend
the forearm, wrist, or fi ngers. Movements of the
ipsilateral shoulder joint appear to be normal. Which of
UPPER LIMB
175
the following nerves was most likely compressed, producing
the symptoms described?
⃣ A. Lateral cord of the brachial plexus
⃣ B. Medial cord of the brachial plexus
⃣ C. Radial nerve
⃣ D. Median nerve
⃣ E. Lateral and medial pectoral nerves
C. The radial nerve is the most likely nerve compressed
to cause these symptoms. This type of nerve
palsy is often called “Saturday night palsy.” One reason
for this nickname is that people would supposedly
fall asleep after being intoxicated on a Saturday
night with their arm over the back of a chair, thereby
compressing the nerve in the spiral groove. The radial
nerve innervates all of the extensors of the elbow,
wrist, and fi ngers. Paralysis of the lateral cord of the
brachial plexus would result in loss of the musculocutaneous
nerve and the pectoral nerves, which do not
mediate extension of the forearm or hand. The medial
cord of the brachial plexus branches into the median
nerve and ulnar nerve. Neither of these nerves innervates
muscles that control extension. The median
nerve innervates fl exors of the forearm and the thenar
muscles. The lateral and median pectoral nerves do
not extend into the arm and innervate the pectoralis
major and minor muscles.
GAS 789-790; GA 366, 371
The fact that the kidneys of a 32-year-old female
patient were failing required that she be placed on dialysis.
However, the search in her upper limb for a
suitable vein was unexpectedly diffi cult. The major
vein on the lateral side of the arm was too small; others
were too delicate. Finally, a vein was found on the medial
side of the arm that passed through the superfi cial
and deep fascia to join veins beside the brachial artery.
Which of the following veins was this?
⃣ A. Basilic
⃣ B. Lateral cubital
⃣ C. Cephalic
⃣ D. Medial cubital
⃣ E. Medial antebrachial
A. The basilic vein can be used for dialysis, especially
when the cephalic vein is judged to be too
small, as in this case. The basilic vein can be elevated
from its position as it passes through the fascia on the
medial side of the arm. The cephalic vein passes more
laterally up the limb. The lateral cubital vein is a
tributary to the cephalic vein, and the medial cubital
vein joins the basilic vein—both rather superfi cial in
position. The medial antebrachial vein courses up the
midline of the forearm (antebrachium) ventrally.
GAS 663, 697, 720, 770; GA 350, 360, 377
A 29-year-old female had sustained a deep laceration
in the proximal part of the forearm. After the
wound is closed, the following functional defi cits are
observed by the neurologist on the service: The fi rst
three digits are in a position of extension and cannot be
fl exed. Digits 4 and 5 are partially fl exed at the metacarpophalangeal
joints and noticeably more fl exed at
the distal interphalangeal joints. Sensation is absent in
the lateral side of the palm and the palmar surfaces of
digits 1 to 3 and half of the fourth digit. Which of the
following nerves has (have) most likely been injured?
⃣ A. Median nerve
⃣ B. Ulnar and median nerve
⃣ C. Ulnar nerve
⃣ D. Radial and ulnar nerve
⃣ E. Radial nerve
A. The patient exhibits the classic “benediction
attitude” of the thumb and fi ngers from injury to the
median nerve proximally in the forearm. The thumb
is somewhat extended (radial supplied abductor and
extensors unopposed); digits 2 and 3 are extended
(by intact interossei); digits 4 and 5 are partially
fl exed (by their intact fl exor digitorum profundus). A
lesion of the median nerve would result in weakened
fl exion of the PIP joints of all digits (fl exor digitorum
superfi cialis), loss of fl exion of the interphalangeal
joint of the thumb, the DIP joints of digits 2 and 3
(fl exor digitorum profundus), and weakened fl exion
of the metacarpophalangeal joints of the second and
third digits (fi rst and second lumbricals). A lesion of
both the ulnar and median nerves would cause
weakness or paralysis of fl exion of all of the digits.
