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 161
Topic: Nerve & Tendon
A 42-year-old office worker presents to the clinic 8 weeks after suffering a soft-tissue mallet finger injury to her right ring finger. She never sought medical treatment and currently has a 40-degree extensor lag at the DIP joint. The joint is completely passively correctable. What is the most appropriate initial treatment recommendation?
Correct Answer & Explanation
. A trial of continuous DIP extension splinting for 8 weeks
Explanation
Even in chronic settings (up to 12 weeks or more post-injury), a trial of continuous extension splinting for 8 weeks remains the recommended first-line treatment for a passively correctable soft-tissue mallet finger, as it still yields successful outcomes in many patients.
Question 162
Topic: Nerve & Tendon
A 34-year-old male presents with a tendinous mallet finger injury sustained while catching a baseball 2 days ago. He is prescribed a DIP extension splint. Which of the following is the most critical patient instruction regarding the splinting protocol?
Correct Answer & Explanation
. Keep the splint on continuously for 6 to 8 weeks, restarting the timeline if the DIP joint falls into flexion.
Explanation
Treatment of a tendinous mallet finger requires strict, continuous DIP extension splinting for 6-8 weeks. Any lapse allowing the DIP joint to flex disrupts healing and requires the 6-8 week timeline to be restarted.
Question 163
Topic: Nerve & Tendon
A 45-year-old woman presents with a chronic, untreated mallet finger of 4 months duration. She has now developed a swan neck deformity. What is the primary pathophysiologic mechanism for the development of this deformity?
Correct Answer & Explanation
. Proximal retraction of the extensor mechanism concentrating extension force on the central slip
Explanation
In chronic mallet finger, the loss of terminal extensor continuity causes proximal retraction of the entire extensor mechanism. This concentrates extension forces on the central slip, leading to PIP joint hyperextension and a subsequent swan neck deformity.
Question 164
Topic: Nerve & Tendon
Following the clinical examination, a Duplex Ultrasound (DUS) with Doppler Flow Study is performed. Given the suspected diagnosis and clinical findings, which of the following findings would be most consistent with Hypothenar Hammer Syndrome?
Correct Answer & Explanation
. A fusiform aneurysm of the ulnar artery within Guyon's canal with intraluminal thrombus and distal occlusion.
Explanation
Correct Answer: CThe DUS findings described in the case directly confirm the diagnosis of Hypothenar Hammer Syndrome: 'Demonstrated a fusiform aneurysm of the ulnar artery within Guyon's canal, measuring approximately 5mm in diameter, with evidence of intraluminal thrombus formation. Distal to the aneurysm, there was significant post-stenotic turbulent flow and a segment of complete occlusion of the ulnar artery.' This directly explains the patient's ischemic symptoms and the positive Allen's test.Why other options are incorrect:A. Evidence of ulnar nerve compression by a ganglion cyst within Guyon's canal:While ulnar nerve compression can occur, a ganglion cyst would be a primary cause of Guyon's canal syndrome, not HHS, and would not explain the arterial pathology or digital ischemia.B. Normal caliber ulnar artery with triphasic flow and no evidence of thrombus:This finding would rule out HHS, as the syndrome is characterized by ulnar artery pathology.D. Diffuse atherosclerotic changes throughout the palmar arch:While atherosclerosis can cause vascular disease, HHS is specifically related to focal trauma to the ulnar artery, often leading to aneurysm and thrombosis, rather than diffuse atherosclerotic changes, especially in a 48-year-old non-smoker without diabetes.E. Significant calcification within the ulnar artery wall, indicative of chronic vasculitis:Calcification is not a typical feature of HHS, which involves intimal injury, aneurysm, and thrombosis. Vasculitis would present differently and would be less likely given the specific trauma history.
Question 165
Topic: Nerve & Tendon
The patient's symptoms include both digital ischemia and mild ulnar nerve deficits. During the differential diagnosis process, it is crucial to distinguish Hypothenar Hammer Syndrome (HHS) from primary Ulnar Nerve Entrapment at Guyon's Canal. Which of the following features is most characteristic of HHS and helps differentiate it from isolated ulnar nerve entrapment?
Correct Answer & Explanation
. Digital pallor, cyanosis, cold intolerance, and a diminished ulnar pulse.
