Great Auricular Nerve: Failsafe Method To Avoid Injury

Goals/Purpose: Most anatomic descriptions of the great auricular nerve identify its course along the midbelly of the sternocleidomastoid muscle. From a practical point injury can also occur in closer proximity to the ear. The purpose of our study was to identify the distal course of the great auricular nerve as it approaches the lobule.

Methods/Technique: Dissections were performed in twenty four hemi-necks. A vertical line through the mid-lobule was drawn perpendicular to the Frankfort`s horizontal acting as a reference point to the course of the great auricular nerve. (Figure 1) Paper overlay tracings were then done to record each nerve`s course. The distance from the bony external auditory canal to the nerve was measured at its emergence from under sternocleidomastoid muscle, at midbelly of sternocleidomastoid muscle and at anterior muscle border. Branching patterns of the nerve and relation to external jugular vein were identified.

Results/Complications: In 100% of the dissections the distal course of the great auricular nerve fell within a 30 degree angle constructed using the vertical limb perpendicular to the Frankfurt`s horizontal and a second limb drawn posteriorly from the midlobule. (Figure 2) The distance from the bony external auditory canal to the nerve was found to be 10.0cm at its emergence from under sternocleidomastoid muscle, 7.4cm at midbelly of sternocleidomastoid muscle and 5.0cm at anterior muscle border. Four types of branching patterns were identified and will be presented.

Conclusion: Injury to the great auricular nerve can be minimized by superficial dissection of the skin flap beginning in the preauricular area and extending posteriorly in a superficial subcutanous plane. The 30 degree angle decribed above accurately identifies the nerve`s distal course in 100% of our dissections.

Figure1. Vertical line passes through midlobule.

Figure. The nerve falls within the 30 degree angle.