Lateral Femoral Cutaneous Nerve Entrapment

Fine architecture of the fascial planes around the lateral femoral cutaneous nerve at its pelvic exit: an epoxy sheet plastination and confocal microscopy study (2018). Xu Z, Tu L, Zheng Y, Ma X, Zhang H, Zhang M. 

Tendinous Canal: Iliac Fascia and Internal Oblique

Within the pelvis, the Lateral Femoral Cutaneous Nerve lies is enveloped by the posterior aspect of the psoas fascia and the iliacus fascia (Kulow et al 2021), it then pierces the fibrous septum of the iliac fascia and aponeurotic fibers of the internal oblique. These internal oblique aponeurotic fibers, which fuses and intermingles with the iliac fascia is inserted to the ASIS. It then traverses within a rigid tendinous canal formed from the iliac fascia and the aponeurotic fibers of the internal oblique. The iliac fascia is reinforced by the transverse abdominis aponeurosis. The nerve exits the pelvis via this tendinous canal within the internal oblique-iliac fascia septum.

The abdominal muscles, particularly the internal oblique and transversus abdominis, have a significant impact on the tendinous canal because the stretching of these muscles may tighten and narrow the canal.

Adipose Compartment & Iliolata Ligaments

On the medial side of the sartorius, after piercing the tendinous canal, the Lateral Femoral Cutaneous nerve runs between the sartorius the inferior extension of the inguinal ligament. The nerve then passes under the inferior aponeurotic extension of the external oblique and enters into an adipose compartment that lies over the sartorius.

This adipose compartment is sandwiched between the fascia lata (iliolata ligaments) and the sartorius inferior to the ASIS.

The part of the fascia lata inferior to the ASIS is composed of the inferior extension of the superficial fibers of the external oblique aponeurosis and the iliolata ligaments. The iliolata ligaments are 2-3 curtain strip-like structures of the fascia lata which attach, superiorly, to the ASIS and other parts of the fascia lata e.g. the inferior extension of the inguinal ligament and, inferiorly, are interwoven with the fascia lata inferomedially, being continued laterally as skin ligaments anchoring to the skin. One of the iliolata ligaments intermingles with the sartorius along the lateral border of the muscle.

Ligamentous Canal: Sartorius & Tensor Fascia Lata

The Lateral Femoral Cutaneous Nerve then pierced iliolata ligament that attaches to the lateral boarder of the sartorius to run in a longitudinal ligamental canal between the sartorius (medially) and tensor fasciae latae (laterally). 

Putzer et al (2017) noted dense fascial fibers after dissecting the interval between the tensor fascia lata, sartorius, and rectus femoris. They described a strong band of fibers extending from a proximal-lateral to distal-medial direction. Henry (1957) possibly described these same fascial webs that are found in the layers that occupy “the space between the origins of the rectus femoris and tensor fasciae [lata] muscles, uniting the deep aspects of their sheaths”. 

Could the Lateral Femoral Cutaneous Nerve also get entrapped in the dense fascia between the sartorius and tensor fascia lata?

References

The deep layer of the tractus iliotibialis and its relevance when using the direct anterior approach in total hip arthroplasty: a cadaver study (2017). David Putzer, Matthias Haselbacher, Romed Hörmann, Günter Klima, and Michael Nogler

Extensile Exposure. 2nd ed. (1957). Henry AK. pp. 209–210.

Kulow C, Reske A, Leimert M, Bechmann I, Winter K, Steinke H (2021). Topography and evidence of a separate “fascia plate” for the femoral nerve inside the iliopsoas – A dorsal approach