Menu

Cervical Spine MCQs

Practice Set 19 of 24

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

Question 361

Topic: Cervical Spine

An anterior cervical discectomy and fusion (ACDF) is performed at the C6-C7 level via a left-sided approach. Which of the following fascial layers must be incised to access the interval between the carotid sheath and the midline visceral structures?

. Superficial cervical fascia
. Pretracheal fascia
. Prevertebral fascia
. Alar fascia
. Investing fascia

Correct Answer & Explanation

. Pretracheal fascia

Explanation

The pretracheal fascia envelops the visceral structures (trachea, esophagus, thyroid). It must be divided to enter the avascular plane between the midline viscera and the laterally retracted carotid sheath.

Question 362

Topic: Cervical Spine

A 6-year-old child with normal intelligence presents with short-trunk dwarfism, corneal clouding, and striking knock-knees. Radiographs demonstrate platyspondyly and hypoplasia of the odontoid. What enzyme is deficient?

. Alpha-L-iduronidase
. N-acetylgalactosamine-6-sulfatase (GALNS)
. Glucocerebrosidase
. Sphingomyelinase
. Iduronate sulfatase

Correct Answer & Explanation

. N-acetylgalactosamine-6-sulfatase (GALNS)

Explanation

This is a classic presentation of Morquio syndrome (Mucopolysaccharidosis Type IV), which features normal intelligence, odontoid hypoplasia, and severe genu valgum. It is caused by a deficiency in N-acetylgalactosamine-6-sulfatase (GALNS) or beta-galactosidase.

Question 363

Topic: Cervical Spine

In patients with Morquio Syndrome (Mucopolysaccharidosis IV), which specific substance is found in excess in the urine due to a deficiency of N-acetylgalactosamine-6-sulfatase?

. Heparan sulfate
. Dermatan sulfate
. Keratan sulfate
. Chondroitin sulfate
. Hyaluronic acid

Correct Answer & Explanation

. Keratan sulfate

Explanation

Correct Answer: CMorquio Syndrome (MPS IV) is characterized by the accumulation of Keratan sulfate. Unlike other mucopolysaccharidoses, Morquio syndrome is notable for significant skeletal involvement (platyspondyly, odontoid hypoplasia) and ligamentous laxity, but typically presents with normal intelligence.

Question 364

Topic: Cervical Spine

A 7-year-old girl with Morquio syndrome (MPS IV) presents with progressive endurance loss and generalized hyperreflexia. Lateral flexion-extension radiographs of the cervical spine demonstrate 8 mm of atlantoaxial translation. What is the primary anatomic cause of this instability?

. Incompetence of the transverse ligament only
. Odontoid hypoplasia combined with ligamentous laxity
. Congenital absence of the C1 anterior arch
. Hypertrophy of the posterior longitudinal ligament
. Premature fusion of the C1-C2 facet joints

Correct Answer & Explanation

. Odontoid hypoplasia combined with ligamentous laxity

Explanation

In Morquio syndrome, atlantoaxial instability is characteristically caused by odontoid hypoplasia (due to defective endochondral ossification) coupled with systemic ligamentous laxity. This combination severely compromises the stability of the upper cervical spine, necessitating surgical fusion.

Question 365

Topic: Cervical Spine

In patients with Mucopolysaccharidoses (such as Hurler or Hunter syndromes), neurological compromise at the craniocervical junction is predominantly caused by which of the following pathomechanical factors?

. Progressive ossification of the posterior longitudinal ligament (OPLL)
. Accumulation of glycosaminoglycans leading to periodontoid soft tissue thickening
. Congenital absence of the transverse atlantal ligament
. Spontaneous resorption of the anterior arch of the atlas
. Basilar invagination due to primary osteopenia of the clivus

Correct Answer & Explanation

. Accumulation of glycosaminoglycans leading to periodontoid soft tissue thickening

Explanation

While odontoid hypoplasia contributes to instability, the primary mechanism of cervical cord compression in many MPS patients is the massive accumulation of glycosaminoglycans (GAGs) creating a thick pannus in the periodontoid soft tissues.

Question 366

Topic: Cervical Spine

Which of the following is the most common underlying cause of atlantoaxial instability in a patient with Spondyloepiphyseal Dysplasia Congenita (SEDC)?

