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6. Spine MCQs

Practice Set 349 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 6961

Topic: 6. Spine

A 68-year-old man presents with bilateral lower extremity pain radiating down his posterior thighs when walking. He undergoes a stationary bicycling test in the clinic. The patient notes that his leg symptoms do not occur while leaning forward and pedaling on the bicycle. What is the anatomical rationale for this improvement, confirming the diagnosis of neurogenic claudication?

. Exacerbates symptoms due to increased lumbar lordosis
. Improves symptoms due to increased lumbar lordosis
. Exacerbates symptoms due to decreased lumbar lordosis
. Improves symptoms due to decreased lumbar lordosis
. Has no effect on neurogenic claudication; it only differentiates vascular disease

Correct Answer & Explanation

. Improves symptoms due to decreased lumbar lordosis

Explanation

The stationary bicycle test differentiates neurogenic claudication (lumbar spinal stenosis) from vascular claudication. Patients with neurogenic claudication typically experience symptom relief when seated or leaning forward (such as riding a bike or pushing a shopping cart). This forward-flexed posture decreases lumbar lordosis, which temporarily opens the intervertebral foramina and increases the cross-sectional area of the spinal canal, relieving pressure on the nerve roots.

Question 6962

Topic: Cervical Spine

A 25-year-old male presents to the emergency department after a diving accident. He is awake, alert, and cooperative. Examination reveals weakness in his hands and intrinsic muscles, but intact lower extremity function. Imaging shows a bilateral C6-C7 jumped facet. What is the most appropriate next step in management?

. Perform awake closed reduction with cranial skeletal traction
. Obtain an urgent MRI before attempting any reduction maneuvers
. Proceed immediately to posterior open reduction and stabilization
. Proceed immediately to anterior cervical discectomy and fusion
. Place the patient in a rigid cervical collar and observe for 24 hours

Correct Answer & Explanation

. Perform awake closed reduction with cranial skeletal traction

Explanation

In an awake, alert, and examinable patient with cervical facet dislocations, emergent closed reduction with skeletal traction is indicated and safe without a prior MRI. MRI is required prior to reduction primarily in comatose or unexaminable patients to rule out an extruded disc.

Question 6963

Topic: 6. Spine

A 65-year-old male presents with worsening hand clumsiness, difficulty buttoning his shirt, and a broad-based gait. Physical examination reveals a positive Hoffmann sign bilaterally. Elicitation of the brachioradialis reflex results in isolated flexion of the fingers without elbow flexion. This specific reflex finding strongly localizes a cervical spine lesion to which neurologic level?

. C4-C5
. C5-C6
. C6-C7
. C7-T1
. T1-T2

Correct Answer & Explanation

. C5-C6

Explanation

The "inverted radial reflex" (or inverted brachioradialis reflex) is a hallmark of cervical spondylotic myelopathy. It localizes the lesion specifically to the C5-C6 level, demonstrating lower motor neuron absence at C6 (no elbow flexion) and upper motor neuron hyperreflexia below this level (finger flexion).

Question 6964

Topic: 6. Spine

A 25-year-old male is brought to the emergency department after a high-speed motor vehicle collision. He is hypotensive, bradycardic, and lacks motor or sensory function below the C6 level. Which of the following best explains his cardiovascular presentation?

. Loss of sympathetic tone due to spinal cord injury
. Loss of vagal tone leading to unopposed sympathetic activity
. Hypovolemia from occult intra-abdominal hemorrhage
. Direct myocardial contusion impairing cardiac output
. Autonomic dysreflexia triggered by a distended bladder

Correct Answer & Explanation

. Loss of sympathetic tone due to spinal cord injury

Explanation

Neurogenic shock presents with hypotension and bradycardia due to the loss of sympathetic vasomotor tone following a high cervical or high thoracic spinal cord injury. This loss leaves vagal parasympathetic tone unopposed.

Question 6965

Topic: 6. Spine

A 35-year-old male is involved in a motor vehicle collision and sustains a traumatic spondylolisthesis of the axis (Hangman's fracture). The mechanism of injury typically involves which of the following forces?