Explanation
Correct Answer: DThe most characteristic features of Hypothenar Hammer Syndrome that differentiate it from isolated ulnar nerve entrapment are the vascular symptoms and signs. These include digital pallor, cyanosis, cold intolerance, and a diminished ulnar pulse, all indicative of arterial compromise. The case explicitly highlights these as primary symptoms and findings.Why other options are incorrect:A. Intrinsic muscle atrophy and a positive Froment's sign:These are classic signs of significant ulnar nerve motor weakness, which can be present in both severe ulnar nerve entrapment and, to a milder degree, in HHS due to secondary nerve irritation. However, they are not specific to HHS and are more pronounced in primary nerve entrapment. The case notes 'No obvious clawing of the fingers or Froment's sign was present.'B. Paresthesia and numbness in the ulnar nerve distribution:These are common to both ulnar nerve entrapment and HHS (due to secondary nerve involvement) and therefore do not serve as a differentiating factor.C. A history of repetitive wrist flexion/extension:While repetitive movements can contribute to nerve entrapment, the specific history of using the hypothenar region as a 'hammer' (blunt trauma) is more indicative of HHS.E. Normal Allen's test with definite sensory deficits:A normal Allen's test would argue against significant ulnar artery compromise, making primary ulnar nerve entrapment more likely. In HHS, the Allen's test is typically positive (compromised ulnar flow).
Question 166
Topic: Nerve & Tendon
The Nerve Conduction Studies (NCS) and Electromyography (EMG) findings indicate a mild ulnar neuropathy at the wrist, with mildly reduced sensory nerve action potential (SNAP) amplitudes and sparse positive sharp waves in intrinsic muscles. Based on the overall clinical picture and imaging, what is the most likely etiology of this ulnar neuropathy?
Correct Answer & Explanation
. Secondary compression or irritation of the ulnar nerve by the adjacent ulnar artery aneurysm and surrounding edema.
Explanation
Correct Answer: CThe case explicitly states that the ulnar nerve appeared 'mildly compressed and displayed increased signal intensity on T2-weighted images proximal to the aneurysm, suggesting demyelination or irritation, but no definite nerve transection or severe structural damage.' The conclusion from NCS/EMG was that findings suggested 'a mild ulnar neuropathy at the wrist, likely secondary to external compression or irritation from the adjacent vascular pathology, rather than a primary severe ulnar nerve entrapment syndrome.' This indicates the neuropathy is a consequence of the vascular pathology.Why other options are incorrect:A. Primary ulnar nerve entrapment due to a space-occupying lesion unrelated to the artery:While possible, the primary pathology identified is the ulnar artery aneurysm, and the nerve symptoms are mild and secondary, making an unrelated primary entrapment less likely.B. A severe, isolated ulnar nerve transection at Guyon's canal:The NCS/EMG findings indicate 'mild' neuropathy, and MRI showed 'no definite nerve transection or severe structural damage,' ruling out a severe transection.D. A systemic vasculitis causing diffuse neuropathy:The patient has no history of autoimmune disease or other known vasculitis, and the symptoms are localized to one hand, making a diffuse systemic neuropathy less likely.E. Proximal ulnar nerve entrapment at the cubital tunnel:While cubital tunnel syndrome is common, the clinical examination (Tinel's sign over Guyon's canal, negative Phalen's) and imaging (aneurysm at Guyon's canal) localize the pathology to the wrist, not the elbow.
Question 167
Topic: Nerve & Tendon
The patient is classified as Type II Hypothenar Hammer Syndrome based on diagnostic findings. The decision is made to proceed with surgical intervention. Which of the following is the most compelling indication for surgical management in this patient?
Correct Answer & Explanation
. Persistent and worsening digital ischemia, symptomatic ulnar artery aneurysm with thrombus, and inadequate collateral circulation.
Explanation
Correct Answer: CThe case explicitly outlines the critical factors for surgical decision-making:Persistent and Worsening Digital Ischemia:'The patient's symptoms of cold intolerance, intermittent pallor/cyanosis, and trophic changes were progressive and indicative of critical arterial insufficiency.'Symptomatic Ulnar Artery Aneurysm with Thrombus:'The presence of a palpable, tender, pulsatile mass, confirmed by DUS and CTA to be an ulnar artery aneurysm with significant intraluminal thrombus, presented a clear risk of further distal embolization and complete digital necrosis.'Inadequate Collateral Circulation:'The positive Allen's test and CTA findings confirmed insufficient collateral flow from the radial artery to adequately perfuse the ulnar digits.'These three factors combined represent a clear and urgent indication for surgical intervention to restore perfusion and prevent further tissue loss.Why other options are incorrect:A. Mild ulnar nerve paresthesia and numbness:While present, the nerve symptoms are described as 'mild' and secondary. Isolated mild neuropathy would typically be managed conservatively first.B. The patient's desire to return to carpentry without activity modification:While a factor in patient counseling, it is not a medical indication for surgery. Activity modification is often part of long-term management.D. A positive Tinel's sign over Guyon's canal:This indicates nerve irritation but, similar to mild paresthesia, is not a standalone compelling indication for surgery, especially when compared to critical ischemia.E. The presence of well-controlled hypertension and hyperlipidemia:These are comorbidities that need management but are not indications for hand surgery.
