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7. Hand and Wrist MCQs

Practice Set 154 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 3061

Topic: 7. Hand and Wrist

A patient presents with ulnar-sided wrist pain, particularly with pronation, supination, and gripping. MRI reveals a tear within the Triangular Fibrocartilage Complex (TFCC). Which carpal bone articulates directly with the articular disc (TFC proper) of the TFCC?

. Scaphoid
. Lunate
. Triquetrum
. Hamate
. Capitate

Correct Answer & Explanation

. Scaphoid

Explanation

The articular disc (TFC proper) of the TFCC is a biconcave, triangular structure that separates the distal ulna from the carpus. It articulates directly with the triquetrum and also with the lunate to a lesser extent, forming the ulnocarpal joint. The scaphoid and lunate articulate primarily with the distal radius. The hamate articulates with the 4th and 5th metacarpals and partially with the triquetrum, but not directly with the TFC articular disc. The capitate is centrally located. Therefore, the triquetrum is the primary carpal bone articulating directly with the articular disc.

Question 3062

Topic: 7. Hand and Wrist

Dupuytren's contracture involves progressive fibrosis and shortening of the palmar fascia. Which specific anatomical structure is primarily affected in this condition, leading to flexion contractures of the digits?

. Flexor digitorum superficialis tendons
. Flexor digitorum profundus tendons
. Palmar aponeurosis and its digital extensions
. Lumbrical muscles
. Interossei muscles

Correct Answer & Explanation

. Flexor digitorum superficialis tendons

Explanation

Dupuytren's contracture is a fibrotic disorder characterized by the thickening and shortening of the palmar aponeurosis and its extensions (pretendinous bands, natatory ligaments, spiral bands, etc.). This leads to flexion contractures, most commonly affecting the ring and little fingers. It is a disease of the superficial fascia, not the underlying flexor tendons or intrinsic muscles. The contractures result from nodules and cords forming within these fascial structures. The flexor tendons and intrinsic muscles are typically not primarily involved, although their function may be impaired secondarily by the contracture.

Question 3063

Topic: Nerve & Tendon

During surgical exposure of the medial epicondyle for ulnar nerve transposition, the surgeon identifies various muscle attachments. Which of the following muscles does not originate from the common flexor tendon of the medial epicondyle?

. Pronator teres
. Flexor carpi radialis
. Palmaris longus
. Flexor digitorum superficialis
. Flexor pollicis longus

Correct Answer & Explanation

. Pronator teres

Explanation

The common flexor tendon (CFT) originates from the medial epicondyle of the humerus and serves as the origin for five muscles: pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis (humeral head), and flexor carpi ulnaris (humeral head). The flexor pollicis longus (FPL) originates from the anterior surface of the radius and the interosseous membrane, not from the medial epicondyle. Therefore, FPL is the correct answer.

Question 3064

Topic: 7. Hand and Wrist

A patient presents with wrist pain and a palpable mass in the distal forearm. Physical examination reveals a ganglion cyst associated with the flexor carpi radialis (FCR) tendon. Which of the following structures is the FCR tendon enclosed by a distinct synovial sheath, unlike the flexor carpi ulnaris (FCU)?

. Transverse carpal ligament
. Extensor retinaculum
. Radial bursa
. Ulnar bursa
. Its own separate synovial sheath

Correct Answer & Explanation

. Transverse carpal ligament

Explanation

The flexor carpi radialis (FCR) tendon has its own distinct synovial sheath as it passes through a separate tunnel within the flexor retinaculum and then over the trapezium. In contrast, the flexor carpi ulnaris (FCU) tendon typically does not have a synovial sheath where it passes superficial to the flexor retinaculum, although its distal insertion onto the pisiform and fifth metacarpal may have some associated bursae. The radial bursa (for FPL) and ulnar bursa (for FDS/FDP tendons) are larger synovial sheaths for other flexor tendons within the carpal tunnel. The extensor retinaculum is on the dorsal side.

Question 3065

Topic: Nerve & Tendon

A patient presents with insidious onset of pain and paresthesias in the dorsoradial forearm, exacerbated by repetitive pronation and supination. Examination reveals tenderness over the supinator muscle. Which nerve is most commonly entrapped in the 'radial tunnel' in this scenario?

