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7. Hand and Wrist MCQs

Practice Set 26 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 501

Topic: 7. Hand and Wrist
A 30-year-old carpenter lacerates his index finger volar surface at the level of the proximal phalanx, cutting both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP). Which zone of flexor tendon injury does this represent, and what is its historical designation?
. Zone I; 'sweater finger' zone
. Zone II; 'no man's land'
. Zone III; lumbrical origin zone
. Zone IV; carpal tunnel
. Zone V; forearm zone

Correct Answer & Explanation

. Zone II; 'no man's land'

Explanation

Zone II extends from the A1 pulley (distal palmar crease) to the FDS insertion at the middle phalanx. It is historically termed 'no man's land' due to the poor historical outcomes and high rate of adhesions when both FDS and FDP are repaired in this tight fibro-osseous sheath.

Question 502

Topic: 7. Hand and Wrist

When performing a wide exposure for a delayed flexor tendon repair in the hand, which of the following annular pulleys are considered the most critical biomechanically to preserve or reconstruct to prevent tendon bowstringing?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the most critical annular pulleys. Preserving or reconstructing them is essential to prevent bowstringing and maintain the mechanical advantage of the flexor tendons.

Question 503

Topic: Nerve & Tendon

A 21-year-old rugby player presents with an inability to actively flex the distal interphalangeal joint of his ring finger after grabbing an opponent's jersey. Examination reveals a tender mass in the palm. According to the Leddy-Packer classification, what is the recommended timeframe for surgical intervention for this specific injury pattern?

. Within 7 to 10 days
. Within 3 to 4 weeks
. Within 6 weeks
. Primary arthrodesis is indicated immediately
. Nonoperative management is preferred

Correct Answer & Explanation

. Within 7 to 10 days

Explanation

This is a Type I FDP avulsion (jersey finger) where the tendon retracts into the palm, completely disrupting its vincula blood supply. Early surgical repair within 7 to 10 days is critical to prevent tendon necrosis and fixed contracture.

Question 504

Topic: 7. Hand and Wrist

The flexor tendons of the hand receive their nutrition through both synovial diffusion and a direct vascular supply. Which structures carry the direct segmental blood supply to the flexor digitorum superficialis and profundus tendons within the digital sheath?

. Lumbrical muscle bellies
. Transverse carpal ligament reflections
. Annular and cruciate pulleys
. Vincula tendinum (longus and brevis)
. Cleland's and Grayson's ligaments

Correct Answer & Explanation

. Vincula tendinum (longus and brevis)

Explanation

The vincula tendinum (vincula longus and brevis) foldings of the mesotendon carry the segmental vascular supply to the FDS and FDP tendons within the otherwise avascular digital flexor sheath.

Question 505

Topic: 7. Hand and Wrist
A 30-year-old carpenter sustains a volar laceration over the proximal phalanx of his ring finger, resulting in an inability to actively flex the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. He is scheduled for primary flexor tendon repair. This injury occurred in which of the following flexor tendon zones?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II extends from the A1 pulley (distal palmar crease) to the FDS insertion at the middle phalanx. Lacerations here typically involve both the FDS and FDP tendons and were historically termed "no man's land" due to poor repair outcomes prior to modern techniques.

Question 506

Topic: 7. Hand and Wrist
A 21-year-old collegiate rugby player sustains an avulsion of the flexor digitorum profundus (FDP) of his ring finger (Jersey finger). Radiographs reveal a large bony fragment retracted to the level of the proximal interphalangeal (PIP) joint. This represents which type of Leddy-Packer injury?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type III

Explanation

A Leddy-Packer Type III injury involves a large bony avulsion fragment that catches at the A4 pulley, limiting retraction to the level of the distal aspect of the middle phalanx or PIP joint. Type I retracts to the palm, and Type II retracts to the level of the PIP joint but without a large bony fragment.

Question 507

Topic: 7. Hand and Wrist

A patient with long-standing Rheumatoid Arthritis presents with an inability to actively flex the interphalangeal joint of the thumb. History reveals a sudden loss of function without preceding trauma. What is the most likely etiology of this tendon rupture (Mannerfelt syndrome)?

. Attrition of the FPL over a volar scaphoid osteophyte
. Ischemic necrosis from severe tenosynovitis in the carpal tunnel
. Direct invasion of the FPL tendon by rheumatoid nodules
. Attrition of the FPL over Lister's tubercle
. Rupture of the A1 pulley leading to bowstringing and subsequent failure

Correct Answer & Explanation

. Attrition of the FPL over a volar scaphoid osteophyte

Explanation

Mannerfelt syndrome refers to the spontaneous rupture of the flexor pollicis longus (FPL) tendon in rheumatoid arthritis patients. It is most commonly caused by attritional wear over a bony spur on the volar aspect of the scaphoid.

