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6. Spine MCQs

Practice Set 207 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 4121

Topic: 6. Spine
A 3-year-old girl is diagnosed with congenital scoliosis secondary to a fully segmented hemivertebra at T8. Before proceeding with any surgical intervention, which of the following screening evaluations is most critical to perform?
. Renal ultrasound, echocardiogram, and entire spine MRI
. Pulmonary function tests and brain MRI
. Skeletal survey and genetic karyotyping
. DEXA scan and serum calcium
. Electromyography (EMG) and nerve conduction studies

Correct Answer & Explanation

. Renal ultrasound, echocardiogram, and entire spine MRI

Explanation

Congenital scoliosis occurs due to a failure of formation (hemivertebra) or segmentation during early embryogenesis. This critical period coincides with the development of the genitourinary, cardiovascular, and central nervous systems. As a result, up to 60% of patients with congenital scoliosis have associated anomalies (VACTERL association). Renal anomalies are present in 20-30%, requiring a renal ultrasound. Cardiac defects are found in 10-15%, necessitating an echocardiogram. Additionally, intraspinal anomalies (such as tethered cord, diastematomyelia, or syringomyelia) occur in 20-40% of cases, making an MRI of the entire neuraxis mandatory before surgical intervention.

Question 4122

Topic: Thoracolumbar Spine & Deformity

A 14-year-old female gymnast presents with progressive low back pain. Radiographs demonstrate a grade II isthmic spondylolisthesis at L5-S1. She has failed 6 months of conservative management (rest, bracing, physical therapy), and her pain significantly limits her activities of daily living. Neurologic examination is entirely normal. What is the most appropriate surgical treatment?

. L5-S1 anterior lumbar interbody fusion
. L5-S1 posterior in situ posterolateral fusion
. L5 laminectomy without fusion
. L5-S1 reduction and posterior instrumented fusion
. Pars interarticularis repair

Correct Answer & Explanation

. L5-S1 anterior lumbar interbody fusion

Explanation

For symptomatic low-grade (Meyerding Grade I or II) isthmic spondylolisthesis in children and adolescents that fails conservative management, the gold standard surgical treatment is a posterior in situ posterolateral fusion. Neurologic decompression is generally not required if there are no neurologic deficits. Reduction of low-grade slips does not significantly improve outcomes and increases the risk of L5 nerve root injury. Pars repair is typically reserved for select patients with early pars stress fractures or very low-grade slips without significant disc degeneration.

Question 4123

Topic: 6. Spine

A 14-year-old female gymnast complains of lower back pain that worsens with extension activities. Neurological exam is normal. AP and lateral radiographs of the lumbar spine are normal. What is the most appropriate next step in imaging to diagnose an acute pars interarticularis stress reaction?

. Oblique radiographs of the lumbar spine
. Computed tomography (CT) scan of the lumbar spine
. Magnetic resonance imaging (MRI) of the lumbar spine
. Technetium-99m bone scan
. Flexion-extension radiographs of the lumbar spine

Correct Answer & Explanation

. Oblique radiographs of the lumbar spine

Explanation

In a pediatric athlete presenting with extension-related low back pain and normal radiographs, an acute pars interarticularis stress reaction (spondylolysis) must be suspected. While CT scans offer excellent bony detail, they involve significant ionizing radiation. A bone scan combined with SPECT is sensitive but also entails high radiation exposure. Magnetic resonance imaging (MRI) of the lumbar spine, specifically utilizing fluid-sensitive (STIR or T2 fat-suppressed) sequences, is now considered the gold standard for early diagnosis as it can detect bone marrow edema in the pars interarticularis without exposing the pediatric patient to ionizing radiation.

Question 4124

Topic: 6. Spine



A 72-year-old woman with a prior multi-level lumbar spinal fusion (L2-Pelvis) is planned for a THA. How does her spinal fusion alter her spinopelvic mechanics, and what intraoperative adjustment should be considered?

. Her pelvis will hyper-tilt posteriorly in sitting, requiring decreased cup anteversion.
. Her pelvis has decreased posterior tilt in sitting, requiring increased cup anteversion to prevent anterior dislocation.
. Her pelvis has decreased posterior tilt in sitting, requiring increased cup anteversion to prevent posterior dislocation.
. Her spinopelvic mobility is unaffected by the fusion, and standard safe zone targets apply.
. Her pelvis will hyper-tilt anteriorly in standing, requiring decreased cup inclination.

Correct Answer & Explanation

. Her pelvis will hyper-tilt posteriorly in sitting, requiring decreased cup anteversion.

Explanation

Patients with lumbar fusions to the pelvis have a "stiff" spine and lack the normal posterior pelvic tilt that accommodates hip flexion when sitting. This limits functional cup anteversion, increasing the risk of posterior impingement and posterior dislocation, thereby requiring the surgeon to target increased operative cup anteversion.

Question 4125

Topic: 6. Spine

A 4-year-old child presents with bleeding gums, petechiae, and subperiosteal hemorrhages. Radiographs show a "white line of Frankel." This condition is caused by a nutritional deficiency that impairs which specific step of collagen synthesis?

