Spine

Os Odontoideum

• Anatomic variant associated with atlanto-axial instability

• Associated with Marquio syndrome (Mucopolysaccharidosis type 4)

Klippel-Feil Syndrome

• Poor segmentation of embryo in weeks 3-8 results in multiple deformities, most notable in cervical spine

• Triad

  • Short neck (secondary to cervical fusion)

  • Poor neck mobility (secondary to cervical fusion)

  • Low hairline

• Multilevel cervical fusion is the major finding

  • Associated spine issues such as disc herniations, scoliosis, etc. are also seen, likely as sequelae of having bad cervical spine

• Other important irregularities associated with K-F

  • Aortic arch and great vessel anomalies

  • GU tract anomalies (unilateral renal agenesis)

  • Sprengel deformity

    • Unilateral elevation of scapula

    • Classically has omovertebral bone - osseous/cartilagenous/fibrous connection of scapula to spine

    • Cavendish & Rigault classifications further characterize but too much detail to care

    • If you see this deformity you should look for other anomalies associated with K-F (cardiac, GU, etc) !

Left:

• Multilevel cervical fusion shown well

Right:

• Demonstrates left sided omnovertebral bone adjacent to C7-T3

Atlantodental interval

• Basically space between anterior aspect of dens and posterior aspect of C1

• Normal

  • < 3 mm on XR

  • < 2 mm on CT

• Widening of the atlantodental interval is highly suggestive of transverse ligament injury

Sources:

• Case courtesy of Vincent Tatco, Radiopaedia.org, rID: 40862 (K-F case)

• Case courtesy of Craig Hacking, Radiopaedia.org, rID: 40491 (atlantodental case)