COMSAE PHASE 1 MUSCULOSKELETAL
ANATOMY PRACTICE EXAM WITH ACTUAL
QUESTIONS AND VERIFIED ANSWERS,
PLUS EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Rotator cuff anatomy
A 42-year-old patient develops shoulder pain and difficulty initiating
abduction after repeatedly lifting heavy objects overhead. Physical
examination demonstrates weakness during the first 15° of active
shoulder abduction, while passive range of motion is preserved. MRI
demonstrates a tear involving a rotator cuff tendon that passes beneath
the acromion and inserts on the greater tubercle of the humerus. Which
muscle is most directly affected?
A. Infraspinatus
B. Teres minor
C. Supraspinatus
D. Subscapularis
Answer: C. Supraspinatus
Rationale: The supraspinatus originates from the supraspinous fossa
of the scapula and inserts on the superior facet of the greater tubercle
of the humerus. It initiates the first approximately 15° of shoulder
abduction before the deltoid becomes the major abductor. Its tendon
passes beneath the acromion, making it particularly vulnerable to
impingement and rotator cuff tears. Infraspinatus and teres minor
1
,primarily externally rotate the humerus, whereas subscapularis
internally rotates it.
2. Axillary nerve injury
A patient sustains an anterior shoulder dislocation. Several days later,
examination reveals impaired sensation over the lateral aspect of the
proximal arm and marked weakness with shoulder abduction from
approximately 15° to 90°. Which nerve was most likely injured?
A. Suprascapular nerve
B. Axillary nerve
C. Musculocutaneous nerve
D. Radial nerve
Answer: B. Axillary nerve
Rationale: The axillary nerve travels through the quadrangular space
with the posterior circumflex humeral artery and winds around the
surgical neck of the humerus. It innervates the deltoid and teres minor
and supplies cutaneous sensation over the superior lateral arm via the
superior lateral cutaneous nerve of the arm. Anterior shoulder
dislocation is a classic mechanism of axillary nerve injury.
3. Scapular winging
A patient undergoes lymph-node dissection in the posterior triangle of
the neck and subsequently develops prominent medial displacement of
the scapula when pushing against a wall. Which muscle is most likely
paralyzed?
A. Serratus anterior
B. Rhomboid major
2
,C. Trapezius
D. Levator scapulae
Answer: B. Rhomboid major
Rationale: The rhomboid major and minor retract the scapulae and
contribute to downward rotation. They are innervated by the dorsal
scapular nerve, which can be injured during procedures in the
posterior triangle. Classic medial scapular winging can also result
from serratus anterior paralysis due to long thoracic nerve injury, but
serratus anterior paralysis produces particularly prominent lateral
winging and difficulty pushing the scapula against the thoracic wall.
4. Long thoracic nerve
A 28-year-old athlete develops difficulty raising the arm above the head
after blunt trauma to the lateral thoracic wall. Examination reveals
medial scapular winging that becomes particularly prominent when the
patient pushes against a wall. Which nerve supplies the affected muscle?
A. Dorsal scapular nerve
B. Spinal accessory nerve
C. Long thoracic nerve
D. Suprascapular nerve
Answer: C. Long thoracic nerve
Rationale: The serratus anterior is innervated by the long thoracic
nerve, derived from C5-C7 ventral rami. It holds the scapula against
the thoracic wall and produces scapular protraction and upward
rotation. Injury causes medial winging of the scapula and difficulty
elevating the arm above 90°.
5. Carpal tunnel anatomy
3
, A 55-year-old office worker has nocturnal numbness involving the
thumb, index finger, middle finger, and radial half of the ring finger.
Symptoms worsen when the wrist is flexed. Which structure passes
through the carpal tunnel and is therefore most directly implicated?
A. Ulnar nerve
B. Median nerve
C. Radial nerve
D. Palmar cutaneous branch of the median nerve
Answer: B. Median nerve
Rationale: The carpal tunnel contains the median nerve and nine
flexor tendons: four flexor digitorum superficialis tendons, four flexor
digitorum profundus tendons, and one flexor pollicis longus tendon.
The median nerve supplies sensation to the palmar surface of the
lateral 3½ digits and motor innervation to most thenar muscles. The
palmar cutaneous branch of the median nerve travels superficial to the
flexor retinaculum and is spared in classic carpal tunnel syndrome.
6. Anatomical snuffbox
A 21-year-old cyclist falls on an outstretched hand and develops
tenderness in the anatomical snuffbox. Which bone is most likely
fractured?
