The posterior femoral cutaneous nerve contributes significantly to sensory innervation of the lower leg: an anatomical investigation

Abstract

Background: Incomplete peripheral nerve blocks distal to the popliteal region are commonly considered a sciatic and femoral/saphenous nerve block failure. The existence of a much more distal innervation area of the posterior femoral cutaneous nerve (PFCN) as described has not been assumed yet. We therefore investigated the distal termination of the PFCN in the lower leg. Methods: In 83 human lower extremities embalmed with Theil's method, the course of the PFCN was investigated from the sub-gluteal fold to the most distal macroscopically dissectible branch. The topographic connection to other landmarks, such as the small saphenous vein or small arteries, was investigated. Results: Popliteal ending of the PFCN was found in 9.7% of cases. The PFCN terminated at the proximal or distal lower leg in 45.7% and 44.6% of cases, respectively. The PFCN had a close connection to the Achilles tendon in 13.2% of cases and was found distally to the medial malleolus in one case. The small saphenous vein was close to the PFCN in 90.3% of cases and can therefore be used as a landmark to identify the nerve. In 40.9% of cases, the PFCN was accompanied by a small descending branch of the inferior gluteal artery. In two cases, an innervation of the fibula or calcaneus periosteum was found. Conclusions: The PFCN has a much more distal termination in the lower leg than previously demonstrated. To ensure complete anaesthesia of the lower leg and foot, the PFCN must be included in combined peripheral nerve block procedures.

Posterior Lumbar Plexus Block Anesthesia for Elderly Patients with Lower Limb Fracture

“…These results might be owing to the rapid absorption rate of anesthetics by the epidural space during epidural anesthesia, which easily leads to an excessive anesthesia plane and subsequent fluctuations in the circulatory and respiratory functions during the perioperative period, manifesting as abnormal changes in hemodynamic indicators. The posterior lumbar plexus block can avoid the above shortcomings [ 17 ]. Meanwhile, the lumbar plexus involves the obturator, femoral, and lateral femoral cutaneous nerves.…”

Unique Considerations for Complete Surgical Analgesia for Below-the-Knee Amputations

“…In their studies of 83 human cadavers, popliteal ending of the PFCN was found in only 9.7% of the cases, whereas in 44.6% of the cases it was found to end within 10 cm of the most distal point of medial malleolus. In 13.2% of the cases, PFCN showed a close connection to the Achilles tendon [5]. The results of these cadaveric anatomical studies cannot be directly translated into clinical significance, given the fact that the vast majority of the patients tolerate BKA surgeries very well after receiving just saphenous and sciatic nerve blocks [6].…”

“…It is not commonly considered as a block target for surgical procedures below the knee. However, there is emerging anatomical evidence suggesting that PFCN may contribute to the sensory innervation of the posterior lower leg [5]. In this report, we present a case in which a combination of femoral and sciatic nerve blocks failed to provide adequate surgical analgesia in the posterior lower leg region for a patient who underwent below-the-knee amputation (BKA) and subsequent formalization surgery.…”

The Importance of Sacral Neuroanatomy in Pain Syndromes and Procedures

“…This nerve is the pure sensory nerve and has no motor innervations. The PFCN innervates the skin of the perineum, the posterior surface of the thigh, and various areas of the back of the leg (28,29).…”