Question 508

Topic: 7. Hand and Wrist

Biomechanical studies of the digital flexor tendon pulleys have demonstrated that preserving or repairing certain pulleys is critical to prevent clinically significant bowstringing. Which two pulleys are deemed most critical in this regard?

. A1 and A3
. A2 and A4
. A3 and A5
. A1 and A5
. C1 and C3

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the most biomechanically important pulleys in the hand. Loss of these pulleys leads to significant bowstringing, loss of excursion, and decreased flexion power.

Question 509

Topic: Nerve & Tendon
A 28-year-old carpenter sustains a deep laceration to the volar aspect of his index finger precisely at the level of the proximal interphalangeal (PIP) joint, severing both the FDS and FDP tendons. In which flexor tendon zone did this injury occur?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II extends from the proximal edge of the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) tendon near the PIP joint. Historically called 'no man's land', injuries here involve both FDS and FDP within the tight fibro-osseous sheath.

Question 510

Topic: 7. Hand and Wrist

During the surgical exploration and repair of a Zone II flexor tendon laceration, the surgeon must be meticulous in preserving or reconstructing the pulley system to prevent bowstringing. Which of the following pairs of annular pulleys are biomechanically most critical to preserve?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the major biomechanical restraints in the digital flexor sheath. Their preservation is critical to prevent bowstringing of the flexor tendons and resultant loss of digital flexion arc.

Question 511

Topic: 7. Hand and Wrist

When performing a primary flexor tendon repair in the hand, the tensile strength of the repair site is most directly proportional to which of the following technical factors?

. The caliber and material of the epitendinous suture
. The number of core suture strands crossing the repair site
. The distance of the core suture purchase from the cut edge of the tendon
. The use of a grasping rather than a locking core knot technique
. The placement of the knot within the substance of the repair (inside) versus outside

Correct Answer & Explanation

. The number of core suture strands crossing the repair site

Explanation

The tensile strength of a flexor tendon repair is directly proportional to the number of core suture strands crossing the repair site. For example, a 4-strand repair is significantly stronger than a 2-strand repair, allowing for safer early active mobilization protocols.

Question 512

Topic: 7. Hand and Wrist

A patient presents with a volar laceration to the hand. To isolate and test the integrity of the Flexor Digitorum Superficialis (FDS) of the ring finger, the examiner holds all other digits in full extension and asks the patient to flex the ring finger at the PIP joint. What anatomical principle makes this test valid?

. The FDS tendons to all fingers share a single common muscle belly
. The FDP tendons to the middle, ring, and small fingers share a common muscle belly, restricting independent excursion when adjacent fingers are extended
. Extending the adjacent digits completely relaxes the intrinsic lumbrical muscles
. Extending the adjacent digits stabilizes the metacarpophalangeal joints to isolate PIP motion
. The FDS tendon to the ring finger lacks an independent muscle belly and relies on the FDP

Correct Answer & Explanation

. The FDP tendons to the middle, ring, and small fingers share a common muscle belly, restricting independent excursion when adjacent fingers are extended

Explanation

The flexor digitorum profundus (FDP) tendons to the ulnar three digits share a common muscle belly (the quadriga effect). Holding the adjacent digits in extension mechanically prevents the FDP of the ring finger from firing, thereby isolating flexion to the FDS tendon.

Question 513

Topic: 7. Hand and Wrist
A newborn is noted to have a congenital hemivertebra at T8 on a chest radiograph. During a comprehensive workup for VACTERL association, which screening imaging modalities are most critical to obtain to rule out associated life-threatening anomalies?
. Head ultrasound and brain MRI
. Renal ultrasound and echocardiogram
. Pelvic radiograph and bilateral hip ultrasound
. Cervical spine MRI and swallowing study
. Abdominal CT and upper GI series

Correct Answer & Explanation

. Renal ultrasound and echocardiogram

Explanation

Patients with congenital scoliosis have a high incidence of associated VACTERL anomalies, specifically genitourinary abnormalities (up to 30%) and cardiac defects (up to 15%). Renal ultrasound and echocardiography are mandatory screening tests before any surgical intervention.

Question 514

Topic: 7. Hand and Wrist
A newborn is noted to have a congenital scoliosis secondary to multiple hemivertebrae. Given the known associations with this condition, which of the following screening tests must be routinely obtained?
. Renal ultrasound and echocardiogram
. DEXA scan
. Serum protein electrophoresis
. Upper gastrointestinal (UGI) series
. Brain MRI

Correct Answer & Explanation

. Renal ultrasound and echocardiogram

Explanation

Congenital scoliosis is frequently associated with VACTERL anomalies. Up to 30% of patients have genitourinary abnormalities and 10-15% have cardiac defects, mandating a screening renal ultrasound and echocardiogram.

