Lateral femoral cutaneous nerve: anatomy and sonoanatomy

Which of the following statements is NOT correct about the lateral femoral cutaneous nerve (LFCN)?

A. It usually arises from the ventral ramus of the L2 and L3 nerve roots
B. It is at high risk for injury with the anterior approach to a total hip arthroplasty.
C. Its course and sensory distribution is variable
D. It is a mixed sensory/motor neuron

Show Answer

Correct answer: D

Explanation:

All other statements are true except D. The LFCN is a purely sensory nerve arising from the posterior divisions of the ventral rami of the L2 and L3 nerve roots where it courses lateral to the psoas muscle and anterior to the iliacus muscle before coming from underneath the inguinal ligament to divide into an anterior and posterior branch medial to the ASIS and superficial to the sartorius muscle. Its cutaneous distribution can be variable, though it usually provides sensory innervation to the anterolateral thigh. This nerve can be injured with the anterior approach to a total hip arthroplasty roughly 30% of the time.

References:

Rudin D, Manestar M, Ullrich O, Erhardt J, Grob K. “The Anatomical Course of the Lateral Femoral Cutaneous Nerve with Special Attention to the Anterior Approach to the Hip Joint.” J Bone Joint Surg Am 2016;98:561-7.

Corujo A, Franco CD, Williams JM. “The Sensory Territory of the Lateral Cutaneous Nerve of the Thigh as Determined by Anatomic Dissections and Ultrasound-Guided Blocks.” Reg Anesth Pain Med 2012;37:561-4.

Hide Answer