Menu

6. Spine MCQs

Practice Set 40 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 781

Topic: 6. Spine

A patient who underwent an uncomplicated posterior lumbar spinal fusion 10 days ago presents with increasing incisional pain, wound erythema, and a temperature of 38.5 C. There is purulent drainage from the incision. What is the most appropriate initial management?

. Intravenous antibiotics based on empiric coverage alone
. Surgical irrigation and debridement with deep tissue cultures
. Outpatient oral antibiotics
. Lumbar puncture to rule out meningitis
. Immediate removal of all spinal instrumentation

Correct Answer & Explanation

. Surgical irrigation and debridement with deep tissue cultures

Explanation

Acute deep postoperative spinal infections require prompt surgical irrigation and debridement (I&D) to obtain deep cultures and reduce bioburden. Spinal instrumentation is typically retained if it is stable, especially in the acute setting.

Question 782

Topic: 6. Spine

A 45-year-old patient presents with acute right-sided L4 radiculopathy. MRI reveals a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is typically compressed by a far lateral disc herniation at this specific anatomical level?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

Far lateral (extraforaminal) disc herniations impinge the exiting nerve root at the same level. Therefore, an L4-L5 far lateral herniation compresses the L4 nerve root, whereas a paracentral herniation would compress the traversing L5 nerve root.

Question 783

Topic: Thoracolumbar Spine & Deformity

A 15-year-old male gymnast presents with a 4-month history of localized low back pain exacerbated by extension. Oblique radiographs of the lumbar spine are obtained.

A defect in which anatomical structure represents the collar on the "Scotty dog"?

. Pedicle
. Transverse process
. Pars interarticularis
. Superior articular facet
. Spinous process

Correct Answer & Explanation

. Pars interarticularis

Explanation

The 'collar' on the Scotty dog sign seen on oblique lumbar radiographs represents a defect (fracture or lysis) in the pars interarticularis, indicating spondylolysis.

Question 784

Topic: 6. Spine

A 62-year-old female presents with severe neurogenic claudication and a grade I degenerative spondylolisthesis at L4-L5. Which nerve root is most likely to be compressed in this condition?

. Exiting L4 root
. Traversing L4 root
. Exiting L5 root
. Traversing L5 root
. Traversing S1 root

Correct Answer & Explanation

. Traversing L5 root

Explanation

In degenerative spondylolisthesis, the slip most commonly occurs at L4-L5 with intact pars interarticularis. The central canal and lateral recess stenosis primarily compresses the traversing L5 nerve root.

Question 785

Topic: 6. Spine

A 16-year-old elite gymnast complains of lower back pain exacerbated by extension. Plain radiographs are normal. What is the most appropriate next imaging modality to detect an acute pars interarticularis stress reaction without radiation exposure?

. CT scan of the lumbar spine
. MRI of the lumbar spine
. Bone scintigraphy with SPECT
. Flexion-extension radiographs
. Diagnostic ultrasound

Correct Answer & Explanation

. MRI of the lumbar spine

Explanation

MRI is highly sensitive for detecting marrow edema associated with acute pars stress reactions and avoids ionizing radiation, making it the preferred initial advanced imaging in pediatric patients. SPECT is also highly sensitive but involves significant radiation.

Question 786

Topic: 6. Spine

A 45-year-old male presents with acute severe back pain, bilateral leg radicular symptoms, and perineal numbness. What is the most sensitive clinical symptom or sign for the diagnosis of cauda equina syndrome?

. Saddle anesthesia
. Bilateral lower extremity weakness
. Urinary retention
. Fecal incontinence
. Absent bulbocavernosus reflex

Correct Answer & Explanation

. Urinary retention

Explanation

Urinary retention is the most sensitive finding (approximately 90%) in cauda equina syndrome. Its absence can be heavily relied upon to help rule out the condition.

Question 787

Topic: 6. Spine

A 50-year-old male is diagnosed with a far lateral (extraforaminal) disc herniation at the L4-L5 level. Which nerve root is most likely affected?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L4

Explanation

Far lateral disc herniations compress the exiting nerve root at the level of the herniation. Therefore, an L4-L5 far lateral disc compresses the exiting L4 nerve root.