. Hyperflexion and compression
. Hyperextension and axial loading
. Lateral bending and rotation
. Pure shear
. Distraction and hyperflexion

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A Hangman's fracture (traumatic spondylolisthesis of C2) is classically caused by hyperextension and axial loading forces. This leads to bilateral fractures of the pars interarticularis of the axis.

Question 6966

Topic: 6. Spine

A 65-year-old male presents to the emergency department after a high-speed rear-end motor vehicle collision. He sustained a hyperextension injury to his cervical spine. On examination, he exhibits severe motor weakness in his upper extremities with relative sparing of his lower extremities, alongside patchy sensory deficits. Which of the following is the most likely diagnosis?

. Anterior cord syndrome
. Brown-Sequard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs after hyperextension injuries in older patients with pre-existing cervical spondylosis. It affects the centrally located cervical tracts of the upper extremities more severely than the peripherally located tracts of the lower extremities.

Question 6967

Topic: Thoracolumbar Spine & Deformity

A 14-year-old male gymnast presents with lower back pain that is exacerbated by extension activities. Oblique lumbar radiographs show a 'scotty dog with a collar' sign at L5. A lateral radiograph reveals a 15% anterior translation of L5 on S1. What is the most appropriate initial management?

. Posterior spinal fusion of L5-S1
. Direct pars interarticularis repair
. Activity modification, core strengthening, and physical therapy
. Rigid TLSO bracing for 1 year
. Epidural steroid injections

Correct Answer & Explanation

. Activity modification, core strengthening, and physical therapy

Explanation

The patient has a Grade 1 isthmic spondylolisthesis. Initial management for symptomatic low-grade spondylolisthesis is conservative, consisting of activity modification, NSAIDs, and targeted physical therapy focusing on core and hamstring stretching.

Question 6968

Topic: 6. Spine

A 35-year-old male is involved in a high-speed motor vehicle collision resulting in a burst fracture of T12 and complete paraplegia. He exhibits flaccid paralysis, absent bowel sounds, and profound hypotension with bradycardia. Which of the following clinical findings most definitively marks the end of the spinal shock phase?

. Normalization of blood pressure and heart rate
. Return of the bulbocavernosus reflex
. Spontaneous voluntary toe movement
. Development of spasticity in the lower extremities
. Resolution of the paralytic ileus

Correct Answer & Explanation

. Return of the bulbocavernosus reflex

Explanation

Spinal shock represents a temporary physiological suppression of reflex activity below the level of spinal cord injury. Its termination is clinically marked by the return of the lowest spinal reflex, typically the bulbocavernosus reflex. Normalization of hemodynamics refers to the resolution of neurogenic shock, not spinal shock.

Question 6969

Topic: Thoracolumbar Spine & Deformity

A 15-year-old gymnast presents with lower back pain exacerbated by extension. Radiographs reveal an L5-S1 isthmic spondylolisthesis. During physical examination, if a palpable step-off is appreciated, where is it most likely located?

. Between L3 and L4 spinous processes
. Between L4 and L5 spinous processes
. Between L5 and S1 spinous processes
. Between S1 and S2 spinous processes
. Directly over the sacral promontory

Correct Answer & Explanation

. Between L3 and L4 spinous processes

Explanation

In an isthmic spondylolisthesis at L5-S1, the pars interarticularis defect separates the L5 body from its posterior neural arch. The L5 body slips anteriorly on S1, carrying the L4 vertebra with it. However, the posterior elements of L5 remain behind with the sacrum. Therefore, the step-off is palpable between the spinous processes of L4 (which has moved forward) and L5 (which remains posterior).

Question 6970

Topic: 6. Spine

During the evaluation of a 60-year-old patient with suspected cervical spondylotic myelopathy, the examiner asks the patient to hold their hands out with fingers fully extended and adducted. The patient is unable to maintain the ulnar digits in adduction. What is this physical sign called?

