Abstract
Background Surgical intervention has established a vital role in the management of chronic headaches.
The lesser occipital nerve (LON) is a common target in patients suffering from occipital
neuralgia and is often resected as a first-line option. We endeavored to define the
relationships of the LON in the posterolateral neck to facilitate its safe and rapid
intraoperative identification.
Methods Seven fresh cadavers (14 nerves) were dissected, and their relationships to the mastoid
prominence and nearby spinal accessory nerve (SAN) and greater auricular nerve were
noted.
Results The distance from the mastoid to the emergence of the LON along the posterior sternocleidomastoid
ranged from 36 to 51 mm (mean: 45.2 mm), with relative symmetry between the two nerves
in the same cadaver. The SAN emerged an average of 54 mm from the mastoid prominence.
Conclusion Exploration for the LON should begin at a point 40 mm from the mastoid prominence
along the posterior border of the sternocleidomastoid muscle. If the point of exit
of the LON is not identified within 10 mm of this exposure, our dissection continues
cranially along the posterior border of the sternocleidomastoid, anterior to the trapezius.
In rare cases the nerve may pierce the fibers of the muscle and ascend directly on
top of the muscle belly. By limiting the caudal extend of the dissection, we can avoid
exposure of the SAN and minimize the risk of iatrogenic nerve injury.
Keywords
occipital neuralgia - headache - anatomy