Question 168
Topic: Nerve & Tendon
A 29-year-old G1 P0 woman, 7 months pregnant, presents with bilateral thumb numbness, worse at night. On examination, direct compression over the median nerve at the carpal tunnel for 30 seconds elicits paresthesias in the median nerve distribution. This maneuver is known as the Durkan test. Which of the following statements regarding the Durkan test is most accurate?
Correct Answer & Explanation
. Its approximate sensitivity and specificity are 90%.
Explanation
Correct Answer: CThe Durkan test involves direct compression over the median nerve at the carpal tunnel for approximately 30 seconds, with a positive result being the onset of paresthesias or pain in the median nerve distribution. The discussion explicitly states that its approximate sensitivity and specificity are 90%. This makes option C correct.Option A is incorrectbecause the Durkan test specifically assesses median nerve compression, not ulnar nerve compression.Option B is incorrectbecause sustained wrist flexion is characteristic of the Phalen test, not the Durkan test. The Durkan test involves direct compression.Option D is incorrectbecause the discussion states that the sensitivity and specificity of the Durkan test are generally thought to begreaterthan that for the Phalen test.Option E is incorrectbecause a positive Durkan test indicates median nerve compression, which can cause paresthesias or pain, but it does not directly indicate thenar muscle atrophy. While chronic median nerve compression can lead to atrophy, the test itself is for sensory symptoms.
Question 169
Topic: Nerve & Tendon
The patient's primary symptom is numbness in her thumbs bilaterally. Given a diagnosis of carpal tunnel syndrome, which of the following anatomical structures is primarily responsible for the sensory innervation of the thumb that is affected in this condition?
Correct Answer & Explanation
. Median nerve
Explanation
Correct Answer: CCarpal tunnel syndrome is caused by compression of the median nerve. The median nerve provides sensory innervation to the palmar aspect of the thumb, index finger, middle finger, and the radial half of the ring finger. Therefore, numbness in the thumbs is a classic symptom of median nerve compression.Option A is incorrectas the ulnar nerve primarily innervates the little finger and the ulnar half of the ring finger.Option B is incorrectas the radial nerve primarily provides sensory innervation to the dorsal aspect of the thumb, index, middle, and radial half of the ring finger, but not the palmar aspect of the thumb which is typically affected in CTS.Option D is incorrectas the anterior interosseous nerve is a motor branch of the median nerve and does not provide sensory innervation to the thumb.Option E is incorrectas the posterior interosseous nerve is a motor branch of the radial nerve and does not provide sensory innervation to the thumb.
Question 170
Topic: Nerve & Tendon
A patient with Hypothenar Hammer Syndrome complains of concurrent numbness and tingling in the small finger. Compression of which specific neurological structure is most likely occurring?
Correct Answer & Explanation
. Superficial sensory branch of the ulnar nerve in Guyon's canal
Explanation
An enlarging ulnar artery aneurysm in the hypothenar region can compress the adjacent ulnar nerve in Guyon's canal. Numbness in the small finger indicates involvement of the superficial sensory branch of the ulnar nerve.
Question 171
Topic: Nerve & Tendon
Patients with Hypothenar Hammer Syndrome are at highest risk for severe digit ischemia and necrosis if they possess which of the following anatomic variants?
Correct Answer & Explanation
. Incomplete superficial palmar arch
Explanation
An incomplete superficial palmar arch means there is no collateral blood supply from the radial artery to the ulnar digits. If the ulnar artery thromboses in a patient with an incomplete arch, the ulnar-sided digits are at extreme risk for profound ischemia.
Question 172
Topic: Nerve & Tendon
In Hypothenar Hammer Syndrome, ischemic changes typically affect the ring and small fingers. What is the pathophysiological mechanism responsible for ischemia specifically in these digits?
Correct Answer & Explanation
. Microemboli shedding from an ulnar artery aneurysm
Explanation
The repetitive trauma in HHS causes ulnar artery thrombosis or aneurysm formation. Microemboli can subsequently shed from this site and travel distally, occluding the proper digital arteries of the ring and small fingers.
Question 173
Topic: Nerve & Tendon
A patient with suspected Hypothenar Hammer Syndrome presents with a pulsatile mass in the proximal hypothenar region. What physical examination test is most diagnostic for localizing the vascular deficit before advanced imaging?
