Extraforaminal ligaments of the cervical spinal nerves in humans.

Background Context: During the last 120 years, several mechanisms to protect the spinal nerve against traction have been described. All the described structures were located inside the spinal canal proximal to the intervertebral foramen. Ligaments with a comparable function just outside the intervertebral foramen are mentioned ephemerally. No studies are available about ligamentous attachments of cervical spinal nerves to adjacent vertebrae.

Purpose: To identify and describe ligamentous structures at each cervical level that attaches spinal nerves to structures in the extraforaminal region.

Study Design/setting: An anatomical study of the extraforaminal attachments of the cervical spinal nerves was performed using human spinal columns.

Methods: Five embalmed human cervical spines (C1-C8) were dissected. The extraforaminal region was dissected bilaterally to describe and measure anatomical structures and their relationships with the cervical spinal nerves. Histology was done on the ligamentous connections of nerves to the adjacent vertebral structures.

Results: The cervical spinal nerves are attached to the transverse process of the vertebrae. The connecting ligaments consist mainly of collagenous fibers.

Conclusions: At the cervical level, direct ligamentous connections exist between extraforaminal cervical spinal nerves and nearby structures. They may serve as a protective mechanism against traction. In addition, these ligaments play an important role in the positioning of the nerves in the intervertebral foramen.