. Rupture of the transverse ligament
. Congenital absence of the C1 anterior arch
. Odontoid hypoplasia
. Degenerative facet arthropathy
. Assimilation of the atlas

Correct Answer & Explanation

. Odontoid hypoplasia

Explanation

Patients with SEDC (a COL2A1 defect) frequently exhibit defective ossification of the odontoid process, resulting in odontoid hypoplasia. This structural defect directly leads to significant atlantoaxial instability.

Question 367

Topic: Cervical Spine

A 7-year-old girl with Morquio syndrome has documented atlantoaxial instability with 8 mm of translation and early myelopathic signs. What is the recommended surgical management?

. Anterior odontoidectomy only
. Posterior C1-C2 fusion with rigid instrumentation
. Occipitocervical fusion
. Cervical laminectomy C1-C4
. Halo gravity traction alone

Correct Answer & Explanation

. Occipitocervical fusion

Explanation

In Morquio syndrome, generalized ligamentous laxity, odontoid hypoplasia, and a dysplastic C1 arch make isolated C1-C2 fusion highly prone to failure. Occipitocervical fusion is the most reliable method to achieve stability and decompress the neuraxis.

Question 368

Topic: Cervical Spine

An 8-year-old boy with Down syndrome presents with hyperreflexia, a new wide-based gait, and neck pain.

Dynamic flexion-extension radiographs reveal an atlanto-dens interval (ADI) of 11 mm. What is the most appropriate management?

. Observation and permanent restriction from contact sports
. Rigid cervical collar for 6 weeks followed by re-evaluation
. Anterior cervical discectomy and fusion (ACDF)
. Posterior C1-C2 fusion
. Suboccipital decompression without fusion

Correct Answer & Explanation

. Posterior C1-C2 fusion

Explanation

The patient has symptomatic atlantoaxial instability (AAI) with an ADI greater than 10 mm and myelopathic signs. The gold standard treatment is a posterior C1-C2 arthrodesis to stabilize the joint and decompress the spinal cord.

Question 369

Topic: Cervical Spine

A 7-year-old boy with Down syndrome presents for cervical spine screening. Radiographs demonstrate an atlanto-dens interval (ADI) of 6 mm and a Space Available for Cord (SAC) of 16 mm. He is neurologically intact. According to AAOS guidelines, what is the most appropriate management?

. Immediate posterior C1-C2 fusion
. Halo-vest immobilization for 6 weeks
. Restriction from contact sports and routine clinical follow-up
. Occipitocervical fusion
. Anterior odontoid screw fixation

Correct Answer & Explanation

. Restriction from contact sports and routine clinical follow-up

Explanation

In asymptomatic children with Down syndrome and an ADI of 5-9 mm (with SAC > 14 mm), the recommended management is restriction from high-risk or contact sports and regular monitoring. Surgical stabilization is indicated for ADI > 10 mm, SAC < 14 mm, or the presence of neurologic symptoms.

Question 370

Topic: Cervical Spine

A 7-year-old child with Down syndrome wishes to participate in the Special Olympics. Cervical spine flexion-extension radiographs reveal an anterior atlantodens interval (ADI) of 6 mm. The patient has no neurologic symptoms. What is the most appropriate management according to current guidelines?

. Unrestricted activity clearance
. Clearance for non-contact sports only and serial observation
. Immediate posterior C1-C2 fusion
. Rigid cervical collar placement
. Cervical traction followed by halo vest immobilization

Correct Answer & Explanation

. Clearance for non-contact sports only and serial observation

Explanation

In children with Down syndrome, an ADI between 4.5 mm and 10 mm without neurologic symptoms indicates atlantoaxial instability requiring restriction from collision sports and gymnastics. Surgery is generally reserved for patients with an ADI >10 mm or those with neurologic deficits.

Question 371

Topic: Cervical Spine

A 6-year-old boy with Down syndrome presents for a routine orthopedic evaluation prior to participating in the Special Olympics. Lateral flexion-extension cervical radiographs are obtained.

At what Atlanto-Dens Interval (ADI) threshold is surgical stabilization typically recommended in an entirely asymptomatic child with Down syndrome?