. Superficial radial nerve
. Median nerve
. Anterior interosseous nerve
. Posterior interosseous nerve (PIN)
. Ulnar nerve

Correct Answer & Explanation

. Superficial radial nerve

Explanation

Radial tunnel syndrome involves compression of the radial nerve or its deep branch, the posterior interosseous nerve (PIN), within the radial tunnel. The radial tunnel is a potential space from the radiocapitellar joint to the distal edge of the supinator muscle. The PIN is particularly vulnerable as it passes through the arcade of Frohse, the most proximal part of the supinator muscle. Symptoms include pain in the dorsoradial forearm, often without motor weakness initially, distinguishing it from PIN palsy. The superficial radial nerve is sensory. The median and ulnar nerves are on the anterior and medial aspects of the forearm, respectively.

Question 3066

Topic: 7. Hand and Wrist

A patient presents with a painful mass in the wrist, often described as a 'ganglion.' If this cyst arises from the radiocarpal joint capsule on the volar aspect, displacing the radial artery radially, what specific location is it most likely to be?

. Dorsal wrist ganglion
. Scapholunate ganglion
. Volar wrist ganglion (from radiocarpal joint)
. Flexor tendon sheath ganglion
. Carpometacarpal joint ganglion

Correct Answer & Explanation

. Dorsal wrist ganglion

Explanation

Volar wrist ganglions are common and typically arise from the volar aspect of the radiocarpal joint capsule. They are often located on the radial side of the volar wrist crease, proximal to the thenar eminence, and characteristically displace the radial artery radially. Dorsal wrist ganglions arise from the dorsal radiocarpal joint. Scapholunate ganglions are a type of dorsal ganglion. Flexor tendon sheath ganglions are in the palm. Carpometacarpal joint ganglions are typically dorsal and distal. The description points directly to a volar wrist ganglion from the radiocarpal joint.

Question 3067

Topic: 7. Hand and Wrist

A 32-year-old professional cyclist presents with severe intrinsic muscle weakness in his right hand and numbness isolated to his small finger and the ulnar half of his ring finger. The surgeon plans an operative decompression of Guyon's canal. Which of the following structures forms the floor of Guyon's canal?

. Volar carpal ligament
. Palmaris brevis muscle
. Transverse carpal ligament
. Flexor carpi ulnaris tendon
. Palmar aponeurosis

Correct Answer & Explanation

. Volar carpal ligament

Explanation

Guyon's canal (the ulnar tunnel) contains the ulnar nerve and artery at the wrist. Its floor is formed by the transverse carpal ligament (flexor retinaculum) and the pisohamate ligament. The roof is formed by the volar carpal ligament and the palmaris brevis muscle.

Question 3068

Topic: 7. Hand and Wrist

A 28-year-old skier presents with an acute Stener lesion following a fall on an abducted thumb. Operative repair of the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (MCP) joint is performed. During the exposure, which specific structure is identified as being interposed between the torn, proximally retracted UCL and its anatomical insertion at the base of the proximal phalanx?

. Adductor pollicis aponeurosis
. Abductor pollicis brevis tendon
. Flexor pollicis longus tendon
. Extensor pollicis brevis tendon
. Volar plate

Correct Answer & Explanation

. Adductor pollicis aponeurosis

Explanation

A Stener lesion occurs when the distal attachment of the ulnar collateral ligament (UCL) of the thumb is avulsed and becomes displaced superficial to the adductor pollicis aponeurosis. This interposition prevents spontaneous healing of the ligament to the proximal phalanx, necessitating surgical repair.

Question 3069

Topic: 7. Hand and Wrist

A 28-year-old carpenter sustains a deep volar laceration over the proximal phalanx of his index finger, transecting the flexor digitorum profundus (FDP) tendon. During the repair, the surgeon evaluates the lumbrical muscles for integrity. Unlike the third and fourth lumbricals, the first lumbrical originates exclusively from which of the following structures?

