Posterior Femoral Cutaneous Nerve

Introduction[edit|edit source]

Theposterior cutaneous nerve of the thigh, also known as theposterior femoral cutaneous nerve的感觉神经sacral plexus. It supplies the skin of the posterior thigh, buttock, posterior aspect of the scrotum or labia and a variable area of the posterior calf^[1].

结构体ure & Origin[edit|edit source]

The fibers contributing to the posterior cutaneous nerve of the thigh arise from the posterior divisions of the anterior rami of the S1 and S2 nerves, and the anterior divisions of the anterior rami of nerves S2 and S3^[2].

The nerve first appears lateral to the anteriorsacral foramina, positioned underneath the psoas muscle's parietal pelvic fascia. It exits the pelvis inferior to thepiriformismuscle via thegreater sciatic foramen.

Course[edit|edit source]

After exiting the pelvis via the greater sciatic foramen, the posterior cutaneous nerve of the thigh travels with theInferior Gluteal Arterydeep to thegluteus maximus, overlying thesciatic nerve. It descends down the posterior thigh towards the back of the knee, deep to thefascia lataand superficial to the thebiceps femoris(long head). Once the nerve reaches thepopliteal fossa(posterior knee), it pierces through the deep fascia and travels towards the first half of the posterior leg with theSmall Saphenous Vein. Its terminating branches connect to thesural nerve.

Branches & Supply[edit|edit source]

The posterior femoral cutaneous nerve of the thigh gives off three cutaneous branches. The branches are dispersed to the region of the buttock, the perineum and to the posterior thigh and leg.

• Thegluteal branch, aka theinferior cluneal nerve(originating from posterior divisions of the S1 and S2 anterior rami), travels upward around the inferior boarder of the gluetus maximus muscle to supply the skin overlying the inferior and lateral aspect of the buttock.

• Theperineal branchcourses medially between thegracilismuscle and the fascia lata to supply the skin located over the proximal and medial aspect of the thigh. The perineal branch also supplies the posterior aspect of the labia majora or scrotum.
• The nerve branch supplying the cutaneous distribution of the posterior thigh gives off perforating branches for cutaneous innervation as it courses inferiorly between thehamstringsand fascia lata, innervating the skin over the posterior thigh. It also provides cutaneous innervation to the skin over the medial thigh,popliteal fossaand sometimes the proximal aspect of the posterior leg. It can terminate as low as the area of the inferiorgastrocnemiusmuscle belly over the mid-calf.

Relations[edit|edit source]

The inferior gluteal artery and nerve are in close proximity to the posterior femoral cutaneous nerve as these structures exit the greater sciatic foramen, inferior to thepiriformismuscle and superior to thesciatic nerve. Furthermore, other structures also travel inferior to thepiriformismuscle, including the nerve toobturator internus,pudendal nerveand theinternal pudendal artery.

Anatomical Variants[edit|edit source]

Occasionally, the S4 nerve root can contribute to the posterior femoral cutaneous nerve. According to one study, the posterior femoral cutaneous nerve has been discovered as a coupled structure in 18% of cadavers^[3].

Related Pathology[edit|edit source]

It is possible that pain attributed to pelvic pathology can refer to the posterior thigh, and may be confused with other pathology such assciatica. This is because the posterior femoral cutaneous nerve shares the same S2/3 nerve segments as the parasympathetic nerve fibers that contribute to the pelvic splanchnic nerves. The posterior femoral cutaneous nerve may play a role in pelvic pain syndrome^[4].

References[edit|edit source]