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6. Spine MCQs

Practice Set 272 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 5421

Topic: 6. Spine

A 55-year-old patient presents with severe right arm pain, weakness in elbow flexion, and a diminished biceps reflex. MRI reveals a unilateral posterolateral disc herniation. Between which two vertebrae is the herniation most likely located, and which nerve root is affected?

. C4-C5 disc, affecting the C4 root
. C4-C5 disc, affecting the C5 root
. C5-C6 disc, affecting the C5 root
. C5-C6 disc, affecting the C6 root
. C6-C7 disc, affecting the C6 root

Correct Answer & Explanation

. C5-C6 disc, affecting the C6 root

Explanation

Weakness in elbow flexion (biceps) and a diminished biceps reflex indicate a C6 radiculopathy. In the cervical spine, the exiting nerve root is named for the lower vertebral segment, so the C6 root exits at the C5-C6 level.

Question 5422

Topic: Thoracolumbar Spine & Deformity

When placing lumbar pedicle screws, the identification of correct anatomic landmarks is crucial to avoid neurologic injury. The ideal starting point for a lumbar pedicle screw is located at the intersection of which of the following structures?

. Pars interarticularis and superior articular process
. Mid-transverse process and pars interarticularis
. Superior border of the transverse process and lateral border of the superior articular process
. A line bisecting the transverse process and the lateral border of the superior articular process
. Inferior border of the transverse process and medial border of the superior articular process

Correct Answer & Explanation

. A line bisecting the transverse process and the lateral border of the superior articular process

Explanation

In the lumbar spine, the anatomic starting point for a pedicle screw is the intersection of a horizontal line bisecting the transverse process and a vertical line tangential to the lateral border of the superior articular process.

Question 5423

Topic: 6. Spine

During an anatomic reconstruction of the anterolateral ligament (ALL) of the knee, the surgeon must be mindful of its precise anatomic landmarks. What is the correct tibial insertion site of the ALL?

. Posterior to the fibular head
. Anterior to Gerdy's tubercle
. Midway between Gerdy's tubercle and the fibular head
. Directly onto the lateral meniscus
. The lateral tibial spine

Correct Answer & Explanation

. Midway between Gerdy's tubercle and the fibular head

Explanation

The ALL originates proximal and posterior to the lateral epicondyle and inserts on the proximal tibia midway between Gerdy's tubercle and the anterior margin of the fibular head. It helps control anterolateral rotatory instability.

Question 5424

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 5425

Topic: 6. Spine

A multidisciplinary team is evaluating a newborn with suspected Chondroectodermal Dysplasia. Which of the following skeletal or systemic anomalies is classically associated with this syndrome and should be screened for?

. Broad, barrel-shaped chest
. Hyperplastic maxilla
. Aortic stenosis
. Autosomal dominant inheritance
. Absence of clavicles

Correct Answer & Explanation

. Absence of clavicles

Explanation

Correct Answer: Absence of claviclesEllis-van Creveld's syndrome is associated with several systemic and skeletal anomalies, including the absence of clavicles, a narrow chest (not broad/barrel-shaped), a hypoplastic maxilla (not hyperplastic), and urinary tract anomalies. It is inherited in an autosomal recessive pattern.

Question 5426

Topic: Thoracolumbar Spine & Deformity

A patient presents with the foot deformities shown in the clinical and radiographic images below. Which of the following skeletal anomalies is also classically associated with this syndrome?




. Absence of clavicles
. Enlarged chest cavity
. Hyperplastic maxilla
. Atlantoaxial instability
. Scoliosis

Correct Answer & Explanation

. Absence of clavicles

Explanation

Correct Answer: AThe images show shortening of the digits of the toes and feet typical of Ellis-van Creveld syndrome. Associated skeletal anomalies include the absence of clavicles, a narrow chest, and a hypoplastic maxilla.

Question 5427

Topic: 6. Spine

You are evaluating a 4-year-old with disproportionate dwarfism. Which of the following radiographic features best differentiates Ellis-van Creveld syndrome from achondroplasia?

. Narrowing of the interpedicular distances in the lumbar spine
. Normal spinal alignment and canal dimensions
. Presence of a bullet-shaped vertebra at the thoracolumbar junction
. Severe platyspondyly of the cervical spine
. Exaggerated lumbar lordosis with severe sacral tilting

Correct Answer & Explanation

. Normal spinal alignment and canal dimensions

Explanation

Unlike achondroplasia, which characteristically features narrowing of the lumbar interpedicular distances and spinal stenosis, the spine in Ellis-van Creveld syndrome is typically normal in alignment and dimension.