A lesion of the ulnar nerve would mostly cause
weakness in fl exion of the DIP of the fourth and fi fth
digits and would affect all of the interosseous muscles
and the lumbricals of the third and fourth digits.
A lesion of the radial nerve would cause weakness
in extension of the wrist, thumb, and metacarpophalangeal
joints.
GAS 724, 789-790; GA 371, 376
A 35-year-old male wrestler is admitted to the
emergency department with excruciating pain in his
right shoulder and proximal arm. During physical examination
the patient clutches the arm at the elbow with
his opposite hand and is unable to move the injured
limb. Radiographic studies show that the patient has a
dislocation of the humerus at the glenohumeral joint.
Which of the following conditions is the most likely?
⃣ A. The head of the humerus is displaced
anteriorly.
⃣ B. The head of the humerus is displaced
posteriorly.
⃣ C. The head of the humerus is displaced
inferiorly.
⃣ D. The head of the humerus is displaced
superiorly.
⃣ E. The head of the humerus is displaced
medially.
C. The head of the humerus is displaced inferiorly
because in that location it is not supported by
rotator cuff muscle tendons or the coracoacromial
arch. It is also pulled anteriorly beneath the coracoid
process by pectoralis and subscapularis muscles. It
would not be displaced posteriorly because it is supported
by the teres minor and infraspinatus muscle
tendons. It would not be displaced superiorly because
the acromioclavicular ligament and supraspinatus reinforce
in that direction. A medial dislocation is
blocked by the subscapularis tendon.
GAS 667; GA 355
The 35-year-old female patient has a hard nodule
about 1 cm in diameter slightly above and lateral to her
right areola. A specifi c dye is injected into the tissue
around the tumor, and an incision is made to expose
the lymphatic vessels draining the area, for the lymphatic
vessels take up the dye—which is visible to the
eye. The vessels can then be traced to surgically expose
the lymph nodes receiving the lymph from the tumor.
Which of the following nodes will most likely fi rst encounter
the lymph from the tumor?
⃣ A. Anterior axillary (pectoral) nodes
⃣ B. Rotter interpectoral nodes
⃣ C. Parasternal nodes along the internal thoracic
artery and vein
⃣ D. Central axillary nodes
⃣ E. Apical or infraclavicular nodes
A. The anterior axillary (or anterior pectoral)
nodes are the fi rst lymph nodes to receive most of the
lymph from the breast parenchyma, areola, and nipple.
From there, lymph fl ows through central axillary,
apical, and supraclavicular nodes in sequence. Rotter’s
nodes lie between the pectoral muscles and are,
unfortunately, an alternate route in some patients,
speeding the rate of metastasis. The parasternal nodes
receive lymph from the medial part of the breast and
lie along the internal thoracic artery and vein.
GAS 709; GA 63
During a fi ght in a tavern, a 45-year-old male construction
worker received a shallow stab wound from a
broken beer bottle at a point near the middle of the left
posterior triangle of his neck. Upon physical examination
it is observed that the left shoulder is drooping
lower than the right shoulder, and the superior angle of
the scapula juts out slightly. Strength in turning the head
to the right or left appears to be symmetric. Which of the
following nerves is most likely injured?
⃣ A. Suprascapular nerve in the supraspinous fossa
⃣ B. The terminal segment of the dorsal scapular
nerve
⃣ C. The upper trunk of the brachial plexus
⃣ D. The spinal accessory nerve in the posterior
cervical triangle
⃣ E. The thoracodorsal nerve in the axilla
D. The left spinal accessory nerve has been injured
distal to the sternocleidomastoid muscle, resulting
in paralysis of the trapezius, allowing the shoulder
to droop and the superior angle to push out posteriorly.
The sternocleidomastoid muscles are intact, as
demonstrated by symmetry in strength in turning the
head to the right and left. There is no indication of
paralysis of the lateral rotators of the shoulder or elbow
fl exors (suprascapular nerve or upper trunk).