Question 515

Topic: Nerve & Tendon

During the deltopectoral approach for open reduction and internal fixation of a proximal humerus fracture, as planned for the patient in the case, which of the following anatomical structures is most susceptible to iatrogenic injury?

. A. Radial nerve
. B. Ulnar nerve
. C. Axillary nerve
. D. Median nerve
. E. Long thoracic nerve

Correct Answer & Explanation

. C. Axillary nerve

Explanation

Correct Answer: CThe axillary nerve is the most vulnerable neurovascular structure during a deltopectoral approach for proximal humerus plating. It courses around the surgical neck of the humerus, approximately 5-7 cm distal to the acromion, and innervates the deltoid and teres minor muscles. Retraction of the deltoid or placement of screws too distally can put this nerve at significant risk of injury, leading to deltoid weakness and sensory deficits over the lateral shoulder.Option A (Radial nerve):The radial nerve is primarily at risk with humeral shaft fractures or approaches to the posterior humerus, not typically the deltopectoral approach for the proximal humerus.Option B (Ulnar nerve):The ulnar nerve is located medially in the arm and elbow, far from the surgical field of a deltopectoral approach.Option D (Median nerve):The median nerve is also located medially in the arm, distant from the proximal humerus surgical site.Option E (Long thoracic nerve):The long thoracic nerve innervates the serratus anterior and is located on the chest wall, not typically at risk during a deltopectoral approach to the proximal humerus.

Question 516

Topic: 7. Hand and Wrist

A 30-year-old male presents with persistent wrist pain and instability following a radial head fracture managed non-operatively 6 weeks ago. Initial radiographs showed a Mason-Johnston Type II radial head fracture. On examination, there is tenderness over the distal radio-ulnar joint (DRUJ) and a positive 'shuck test' at the wrist. What is the most likely underlying diagnosis causing these new symptoms?

. Radial head non-union
. Heterotopic ossification of the elbow
. Essex-Lopresti lesion
. Chronic lateral collateral ligament insufficiency
. Cubital tunnel syndrome

Correct Answer & Explanation

. Essex-Lopresti lesion

Explanation

Correct Answer: CThe combination of a radial head fracture, interosseous membrane disruption (leading to proximal radial migration), and distal radio-ulnar joint (DRUJ) injury (manifested by wrist pain and instability/positive shuck test) constitutes an Essex-Lopresti lesion. This severe injury often leads to chronic pain and dysfunction if not recognized and treated appropriately, typically with radial head replacement and potentially DRUJ stabilization. Radial head non-union might cause local pain but wouldn't explain DRUJ instability. Heterotopic ossification and LCL insufficiency are elbow-centric and wouldn't directly cause DRUJ instability in this context. Cubital tunnel syndrome is a nerve compression issue.

Question 517

Topic: Nerve & Tendon

During the surgical exposure for a distal humerus fracture, which anatomical structure is at highest risk of iatrogenic injury, particularly during posteromedial dissection?

. Radial nerve
. Musculocutaneous nerve
. Median nerve
. Ulnar nerve
. Brachial artery

Correct Answer & Explanation

. Ulnar nerve

Explanation

Correct Answer: DThe ulnar nerve is the most vulnerable neurological structure during posterior approaches to the distal humerus. It courses through the cubital tunnel posterior to the medial epicondyle and is often directly exposed, mobilized, and protected (often transposed anteriorly) during complex distal humerus fracture fixation to prevent iatrogenic injury or secondary compression. The radial nerve is at risk more proximally in the humeral shaft, the median nerve and brachial artery are anterior and generally protected by muscle bellies, and the musculocutaneous nerve is even further anterior and lateral.

Question 518

Topic: 7. Hand and Wrist
A 30-year-old professional football player sustains an injury to his ring finger during a game. He reports his finger was forcibly extended while gripping an opponent's jersey. On examination, he has swelling and tenderness over the palmar aspect of the distal phalanx. He is unable to actively flex the DIP joint of the ring finger. The remaining fingers show a normal cascade. Passive DIP flexion is full. Initial X-rays are negative for any bony avulsion. Given this presentation, what is the most likely Leddy and Packer classification, and what is the primary concern dictating the urgency of surgical intervention?
. Type II; risk of FDS tendon rupture.
. Type III; prevention of articular incongruity.
. Type I; preservation of FDP tendon vascularity.
. Type IV; management of the avulsed bone fragment.
. Type I; prevention of intrinsic muscle contracture.

Correct Answer & Explanation

. Type I; preservation of FDP tendon vascularity.