Question 5428

Topic: 6. Spine

A 65-year-old male with long-standing untreated joint pain presents with a swollen, nodular foot. Radiographs display punched-out lytic lesions with overhanging sclerotic margins.

What is the eponymous term for this specific radiographic finding?

. Martel sign
. Pencil-in-cup deformity
. Bamboo spine
. Gull-wing deformity
. Terry Thomas sign

Correct Answer & Explanation

. Martel sign

Explanation

The Martel sign represents punched-out lytic lesions with overhanging sclerotic margins, classically seen in chronic tophaceous gout. This is due to the intraosseous extension of gouty tophi.

Question 5429

Topic: 6. Spine

A lateral radiograph of the lumbar spine in a patient with end-stage renal disease demonstrates alternating radiolucent and radiopaque bands parallel to the vertebral endplates.

This "rugger jersey" appearance is most characteristic of which condition?

. Osteopetrosis
. Paget's disease
. Secondary hyperparathyroidism
. Ankylosing spondylitis
. Multiple myeloma

Correct Answer & Explanation

. Secondary hyperparathyroidism

Explanation

The rugger jersey spine is highly suggestive of secondary hyperparathyroidism (renal osteodystrophy). It is caused by sclerotic bands of excess osteoid accumulation at the superior and inferior vertebral endplates.

Question 5430

Topic: 6. Spine

A 48-year-old female with long-standing secondary hyperparathyroidism undergoes spine radiography for chronic back pain. Which of the following radiographic signs is classically associated with her condition?

. Bamboo spine
. Rugger jersey spine
. Picture frame vertebra
. Ivory vertebra

Correct Answer & Explanation

. Rugger jersey spine

Explanation

Secondary hyperparathyroidism can cause the 'rugger jersey spine,' which is characterized by prominent sclerotic bands at the superior and inferior endplates of the vertebral bodies, interspersed with relatively lucent central bone.

Question 5431

Topic: 6. Spine

A patient with long-standing end-stage renal disease presents with back pain. Lateral radiographs of the lumbar spine demonstrate prominent radiodense bands at the superior and inferior endplates of the vertebral bodies. This classic 'rugger jersey spine' is indicative of which condition?

. Primary hyperparathyroidism
. Secondary hyperparathyroidism
. Paget's disease of bone
. Ankylosing spondylitis
. Osteopetrosis

Correct Answer & Explanation

. Secondary hyperparathyroidism

Explanation

The 'rugger jersey spine' is characterized by sclerotic bands adjacent to the vertebral endplates. It is a classic radiographic sign of osteosclerosis associated with secondary hyperparathyroidism (renal osteodystrophy).

Question 5432

Topic: 6. Spine

A 48-year-old man with end-stage renal disease presents with severe diffuse bone pain. Radiographs demonstrate a 'rugger-jersey' spine and diffuse osteopenia. His condition is primarily driven by the failure of the kidneys to synthesize which of the following?

. 25-hydroxyvitamin D
. 1,25-dihydroxyvitamin D
. Parathyroid hormone
. Calcitonin
. Fibroblast growth factor 23

Correct Answer & Explanation

. 1,25-dihydroxyvitamin D

Explanation

In renal osteodystrophy (secondary hyperparathyroidism), the failing kidneys cannot convert 25-hydroxyvitamin D to its active form, 1,25-dihydroxyvitamin D. This leads to hypocalcemia, which chronically stimulates the parathyroid glands to secrete excessive PTH.

Question 5433

Topic: 6. Spine

A 66-year-old man with polyostotic Paget's disease presents with progressively worsening lower extremity weakness, numbness, and difficulty walking. Radiographs of the lumbar spine reveal an enlarged 'ivory vertebra' at L3. What is the most likely etiology of his neurological symptoms?

. Malignant transformation to osteosarcoma within the spinal canal
. Bony expansion of the pagetic vertebra causing spinal stenosis
. Ischemic neuropathy from vascular steal phenomenon
. Pathologic compression fracture with retropulsion
. Epidural hematoma secondary to hypervascularity

Correct Answer & Explanation

. Bony expansion of the pagetic vertebra causing spinal stenosis

Explanation

In Paget's disease of the spine, the involved vertebrae undergo disorganized remodeling, leading to an overall increase in bone size (bony expansion). This expansion narrows the spinal canal or neural foramina, frequently causing compressive myelopathy or spinal stenosis.