Thoracodorsal nerve injury would result in paralysis
of the latissimus dorsi, an extensor, and medial rotator
of the humerus.
GAS 667, 973-974; GA 370
A 44-year-old woman is diagnosed with radial
nerve palsy. When muscle function is examined at the
metacarpophalangeal (MCP), proximal interphalangeal
(PIP), and distal interphalangeal (DIP) joints, what
fi ndings are most likely to be present?
⃣ A. Inability to abduct the digits at the MCP joint
⃣ B. Inability to adduct the digits at the MCP joint
⃣ C. Inability to extend the MCP joints only
⃣ D. Inability to extend the MCP, PIP, and DIP
joints
⃣ E. Inability to extend the PIP and DIP joints
C. Inability to extend MCP joints. The tendons
of the extensor digitorum and extensor digiti minimi,
innervated by the radial nerve, are responsible for
extension of the MCP, and to a much lesser degree,
the PIP and DIP joints. Abduction and adduction of
the MCP joints are functions of the interossei, all of
which are innervated by the deep ulnar nerve. Extension
of the PIP and DIP joints is performed by the
lumbricals and interossei. The fi rst two lumbricals
are supplied by the median nerve; the other lumbricals
and the interossei, by the deep branch of the
ulnar nerve.
GAS 655; GA 395
A 27-year-old male painter is admitted to the hospital
after falling from a ladder. Physical examination
reveals that the patient is unable to abduct his arm
more than 15 ° and cannot rotate the arm laterally. A
radiographic examination reveals an oblique fracture of
the humerus. He has associated sensory loss over the
shoulder area. Which of the following injuries will
most likely correspond to the symptoms of the physical
examination?
⃣ A. Fracture of the medial epicondyle
⃣ B. Fracture of the glenoid fossa
⃣ C. Fracture of the surgical neck of the humerus
⃣ D. Fracture of the anatomic neck of the humerus
⃣ E. Fracture of the middle third of the humerus
C. Fracture of the surgical neck of the humerus
often injures the axillary nerve, which innervates the
deltoid and teres minor muscles. Abduction of the
humerus between 15 ° and the horizontal is performed
by the deltoid muscle. Lateral rotation of the
humerus is mainly performed by the deltoid muscle,
teres minor, and the infraspinatus. The deltoid and
teres minor are both lost in this case. Fracture of the
glenoid fossa would lead to drooping of the shoulder.
Fracture of the anatomic neck of the humerus will
similarly lead to a drooping of the shoulder but would
not necessarily affect abduction of the humerus. It is
also quite unusual. Fracture of the middle third of the
humerus would most likely injure the radial nerve.
The ulnar nerve would be potentially compromised in
a fracture of the medial epicondyle of the humerus.
GAS 667, 668; GA 355
A 47-year-old female patient’s right breast exhibited
characteristics of peau d’orange; that is, the skin
resembled orange peel. This condition is primarily a
result of which of the following?
⃣ A. Shortening of the suspensory ligaments by
cancer in the axillary tail
⃣ B. Blockage of cutaneous lymphatic vessels
⃣ C. Contraction of the retinacula cutis of the areola
and nipple
⃣ D. Invasion of the pectoralis major by the cancer
⃣ E. Ipsilateral (same side) inversion of the periareolar
skin from ductular cancer
B. When cutaneous lymphatics of the breast are
blocked by cancer, the skin becomes edematous, except
where hair follicles cause small indentations of
the skin, giving an overall resemblance to orange
peel. Shortening of the suspensory ligaments or retinacula
cutis leads to pitting of the overlying skin,
pitting that is intensifi ed if the patient raises her arm
above her head. Invasion of the pectoralis major by
cancer can result in fi xation of the breast, seen upon
elevation of the ipsilateral limb. Inversion of areolar
skin with involvement of the ducts would also be due
to involvement of the retinacula cutis.
GAS 709; GA 381
A 29-year-old female is examined in the emergency
department after falling from her balcony. Radiographic
examination reveals that she has suffered a
broken clavicle, with associated internal bleeding.
