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6. Spine MCQs

Practice Set 348 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 6941

Topic: 6. Spine

According to the Denis three-column classification of the spine, a true burst fracture is defined by structural failure involving which specific anatomic columns?

. Anterior column only
. Middle column only
. Anterior and middle columns
. Middle and posterior columns
. Anterior, middle, and posterior columns

Correct Answer & Explanation

. Anterior and middle columns

Explanation

A burst fracture is defined by mechanical failure under axial load involving both the anterior and middle columns of the spine. Retropulsion of middle column bone fragments into the spinal canal is a classic hallmark of this injury pattern.

Question 6942

Topic: 6. Spine

A 45-year-old male presents with a large L4-L5 herniated nucleus pulposus and suspected cauda equina syndrome. Which of the following objective findings has the highest sensitivity for establishing the diagnosis?

. Asymmetrical absent Achilles reflexes
. Unilateral foot drop
. Post-void residual bladder volume greater than 100-200 mL
. Bilateral positive straight leg raise tests
. Decreased rectal tone on digital examination

Correct Answer & Explanation

. Post-void residual bladder volume greater than 100-200 mL

Explanation

Urinary retention with overflow incontinence is a hallmark of cauda equina syndrome. A post-void residual volume greater than 100-200 mL is highly sensitive for the condition, whereas sphincter tone can be subjective and a late finding.

Question 6943

Topic: 6. Spine

A 65-year-old male presents with deteriorating handwriting, frequent stumbling, and diffuse hand numbness. On examination, flicking the nail of his middle finger results in involuntary flexion of his thumb and index finger. This specific physical exam finding is indicative of a lesion in which of the following tracts?

. Spinothalamic tract
. Dorsal columns
. Corticospinal tract
. Vestibulospinal tract
. Spinocerebellar tract

Correct Answer & Explanation

. Corticospinal tract

Explanation

The described test is Hoffmann's sign, which is indicative of an upper motor neuron lesion, specifically involving the corticospinal tract. It is a hallmark sign of cervical spondylotic myelopathy. The corticospinal tract is responsible for voluntary motor control.

Question 6944

Topic: 6. Spine

A 19-year-old male sustains an L2 flexion-distraction injury (Chance fracture) during a motor vehicle collision while wearing a lap belt. Which of the following associated injuries has the highest incidence in this patient profile?

. Aortic transection
. Hollow viscus intra-abdominal injury
. Renal laceration
. Splenic rupture
. Diaphragmatic hernia

Correct Answer & Explanation

. Hollow viscus intra-abdominal injury

Explanation

Chance fractures (flexion-distraction injuries of the spine) are classic 'seatbelt injuries' caused by the body flexing over a lap belt acting as a fulcrum. They are highly associated with intra-abdominal injuries, most commonly hollow viscus injuries (e.g., bowel perforation or mesenteric tearing), occurring in up to 40-50% of cases. A high index of suspicion and general surgery consultation is mandatory.

Question 6945

Topic: 6. Spine

A 65-year-old male presents with progressive clumsiness of the hands and an unsteady, broad-based gait. Examination reveals a positive Hoffmann sign and hyperreflexia. MRI shows severe cervical stenosis at C4-C5. Which of the following MRI findings of the spinal cord is most predictive of a poor prognosis for neurologic recovery postoperatively?

. High signal on T2-weighted images alone
. High signal on T2-weighted images combined with low signal on T1-weighted images
. Enhancement of the cord on T1-weighted images with gadolinium
. Loss of the subarachnoid space without intrinsic cord signal changes
. High signal on STIR imaging extending over three vertebral levels

Correct Answer & Explanation

. High signal on T2-weighted images combined with low signal on T1-weighted images

Explanation

In cervical spondylotic myelopathy, intrinsic spinal cord signal changes carry prognostic value. High T2 signal alone indicates edema or gliosis and can be reversible. However, a high T2 signal accompanied by a focal low T1 signal indicates myelomalacia (cystic necrosis or permanent cavitary changes of the cord) and is strongly correlated with a poor potential for clinical recovery after surgical decompression.

