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Nerve & Tendon MCQs

Practice Set 49 of 53

This practice set contains high-yield board review questions covering key concepts in Nerve & Tendon. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 961

Topic: Nerve & Tendon

During elbow arthroscopy, the proximal anteromedial portal is established 2 cm proximal to the medial epicondyle, just anterior to the medial intermuscular septum. Which of the following nerves is at the greatest risk of injury during the establishment of this portal?

. Ulnar nerve
. Median nerve
. Medial antebrachial cutaneous nerve (MACN)
. Musculocutaneous nerve
. Radial nerve

Correct Answer & Explanation

. Medial antebrachial cutaneous nerve (MACN)

Explanation

The proximal anteromedial portal places the medial antebrachial cutaneous nerve (MACN) at greatest risk as it courses through the subcutaneous tissue. The ulnar nerve is posterior to the medial intermuscular septum and is protected provided the portal remains anterior to the septum.

Question 962

Topic: Nerve & Tendon

A 26-year-old weightlifter presents with medial elbow pain and a snapping sensation when flexing and extending the elbow beyond 90 degrees. Examination demonstrates a reproducible palpable 'snap' over the medial epicondyle, accompanied by paresthesias radiating into the ring and small fingers. Which two structures are most likely translocating over the medial epicondyle?

. Median nerve and flexor carpi radialis
. Ulnar nerve and medial head of the triceps
. Ulnar nerve and anconeus epitrochlearis
. Medial antebrachial cutaneous nerve and pronator teres
. Ulnar nerve and long head of the triceps

Correct Answer & Explanation

. Ulnar nerve and medial head of the triceps

Explanation

Snapping triceps syndrome occurs when the ulnar nerve and the medial edge of the medial head of the triceps recurrently dislocate anteriorly over the medial epicondyle during dynamic elbow flexion, causing a palpable double snap and symptoms of ulnar neuritis.

Question 963

Topic: Nerve & Tendon

A 24-year-old weightlifter presents with medial elbow pain, intermittent tingling in the ring and small fingers, and a distinct 'popping' sensation over the medial elbow when actively extending the elbow from a flexed position. Ultrasound dynamically visualizes a structure snapping over the medial epicondyle, dislocating the ulnar nerve. Which anatomic structure is the primary cause of this phenomenon?

. Osborne's ligament
. Arcade of Struthers
. Medial head of the triceps
. Flexor carpi ulnaris fascial band
. Anconeus epitrochlearis

Correct Answer & Explanation

. Medial head of the triceps

Explanation

Snapping triceps syndrome occurs when the medial margin of the medial head of the triceps dislocates over the medial epicondyle during elbow flexion and snaps back during extension. This dynamic impingement frequently causes secondary friction and subluxation of the ulnar nerve, leading to cubital tunnel symptoms.

Question 964

Topic: Nerve & Tendon

During an elbow arthroscopy for the removal of loose bodies, the surgeon establishes the standard anteromedial portal. Which of the following neurological structures is at greatest risk of iatrogenic injury during the creation of this specific portal?

. Radial nerve
. Ulnar nerve
. Median nerve
. Medial antebrachial cutaneous nerve (MABC)
. Posterior interosseous nerve

Correct Answer & Explanation

. Medial antebrachial cutaneous nerve (MABC)

Explanation

The medial antebrachial cutaneous nerve (MABC) is the structure at greatest risk during the establishment of the anteromedial portal. It runs very close to the standard anteromedial portal site (typically 2 cm distal and 2 cm anterior to the medial epicondyle). The median nerve is also at risk if the portal is placed too far anteriorly. The radial nerve is primarily at risk during the creation of the anterolateral portal.

Question 965

Topic: Nerve & Tendon

A 35-year-old male presents with recurrent episodes of a 'popping' sensation over the medial aspect of his elbow during active flexion and extension. He also reports intermittent numbness in his ring and small fingers. Physical examination reveals two distinct palpable 'snaps' over the medial epicondyle as the elbow is flexed from 0 to 120 degrees. What is the most likely diagnosis?

. Isolated ulnar nerve subluxation
. Medial epicondylitis
. Snapping triceps syndrome
. Cubital tunnel syndrome from an anconeus epitrochlearis
. Ulnar collateral ligament insufficiency

Correct Answer & Explanation

. Snapping triceps syndrome

Explanation

Snapping triceps syndrome occurs when both the ulnar nerve and the medial head of the triceps subluxate over the medial epicondyle during elbow flexion. The presence of two distinct snaps—one from the ulnar nerve and the second from the medial head of the triceps—is pathognomonic for snapping triceps syndrome. Isolated ulnar nerve subluxation would typically produce only a single snap.