Which of the following vessels is most likely to be injured
in clavicular fractures?
⃣ A. Subclavian artery
⃣ B. Cephalic vein
⃣ C. Lateral thoracic artery
⃣ D. Subclavian vein
⃣ E. Internal thoracic artery
D. The subclavian vein traverses between the
clavicle and fi rst rib and is the most superfi cial structure
to be damaged following a fracture of the clavicle.
The subclavian artery runs deep to the subclavian
vein, and though it is in the appropriate location, it
would likely not be damaged because of its deep anatomic
position. The cephalic vein is a tributary to the
axillary vein after ascending on the lateral side of the
arm. Its location within the body is too superfi cial and
lateral to the site of injury. The lateral thoracic artery
is a branch from the axillary artery that runs lateral to
the pectoralis minor. It courses inferior and medial
from its point of origin from the axillary artery, and it
does not maintain a position near the clavicle during
its descent. The internal thoracic artery arises from
the fi rst part of the subclavian artery before descending
deep to the costal cartilages. Its point of origin
from the subclavian artery is lateral to clavicular injury.
Furthermore, its course behind the costal cartilages
is quite medial to the clavicular fracture.
GAS 697, 952, 961, 973, 978; GA 37
A 68-year-old female is examined by the senior
resident in emergency medicine after her fall on a wet
bathroom fl oor in the shopping center. Physical examination
reveals a posterior displacement of the left distal
wrist and hand. Radiographic examination reveals an
oblique fracture of the radius. Which of the following
is the most likely fracture involved in this case?
⃣ A. Colles’ fracture
⃣ B. Scaphoid fracture
⃣ C. Bennett’s fracture
⃣ D. Volkmann’s ischemic contracture
⃣ E. Boxer’s fracture
A. Colles’ fracture is a fracture of the distal end of
the radius. The proximal portion of the radius is displaced
anteriorly, with the distal bone fragment projecting
posteriorly. The displacement of the radius from the
wrist often gives the appearance of a dinner fork, thus
a Colles’ fracture is often referred to as a “dinner fork”
deformity. A scaphoid fracture results from a fracture of
the scaphoid bone and would thus not cause displace-
ment of the radius. This fracture usually occurs at the
narrow aspect (“waist”) of the scaphoid bone. Bennett’s
and boxer’s fractures both result from fractures of the
metacarpals (fi rst and fi fth, respectively). Volkmann’s
ischemic contracture is a muscular deformity that can
follow a supracondylar fracture of the humerus, with
arterial laceration into the fl exor compartment of the
forearm. Ischemia and muscle contracture, with extreme
pain, accompany this fracture.
GAS 734; GA 392
A 34-year-old female skier was taken by ambulance
to the hospital after she struck a tree on the ski slope.
Imaging gives evidence of a shoulder separation. Which
of the following typically occurs in this kind of injury?
⃣ A. Displacement of the head of the humerus
from the glenoid cavity
⃣ B. Partial or complete tearing of the coracoclavicular
ligament
⃣ C. Partial or complete tearing of the coracoacromial
ligament
⃣ D. Rupture of the transverse scapular ligament
⃣ E. Disruption of the glenoid labrum
B. In shoulder separation, either or both the acromioclavicular
and coracoclavicular ligaments can
be partially or completely torn through. The acromioclavicular
joint can be interrupted and the distal end
of the clavicle may deviate upward in a complete
separation, while the upper limb droops away inferiorly,
causing a “step off” that can be palpated and
sometimes observed. Displacement of the head of the
humerus is shoulder dislocation, not separation. The
coracoacromial ligament is not torn in separation (but
it is sometimes used in the repair of the torn coracoclavicular
ligament). Disruption of the glenoid labrum
often accompanies shoulder dislocation.
GAS 669; GA 354
A 22-year-old male construction worker is admitted
to the hospital after he suffers a penetrating injury
to his upper limb from a nail gun. Upon physical examination
the patient is unable to fl ex the distal interphalangeal
joints of digits 4 and 5. What is the most
likely cause of his injury?
