Quantitative anatomy of cervical spine ligaments. Part I. Upper cervical spine.

The quantitative anatomy of the ligaments of the upper cervical spine was determined from six human cadaveric specimens. For the apical, transverse, and alar ligaments, the origins, lengths, and orientations were determined in three-dimensional space. The apical ligament was 23.5 (3.8) mm long with a 20 degrees anterior tilt from the frontal plane. The transverse ligament was 21.9 (3.7) mm long, whereas the alar ligaments averaged 10.3 (2.0) mm in length. The alar ligaments were oriented 70 degrees from the sagittal plane with much variation in its angle with both the frontal and transverse planes.