- Discussion:
- highest percentage of missed injuries occur in this region;
- Exam:
- Torticollis:
- Radiographs:
- Atlanto-occipital Disassociation
- C1-C2 interspinous space should not be greater than 10 mm;
- occipital condyles should articulate w/ lateral masses of C1, but this relationship cannot be evaluated on single lateral film;
- Atlanto-axial Subluxation
- ADI in children (< 10 yrs) < 3.5 mm; (see pediatric C-spine)
- ADI in adults < 3 mm;
- an anterior shift of C1 on C2 of more than 3-5 mm implies injury to transverse ligament (see atlanto-axial subluxation;
- shift > 5 mm implies injury transverse & alar ligaments;
- SAC:
- > 18 mm - normal;
- 15-17 mm - grey zone;
- < 14 mm - cord compression;
- Atlas (Jefferson frx)
- Odontoid Frx / Hangman frx)
- Wachenheim's line
- used to determine anterior / posterior subluxation
- this line is drawn down posterior surface of clivus & its inferior extension should barely touch posterior aspect of odontoid tip;
- this relationship does not change in flexion and extension;
- if this line runs behind the odontoid, posterior subluxation has occured and vice versa;
- Posterior relationships are assessed by a line extending from the posterior foramen magnum to the posterior laminae of C1;
- this line may curve gently, but should not have a sig step off
Occipitocervical arthrodesis in children
Occipito-atlantal instability in children. A report of five cases and review of the literature.
Occipitocervical arthrodesis in children. A new technique and analysis of results.