. Cleavage of procollagen to tropocollagen
. Hydroxylation of proline and lysine residues
. Glycosylation of hydroxylysine
. Cross-linking of tropocollagen by lysyl oxidase
. Translation of preprocollagen chains

Correct Answer & Explanation

. Cleavage of procollagen to tropocollagen

Explanation

Scurvy is caused by Vitamin C deficiency, an essential cofactor for prolyl and lysyl hydroxylase enzymes. Impaired hydroxylation of proline and lysine residues leads to defective collagen triple-helix formation and consequently weak connective tissue.

Question 4126

Topic: 6. Spine

During an anterior approach to the cervical spine, the recurrent laryngeal nerve is at greatest risk of injury on the right side due to its varied anatomical path around which structure?

. Aortic arch
. Right subclavian artery
. Right common carotid artery
. Inferior thyroid artery
. Brachiocephalic vein

Correct Answer & Explanation

. Aortic arch

Explanation

The right recurrent laryngeal nerve loops under the right subclavian artery and ascends obliquely, making its path more variable and susceptible to surgical injury. The left recurrent laryngeal nerve loops safely lower down under the aortic arch.

Question 4127

Topic: 6. Spine

A 45-year-old man presents with severe back pain radiating down his leg. MRI reveals a posterolateral disc herniation at the L4-L5 level. Which nerve root is most likely compressed?

. L3
. L4
. L5
. S1
. S2

Correct Answer & Explanation

. L3

Explanation

In the lumbar spine, exiting nerve roots leave the canal above the intervertebral disc. Therefore, a posterolateral disc herniation at the L4-L5 level typically spares the exiting L4 root but compresses the traversing L5 nerve root.

Question 4128

Topic: 6. Spine

A 45-year-old woman complains of painful numbness and paresthesias over the anterolateral aspect of her thigh three months after an anterior iliac crest bone graft harvest. The nerve most likely injured typically exits the pelvis in which anatomical location relative to the anterior superior iliac spine (ASIS)?

. Medial and inferior to the ASIS, under the inguinal ligament
. Lateral and superior to the ASIS
. Directly through the greater sciatic foramen
. Through the obturator foramen
. Posterior and superior to the iliac tubercle

Correct Answer & Explanation

. Medial and inferior to the ASIS, under the inguinal ligament

Explanation

The lateral femoral cutaneous nerve (LFCN) provides sensory innervation to the anterolateral thigh and is at risk during anterior iliac crest grafting. It typically courses medial and inferior to the ASIS, passing under or through the inguinal ligament.

Question 4129

Topic: 6. Spine

The pudendal nerve is at risk during certain pelvic fracture fixations and ischial spine procedures. Through which anatomical sequence does the pudendal nerve course to reach the perineum?

. Exits greater sciatic foramen superior to piriformis, enters lesser sciatic foramen
. Exits greater sciatic foramen inferior to piriformis, enters lesser sciatic foramen
. Exits obturator foramen, travels along ischiopubic ramus
. Exits lesser sciatic foramen, enters greater sciatic foramen
. Travels within the substance of the levator ani muscle

Correct Answer & Explanation

. Exits greater sciatic foramen superior to piriformis, enters lesser sciatic foramen

Explanation

The pudendal nerve exits the pelvis through the greater sciatic foramen inferior to the piriformis muscle. It then crosses posterior to the sacrospinous ligament and re-enters the perineum via the lesser sciatic foramen to enter Alcock's canal.

Question 4130

Topic: 6. Spine

During a posterior lumbar decompression for spinal stenosis, the surgeon removes a thickened ligament that bridges the laminae of adjacent vertebrae. Which of the following tissues is most abundant in this structure?

. Type I collagen
. Type II collagen
. Elastin
. Reticular fibers
. Fibrocartilage

Correct Answer & Explanation

. Type I collagen

Explanation

The ligamentum flavum connects the laminae of adjacent vertebrae and is composed primarily of elastin (up to 80%). This gives it a yellow appearance and allows it to stretch and contract during spinal flexion and extension.

Question 4131

Topic: 6. Spine

A 45-year-old male sustains a Jefferson burst fracture of C1. The stability of the C1-C2 complex depends significantly on the transverse ligament. This ligament attaches to which of the following osseous structures?

. The anterior arch of C1
. The dens of C2
. The medial tubercles of the lateral masses of C1
. The posterior arch of C1
. The occipital condyles

Correct Answer & Explanation

. The anterior arch of C1

Explanation

The transverse ligament of the atlas runs behind the dens, holding it tightly against the anterior arch of C1. It attaches to a small tubercle on the medial surface of each lateral mass of the atlas.

Question 4132

Topic: 6. Spine

During anterior cervical spine surgery, care must be taken to avoid injury to the vertebral artery. At which cervical level does the vertebral artery typically first enter the foramen transversarium?