. The adjacent sides of the index and long finger FDP tendons
. The radial side of the index finger FDP tendon
. The ulnar side of the index finger FDP tendon
. The transverse carpal ligament
. The flexor digitorum superficialis tendon of the index finger

Correct Answer & Explanation

. The adjacent sides of the index and long finger FDP tendons

Explanation

The lumbrical muscles originate from the tendons of the flexor digitorum profundus (FDP). The first and second lumbricals are unipennate and originate from the radial sides of the index and long finger FDP tendons, respectively. They are innervated by the median nerve. The third and fourth lumbricals are bipennate, originating from the adjacent sides of the long/ring and ring/small finger FDP tendons, and are innervated by the ulnar nerve.

Question 3070

Topic: Wrist & Carpus

A 24-year-old elite gymnast presents with ulnar-sided wrist pain after a fall. An MR arthrogram demonstrates a Palmer Class 1A tear in the central articular disc of the triangular fibrocartilage complex (TFCC). Following a failed trial of conservative management, arthroscopic debridement is planned instead of primary repair. What is the fundamental anatomical rationale for debriding rather than repairing this specific type of tear?

. Central tears destabilize the distal radioulnar joint (DRUJ) requiring bony reconstruction.
. The central portion of the TFCC is avascular and lacks healing capacity.
. The central portion is highly vascularized leading to exuberant, painful scarring if sutured.
. Repair of the central portion inherently restricts forearm pronation and supination.
. Central tears are invariably associated with ulnar minus variance, negating repair efficacy.

Correct Answer & Explanation

. Central tears destabilize the distal radioulnar joint (DRUJ) requiring bony reconstruction.

Explanation

The vascular supply to the TFCC is derived primarily from the ulnar artery branches, supplying only the peripheral 10% to 20% of the complex. The central articular disc is completely avascular and relies on synovial fluid for nutrition. Consequently, central tears (Palmer Class 1A) have no inherent healing potential and are treated with arthroscopic debridement, whereas peripheral tears (Palmer Class 1B) are well-vascularized and amenable to primary surgical repair.

Question 3071

Topic: 7. Hand and Wrist

A 38-year-old carpenter presents with a deep space infection of the hand following a penetrating injury. Purulent fluid is found communicating between the flexor tendon sheaths of the thumb and the small finger, creating a 'horseshoe abscess.' This proximal communication occurs in Parona's space. What are the specific anatomical boundaries that define the floor (dorsal aspect) and the roof (volar aspect) of Parona's space in the distal forearm?

. Floor: Pronator quadratus; Roof: Flexor digitorum profundus tendons
. Floor: Interosseous membrane; Roof: Flexor digitorum superficialis tendons
. Floor: Flexor pollicis longus; Roof: Transverse carpal ligament
. Floor: Flexor digitorum profundus; Roof: Flexor retinaculum
. Floor: Radius and ulna; Roof: Pronator teres

Correct Answer & Explanation

. Floor: Pronator quadratus; Roof: Flexor digitorum profundus tendons

Explanation

Parona's space is a deep potential space in the distal volar forearm. Its floor (dorsal boundary) is formed by the pronator quadratus muscle and its overlying fascia, while its roof (volar boundary) is formed by the deep surface of the flexor digitorum profundus (FDP) tendons and flexor pollicis longus. It serves as a conduit for infections to track from the radial bursa to the ulnar bursa, resulting in a horseshoe abscess.

Question 3072

Topic: Nerve & Tendon

A 50-year-old female presents with weakness in extending her fingers and thumb at the metacarpophalangeal joints. She has no sensory deficits, and wrist extension results in radial deviation. She is diagnosed with Posterior Interosseous Nerve (PIN) syndrome. During surgical decompression, the surgeon meticulously explores the radial tunnel. Which of the following is considered the most common site of PIN compression?

. The fibrous bands anterior to the radiocapitellar joint
. The recurrent radial vessels (Leash of Henry)
. The tendinous margin of the extensor carpi radialis brevis (ECRB)
. The proximal fibrous edge of the superficial head of the supinator muscle
. The distal edge of the supinator muscle at the exit of the radial tunnel

Correct Answer & Explanation

. The fibrous bands anterior to the radiocapitellar joint

Explanation

The posterior interosseous nerve (PIN) is the deep motor branch of the radial nerve. The most common site of PIN compression in the radial tunnel is the Arcade of Frohse, which is the thickened proximal fibrous edge of the superficial head of the supinator muscle. Other potential, less common compression sites from proximal to distal include fibrous bands at the radiocapitellar joint, the Leash of Henry (recurrent radial vessels), the medial edge of the ECRB, and the distal edge of the supinator.