Question 788

Topic: 6. Spine

A 70-year-old male presents with neck and back stiffness. Radiographs demonstrate flowing anterior osteophytes over six contiguous vertebral bodies. Which of the following is a requisite radiographic criterion for the diagnosis of Diffuse Idiopathic Skeletal Hyperostosis (DISH)?

. Erosion of the sacroiliac joints
. Preservation of intervertebral disc heights
. Bamboo spine appearance
. Marginal syndesmophytes
. Facet joint ankylosis

Correct Answer & Explanation

. Preservation of intervertebral disc heights

Explanation

DISH requires flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies with relative preservation of intervertebral disc height. Sacroiliac and facet joint fusion or erosions are notably absent, distinguishing it from Ankylosing Spondylitis.

Question 789

Topic: 6. Spine

A 68-year-old woman complains of bilateral leg pain that worsens with walking and improves when sitting or leaning over a shopping cart. What is the most likely mechanism providing relief in this patient?

. Increased arterial blood flow to the lower extremities
. Decreased venous pooling in the lower extremities
. Increased cross-sectional area of the spinal canal
. Reduction of a dynamic spondylolisthesis
. Relaxation of the paraspinal musculature

Correct Answer & Explanation

. Increased cross-sectional area of the spinal canal

Explanation

Lumbar flexion increases the cross-sectional area of the central spinal canal and neural foramina, relieving compression on the cauda equina and traversing nerve roots in neurogenic claudication.

Question 790

Topic: 6. Spine

A 35-year-old male experiences acute radicular leg pain following heavy lifting. An MRI reveals a massive paracentral disc herniation at L5-S1. Which of the following physical examination findings is most anticipated?

. Weakness in ankle dorsiflexion
. Decreased patellar reflex
. Weakness in great toe extension
. Decreased Achilles reflex
. Sensory loss over the medial malleolus

Correct Answer & Explanation

. Decreased Achilles reflex

Explanation

A paracentral disc herniation at L5-S1 typically compresses the traversing S1 nerve root. S1 radiculopathy presents with weakness in plantar flexion, decreased Achilles reflex, and sensory loss over the lateral foot.

Question 791

Topic: 6. Spine

Patients with ankylosing spondylitis who sustain minor trauma are at high risk for highly unstable spinal fractures. What unique associated complication is significantly more common in these patients following such fractures?

. Rapid spontaneous fusion at the fracture site
. Spinal epidural hematoma
. Development of an adjacent level spondylolysis
. Pyogenic discitis
. Progressive pars interarticularis defects

Correct Answer & Explanation

. Rapid spontaneous fusion at the fracture site

Explanation

The ankylosed spine fractures like a long bone, leading to highly unstable, shearing fractures. These patients are at an exceptionally high risk of developing a spinal epidural hematoma due to the highly vascular fractured epidural bone and altered spinal biomechanics.

Question 792

Topic: Thoracolumbar Spine & Deformity

A 22-year-old male presents with axial back pain.

Based on a lateral lumbar spine radiograph showing isthmic spondylolisthesis, what is the primary anatomical defect responsible for this specific etiology?

. Facet joint degeneration
. Pars interarticularis defect
. Pedicle elongation
. Vertebral body fracture
. Ligamentum flavum hypertrophy

Correct Answer & Explanation

. Facet joint degeneration

Explanation

Isthmic spondylolisthesis is characterized by a defect in the pars interarticularis (spondylolysis), which allows the anterior column to translate forward while the posterior elements remain behind.

Question 793

Topic: 6. Spine

A 65-year-old male presents with leg pain on walking.

MRI commonly demonstrates severe central canal stenosis. Which of the following anatomical structures is LEAST likely to be a primary contributor to acquired degenerative central spinal stenosis?

. Ligamentum flavum
. Intervertebral disc
. Facet joint osteophytes
. Anterior longitudinal ligament
. Posterior longitudinal ligament

Correct Answer & Explanation

. Ligamentum flavum

Explanation

Central canal stenosis is typically caused by anterior disc bulging, posterior ligamentum flavum hypertrophy, and posterolateral facet joint arthropathy. The anterior longitudinal ligament is located on the ventral aspect of the vertebral bodies and does not narrow the spinal canal.