. Hoffman sign
. Finger escape sign
. Inverted radial reflex
. Lhermitte phenomenon
. Babinski sign

Correct Answer & Explanation

. Finger escape sign

Explanation

The finger escape sign (Wartenberg's sign of myelopathy) occurs due to intrinsic muscle weakness resulting from cervical myelopathy. The patient cannot overcome the extensor digiti minimi's unopposed pull, causing the small finger to drift into abduction.

Question 6971

Topic: 6. Spine

A 65-year-old male with long-standing rheumatoid arthritis presents with progressive clumsiness in his hands and a wide-based gait. Cervical flexion and extension radiographs show an anterior atlantodens interval (ADI) of 8 mm. What is the most critical radiographic measurement to evaluate the risk of neurologic progression?

. Measurement of the posterior atlantodens interval (PADI)
. Dynamic MRI of the cervical spine
. Measurement of the clivus-canal angle
. CT scan with 3D reconstruction
. Measurement of the Ranawat line

Correct Answer & Explanation

. Measurement of the posterior atlantodens interval (PADI)

Explanation

In the setting of atlantoaxial subluxation, the posterior atlantodens interval (PADI)โ€”also known as the space available for the cord (SAC)โ€”is the most critical and reliable predictor of neurologic deficit. A PADI of <14 mm is highly correlated with the development of myelopathy and is an absolute indication for surgery.

Question 6972

Topic: 6. Spine

A patient arrives at the trauma bay with flaccid paralysis below the C6 level, profound bradycardia (HR 45), and hypotension (BP 80/50). The extremities are remarkably warm and well-perfused. What is the primary pathophysiological mechanism causing the hypotension?

. Loss of sympathetic vascular tone
. Hypovolemia from occult retroperitoneal hemorrhage
. Loss of parasympathetic tone
. Direct myocardial contusion resulting in cardiogenic shock
. Systemic inflammatory response syndrome (SIRS)

Correct Answer & Explanation

. Loss of sympathetic vascular tone

Explanation

The patient is in neurogenic shock, typical of high spinal cord injuries (above T6). The disruption of descending sympathetic pathways leads to a loss of sympathetic vascular tone, resulting in severe vasodilation and hypotension (hence warm extremities). Unopposed vagal (parasympathetic) tone leads to the classic bradycardia.

Question 6973

Topic: 6. Spine

What specific radiographic finding is considered classic for scurvy (Vitamin C deficiency) in the pediatric population?

. Looser zones
. Pelger-Huet anomaly
. Frankel line
. Erlenmeyer flask deformity
. Rugger jersey spine

Correct Answer & Explanation

. Frankel line

Explanation

The Frankel line (or white line of Frankel) is an irregularly dense zone of provisional calcification seen in the metaphysis of patients with scurvy. Other classic findings include the Wimberger ring sign and Pelkan spurs.

Question 6974

Topic: 6. Spine

When evaluating a patient with suspected cervical radiculopathy, which electromyography (EMG) finding is the earliest indicator of acute axonal injury following a nerve root compression?

. Fibrillation potentials
. Positive sharp waves
. Decreased recruitment of motor unit action potentials (MUAPs)
. Polyphasic motor unit action potentials
. Complex repetitive discharges

Correct Answer & Explanation

. Decreased recruitment of motor unit action potentials (MUAPs)

Explanation

Decreased recruitment of MUAPs is the earliest EMG finding in an acute nerve injury, seen immediately after the insult. Fibrillations and positive sharp waves typically do not appear until 2 to 3 weeks post-injury.

Question 6975

Topic: 6. Spine

According to the Nachemson studies on in vivo intervertebral disc pressure, which of the following activities or positions generates the highest pressure in the L3-L4 intervertebral disc?

. Standing upright
. Lying supine
. Sitting leaning forward with weights in hand
. Walking at a normal pace
. Sitting slouched without weights

Correct Answer & Explanation

. Sitting leaning forward with weights in hand

Explanation

Nachemson's classic in vivo pressure studies demonstrated that intradiscal pressure varies significantly with position. Sitting leaning forward while holding weights generates the highest pressure due to the increased flexion moment and muscle forces acting across the lumbar spine.