A. Lunate
B. Scaphoid
C. Triquetrum
D. Pisiform
Answer: B. Scaphoid
Rationale: The scaphoid forms the floor of the anatomical snuffbox. It
is commonly fractured after a fall onto an outstretched hand. Because
its blood supply enters predominantly distally and travels proximally, a
4
ANATOMY PRACTICE EXAM WITH ACTUAL
QUESTIONS AND VERIFIED ANSWERS,
PLUS EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Rotator cuff anatomy
A 42-year-old patient develops shoulder pain and difficulty initiating
abduction after repeatedly lifting heavy objects overhead. Physical
examination demonstrates weakness during the first 15° of active
shoulder abduction, while passive range of motion is preserved. MRI
demonstrates a tear involving a rotator cuff tendon that passes beneath
the acromion and inserts on the greater tubercle of the humerus. Which
muscle is most directly affected?
A. Infraspinatus
B. Teres minor
C. Supraspinatus
D. Subscapularis
Answer: C. Supraspinatus
Rationale: The supraspinatus originates from the supraspinous fossa
of the scapula and inserts on the superior facet of the greater tubercle
of the humerus. It initiates the first approximately 15° of shoulder
abduction before the deltoid becomes the major abductor. Its tendon
passes beneath the acromion, making it particularly vulnerable to
impingement and rotator cuff tears. Infraspinatus and teres minor
1
,primarily externally rotate the humerus, whereas subscapularis
internally rotates it.
2. Axillary nerve injury
A patient sustains an anterior shoulder dislocation. Several days later,
examination reveals impaired sensation over the lateral aspect of the
proximal arm and marked weakness with shoulder abduction from
approximately 15° to 90°. Which nerve was most likely injured?
A. Suprascapular nerve
B. Axillary nerve
C. Musculocutaneous nerve
D. Radial nerve
Answer: B. Axillary nerve
Rationale: The axillary nerve travels through the quadrangular space
with the posterior circumflex humeral artery and winds around the
surgical neck of the humerus. It innervates the deltoid and teres minor
and supplies cutaneous sensation over the superior lateral arm via the
superior lateral cutaneous nerve of the arm. Anterior shoulder
dislocation is a classic mechanism of axillary nerve injury.
3. Scapular winging
A patient undergoes lymph-node dissection in the posterior triangle of
the neck and subsequently develops prominent medial displacement of
the scapula when pushing against a wall. Which muscle is most likely
paralyzed?
A. Serratus anterior
B. Rhomboid major
2
,C. Trapezius
D. Levator scapulae
Answer: B. Rhomboid major
Rationale: The rhomboid major and minor retract the scapulae and
contribute to downward rotation. They are innervated by the dorsal
scapular nerve, which can be injured during procedures in the
posterior triangle. Classic medial scapular winging can also result
from serratus anterior paralysis due to long thoracic nerve injury, but
serratus anterior paralysis produces particularly prominent lateral
winging and difficulty pushing the scapula against the thoracic wall.
4. Long thoracic nerve
A 28-year-old athlete develops difficulty raising the arm above the head
after blunt trauma to the lateral thoracic wall. Examination reveals
medial scapular winging that becomes particularly prominent when the
patient pushes against a wall. Which nerve supplies the affected muscle?
A. Dorsal scapular nerve
B. Spinal accessory nerve
C. Long thoracic nerve
D. Suprascapular nerve
Answer: C. Long thoracic nerve
Rationale: The serratus anterior is innervated by the long thoracic
nerve, derived from C5-C7 ventral rami. It holds the scapula against
the thoracic wall and produces scapular protraction and upward
rotation. Injury causes medial winging of the scapula and difficulty
elevating the arm above 90°.
5. Carpal tunnel anatomy
3
, A 55-year-old office worker has nocturnal numbness involving the
thumb, index finger, middle finger, and radial half of the ring finger.
Symptoms worsen when the wrist is flexed. Which structure passes
through the carpal tunnel and is therefore most directly implicated?
A. Ulnar nerve
B. Median nerve
C. Radial nerve
D. Palmar cutaneous branch of the median nerve
Answer: B. Median nerve
Rationale: The carpal tunnel contains the median nerve and nine
flexor tendons: four flexor digitorum superficialis tendons, four flexor
digitorum profundus tendons, and one flexor pollicis longus tendon.
The median nerve supplies sensation to the palmar surface of the
lateral 3½ digits and motor innervation to most thenar muscles. The
palmar cutaneous branch of the median nerve travels superficial to the
flexor retinaculum and is spared in classic carpal tunnel syndrome.
6. Anatomical snuffbox
A 21-year-old cyclist falls on an outstretched hand and develops
tenderness in the anatomical snuffbox. Which bone is most likely
fractured?
A. Lunate
B. Scaphoid
C. Triquetrum
D. Pisiform
Answer: B. Scaphoid
Rationale: The scaphoid forms the floor of the anatomical snuffbox. It
is commonly fractured after a fall onto an outstretched hand. Because
its blood supply enters predominantly distally and travels proximally, a
4
