A Comprehensive Study of the Potential Compression Points of the Third Occipital Nerve and Its Possible Clinical Interests.

BACKGROUND

The anatomic features of the third occipital nerve (TON) are the least studied among the occipital nerves. This study aimed to analyze the anatomic features and potential compression points of the TON.

METHODS

The posterior neck and scalp of 39 cadavers were dissected. The TON was carefully followed from the emerging point from C2-C3 vertebrae distally. Its muscular investments were detected. The determined points were marked superficially and measured according to external occipital protuberance with Image J software.

RESULTS

The TON revealed 4 different potential entrapment points along its course. The most proximal point was between the C2 and C3 vertebrae. The second and third points were at their piercing points of semispinalis capitis and splenius capitis muscles, respectively. The final point was at its penetrating point of the trapezius muscle. The TON did not pierce the semispinalis capitis muscle on 6 sides, and pierced this muscle from 3 different points by splitting into 3 branches on 1 side. On 5 sides, the TON split into 2 branches and perforated the splenius capitis muscle from 2 different points.

CONCLUSIONS

There were 4 potential compression points regarding the TON. These entrapment points and variations of the TON may play a significant role in understanding the reason for TON-related headaches and the treatment of headaches caused by the TON.