Question 6976

Topic: 6. Spine

A 65-year-old male presents with deteriorating hand dexterity and difficulty with balance. Examination reveals a positive Hoffmann sign and hyperreflexia. Which of the following physical exam findings is also highly specific for cervical spondylotic myelopathy?

. Spurling sign
. Lhermitte phenomenon
. Absent biceps reflex with hyperactive triceps reflex
. Inverted brachioradialis reflex
. Phalen test

Correct Answer & Explanation

. Inverted brachioradialis reflex

Explanation

The inverted brachioradialis (supinator) reflex is a highly specific sign of cervical myelopathy at the C5-C6 level. Striking the brachioradialis tendon produces paradoxical finger flexion due to an absent C6 reflex arc paired with hyperactive lower cervical segments.

Question 6977

Topic: 6. Spine

Neurogenic claudication secondary to lumbar spinal stenosis can often be differentiated from vascular claudication based on the patient's symptoms. Which of the following classically alleviates symptoms in neurogenic claudication but not vascular claudication?

. Standing still upright
. Walking on a flat surface
. Walking down an incline
. Riding a stationary bicycle
. Stopping exercise without changing posture

Correct Answer & Explanation

. Walking down an incline

Explanation

Neurogenic claudication is exacerbated by lumbar extension (standing, walking down an incline) and relieved by lumbar flexion (sitting, leaning over a shopping cart, or riding a stationary bicycle). Standing still relieves vascular claudication but typically aggravates neurogenic claudication due to sustained extension.

Question 6978

Topic: 6. Spine

A 22-year-old male is involved in a high-speed motor vehicle collision while wearing a lap belt. Radiographs show a fracture line passing horizontally through the spinous process, pedicles, and vertebral body of L2. What is the most commonly associated intra-abdominal injury?

. Hepatic laceration
. Splenic rupture
. Hollow viscus injury
. Renal artery avulsion
. Pancreatic transection

Correct Answer & Explanation

. Hollow viscus injury

Explanation

The patient has a Chance fracture, which is a flexion-distraction injury of the spine typically occurring in the thoracolumbar junction (often from lap belt use). These fractures are highly associated with intra-abdominal hollow viscus injuries (e.g., bowel perforations or mesenteric tears), which occur in up to 50% of cases.

Question 6979

Topic: Thoracolumbar Spine & Deformity

Degenerative spondylolisthesis most commonly occurs at the L4-L5 level. Which anatomic feature of the L4-L5 segment heavily predisposes it to this condition compared to other lumbar levels?

. Coronally oriented facet joints
. A naturally larger intervertebral disc height
. Sagittally oriented facet joints
. The attachment of the iliolumbar ligament
. The presence of an elongated pars interarticularis

Correct Answer & Explanation

. Sagittally oriented facet joints

Explanation

Degenerative spondylolisthesis is most common at L4-L5. A major predisposing factor is the presence of sagittally oriented facet joints at this level. Coronal orientation resists forward translation better; sagittal orientation provides less mechanical resistance to anterior sheer, leading to translation as the disc and ligaments degenerate. L5-S1 facets are more coronal, making degenerative slip less common there.

Question 6980

Topic: 6. Spine

A 45-year-old patient with an acute massive L4-L5 disc herniation presents with urinary retention and saddle anesthesia. What is the most critical time-dependent variable influencing the return of bladder function?

. The patient's age at presentation
. The duration of symptoms prior to surgical decompression
. The use of high-dose perioperative corticosteroids
. The specific surgical approach utilized (laminectomy vs microdiscectomy)
. The presence of concurrent central canal stenosis

Correct Answer & Explanation

. The duration of symptoms prior to surgical decompression

Explanation

Cauda equina syndrome is a surgical emergency. Decompression within 48 hours of symptom onset is the most critical factor for maximizing the recovery of bladder and bowel function.

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