Relationship of cervical spinal rootlets and the inferior vertebral notch

The anatomic features of cervical spinal rootlets from C5 to T1 and their relationships to the inferior vertebral notches were studied. Fifteen fresh cadavers were dissected and the cervical spinal cord and spinal rootlets were exposed by posterior total laminectomy. The dorsal rootlet entry zone of each spinal root was located proximal to the inferior vertebral notch, with an increasing distance from 15 mm at C5 to 28 mm at T1. The angle sustained by the rootlets to the cord decreased from 45degrees to 89degrees at C5 and to 23degrees to 410 at T1. Ventral rootlet exit zones shared similar arrangements and orientations, but they could not be exposed with posterior laminectomy only. Spinal rootlets of a particular cervical spinal segment may be found medial to the pedicles or through the intervertebral foramen one level above. They may be exposed by foraminotomy or partial excision of the pedicles. The inferior vertebral notch, which is the inferior border of the pedicle, is a reliable landmark for location of the rootlets. The information is useful for safe surgical manipulation and instrumentation around the pedicles, and when reimplantation of spinal nerve roots is considered for total brachial palsy.