Question 6946

Topic: 6. Spine

During the physical examination of a 65-year-old male with progressive hand clumsiness and gait instability, the examiner sharply flicks the distal phalanx of the middle finger, resulting in reflex flexion of the thumb and index finger. What does this specific clinical test indicate?

. C5 cervical radiculopathy
. Severe carpal tunnel syndrome
. An upper motor neuron lesion
. Advanced peripheral neuropathy
. Posterior column spinal cord dysfunction

Correct Answer & Explanation

. An upper motor neuron lesion

Explanation

This describes the Hoffmann sign, which is indicative of upper motor neuron dysfunction, commonly seen in conditions like cervical spondylotic myelopathy. It is considered the upper extremity equivalent of the Babinski sign.

Question 6947

Topic: 6. Spine

A 45-year-old female presents with acute severe lower back pain and bilateral sciatica. Which of the following clinical findings has the highest sensitivity for diagnosing Cauda Equina Syndrome?

. Loss of Achilles reflexes
. Urinary retention
. Saddle anesthesia
. Decreased anal sphincter tone
. Bilateral foot drop

Correct Answer & Explanation

. Urinary retention

Explanation

Urinary retention is the most consistent and sensitive finding in Cauda Equina Syndrome. A post-void residual volume of less than 100-200 mL effectively rules out the diagnosis in most cases.

Question 6948

Topic: 6. Spine

A 25-year-old male sustains a traumatic spondylolisthesis of the axis (Hangman's fracture) following a motor vehicle accident. What is the classic mechanism of injury for this fracture pattern?

. Hyperflexion and distraction
. Axial loading and hyperflexion
. Hyperextension and axial loading
. Lateral bending and rotation
. Pure shear force

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A Hangman's fracture is a traumatic spondylolisthesis of C2, typically resulting from a combined hyperextension and axial loading mechanism. This leads to bilateral fractures through the pars interarticularis of the axis.

Question 6949

Topic: 6. Spine

A 45-year-old female presents with severe right-sided neck pain radiating down her arm. Neurological examination reveals marked weakness in wrist extension and a diminished brachioradialis reflex. Sensation to light touch is decreased over the dorsal aspect of her thumb and index finger. A herniated disc at which cervical level is most likely responsible?

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

Correct Answer & Explanation

. C5-C6

Explanation

The patient's presentation of wrist extension weakness, diminished brachioradialis reflex, and sensory deficits in the thumb and index finger is classic for a C6 radiculopathy. In the cervical spine, the exiting nerve root corresponds to the lower vertebra of the motion segment, so a C5-C6 disc herniation affects the C6 nerve.

Question 6950

Topic: 6. Spine

A 65-year-old male presents with severe neurogenic claudication and L4-L5 degenerative spondylolisthesis (Grade II) with associated spinal stenosis, unresponsive to extensive conservative management. He reports significant functional limitation due to leg pain and numbness. Which surgical approach is most appropriate to address both the instability and the neural compression?

. Decompression (laminectomy) alone.
. Decompression and posterolateral fusion (PLF).
. Decompression and transforaminal lumbar interbody fusion (TLIF).
. Decompression and anterior lumbar interbody fusion (ALIF).
. Decompression with dynamic stabilization.

Correct Answer & Explanation

. Decompression and posterolateral fusion (PLF).

Explanation

For symptomatic degenerative spondylolisthesis (Grade II) with spinal stenosis that has failed conservative management, decompression with fusion is generally recommended to address both the neural compression and the instability. While TLIF and ALIF are also valid fusion options, posterolateral fusion (PLF) following decompression has long been a workhorse procedure for this condition, demonstrating good clinical outcomes and stability. It effectively treats the instability and decompresses the neural elements. Decompression alone carries a higher risk of postoperative instability and progression of spondylolisthesis. The choice between PLF, TLIF, or ALIF can depend on surgeon preference and specific patient factors, but PLF is a well-established and commonly used approach for this scenario in 'General Ortho'.