Correct Answer & Explanation
. Allen's test
Explanation
The modified Allen's test evaluates the patency of the radial and ulnar arteries and the superficial palmar arch. A positive (abnormal) test upon release of the ulnar artery strongly indicates ulnar artery occlusion or poor arch continuity.
Question 174
Topic: Nerve & Tendon
A 42-year-old mechanic presents with right ring finger ischemia and is suspected of having Hypothenar Hammer Syndrome. Against which of the following anatomic structures is the ulnar artery typically compressed, leading to this condition?
Correct Answer & Explanation
. Hook of the hamate
Explanation
Hypothenar hammer syndrome involves repetitive trauma to the ulnar artery as it passes through Guyon's canal. The artery becomes crushed between the external impact and the prominent bony unyielding hook of the hamate.
Question 175
Topic: Nerve & Tendon
A patient with hypothenar hammer syndrome complains of numbness and tingling in the ring and small fingers, in addition to cold intolerance. Which specific neural structure is most likely being compressed by an ulnar artery aneurysm in this condition?
Correct Answer & Explanation
. Superficial sensory branch of the ulnar nerve
Explanation
An aneurysm of the ulnar artery in the hypothenar region typically compresses the adjacent superficial sensory branch of the ulnar nerve in Zone 3 of Guyon's canal. This leads to paresthesias in the volar aspect of the ring and small fingers.
Question 176
Topic: Nerve & Tendon
A 5-year-old girl falls onto an outstretched hand and sustains a minimally displaced (<2 mm) lateral condyle fracture of the humerus. Which of the following represents the most significant long-term complication if this fracture goes on to nonunion?
Correct Answer & Explanation
. Tardy ulnar nerve palsy
Explanation
Nonunion of a lateral condyle fracture typically leads to a progressive cubitus valgus deformity. Over time, this valgus angulation chronically stretches the ulnar nerve, resulting in tardy ulnar nerve palsy.
Question 177
Topic: Nerve & Tendon
A 5-year-old boy is diagnosed with a displaced lateral condyle fracture of the humerus. If this fracture is managed non-operatively and goes on to nonunion, what is the classic long-term complication?
Correct Answer & Explanation
. Cubitus valgus and tardy ulnar nerve palsy
Explanation
A nonunion of a pediatric lateral condyle fracture typically results in progressive cubitus valgus. Over time, this valgus deformity stretches the ulnar nerve, leading to tardy ulnar nerve palsy.
Question 178
Topic: Nerve & Tendon
Following resection of the neuromatous segments of the C5 and C6 roots, the surgical team in the case performed interpositional nerve grafting. Which of the following nerves was harvested and utilized as a multi-fascicular cable graft for this procedure?
Correct Answer & Explanation
. Sural nerve
Explanation
Correct Answer: CThe case explicitly states under "Surgical Reconstruction": "The ipsilateral sural nerve was harvested from the calf as a multi-fascicular cable graft, providing sufficient length and caliber." The sural nerve is a commonly used and preferred donor nerve for nerve grafting in brachial plexus injuries due to several advantages:It is a sensory nerve, so its harvest results in minimal functional deficit (a small area of numbness on the lateral foot).It provides sufficient length and multiple fascicles, making it suitable for bridging gaps in larger nerves.Its harvest is relatively straightforward and has low morbidity.The other nerves listed are either motor nerves (radial, ulnar) whose sacrifice would cause significant functional deficit, or cutaneous nerves that may not provide adequate length or fascicular structure for major nerve grafting.
Question 179
Topic: Nerve & Tendon
A 32-year-old rugby player presents with an inability to actively flex the DIP joint of his right ring finger. Radiographs reveal a small bony avulsion fragment volar to the PIP joint. According to the Leddy-Packer classification, what is the appropriate management timeframe?
Correct Answer & Explanation
. Within 3 to 4 weeks
Explanation
A small bony fragment retracted to the level of the PIP joint indicates a Type II FDP avulsion (Jersey finger). The tendon is held by the intact vincula longus, preserving its blood supply, which safely allows surgical repair to be delayed up to 3 to 4 weeks.
Question 180
Topic: Nerve & Tendon
A 22-year-old baseball batter reports chronic hypothenar hand pain and new-onset weakness in finger abduction and adduction. Sensory examination over the volar small finger is completely normal. Which of the following is the most likely site of neural compression?
Correct Answer & Explanation
. Guyon's canal Zone 2
Explanation
Guyon's canal Zone 2 contains only the deep motor branch of the ulnar nerve. Compression here, often from a hook of hamate fracture in bat-and-racquet sports, causes isolated motor weakness of the intrinsic muscles with sparing of sensation.
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