Fibrous configuration of the fascia iliaca compartment: An epoxy sheet plastination and confocal microscopy study

Background and Objectives: The underlying anatomical mechanism of the ultrasound-guided fascia iliaca compartment (FIC) block for anaesthesia and analgesia in the lower limb has not been illuminated and numerous variations were attempted to achieve an optimal needle placement. This study aimed to define the fibrous configuration of the FIC. Methods: A total of 46 adult cadavers were studied using dissection, latex injection, epoxy sheet plastination and confocal microscopy. Results: (1) The fascia iliaca originated from the peripheral fascicular aponeurotic sheet of the iliopsoas. (2) The FIC was a funnel-shaped adipose space between the fascia iliaca and the epimysium of the iliopsoas, had a superior and an inferior opening and contained the femoral and lateral femoral cutaneous nerves but not obturator nerve. (3) The estimated volume of the FIC in the cadavers was about 23 mls, of which about one third was below the level of the anterior superior iliac spine. Conclusions: This study revealed that the fascia iliaca was aponeurotic and may be less permeable for the local anesthetics. Conclusions: The FIC contained only the femoral and lateral femoral cutaneous nerves and communicated with the extraperitoneal space and femoral triangle adipose space via its superior and inferior opening, respectively.