Explanation

This clinical scenario describes a classic Leddy and Packer Type I Jersey finger. A Type I injury involves a complete avulsion of the flexor digitorum profundus (FDP) tendon from its insertion on the distal phalanx, without an associated bony avulsion. The tendon retracts proximally, stripping the vincula tendinum, which are the primary source of blood supply to the FDP tendon. The primary concern driving the urgency for surgical repair is to re-establish the tendon's blood supply and prevent necrosis.

Question 519

Topic: Nerve & Tendon

A 25-year-old rock climber presents with chronic pain and a noticeable 'bowstringing' of his long finger flexor tendons during active flexion, following a previous injury that was initially managed non-operatively. He reports a significant loss of grip strength. Which of the following anatomical structures is most likely compromised?

. The C1 and C2 pulleys.
. The A1 pulley.
. The A2 and A4 pulleys.
. The FDS decussation.
. The lumbrical muscle origin.

Correct Answer & Explanation

. The A2 and A4 pulleys.

Explanation

Correct Answer: CRationale:The flexor pulley system consists of annular (A) and cruciate (C) pulleys that keep the flexor tendons closely apposed to the phalanges. This close apposition is crucial for maintaining the mechanical advantage of the flexor tendons, preventing 'bowstringing,' and ensuring efficient finger flexion.Option C (The A2 and A4 pulleys)is correct. The A2 pulley (over the proximal phalanx) and the A4 pulley (over the middle phalanx) are considered the most critical annular pulleys for preventing bowstringing and maintaining the mechanical efficiency of the flexor tendons. Rupture or compromise of these pulleys leads to the tendon lifting away from the bone during flexion (bowstringing), resulting in a significant loss of mechanical advantage and grip strength.Option A (The C1 and C2 pulleys)is incorrect. The cruciate pulleys (C1, C2, C3) are thinner and less critical for preventing bowstringing compared to the annular pulleys.Option B (The A1 pulley)is incorrect. The A1 pulley is located at the MCP joint and its rupture typically leads to trigger finger, not bowstringing along the length of the finger.Option D (The FDS decussation)is incorrect. The FDS decussation is where the FDS tendon splits to allow the FDP to pass through. While important for FDS function, its injury does not directly cause bowstringing of the entire flexor system.Option E (The lumbrical muscle origin)is incorrect. The lumbrical muscles originate from the FDP tendons and insert into the extensor mechanism. Their injury or dysfunction is associated with conditions like lumbrical plus phenomenon, not bowstringing.

Question 520

Topic: 7. Hand and Wrist

Following a successful FDP repair for a Jersey finger, a patient is placed on an early active motion rehabilitation protocol. What is the primary goal of this protocol, and what common complication is it specifically designed to mitigate?

. To strengthen the FDP tendon; re-rupture.
. To reduce post-operative pain; nerve irritation.
. To prevent adhesion formation; stiffness and limited range of motion.
. To accelerate bone healing; non-union of the distal phalanx.
. To improve blood supply to the tendon; tendon necrosis.

Correct Answer & Explanation

. To prevent adhesion formation; stiffness and limited range of motion.

Explanation

Correct Answer: CRationale:Early active motion protocols are a cornerstone of modern flexor tendon rehabilitation. They involve controlled, gentle active and passive movements of the repaired digit within a protective splint, starting soon after surgery.Option C (To prevent adhesion formation; stiffness and limited range of motion)is correct. The primary goal of early active motion is to promote tendon gliding within the flexor sheath and prevent the formation of restrictive adhesions between the repaired tendon and the surrounding tissues (e.g., flexor sheath, FDS tendon). Adhesions are the most common cause of post-operative stiffness and limited range of motion following flexor tendon repair. Controlled motion helps maintain a clear gliding surface.Option A (To strengthen the FDP tendon; re-rupture)is incorrect. While strengthening is a later goal, the immediate early active motion phase is not primarily for strengthening the tendon, but for promoting gliding. Excessive force during early motion can actually risk re-rupture, which the protocol aims to prevent by keeping forces low.Option B (To reduce post-operative pain; nerve irritation)is incorrect. While motion can help with swelling and indirectly pain, it's not the primary goal, and nerve irritation is not the main complication it mitigates.Option D (To accelerate bone healing; non-union of the distal phalanx)is incorrect. Early motion protocols are for tendon healing and gliding, not directly for accelerating bone healing. Non-union is a complication of bony avulsion repairs, but not the primary target of early motion.Option E (To improve blood supply to the tendon; tendon necrosis)is incorrect. While motion can improve local circulation, the primary blood supply to the tendon is critical at the time of repair (especially for Type I injuries). Early motion's main role is not to improve blood supply to prevent necrosis, but to prevent adhesions.

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