⃣ A. Trauma to the ulnar nerve near the trochlea
⃣ B. Trauma to the ulnar nerve at the wrist
⃣ C. Median nerve damage proximal to the pronator
teres
⃣ D. Median nerve damage at the wrist
⃣ E. Trauma to spinal nerve root C8
A. The nail was fi red explosively from the nail
gun and then pierced the ulnar nerve near the coronoid
process of the ulna trochlea of the humerus.
Paralysis of the medial half of the fl exor digitorum
profundus would result (among other signifi cant defi -
cits), with loss of fl exion of the distal interphalangeal
joints of digits 4 and 5. Ulnar trauma at the wrist
would not affect the interphalangeal joints, although
it would cause paralysis of interossei, hypothenar
muscles, etc. Median nerve damage proximal to the
pronator teres would affect proximal interphalangeal
joint fl exion and distal interphalangeal joint fl exion of
digits 2 and 3 as well as thumb fl exion. Median nerve
injury at the wrist would cause loss of thenar muscles
but not long fl exors of the fi ngers. Trauma to spinal
nerve root C8 would affect all long fi nger fl exors.
GAS 729, 771; GA 376, 390
The shoulder of a 44-year-old deer hunter had
been penetrated by a bolt released from a crossbow.
The bolt had transected the axillary artery just beyond
the origin of the subscapular artery. A compress is
placed on the wound with deep pressure. After a clamp
is placed on the bleeding artery, thought is given to the
anatomy of the vessel. What collateral arterial pathways
are available to bypass the site of injury?
⃣ A. Suprascapular with circumfl ex scapular artery
⃣ B. Dorsal scapular with thoracodorsal artery
⃣ C. Posterior humeral circumfl ex artery with deep
brachial artery
⃣ D. Lateral thoracic with brachial artery
⃣ E. Supreme thoracic artery with thoracoacromial
artery
C. The injury has occurred just beyond the third
part of the axillary artery. The only collateral arterial
channel between the third part of the axillary artery
and the brachial artery is that between the posterior
humeral circumfl ex and the ascending branch of the
profunda brachii—and this anastomotic path is often
inadequate to supply the arterial needs of the limb.
The posterior humeral circumfl ex arises from the
third part of the axillary artery. It typically anastomoses
with a variably small, ascending branch of the
profunda brachii branch of the brachial artery. The
suprascapular artery anastomoses with the circumfl ex
scapular deep to the infraspinatus. The dorsal scapular
artery (passing beneath the medial border of the
scapula) has no anastomosis with thoracodorsal
within the scope of the injury. The lateral thoracic
artery has no anastomoses with the brachial artery.
The supreme thoracic artery (from fi rst part of axillary)
has no helpful anastomoses with the thoracoacromial
(second part of axillary).
GAS 683, 696, 697; GA 368
A 17-year-old male suffered the most common of fractures of the carpal bones when he fell on his outstretched hand. Which bone would this be? ⃣ A. Trapezium ⃣ B. Lunate UPPER LIMB 177 ⃣ C. Pisiform ⃣ D. Hamate ⃣ E. Scaphoid
E. The scaphoid (or the older term, navicular)
bone is the most commonly fractured carpal bone.
GAS 752-754; GA 392, 394, 422
A 54-year-old male cotton farmer visits the outpatient
clinic because of a penetrating injury to his forearm
with a baling hook. After the limb is anesthetized,
the site of the wound is opened and fl ushed thoroughly
to remove all debris. The patient is not able to oppose
the tip of the thumb to the tip of the index fi nger, as in
making the OK sign. He is able to touch the tips of the
ring and little fi ngers to the pad of his thumb. What
nerve has most likely been injured?
⃣ A. Median
⃣ B. Posterior interosseous
⃣ C. Radial
⃣ D. Recurrent median
⃣ E. Anterior interosseous
E. The anterior interosseous nerve is a branch of
the median nerve that supplies the fl exor pollicis longus,
the lateral half of the fl exor digitorum profundus,
and the pronator quadratus. If it is injured, fl exion of
the interphalangeal joint of the thumb will be compromised.