. C4
. C5
. C6
. C7
. T1

Correct Answer & Explanation

. C4

Explanation

The vertebral artery arises from the subclavian artery and typically enters the transverse foramen at C6. It then travels superiorly through the transverse foramina of C6 to C1.

Question 4133

Topic: 6. Spine

During a posterior suboccipital approach to the cervical spine, the surgeon encounters the suboccipital triangle. Which of the following muscles forms the medial border of this anatomic space?

. Obliquus capitis superior
. Obliquus capitis inferior
. Rectus capitis posterior major
. Rectus capitis posterior minor
. Splenius capitis

Correct Answer & Explanation

. Obliquus capitis superior

Explanation

The suboccipital triangle is bordered medially by the rectus capitis posterior major, laterally by the obliquus capitis superior, and inferiorly by the obliquus capitis inferior. The vertebral artery and suboccipital nerve traverse this triangle.

Question 4134

Topic: 6. Spine
A 40-year-old male sustains a knife wound to the spine resulting in Brown-Sรฉquard syndrome. He exhibits ipsilateral loss of motor function and contralateral loss of pain and temperature sensation. The loss of pain and temperature sensation is due to injury to which spinal cord tract?
. Lateral corticospinal tract
. Dorsal column-medial lemniscus
. Lateral spinothalamic tract
. Vestibulospinal tract
. Anterior corticospinal tract

Correct Answer & Explanation

. Lateral spinothalamic tract

Explanation

The lateral spinothalamic tract carries pain and temperature fibers, which decussate near the level of entry in the anterior white commissure. Therefore, damage to this tract results in a contralateral deficit of pain and temperature sensation below the lesion.

Question 4135

Topic: 6. Spine

In the cervical spine, the vertebral artery typically enters the transverse foramen at which vertebral level?

. C3
. C4
. C5
. C6
. C7

Correct Answer & Explanation

. C3

Explanation

The vertebral artery normally branches from the subclavian artery and enters the transverse foramen at the C6 level. It rarely enters at C7, which instead typically transmits only the accessory vertebral vein.

Question 4136

Topic: 6. Spine

In the standard anterior Smith-Robinson approach to the cervical spine, the dissection interval relies on an internervous plane. Which of the following structures constitutes the medial boundary of this plane?

. Sternocleidomastoid
. Trachea and esophagus
. Longus colli
. Omohyoid
. Carotid sheath

Correct Answer & Explanation

. Sternocleidomastoid

Explanation

The standard anterior approach to the cervical spine utilizes the internervous plane between the carotid sheath laterally and the visceral structures (trachea and esophagus) medially. The recurrent laryngeal nerve lies in the tracheoesophageal groove and must be protected.

Question 4137

Topic: Thoracolumbar Spine & Deformity

When placing lumbar pedicle screws, accurate identification of the starting point is critical to avoid nerve root injury. The medial border of the lumbar pedicle correlates with which anatomic landmark on the posterior elements?

. Lateral border of the superior articular process
. Pars interarticularis
. Lateral border of the pars
. Midpoint of the transverse process
. Medial border of the superior articular process

Correct Answer & Explanation

. Lateral border of the superior articular process

Explanation

The medial border of the lumbar pedicle corresponds roughly to the lateral edge of the superior articular process. The classic starting point for a lumbar pedicle screw is at the intersection of the pars, the midpoint of the transverse process, and the superior articular facet.

Question 4138

Topic: 6. Spine

During a sacral laminectomy or decompression, the surgeon must be acutely aware of the termination of the dural sac. In the normal adult spine, the dural sac typically terminates at which vertebral level?

. L3
. L5
. S2
. S4
. Coccyx

Correct Answer & Explanation

. L3

Explanation

In an adult, the spinal cord typically ends at the conus medullaris around L1-L2, but the dural sac and subarachnoid space usually extend further, terminating at the S2 vertebral level. Knowledge of this anatomy is vital to prevent cerebrospinal fluid leaks during sacral surgery.

Question 4139

Topic: 6. Spine

When approaching the thoracic spine via a costotransversectomy, the artery of Adamkiewicz must be considered to avoid spinal cord ischemia. This critical vessel typically enters the spinal canal through an intervertebral foramen at which levels?

. C5-C7
. T1-T4
. T5-T8
. T9-L2
. L3-L5

Correct Answer & Explanation

. C5-C7

Explanation

The artery of Adamkiewicz (great anterior radiculomedullary artery) provides the major blood supply to the anterior spinal artery for the lower two-thirds of the spinal cord. It typically enters the canal between T9 and L2, most commonly on the left side.

Question 4140

Topic: 6. Spine

The vertebral artery is a critical vascular structure that ascends through the cervical spine. In the majority of the population, at which cervical vertebral level does the vertebral artery typically first enter the transverse foramen?

. C7
. C6
. C5
. C4
. C3

Correct Answer & Explanation

. C7

Explanation

The vertebral artery arises from the subclavian artery and typically enters the transverse foramen at C6. It then ascends vertically through the foramina of C6 to C1 before turning medially to enter the foramen magnum.

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