Question 3073

Topic: 7. Hand and Wrist

A 45-year-old cyclist presents with numbness and tingling in the small finger and the ulnar half of the ring finger, along with weakness in finger abduction. A diagnosis of ulnar nerve compression in Guyon's canal is made. Which of the following structures forms the radial (lateral) border of Guyon's canal?

. Pisiform
. Volar carpal ligament
. Hook of hamate
. Flexor carpi radialis tendon
. Transverse carpal ligament

Correct Answer & Explanation

. Pisiform

Explanation

Guyon's canal (the ulnar tunnel) contains the ulnar nerve and artery. Its anatomical boundaries are: the volar carpal ligament (forming the roof), the transverse carpal ligament and hypothenar muscles (forming the floor), the pisiform and flexor carpi ulnaris (forming the ulnar or medial border), and the hook of hamate (forming the radial or lateral border). The ulnar artery sits radial to the ulnar nerve within this space.

Question 3074

Topic: Nerve & Tendon

A 34-year-old carpenter sustains a penetrating injury to the proximal volar forearm. He subsequently demonstrates an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which of the following muscles is also typically denervated in this specific nerve injury pattern?

. Flexor carpi radialis
. Flexor digitorum superficialis
. Pronator quadratus
. Palmaris longus
. Pronator teres

Correct Answer & Explanation

. Flexor carpi radialis

Explanation

The patient has an injury to the anterior interosseous nerve (AIN), evidenced by paralysis of the flexor pollicis longus (FPL) and the flexor digitorum profundus (FDP) to the index finger. The AIN is a motor branch of the median nerve that innervates three muscles: the FPL, the radial half of the FDP (index and long fingers), and the pronator quadratus.

Question 3075

Topic: 7. Hand and Wrist

A 30-year-old woman presents with intrinsic tightness in her hand, prompting an evaluation of her lumbrical muscles. Which of the following statements accurately describes the anatomy and function of the normal hand lumbricals?

. All four lumbricals are innervated by the ulnar nerve
. They originate from the tendons of the flexor digitorum superficialis
. The bipennate lumbricals are typically innervated by the median nerve
. They insert into the radial lateral band of the extensor expansion
. They function to extend the metacarpophalangeal joints and flex the interphalangeal joints

Correct Answer & Explanation

. All four lumbricals are innervated by the ulnar nerve

Explanation

The lumbrical muscles of the hand originate from the tendons of the flexor digitorum profundus (FDP) and insert into the radial lateral band of the extensor expansion. The first two (radial) lumbricals are unipennate and innervated by the median nerve, while the ulnar two are bipennate and innervated by the ulnar nerve. Their primary function is to flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints.

Question 3076

Topic: 7. Hand and Wrist

A 28-year-old elite rock climber presents with a sudden 'pop' and swelling in his ring finger after a dynamic hold. He is diagnosed with a closed flexor tendon pulley rupture. Biomechanical studies indicate that preserving or reconstructing a specific combination of pulleys is the absolute minimum requirement to prevent clinically significant bowstringing of the flexor tendons. Which combination of pulleys is this?

. A1 and A2
. A1, A3, and A5
. A2 and A4
. A3 and A4
. A2 and A3

Correct Answer & Explanation

. A1 and A2

Explanation

The flexor tendon pulley system consists of five annular (A1-A5) and three cruciate (C1-C3) pulleys. The A2 pulley (located over the proximal phalanx) and the A4 pulley (located over the middle phalanx) are the major structural biomechanical pulleys. They are crucial for maintaining the flexor tendons closely apposed to the bone, thereby preserving the mechanical advantage (moment arm) of the flexor system. Loss of both A2 and A4 leads to significant bowstringing, loss of active flexion range of motion, and weakness.

Question 3077

Topic: Nerve & Tendon

A 34-year-old mechanic sustains a severe laceration to the medial aspect of the elbow, resulting in complete transection of the ulnar nerve. However, clinical examination reveals preserved motor function of the first dorsal interosseous and adductor pollicis muscles, despite complete loss of sensation in the small finger. Which of the following anatomical anomalies best explains these findings?