The median nerve gives rise to the anterior
interosseous nerve but is not a direct enough answer
as injury to it would result in more widespread effects.
The posterior interosseous nerve supplies extensors
in the forearm, not fl exors. The radial nerve gives
rise to the posterior interosseous nerve and is not associated
with the anterior interosseous nerve; therefore,
it would not have any effect on the fl exors of the
forearm. The recurrent median nerve is also a branch
of the median nerve but supplies the thenar eminence
muscles, and its injury would result in problems with
opposable motion of the thumb.
GAS 743, 751; GA 400
Endoscopic examination of the shoulder of a
62-year-old female clearly demonstrated erosion of the
tendon within the glenohumeral joint. What tendon
was this?
⃣ A. Glenohumeral
⃣ B. Long head of triceps
⃣ C. Long head of biceps
⃣ D. Infraspinatus
⃣ E. Coracobrachialis
C. The tendon of the long head of the biceps
brachii muscle passes through the glenohumeral joint,
surrounded by synovial membrane. The glenohumeral
is a ligament that attaches to the glenoid labrum.
The long head of the triceps arises from the
infraglenoid tubercle, beneath the glenoid fossa. The
infraspinatus tendon passes posterior to the head of
the humerus to insert on the greater tubercle. The
coracobrachialis arises from the coracoid process and
inserts on the humerus.
GAS 694, 715-716, 735; GA 370
The orthopedic surgeon exposed the muscle in
the supraspinous fossa so that she could move it laterally,
in repair of an injured rotator cuff. As she refl ected
the muscle from its bed, an artery was exposed crossing
the ligament that bridges the notch in the superior
border of the scapula. What artery was this?
⃣ A. Subscapular
⃣ B. Transverse cervical
⃣ C. Dorsal scapular
⃣ D. Posterior humeral circumfl ex
⃣ E. Suprascapular
E. The suprascapular artery passes over, and the
suprascapular nerve passes under, the superior transverse
scapular ligament. This ligament bridges the
suprascapular notch in the upper border of the scapula.
The artery and nerve then pass deep to the supraspinatus
muscle, thereafter supplying it and then
passing through the spinoglenoid notch to supply the
infraspinatus. The subscapular artery is a branch of
the third part of the axillary artery; it divides into
circumfl ex scapular and thoracodorsal branches. The
transverse cervical artery courses anterior to this site.
The dorsal scapular artery and nerve pass deep to the
medial border of the scapula. The posterior humeral
circumfl ex branch of the axillary artery passes through
the quadrangular space with the axillary nerve.
GAS 696, 697; GA 366, 368
A 61-year-old man was hit by the cricket bat in
the midhumeral region of his left arm. Physical examination
reveals an inability to extend the wrist and loss
of sensation on a small area of skin on the dorsum of
the hand proximal to the fi rst two fi ngers. What nerve
supplies this specifi c region of the hand?
⃣ A. Radial
⃣ B. Posterior interosseous
⃣ C. Lateral antebrachial cutaneous
⃣ D. Medial antebrachial cutaneous
⃣ E. Dorsal cutaneous of ulnar
A. The patient has suffered injury to the radial
nerve in the midhumeral region. The nerve that provides
sensation to the dorsum of the hand proximal to
the thumb and index fi nger is the superfi cial branch of
the radial nerve. The posterior interosseous nerve supplies
a strip of skin on the back of the forearm and
wrist extensors. The lateral antebrachial cutaneous
nerve is a continuation of the musculocutaneous nerve
and supplies the lateral side of the forearm. The medial
antebrachial cutaneous is a direct branch of the medial
cord and supplies skin of the medial side of the forearm.
The dorsal cutaneous branch of the ulnar nerve
supplies the medial side of the dorsum of the hand.
GAS 772-774; GA 417