Question 5434

Topic: 6. Spine

A 68-year-old man presents with bilateral leg pain and neurogenic claudication. Radiographs of the lumbar spine demonstrate an enlarged, dense L4 vertebral body with thickened cortices ('picture frame' vertebra).

What is the most likely pathophysiological mechanism for this patient's neurologic symptoms?

. Herniation of the nucleus pulposus
. Epidural lipomatosis
. Vertebral body enlargement causing bony spinal canal stenosis
. Extramedullary hematopoiesis compressing the thecal sac
. Spontaneous epidural hematoma

Correct Answer & Explanation

. Vertebral body enlargement causing bony spinal canal stenosis

Explanation

The 'picture frame' vertebra with overall enlargement is a classic radiographic sign of Paget's disease. In the spine, the disorganized bone remodeling leads to bony hypertrophy and expansion of the vertebral body, resulting in central canal or foraminal stenosis and subsequent neurogenic claudication.

Question 5435

Topic: 6. Spine

An infant with homozygous achondroplasia presents with progressive hypotonia, central sleep apnea, and profound hyperreflexia. What is the most appropriate next step in management?

. Observation and continuous pulse oximetry
. Cervical spine MRI
. Lumbar decompression
. Growth hormone therapy
. Vitamin D supplementation

Correct Answer & Explanation

. Cervical spine MRI

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis, which can compress the cervicomedullary junction leading to hypotonia, sleep apnea, and sudden death. A cervical spine MRI is urgently required to assess the degree of stenosis for potential surgical decompression.

Question 5436

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 5437

Topic: 6. Spine

A 2-year-old child with achondroplasia presents with central sleep apnea, hyperreflexia, and hypotonia. What is the most appropriate next step in management?

. Cervical spine radiographs
. Polysomnography alone
. MRI of the cervicomedullary junction
. Immediate suboccipital decompression
. Observation and reassurance

Correct Answer & Explanation

. MRI of the cervicomedullary junction

Explanation

Neurological symptoms and central sleep apnea in an achondroplastic child strongly suggest cervicomedullary compression secondary to foramen magnum stenosis. MRI of the cervicomedullary junction is the diagnostic modality of choice to evaluate the need for surgical decompression.

Question 5438

Topic: 6. Spine

A 5-year-old child presents with short trunk dwarfism, corneal clouding, and severe genu valgum. Radiographs reveal platyspondyly and hypoplasia of the odontoid process. What is the most life-threatening orthopedic complication associated with this condition?

. Aortic root dilation
. Atlantoaxial instability
. Severe progressive scoliosis
. Pathologic subtrochanteric fractures
. Tracheal malacia

Correct Answer & Explanation

. Atlantoaxial instability

Explanation

Morquio syndrome (Mucopolysaccharidosis Type IV) frequently involves odontoid hypoplasia and severe ligamentous laxity. This combination leads to atlantoaxial instability, which can cause lethal cervical myelopathy if untreated.

Question 5439

Topic: 6. Spine

A 2-year-old boy presents with irritability, refusal to walk, and bleeding gums. Radiographs of the lower extremities show a transverse sclerotic band at the metaphysis (white line of Frankel) and a radiolucent line adjacent to it. Deficient activity of which enzyme is responsible?

. Prolyl hydroxylase
. Carbonic anhydrase II
. Cathepsin K
. Alkaline phosphatase
. 1-alpha-hydroxylase

Correct Answer & Explanation

. Prolyl hydroxylase

Explanation

Vitamin C is an essential cofactor for prolyl and lysyl hydroxylase, which are required for proper collagen cross-linking. Deficiency causes scurvy, leading to subperiosteal hemorrhage, fragile capillaries, and metaphyseal radiographic signs like the white line of Frankel.

Question 5440

Topic: 6. Spine

A 6-year-old child with short-trunk dwarfism, corneal clouding, and normal intelligence develops progressive bilateral lower extremity weakness. Urine testing is positive for keratan sulfate. What is the most likely cause of the patient's neurologic decline?

. Lumbar spinal stenosis from short pedicles
. Atlantoaxial instability due to odontoid hypoplasia
. Basilar invagination
. Tethered cord syndrome
. Thoracolumbar kyphosis with anterior cord compression

Correct Answer & Explanation

. Atlantoaxial instability due to odontoid hypoplasia

Explanation

Morquio syndrome (MPS IV) is a lysosomal storage disease characterized by the inability to degrade keratan sulfate. Patients frequently develop odontoid hypoplasia leading to atlantoaxial instability, which can cause life-threatening cervical myelopathy if not surgically stabilized.

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