Anatomic Study of Innervation of the Anterior Hip Capsule: Implication for Image-Guided Intervention

Abstract

Background and objectives: The purpose of this cadaveric study was to determine the pattern of anterior hip capsule innervation and the associated bony landmarks for image-guided radiofrequency denervation.

Methods: Thirteen hemipelvises were dissected to identify innervation of the anterior hip capsule. The femoral (FN), obturator (ON), and accessory obturator (AON) nerves were traced distally, and branches supplying the anterior capsule documented. The relationships of the branches to bony landmarks potentially visible with ultrasound were identified.

Results: The anterior hip capsule received innervation from the FNs and ONs in all specimens and the AON in 7 of 13 specimens. High branches of the FN (originating above the inguinal ligament) were found exclusively in 12 specimens and passed between the anterior inferior iliac spine and the iliopubic eminence. The ONs were innervated exclusively by high branches (proximal to the division), by low branches (from the posterior branch), and by both in 4, 5, and 4 specimens, respectively. The most consistent landmark was the inferomedial acetabulum (radiographic "teardrop"). When present, the AON coursed over the iliopubic eminence before innervating the anterior hip capsule.

Conclusions: Branches of the FNs and ONs consistently provided innervation to the anterior hip capsule. The AON also contributed innervation in many specimens. The relationship of the articular branches from these 3 nerves to the inferomedial acetabulum and the space between the anterior inferior iliac spine and iliopubic eminence may suggest potential sites for radiofrequency ablation.