Question 6951

Topic: 6. Spine

A 60-year-old man presents with progressive clumsiness in his hands, difficulty buttoning his shirts, and gait unsteadiness. Physical examination reveals hyperreflexia and a positive Hoffmann's sign. Which of the following is the most likely diagnosis?

. Carpal tunnel syndrome
. Cervical radiculopathy
. Cervical spondylotic myelopathy
. Amyotrophic lateral sclerosis
. Lumbar spinal stenosis

Correct Answer & Explanation

. Cervical spondylotic myelopathy

Explanation

Clumsy hands, gait instability, and upper motor neuron signs (such as a positive Hoffmann's sign and hyperreflexia) are hallmark clinical features of cervical spondylotic myelopathy. It results from compression of the spinal cord in the cervical region.

Question 6952

Topic: 6. Spine

A 75-year-old man complains of bilateral leg and buttock pain that worsens with prolonged standing and walking. He notes significant relief when leaning over a shopping cart at the grocery store. Which of the following features best differentiates this condition from vascular claudication?

. Symptoms are relieved by lumbar flexion such as walking uphill
. Pulses in the lower extremities are typically absent
. Pain is rapidly relieved by standing motionless
. Pain typically begins distally in the calves and radiates proximally
. Associated skin changes and loss of hair on the toes are common

Correct Answer & Explanation

. Symptoms are relieved by lumbar flexion such as walking uphill

Explanation

The patient's 'shopping cart sign' is classic for neurogenic claudication caused by lumbar spinal stenosis. Lumbar flexion (e.g., leaning forward, walking uphill) increases the volume of the spinal canal, thereby relieving neurovascular compression and differentiating it from vascular claudication.

Question 6953

Topic: 6. Spine

A 65-year-old male complains of progressive clumsiness in his hands, difficulty buttoning his shirt, and a wide-based gait. Physical examination reveals a positive Hoffmann sign bilaterally and an inverted supinator reflex. What is the most likely diagnosis?

. Cervical radiculopathy
. Amyotrophic lateral sclerosis
. Carpal tunnel syndrome
. Cervical spondylotic myelopathy
. Guillain-Barre syndrome

Correct Answer & Explanation

. Cervical spondylotic myelopathy

Explanation

The patient's symptoms of loss of fine motor skills, gait instability, and upper motor neuron signs (Hoffmann sign, inverted supinator reflex) are classic for cervical spondylotic myelopathy. It is the most common cause of spinal cord dysfunction in older adults.

Question 6954

Topic: 6. Spine

A 65-year-old male presents with a deteriorating gait, dropping objects, and bilateral hand numbness. Examination reveals intrinsic hand muscle wasting, bilateral hyperreflexia in the lower extremities, and a positive Hoffmann sign. MRI shows severe cervical stenosis at C4-C5 and C5-C6 with T2 hyperintense cord signal changes. What is the most appropriate definitive management?

. Cervical epidural steroid injection
. Physical therapy and rigid cervical collar
. Surgical decompression and fusion
. Oral gabapentin and close observation
. Cervical facet radiofrequency ablation

Correct Answer & Explanation

. Surgical decompression and fusion

Explanation

The patient has distinct signs of cervical spondylotic myelopathy accompanied by upper motor neuron signs and cord signal changes on MRI. Surgical decompression (anterior, posterior, or combined) is indicated to halt the progression of the neurologic deficit.

Question 6955

Topic: 6. Spine

A 72-year-old man presents with bilateral leg pain and heaviness that worsens with walking and standing upright. He notes significant relief when leaning forward to push a shopping cart. An MRI of the lumbar spine is expected to show central canal stenosis primarily caused by the buckling and hypertrophy of which of the following structures?

. Posterior longitudinal ligament
. Ligamentum flavum
. Anterior longitudinal ligament
. Interspinous ligament
. Supraspinous ligament

Correct Answer & Explanation

. Ligamentum flavum

Explanation

The patient has classic symptoms of neurogenic claudication due to lumbar spinal stenosis. The narrowing of the central canal in degenerative stenosis is primarily caused by a combination of disc space loss/bulging, facet joint hypertrophy, and the infolding or hypertrophy of the ligamentum flavum.

