Anatomy of the Pudendal Nerve and Other Neural Structures Around the Proximal Hamstring Origin in Males

Abstract

To define the anatomy of the pudendal nerve in relationship to the proximal hamstring and other nearby neurological structures during proximal hamstring repair. Six fresh-frozen human cadaveric hemi-pelvises from male patients ages 64.0 ± 4.1years were dissected in prone position with hips in 10° flexion to identify the relationship of proximal hamstring origin to surrounding neurologic structures including the pudendal nerve, sciatic nerve, and posterior femoral cutaneous nerve. Two independent observers used digital calipers to measure distances. The pudendal nerve emerged at the inferior border of the piriformis muscle 6.3 ± 1.4cm from the superior aspect of the proximal hamstring origin. It passed the superior border of the sacrotuberous ligament 3.0 ± 0.6cm from the superior aspect and 3.9 ± 0.7cm from the medial aspect of the hamstring origin. It crossed the inferior border of the sacrotuberous ligament 3.0 ± 0.4cm from the superior aspect and 2.7 ± 0.7cm from the medial aspect of the proximal hamstring origin. The shortest distance from the hamstring origin to the pudendal nerve was 2.6 ± 0.5cm from the superior aspect and 2.3 ± 0.8cm from the medial aspect. The shortest distance from the hamstring origin to the pudendal nerve was located deep to the sacrotuberous ligament in all cadavers. The sciatic nerve was an average of 1.1 ± 0.1cm lateral to the lateral aspect of the proximal hamstring origin. The posterior femoral cutaneous nerve was located between the hamstring origin and the sciatic nerve, 0.7 ± 0.2cm lateral to the lateral aspect of the proximal hamstring origin. The proximal hamstring origin lies in close proximity to surrounding nerves, including the pudendal, sciatic, and posterior femoral cutaneous nerves. Knowledge that the pudendal nerve lies 2 to 3cm superior and medial to the proximal hamstring origin may help to prevent iatrogenic damage during surgical dissection and retraction when performing proximal hamstring repair or deep gluteal space endoscopy.