. Greater than 3 mm
. Greater than 5 mm
. Greater than 7 mm
. Greater than 10 mm
. Greater than 14 mm

Correct Answer & Explanation

. Greater than 10 mm

Explanation

In Down syndrome, an ADI greater than 5 mm indicates atlantoaxial instability. However, prophylactic surgical fusion is generally recommended for asymptomatic patients only when the ADI approaches or exceeds 10 mm, or if the Space Available for the Cord (SAC) is less than 14 mm.

Question 372

Topic: Cervical Spine

A 12-year-old girl with Osteogenesis Imperfecta Type IV presents with progressively worsening occipital headaches, hyperreflexia in all four extremities, and a positive Hoffmann's sign. Which of the following radiographic parameters on a lateral cervical spine radiograph is most appropriate to evaluate her suspected condition?

. McGregor's line
. Cobb angle
. Anterior atlantodental interval
. Space available for the cord
. Wiberg angle

Correct Answer & Explanation

. McGregor's line

Explanation

Basilar invagination is a recognized complication of Osteogenesis Imperfecta, presenting with brainstem or upper cervical cord compression. It is radiographically evaluated using McGregor's line or Chamberlain's line to assess the position of the odontoid tip relative to the skull base.

Question 373

Topic: Cervical Spine

A 6-year-old boy presents with short-trunk dwarfism, corneal clouding, and normal intelligence. Radiographs demonstrate severe platyspondyly and odontoid hypoplasia. Urine tests reveal elevated levels of keratan sulfate. This clinical picture is most consistent with a deficiency in which enzyme?

. Alpha-L-iduronidase
. Iduronate-2-sulfatase
. N-acetylgalactosamine-6-sulfatase
. Glucocerebrosidase
. Arylsulfatase B

Correct Answer & Explanation

. N-acetylgalactosamine-6-sulfatase

Explanation

The presentation is classic for Morquio syndrome (MPS Type IV), which features normal intelligence, severe skeletal dysplasia, odontoid hypoplasia, and keratan sulfate in the urine. It is caused by a deficiency in N-acetylgalactosamine-6-sulfatase (Type IVA).

Question 374

Topic: Cervical Spine

In an anterior cervical discectomy and fusion (ACDF), what type of screws are typically used to fix the plate to the vertebral bodies?

. Short cancellous screws for maximum purchase in spongy bone.
. Long, bicortical cortical screws to ensure rigidity.
. Self-tapping locking screws to create a fixed-angle construct.
. Partially threaded lag screws for intervertebral compression.
. Bioabsorbable screws to avoid long-term implant presence.

Correct Answer & Explanation

. Self-tapping locking screws to create a fixed-angle construct.

Explanation

In ACDF, anterior cervical plates are typically secured with self-tapping locking screws. These screws thread into the plate, creating a fixed-angle construct that provides angular stability. This is crucial in the cervical spine to maintain reduction, prevent toggling, and provide a stable environment for fusion. While unicortical purchase is often sufficient due to the locking mechanism, some designs allow for bicortical fixation. The self-tapping feature facilitates insertion in the dense cortical bone of the vertebral bodies.

Question 375

Topic: Cervical Spine

A 6-year-old girl is evaluated for severe knock-knees, short-trunk dwarfism, and corneal clouding. Radiographs show platyspondyly with central anterior beaking of the vertebrae and hypoplastic odontoid. Laboratory testing reveals urinary excretion of keratan sulfate. What is the specific enzymatic deficiency in this patient?

. Alpha-L-iduronidase
. Iduronate-2-sulfatase
. Arylsulfatase B
. N-acetylgalactosamine-6-sulfatase
. Glucocerebrosidase

Correct Answer & Explanation

. N-acetylgalactosamine-6-sulfatase

Explanation

This clinical picture describes Mucopolysaccharidosis Type IVA (Morquio Syndrome). It is caused by a deficiency in N-acetylgalactosamine-6-sulfatase (GALNS), resulting in keratan sulfate accumulation and severe skeletal dysplasia.

Question 376

Topic: Cervical Spine

Morquio syndrome and Spondyloepiphyseal Dysplasia Congenita both present with short trunk dwarfism and atlantoaxial instability. Which of the following clinical features reliably distinguishes Morquio syndrome from SED Congenita on physical examination?

. Presence of short trunk dwarfism
. Presence of odontoid hypoplasia
. Symmetric involvement of the limbs
. Presence of corneal clouding
. Presence of normal intelligence

Correct Answer & Explanation

. Presence of corneal clouding

Explanation

Corneal clouding is a classic feature of Morquio syndrome (a mucopolysaccharidosis), but it is absent in SED Congenita. Both conditions exhibit normal intelligence, short trunk dwarfism, and odontoid hypoplasia.

