Variant anatomy of pudendal nerve and Alcock’s canal in mature women according to magnetic resonance imaging

Background. To optimize treatment methods for pudendal nerve neuropathy and to study the mechanisms of pudendal nerve damage, further research into the variant anatomy of the pudendal nerve and a deeper understanding of the nerve’s interaction with the surrounding tissues are necessary. Objective. To study the variant anatomy of the pudendal nerve and Alcock’s canal in mature women using magnetic resonance imaging data. Material and methods. All study participants were divided into two age groups based on the generally accepted age division of human ontogenesis: the first group (22—35 years old) — 30 women, the second group (36—60 years old) — 30 women. During the analysis of magnetic resonance imaging of the pelvic organs, the following were studied: the length and diameter of the pudendal nerve and its branches, the spinal roots involved in the formation of the pudendal nerve, the topography of the gluteal and internal pudendal arteries, and the length and diameter of the sacrospinous ligament, as one of the main causes of pudendal nerve compression. Results. In all cases, the pudendal nerve in the studied group of women formed from the roots SII, SIII and SIV. The most common types of pudendal nerve branching were: type 1 (with single branching), which was detected in 33 (55.0%) women, and type 2 (with double branching), observed in 12 (20.0%) examined women. The median distance from the beginning of the formation of the main trunk of the pudendal nerve to the level of the middle of the sciatic spine was 28.1 [15.2; 37.4] mm on the left and 27.9 [19.4; 36.8] mm on the right. The median length of the genital canal, measured from the middle of the sciatic spine to the exit point of the largest terminal branch of the pudendal nerve was 38.7 [19.8; 48.5] mm on the left and 39.6 [22.7; 53.9] mm on the right. In 41.6% (n=25) of women, the inferior rectal nerve was observed to pass directly into the genital canal. Conclusion. Magnetic resonance imaging examination of the pelvic organs in various modes and planes allows for a detailed study of the anatomy of the genital nerve and Alcock’s canal in mature women. The results obtained can be used in the diagnosis and treatment of patients with the compression form of pudendal nerve neuropathy.