Unusual formation pattern of the femoral nerve with intramuscular and submuscular courses - a case report.

Background: The femoral nerve typically arises as a single trunk from L2-L4 posterior divisions of ventral rami. Variations are rare but clinically significant.

Materials and methods: During routine dissection of a 80 years old female cadaver, the femoral nerve was found to originate as two distinct trunks - with one passing beneath the psoas major and the other coursing through it. The trunks unified distal to the inguinal ligament. No anomalous muscular slips were present.

Results: This configuration appears to be previously unreported.

Conclusions: Surgeons and clinicians performing femoral nerve blocks or interpreting lumbar plexus imaging (e.g., MRI, CT, or ultrasound) should be aware of this variant, as it may influence both diagnostic interpretation and procedural outcomes.