Question 794

Topic: Thoracolumbar Spine & Deformity
According to the Meyerding classification system for spondylolisthesis, what percentage of vertebral body slip defines a Grade III slip?
. 0-25%
. 25-50%
. 50-75%
. 75-100%
. > 100%

Correct Answer & Explanation

. 50-75%

Explanation

The Meyerding classification grades the degree of forward translation. Grade I is 0-25%, Grade II is 25-50%, Grade III is 50-75%, Grade IV is 75-100%, and Grade V (spondyloptosis) is >100%.

Question 795

Topic: Thoracolumbar Spine & Deformity

In evaluating adult spinal deformity, achieving appropriate sagittal balance is critical. Which of the following equations represents the fixed relationship between key pelvic parameters?

. Pelvic Incidence = Pelvic Tilt + Sacral Slope
. Pelvic Incidence = Pelvic Tilt - Sacral Slope
. Pelvic Tilt = Pelvic Incidence + Sacral Slope
. Sacral Slope = Pelvic Incidence + Pelvic Tilt
. Pelvic Incidence = Sacral Slope - Pelvic Tilt

Correct Answer & Explanation

. Pelvic Incidence = Pelvic Tilt + Sacral Slope

Explanation

Pelvic Incidence (PI) is a fixed morphological parameter unique to each individual. It dictates the functional parameters, specifically that PI = Pelvic Tilt (PT) + Sacral Slope (SS).

Question 796

Topic: 6. Spine

A 55-year-old intravenous drug user presents with fever, back pain, and progressive bilateral leg weakness over the last 12 hours. MRI shows a large posterior epidural fluid collection at T10 causing severe cord compression. What is the most appropriate management?

. Intravenous antibiotics for 6 weeks followed by oral antibiotics
. CT-guided aspiration and blood cultures
. Urgent surgical decompression and debridement
. High-dose intravenous corticosteroids alone
. Radiation therapy and bracing

Correct Answer & Explanation

. Intravenous antibiotics for 6 weeks followed by oral antibiotics

Explanation

A spinal epidural abscess presenting with profound or progressive neurologic deficits is an absolute indication for urgent surgical decompression and debridement to salvage neurologic function.

Question 797

Topic: 6. Spine

A patient presents with a right-sided L5 radiculopathy due to a foraminal disc herniation at L5-S1. Which of the following motor functions is most predictably weakened?

. Hip flexion
. Knee extension
. Ankle plantar flexion
. Great toe extension
. Toe flexion

Correct Answer & Explanation

. Hip flexion

Explanation

The L5 nerve root supplies the extensor hallucis longus (EHL). Consequently, L5 radiculopathy typically causes weakness in great toe extension and potentially foot drop (tibialis anterior, shared with L4).

Question 798

Topic: 6. Spine

An AP radiograph of the thoracic spine in a 60-year-old male with a history of prostate cancer reveals the "winking owl" sign at T9. What does this radiographic sign represent?

. Spinous process fracture
. Unilateral pedicle destruction
. Unilateral facet joint dislocation
. Pars interarticularis defect
. Lateral vertebral body collapse

Correct Answer & Explanation

. Spinous process fracture

Explanation

The 'winking owl' sign on an AP view is caused by the absent cortical outline of one pedicle. In the context of malignancy, this highly suggests metastatic destruction of the pedicle.

Question 799

Topic: 6. Spine

In evaluating a patient for lumbar spinal instability,

flexion-extension radiographs are obtained. Which translation distance in the lumbar spine is generally considered indicative of radiographic instability requiring stabilization?

. > 1 mm
. > 2.5 mm
. > 4.5 mm
. > 8 mm
. > 10 mm

Correct Answer & Explanation

. > 1 mm

Explanation

Radiographic instability in the lumbar spine is classically defined by the White and Panjabi criteria as a dynamic sagittal translation of greater than 4.5 mm or sagittal angulation greater than 15 degrees.

Question 800

Topic: 6. Spine

A 45-year-old male presents with severe left anterior thigh pain and weakness in knee extension. MRI of the lumbar spine reveals an extraforaminal (far lateral) disc herniation at the L4-L5 level. Which nerve root is most likely compressed in this scenario?

. L3
. L4
. L5
. S1

Correct Answer & Explanation

. L3

Explanation

An extraforaminal (far lateral) disc herniation compresses the exiting nerve root at that level. At the L4-L5 level, the exiting nerve root is L4.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page