Question 377

Topic: Cervical Spine

A 7-year-old girl presents with severe torticollis, neck pain, and a 'cock-robin' head position three weeks after undergoing a tonsillectomy. Radiographs show an increased atlantodens interval. In the pathogenesis of Grisel's syndrome, what is the primary mechanism leading to this atlantoaxial subluxation?

. Direct bacterial invasion of the facet joints causing septic arthritis
. Ischemic necrosis of the dens from disruption of the apical artery
. Hyperemic decalcification and laxity of the transverse ligament
. Traumatic rupture of the alar ligaments during endotracheal intubation
. Congenital absence of the apical ligament unmasked by surgery

Correct Answer & Explanation

. Hyperemic decalcification and laxity of the transverse ligament

Explanation

Grisel's syndrome is a non-traumatic atlantoaxial rotatory subluxation associated with head and neck infections (or postoperative states like tonsillectomy/adenoidectomy). The robust venous plexus draining the retropharyngeal space communicates directly with the periodontoid vascular plexus. Inflammatory hyperemia spreads to the periodontoid tissues, causing decalcification of the anterior arch of C1 and subsequent laxity of the transverse ligament, leading to subluxation.

Question 378

Topic: Cervical Spine

A 65-year-old female with an 18-year history of rheumatoid arthritis is being evaluated prior to a total knee arthroplasty. Flexion-extension cervical spine radiographs reveal a 9 mm anterior atlanto-dens interval (ADI). What pathomechanical process is primarily responsible for this finding?

. Traumatic fracture of the odontoid process
. Synovial pannus destruction of the transverse ligament
. Degenerative disc disease causing C1-C2 autofusion
. Ischemic necrosis of the apical ligament
. Congenital hypoplasia of the dens

Correct Answer & Explanation

. Synovial pannus destruction of the transverse ligament

Explanation

Atlantoaxial subluxation is the most common cervical spine manifestation of Rheumatoid Arthritis. It is caused by synovial pannus formation in the retro-odontoid bursa, which subsequently destroys the transverse ligament of the atlas.

Question 379

Topic: Cervical Spine

A 5-year-old child with normal intelligence presents with short-trunk dwarfism, corneal clouding, and knock-knees. Radiographs demonstrate severe platyspondyly with anterior beaking of the vertebral bodies and odontoid hypoplasia. Which of the following substances is excessively accumulating in this patient's tissues?

. Heparan sulfate
. Dermatan sulfate
. Keratan sulfate
. Homogentisic acid
. Glucocerebroside

Correct Answer & Explanation

. Keratan sulfate

Explanation

Morquio Syndrome (Mucopolysaccharidosis Type IV) is an autosomal recessive lysosomal storage disease resulting from a defect in galactosamine-6-sulfatase (Type A) or beta-galactosidase (Type B). This causes the specific accumulation of keratan sulfate. Odontoid hypoplasia makes them highly susceptible to atlantoaxial instability.

Question 380

Topic: Cervical Spine

In the context of anterior cervical discectomy and fusion (ACDF), what is the primary biomechanical advantage of using an anterior plate?

. To prevent dysphagia.
. To increase the rate of pseudarthrosis.
. To provide immediate stability and reduce graft extrusion.
. To facilitate posterior cervical fusion at a later stage.
. To allow for earlier return to full activity without bracing.

Correct Answer & Explanation

. To provide immediate stability and reduce graft extrusion.

Explanation

The primary biomechanical advantage of using an anterior plate in ACDF is to provide immediate stability to the construct and to reduce the risk of graft extrusion or migration. The plate compresses the bone graft or cage between the vertebral bodies, preventing dislodgement and promoting fusion. While it does contribute to stability allowing earlier mobilization, the main goal is preventing graft failure and pseudarthrosis by optimizing the mechanical environment for fusion. It does not prevent dysphagia (which can be a complication of ACDF itself), nor does it increase pseudarthrosis (it aims to decrease it). It doesn't directly facilitate posterior fusion or necessarily allow full activity without bracing (which depends on surgeon preference and patient factors).

Test Yourself

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

On this Page