Question 966

Topic: Nerve & Tendon

A 32-year-old avid cyclist presents with numbness in the volar aspect of his right ring and small fingers, accompanied by weakness of finger abduction. Sensation over the dorsoulnar aspect of his hand is entirely normal. Compression of the ulnar nerve is most likely occurring at which of the following anatomical locations?

. Cubital tunnel
. Zone 1 of Guyon's canal
. Zone 2 of Guyon's canal
. Zone 3 of Guyon's canal
. Arcade of Struthers

Correct Answer & Explanation

. Zone 1 of Guyon's canal

Explanation

The dorsal ulnar sensory branch branches off the ulnar nerve approximately 5-8 cm proximal to the wrist. Because dorsoulnar sensation is spared, the lesion must be at or distal to the wrist (Guyon's canal). The ulnar nerve in Guyon's canal is divided into three zones: Zone 1 is proximal to the bifurcation (contains both motor and sensory fibers), Zone 2 is the deep motor branch, and Zone 3 is the superficial sensory branch. Since both motor (weak finger abduction) and volar sensory (numbness in ring/small fingers) deficits are present, the compression is in Zone 1 of Guyon's canal.

Question 967

Topic: Nerve & Tendon

A patient suffers a severe laceration of the median nerve at the antecubital fossa. During physical examination 3 months later, the patient unexpectedly demonstrates preserved function of several intrinsic hand muscles normally innervated by the ulnar nerve. This phenomenon is best explained by a Martin-Gruber anastomosis, which consists of motor nerve fibers crossing in which specific pattern?

. From the median nerve to the ulnar nerve in the proximal forearm
. From the ulnar nerve to the median nerve in the proximal forearm
. From the median nerve to the ulnar nerve in the palm of the hand
. From the ulnar nerve to the median nerve in the palm of the hand
. From the superficial radial nerve to the ulnar nerve at the wrist

Correct Answer & Explanation

. From the median nerve to the ulnar nerve in the proximal forearm

Explanation

A Martin-Gruber anastomosis is a common anatomical variant (present in about 15% of limbs) where motor nerve branches cross from the median nerve (most commonly from the anterior interosseous nerve branch) to the ulnar nerve in the proximal forearm. These crossing fibers typically innervate intrinsic hand muscles (like the first dorsal interosseous). Riche-Cannieu anastomosis describes a connection between the deep branch of the ulnar nerve and the recurrent motor branch of the median nerve in the hand.

Question 968

Topic: Nerve & Tendon

A 35-year-old woman complains of excruciating, sharp pain in her right ring fingertip, which is markedly exacerbated by cold weather. On exam, there is exquisite point tenderness over the nail matrix and a faint bluish hue beneath the nail plate. Application of a proximal tourniquet to the arm significantly relieves the patient's fingertip pain. What is the name of this diagnostic test?

. Love's pin test
. Hildreth's test
. Froment's sign
. Wartenberg's sign
. Finkelstein's test

Correct Answer & Explanation

. Hildreth's test

Explanation

The patient's symptoms are classic for a glomus tumor, a benign hamartoma of the neuromyoarterial glomus body. The classic triad includes cold hypersensitivity, paroxysmal severe pain, and pinpoint tenderness. Hildreth's test involves inflating a tourniquet proximally to induce ischemia; a positive test occurs when the ischemia temporarily relieves the severe pain of the glomus tumor. Love's pin test utilizes a paperclip or pin to localize the exquisite point tenderness.

Question 969

Topic: Nerve & Tendon

A 22-year-old rugby player sustains an avulsion of the flexor digitorum profundus (FDP) tendon of the ring finger. Imaging and physical exam suggest a Leddy-Packer Type I injury. What is the defining anatomical characteristic and recommended timeframe for management of this specific injury type?

. Tendon retracted to the PIP joint; repair within 3 weeks.
. Tendon retracted into the palm; primary repair within 7-10 days.
. Avulsion with a large bony fragment caught at the A4 pulley; repair within 4 weeks.
. Tendon retracted into the palm; immediate two-stage tendon reconstruction.
. Tendon caught at the A2 pulley; delayed repair at 6 weeks.

Correct Answer & Explanation

. Tendon retracted into the palm; primary repair within 7-10 days.

Explanation

Leddy-Packer Type I injuries involve FDP retraction into the palm. Both the vincula longa and brevia are ruptured, completely compromising the tendon's blood supply. To prevent necrosis and severe contracture, primary repair must be performed within 7-10 days.

Question 970

Topic: Nerve & Tendon

A 45-year-old mechanic presents with cold intolerance, pain, and a pulsatile mass in the hypothenar eminence. An Allen's test indicates delayed capillary refill in the ulnar digits. Ulnar Hammer Syndrome is suspected. This condition involves thrombosis or aneurysm of the ulnar artery resulting from repetitive microtrauma against which bony structure?

