C2-C7 Anomalies

Question 1

Failure of the apical ossification center of the dens to unite to the body of the dens. Should unite by age 12-13

Answer 1

Ossiculum Terminale Persistens (of Bergmann)

Question 2

Non-union of the odontoid process with the body of C2. Typically fuses by age 5-7.

Answer 2

Os Odontoideum

Question 3

The odontoid is considered hypoplastic (underdeveloped) when it measures less than __mm in height

Answer 3

12

Question 4

Cervical blocks involving more than two vertebral bodies

Answer 4

Klippel-Feil Syndrome

Question 5

Failure of descent of the scapula during fetal development. More common in females, usually unilateral

Answer 5

Sprengel’s Deformity

Question 6

A cartilaginous or fibrous band that runs from the C5-6 spinous processes to the superior angle of the scapula. Seen in approximately 30-40% of people with Sprengel’s deformity

Answer 6

Omovertebral bone

Question 7

A cleft in the posterior arch, commonly at C6. Also seen at C2 and C4. Radiographic findings: spina bifida oculta of involved segment. Anterior displacement of involved segment

Answer 7

Cervical spondylolisthesis

Question 8

This anomaly is most common in the cervical spine, followed by lumbar and thoracic spines. The most common level is C6. Two nerve roots exit one large foramen

Answer 8

Absent pedicle