Fusion of the Greater and Suboccipital Nerves: A Case Report With Application to Patients With Occipital Neuralgia.

Atypical presentations of occipital neuralgia might have an anatomical cause. Therefore, a better understanding of variant anatomy in this region can help physicians who treat such patients. During the dissection of the suboccipital region in an 83-year-old at-death male cadaver, an unusual finding was noted between the suboccipital and greater occipital nerves. No branches from this segment of the suboccipital nerve were identified. Therefore, initially, the suboccipital muscles were thought to be innervated not by the suboccipital nerve but rather by branches of the medial (greater occipital nerve) and lateral branches of the C2 dorsal ramus. However, with microdissection, these fibers were found to ascend with the medial branch of the C2 ramus (greater occipital nerve) and to distribute fibers to the rectus capitis minor and major and then continue with the greater occipital nerve to the skin over the occiput. No fibers from the suboccipital nerve traveled to the C2 spinal nerve or its lateral branch. The lateral part of the dorsal ramus of C2 innervated the obliquus capitis superior and obliquus capitis inferior. Additionally, a long slender branch from the lateral branch of the C2 dorsal ramus traveled medially to innervate the skin over the C2 spinous process. This case demonstrates that some fibers in the greater occipital nerve (C2), both cutaneous and motor, can be derived from the suboccipital nerve (C1). This information can help in diagnosing some patients with atypical presentations and can help better target all involved occipital nerves.