The Great Auricular Nerve in Fetuses

Abstract

The great auricular nerve (GAN) is the largest branch of the superficial cervical plexus that winds around the posterior border of the sternocleidomastoid muscle, accompanied by the external jugular vein. Forty fetuses (right side: 40/80; left: 40/ 80) with gestational ages between 15 to 28 weeks were microdissected to document the anatomy of the GAN. The results obtained were classified as: i) Incidence and morphometry: GAN was present in 100% of the fetal specimens with average length on the right and left sides recorded as 12.65 ± 2.14 mm and 12.55 ± 2.82 mm respectively. ii) Course: GAN was located parallel to the transverse cervical nerve and the external jugular vein. Duplicate external jugular veins were observed in 5% (4/80) with GAN located anterior to one of the tributaries; iii) Branching Pattern: 16% (13/80) of specimens depicted a single branch. Duplicate branches in 67% (54/80) (referred to as Type I: anterior and posterior branches and 33% (26/80) referred to as Type II: anterior and posterior branches; iv) Variation: the transverse cervical nerve formed a communication with GAN, inferior to the parotid gland in 1%. The anatomical knowledge of the course, bifurcation pattern and variations of GAN may prevent complications during surgical procedures such as parotidectomies.