. Pisiform
. Scaphoid tubercle
. Hook of hamate
. Lister's tubercle
. Ulnar styloid

Correct Answer & Explanation

. Hook of hamate

Explanation

Ulnar Hammer Syndrome occurs due to repetitive compressive trauma to the ulnar artery within Guyon's canal. The artery is mechanically crushed against the underlying hook of the hamate, which acts as an anvil, leading to thrombosis, intimal damage, or pseudoaneurysm formation.

Question 971

Topic: Nerve & Tendon

A 45-year-old cyclist presents with weakness in thumb adduction and finger abduction/adduction. Sensation over the entire small finger is completely normal, and hypothenar muscle bulk and strength are intact. Which zone of Guyon's canal is the most likely site of ulnar nerve compression?

. Zone 1
. Zone 2, proximal to the hypothenar motor branches
. Zone 2, distal to the hypothenar motor branches
. Zone 3
. Cubital tunnel

Correct Answer & Explanation

. Zone 2, distal to the hypothenar motor branches

Explanation

Guyon's canal is divided into 3 zones. Zone 1 contains the mixed motor/sensory nerve. Zone 2 contains the deep motor branch. Zone 3 contains the superficial sensory branch. A lesion in Zone 2 causes isolated motor weakness. Because the hypothenar muscles are spared, the lesion must be in Zone 2 distal to the takeoff of the hypothenar motor branches, affecting only the interossei and adductor pollicis.

Question 972

Topic: Nerve & Tendon

A 40-year-old man cannot make an 'OK' sign, instead forming a flat pinch between his thumb and index finger pads. His sensation is normal. Which of the following muscles is strictly spared in this specific nerve compression syndrome?

. Flexor pollicis longus (FPL)
. Flexor digitorum profundus (FDP) to the index finger
. Flexor digitorum profundus (FDP) to the middle finger
. Pronator quadratus
. Flexor digitorum superficialis (FDS)

Correct Answer & Explanation

. Flexor digitorum superficialis (FDS)

Explanation

The patient has Anterior Interosseous Nerve (AIN) syndrome, evidenced by the positive 'OK' sign (loss of FPL and FDP to the index finger). The AIN supplies the FPL, the FDP to the index and middle fingers, and the pronator quadratus. The Flexor Digitorum Superficialis (FDS) is innervated by the main branch of the median nerve in the proximal forearm, before the AIN branches off, and is therefore spared.

Question 973

Topic: Nerve & Tendon

A patient with an untreated zone I extensor tendon laceration develops a secondary deformity characterized by PIP joint hyperextension and DIP joint flexion. What is the primary pathoanatomical cause of the PIP hyperextension?

. Rupture of the FDP tendon
. Dorsal subluxation of the lateral bands
. Volar subluxation of the lateral bands
. Proximal retraction of the extensor mechanism and increased tension on the central slip
. Rupture of the volar plate at the DIP joint

Correct Answer & Explanation

. Proximal retraction of the extensor mechanism and increased tension on the central slip

Explanation

An untreated mallet finger can lead to a swan neck deformity. The disrupted terminal extensor tendon allows the entire extensor mechanism to retract proximally, concentrating unchecked extension forces on the central slip, which hyperextends the PIP joint.

Question 974

Topic: Nerve & Tendon

A patient sustains a high ulnar nerve transection at the elbow. During recovery, the claw deformity of the ring and small fingers becomes paradoxically more pronounced. What phenomenon is responsible for this worsening deformity?

. Quadriga effect
. Lumbrical plus finger
. Boutonniere deformity
. Martin-Gruber anastomosis
. Ulnar paradox

Correct Answer & Explanation

. Ulnar paradox

Explanation

The 'ulnar paradox' occurs because a high ulnar nerve injury paralyzes both the intrinsic hand muscles and the FDP to the ring/small fingers, resulting in a mild claw. As the nerve regenerates distally, FDP function returns first, strongly flexing the DIP joints against paralyzed intrinsics, worsening the claw.

Question 975

Topic: Nerve & Tendon

A 22-year-old rugby player is unable to actively flex the distal interphalangeal (DIP) joint of his right ring finger after grabbing an opponent's jersey. MRI demonstrates the flexor digitorum profundus (FDP) tendon retracted completely into the palm. According to the Leddy-Packer classification, what is the expected status of the vincula and the recommended timeframe for surgical repair?

