Furcal nerve

Furcal nerve (furcal meaning ‘forked’) is an independent spinal nerve which arises commonly from the fourth lumbar spinal segment (L4), or sometimes even from the third lumbar spinal segment (L3). It has its own ventral and dorsal roots and a dorsal root ganglion. It is situated anterosuperior to the L4 nerve roots, as it runs beside them to exit through the intervertebral foramen.

Normally the lumbar plexus is connected with the sacral plexus via a lumbosacral trunk (formed from the ventral rami of L4 and L5 spinal nerves). Here furcal nerve serves as an additional link between lumbar and sacral plexuses. The neuronal fibers from the furcal nerve reach out to the branches of lumbar plexus, such as femoral nerve, lumbosacral trunk or to the obturator nerve.

From a clinical perspective, it is important to know about the furcal nerve as it can become a culprit in case of an atypical presentation of the radiculopathy/sciatica, by creating a disparity between imaging and clinical presentation, thus presenting a dilemma to a treating surgeon.