The accessory obturator nerve: an anatomical study with literature analysis

Abstract

The accessory obturator nerve (AON) (Figure 1) was first described in 1672 by Isbrand van Diemerbroeck. [1] He reported that it was found in roughly one out of every three persons and originated from the third and fourth lumbar nerves. [1] Not until 1794 was it described in detail by Schmidt (1794). Since its discovery, it has been called the anterior internal crural nerve, accessory nerve of the internal crural nerve, and the nerve of the coxo-femoral articulation. [2] Some have proposed that it should be named the accessory femoral nerve owing to its typical derivation from the posterior part of the anterior division of L3 and L4, its function, and its anatomicalcourse over the pubic ramus. [3] The lumbar plexus is derived from the ventral rami of L1-L4, often with a contribution from T12. [4] The obturator nerve is most commonly derived from the L2 to L4 ventral rami. [4] The AON is described in Katritsis et al. [5] as being derived from the posterior part of the anterior division of L3 and L4. Typically, the AON passes alongside the obturator nerve toward the obturator foramen. Instead of passing through this foramen, it passes over it. There are multiple variationsof the terminal branches of the AON after it passes over the superior pubic ramus (Tables 1-3). [5-16] Knowledge of the AON and its variations can be important to surgeons, especially regarding anterior and lateral approaches to the spine. [17-19] Misidentification of the nerve can also lead to injury. [20]

A systematic review and meta-analysis of the hip capsule innervation and its clinical implications

“…NS = not stated. Study Number of cadavers included Sample size (hip joints) Range or average age at time of death Sex ratio (female : male) Side ratio (right:left) Ethnicity Berhanu et al (2020) 71 34 67 NS NS 34:33 Ethiopian Nielsen et al 2018 66 8 15 81–98 years 7:1 NS NS Sakamoto et al 2018 64 14 14 73.8 years 5:9 0:14 Japanese Short et al 2018 67 13 13 79.3 years 9:4 NS NS Nielsen et al 2017 68 7 14 NS 4:3 7:7 NS Turgut et al 2017 80 20 40 NS 12:8 20:20 NS Sakamoto et al 2014 65 2 NS Adult NS NS Japanese Roh...…”

Fetal topography of arteries and nerves of muscles of the medial femoral group

“…It should also be noted that the direction of the intramuscular nerves does not coincide with the direction of the intramuscular arteries in all the muscles of the medial group of the thigh. Even the type of intramuscular branching of nerves and arteries in the same muscle can differ 18 .…”

Pelvic Lymphadenectomy in Gynecologic Oncology—Significance of Anatomical Variations

“…The ON crosses the sacroiliac joint behind the CIA, lateral to the internal iliac vessels travels along the lateral wall of the lesser pelvis and enters the obturator foramen. The ON is located cranial to the OA and OV [ 41 , 101 , 102 , 103 , 104 ].…”

“…The incidence of AON in the human population varies from 10% to 30%. Studies did not find differences of AON presence between genders [ 41 , 101 , 102 , 103 , 104 ].…”

“…Surgical considerations. Compression and subsequent neuropathy may occur as a result of damage to the AON [ 103 ]. Such an injury is possible during a dissection of the lateral external iliac, obturator, lateral, and middle common iliac lymph nodes.…”