. Riche-Cannieu anastomosis
. Martin-Gruber anastomosis
. Marinacci anastomosis
. Berrettini anastomosis
. Accessory deep peroneal nerve

Correct Answer & Explanation

. Riche-Cannieu anastomosis

Explanation

The Martin-Gruber anastomosis is a common anatomical variant (present in about 15-20% of the population) where motor fibers from the median nerve cross over to join the ulnar nerve in the proximal forearm. Because these fibers bypass the elbow, an ulnar nerve injury at or above the elbow may present with unexpected preservation of intrinsic hand muscle function (such as the first dorsal interosseous and adductor pollicis). Riche-Cannieu is an anastomosis between the deep branch of the ulnar nerve and the recurrent motor branch of the median nerve in the hand.

Question 3078

Topic: 7. Hand and Wrist

A 26-year-old professional rock climber presents with acute pain and swelling over the volar aspect of his right ring finger after hearing a 'pop' while executing a crimp grip. Ultrasound confirms a complete rupture of the A2 pulley. Anatomically, from which of the following structures does the A2 pulley originate?

. Volar plate of the metacarpophalangeal joint
. Periosteum of the proximal half of the proximal phalanx
. Volar plate of the proximal interphalangeal joint
. Periosteum of the middle third of the middle phalanx
. Flexor digitorum superficialis tendon insertion

Correct Answer & Explanation

. Volar plate of the metacarpophalangeal joint

Explanation

The flexor tendon pulley system of the fingers prevents bowstringing of the flexor tendons. The A2 and A4 pulleys are the most critical biomechanically. The A2 pulley arises from the periosteum of the proximal half of the proximal phalanx. The A4 pulley arises from the periosteum of the middle third of the middle phalanx. The A1, A3, and A5 pulleys typically arise from the volar plates of the MCP, PIP, and DIP joints, respectively.

Question 3079

Topic: 7. Hand and Wrist

A 55-year-old woman with a closed distal radius fracture presents with significant numbness in her little and ring fingers. Electrodiagnostic studies demonstrate delayed motor conduction velocities of the ulnar-innervated intrinsic hand muscles when stimulating at the elbow, but normal conduction velocities when stimulating at the wrist. A Martin-Gruber anastomosis is suspected. Where does this anomalous neural connection typically cross?

. 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 deep motor branch of the ulnar nerve to the recurrent median nerve in the hand
. From the superficial branch of the radial nerve to the dorsal ulnar sensory branch at the wrist
. From the median nerve to the musculocutaneous nerve in the distal arm

Correct Answer & Explanation

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

Explanation

The Martin-Gruber anastomosis is a common anatomic variant (present in approximately 15-30% of the population) consisting of communicating nerve fibers passing from the median nerve (or its anterior interosseous branch) to the ulnar nerve in the proximal forearm. This results in median nerve innervation of some typically ulnar-innervated intrinsic hand muscles. It can lead to confusing electrodiagnostic findings. Option C describes the Riche-Cannieu anastomosis.

Question 3080

Topic: 7. Hand and Wrist

A hand surgeon is releasing the transverse carpal ligament (TCL) endoscopically. To avoid catastrophic injury to the recurrent motor branch of the median nerve, knowledge of its most common anatomical variation is imperative. According to the extraligamentous type (Kaplan's classification), how does the motor branch course to innervate the thenar musculature?

. It branches proximal to the TCL and courses superficial to the ligament.
. It branches distal to the TCL and courses recurrently over the distal edge of the ligament.
. It pierces directly through the substance of the TCL to reach the muscles.
. It branches deep within the carpal tunnel and directly enters the deep surface of the thenar muscles.
. It arises from the ulnar nerve and crosses the distal portion of the TCL.

Correct Answer & Explanation

. It branches proximal to the TCL and courses superficial to the ligament.

Explanation

The extraligamentous recurrent pathway is the most common anatomical variation of the thenar motor branch of the median nerve (type 1). In this configuration, the branch arises from the median nerve distal to the transverse carpal ligament (TCL) and then hooks backward (recurrently) over the distal edge of the TCL to enter the thenar muscles. Subligamentous and transligamentous (piercing the TCL) variations exist but are less common. Because of these variations, releasing the ligament too far radially or without clear visualization can sever the motor branch.

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