Question 6956

Topic: 6. Spine

A 6-year-old boy presents with bleeding gums, petechiae, and severe metaphyseal bone pain. Radiographs reveal a dense "white line of Frankel" at the metaphyses. The underlying dietary deficiency impairs which of the following critical steps in collagen synthesis?

. Cleavage of procollagen to tropocollagen
. Hydroxylation of proline and lysine residues
. Assembly of the procollagen triple helix
. Extracellular cross-linking via lysyl oxidase
. Glycosylation of hydroxylysine residues

Correct Answer & Explanation

. Hydroxylation of proline and lysine residues

Explanation

Vitamin C deficiency (scurvy) impairs the function of prolyl and lysyl hydroxylases, for which ascorbic acid is a necessary cofactor. Without hydroxylation of proline and lysine residues, the procollagen chains cannot form a stable triple helix at body temperature.

Question 6957

Topic: 6. Spine

A 4-year-old child fed a restricted diet presents with bleeding gums, petechiae, and refusal to walk. Radiographs of the lower extremities show a dense provisional zone of calcification (white line of Frankel). The underlying nutritional deficiency impairs which step of collagen synthesis?

. Cleavage of procollagen C- and N-terminals
. Glycosylation of hydroxylysine residues
. Hydroxylation of proline and lysine residues
. Formation of disulfide bonds in the procollagen molecule
. Cross-linking of tropocollagen by lysyl oxidase

Correct Answer & Explanation

. Hydroxylation of proline and lysine residues

Explanation

The child has scurvy due to Vitamin C deficiency. Vitamin C (ascorbic acid) acts as an essential electron donor (reducing agent) for prolyl and lysyl hydroxylases, which are responsible for the hydroxylation of proline and lysine residues during procollagen synthesis.

Question 6958

Topic: 6. Spine
The intervertebral disc is composed of a central nucleus pulposus and a peripheral annulus fibrosus. Which type of collagen provides the primary structural framework for the annulus fibrosus?
. Type I
. Type II
. Type III
. Type IX
. Type X

Correct Answer & Explanation

. Type I

Explanation

The annulus fibrosus is primarily composed of Type I collagen, which resists tensile forces during spinal movement. In contrast, the nucleus pulposus is rich in Type II collagen and proteoglycans to resist compressive loads.

Question 6959

Topic: 6. Spine

A 9-year-old child on a highly restricted diet presents with gingival bleeding, petechiae, and bone pain. Radiographs of the knee show a prominent white line of Frankel and a Pelkan spur. The defective metabolic step in this patient's condition primarily involves which of the following processes?

. Cleavage of procollagen C-terminal propeptides
. Hydroxylation of proline and lysine residues
. Glycosylation of hydroxylysine residues
. Formation of cross-links by lysyl oxidase
. Triple helix formation of alpha chains

Correct Answer & Explanation

. Hydroxylation of proline and lysine residues

Explanation

The clinical presentation is classic for scurvy (Vitamin C deficiency). Vitamin C is an essential cofactor for prolyl hydroxylase and lysyl hydroxylase. Defective hydroxylation of proline and lysine residues results in unstable collagen triple helices and fragile connective tissue.

Question 6960

Topic: 6. Spine

A 45-year-old unrestrained driver is involved in a high-speed motor vehicle collision. Radiographs demonstrate a traumatic spondylolisthesis of the axis (Hangman's fracture) with bilateral pars interarticularis fractures of C2. What is the classic mechanism of injury for this fracture pattern?

. Hyperflexion and distraction
. Hyperextension and axial loading
. Lateral compression
. Vertical shear
. Rotational injury

Correct Answer & Explanation

. Hyperextension and axial loading

Explanation

A classic Hangman's fracture (traumatic spondylolisthesis of the axis) is typically caused by hyperextension and axial loading. This forces the pedicles/pars interarticularis against the superior articular facets of C3, resulting in bilateral fractures of the C2 pars. Historically, judicial hangings caused a similar fracture via hyperextension and distraction, but modern vehicular trauma causes it via extension and axial load.

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