Posterior root of posterior femoral cutaneous nerve
Radix posterior nervi cutanei femoris posterioris
The contribution to the posterior femoral cutaneous nerve that comes from the posterior divisions of the first and second sacral nerves.
At a glance
- English
- Posterior root of posterior femoral cutaneous nerve
- Latin (TA2)
- Radix posterior nervi cutanei femoris posterioris
- System
- Nerve
- Region
- Lower limb
- Side
- Paired, left and right
About the posterior root of posterior femoral cutaneous nerve
The posterior femoral cutaneous nerve is the sensory branch of the sacral plexus that serves the back of the thigh. It is formed from two roots. The posterior root consists of fibres from the posterior (dorsal) divisions of the anterior rami of the first and second sacral nerves. The anterior root, its partner, comes from the anterior (ventral) divisions of the second and third sacral nerves.
The posterior divisions of the sacral plexus also give rise to the superior and inferior gluteal nerves and to the common fibular part of the sciatic nerve, so the posterior root shares its origin with the nerves of the back of the limb girdle. The two roots unite on the front of piriformis, and the single nerve then leaves the pelvis through the greater sciatic foramen below piriformis, alongside the inferior gluteal nerve and vessels.
The posterior-division fibres are often described as reaching the skin of the lower buttock and the back of the thigh, including the inferior cluneal nerves, while the anterior-division fibres pass to the perineal branches. Lesions of the first and second sacral nerves, such as compression of the S1 root by a disc prolapse at the lumbosacral junction, may therefore alter sensation on the back of the thigh in addition to the more familiar changes in the calf and the outer border of the foot.
Course and supply
- Arises from
- Posterior divisions of the anterior rami of the first and second sacral nerves, in the sacral plexus.
- Ends in
- Joins the anterior root on the front of piriformis to form the posterior femoral cutaneous nerve.
- Supplies
- Carries sensory fibres from S1 and S2 into the posterior femoral cutaneous nerve.
Anthromica
See the posterior root of posterior femoral cutaneous nerve where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