. Vincula intact; repair can be delayed up to 3 months
. Vincula ruptured; repair should be performed within 7-10 days
. Vincula intact; repair should be performed within 7-10 days
. Vincula ruptured; necessitating a planned two-stage tendon graft
. Vincula intact; immediate primary repair within 24 hours is mandatory

Correct Answer & Explanation

. Vincula ruptured; repair should be performed within 7-10 days

Explanation

Retraction of the FDP tendon into the palm defines a Type I Jersey finger, meaning the vincula longus and brevis are ruptured. Due to the compromised blood supply, surgical repair must be performed within 7-10 days to prevent tendon necrosis and myostatic contracture.

Question 976

Topic: Nerve & Tendon

A 55-year-old patient with long-standing rheumatoid arthritis presents with a fixed flexion deformity of the proximal interphalangeal (PIP) joint and hyperextension of the distal interphalangeal (DIP) joint of the right index finger. Which of the following represents the primary pathomechanics of this specific deformity?

. Attenuation of the central slip with volar subluxation of the lateral bands
. Rupture of the terminal extensor tendon with dorsal subluxation of the lateral bands
. Volar plate laxity leading to intrinsic muscle contracture
. Sagittal band rupture allowing the extensor tendon to subluxate into the web space
. Isolated rupture of the flexor digitorum superficialis (FDS) tendon

Correct Answer & Explanation

. Attenuation of the central slip with volar subluxation of the lateral bands

Explanation

The patient has a Boutonniere deformity. In rheumatoid arthritis, synovitis at the PIP joint leads to stretching and attenuation of the central slip. This allows the lateral bands to subluxate volarly below the axis of rotation of the PIP joint, where they act as flexors of the PIP joint while continuing to exert a strong extension force on the DIP joint.

Question 977

Topic: Nerve & Tendon

A 22-year-old rugby player felt a sudden 'pop' in his ring finger while trying to grab an opponent's jersey. Examination shows an inability to actively flex the DIP joint. Radiographs show no fractures, and ultrasound indicates the FDP tendon is retracted into the palm (Leddy-Packer Type I). What is the critical timeframe within which primary repair must be performed?

. Within 7 to 10 days
. Within 3 weeks
. Within 6 weeks
. Within 3 months
. Delayed reconstruction with a tendon graft is primarily indicated immediately

Correct Answer & Explanation

. Within 7 to 10 days

Explanation

A Leddy-Packer Type I 'Jersey finger' involves avulsion of the FDP tendon with retraction all the way into the palm. This disrupts all segmental blood supply (vincula), placing the tendon at high risk for myostatic contracture and avascular necrosis. Primary repair must be performed early, ideally within 7 to 10 days, to allow for successful anatomic reinsertion.

Question 978

Topic: Nerve & Tendon
A 22-year-old rugby player avulses his flexor digitorum profundus (FDP) tendon of the ring finger. On surgical exploration, the tendon is found retracted to the level of the A2 pulley but is held there by an intact vinculum longum. According to the Leddy and Packer classification, what type of injury is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Leddy and Packer classification of FDP avulsion (Jersey finger): Type I: Retracted to the palm (blood supply severed, needs repair within 7-10 days). Type II: Retracted to the A3 pulley/PIP joint level (held by an intact vinculum longum). Type III: Bony fragment avulsed, caught at the A4 pulley. Type IV: Bony avulsion with simultaneous FDP tendon avulsion from the fracture fragment.

Question 979

Topic: Nerve & Tendon

A 50-year-old mechanic presents with pain, cold intolerance, and a pulsatile mass in the hypothenar eminence. An Allen test is abnormal. Angiography reveals an occlusion of the superficial palmar arch. Which structure is most likely acting as the source of repetitive trauma to the affected vessel?

. Hook of the hamate
. Pisiform
. Trapezial ridge
. Scaphoid tubercle
. Styloid process of the ulna

Correct Answer & Explanation

. Hook of the hamate

Explanation

Hypothenar hammer syndrome is caused by repetitive trauma to the ulnar artery as it passes over the hook of the hamate in Guyon's canal. This leads to thrombosis or aneurysm formation of the superficial palmar arch.

Question 980

Topic: Nerve & Tendon

During a surgical release for de Quervain's tenosynovitis, the surgeon must be cautious of anatomical variants. The first dorsal extensor compartment typically contains the Extensor Pollicis Brevis (EPB) and the Abductor Pollicis Longus (APL). What is the most common anatomical variation found within this compartment?

. Absence of the EPB tendon
. Multiple slips of the APL tendon
. Multiple slips of the EPB tendon
. An anomalous extensor indicis proprius tendon
. The presence of a septation separating the EPB and APL in 95% of patients

Correct Answer & Explanation

. Multiple slips of the APL tendon

Explanation

Anatomical variations in the first dorsal compartment are a frequent cause of surgical failure in de Quervain's release. The most common variation is the presence of multiple slips of the APL tendon (present in up to 80% of individuals). A separate subcompartment (septation) for the EPB is present in approximately 40-60% of patients, not 95%.

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