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Sacral plexus

Other Terms: Sacral plexus, Plexus sacralis, Plexus sacral


The sacral nerve plexus is formed by the anterior divisions of some of the lower spinal nerves. Just below the brim of the pelvis, a part of the anterior division of the fourth lumbar joins the anterior division of the fifth lumbar nerve to form the lumbosacral trunk. This trunk joins the anterior divisions of the first and parts of the second and third sacral nerves to form the sacral plexus. The fourth sacral nerve also contributes to it by supplying a branch to the pudendal nerve. Therefore, the sacral plexus is formed by these nerves and the lumbosacral trunk. The shape of the plexus is triangular. The base of the triangle is situated at the intervertebral foramina and the apex is formed by the branches of the plexus at the lower part of the greater sciatic foramen. The sacral plexus lies in front of the piriformis muscle. It is covered anteriorly by the parietal pelvic fascia which separates it from the pelvic vessels and viscera. The superior roots are longer than the inferior roots. The inferior gluteal artery passes between the nerve roots at the lower part of the plexus, and the superior gluteal artery between the lumbosacral trunk and the anterior division of the first sacral nerve. The branches of this plexus are divided into collateral and terminal. They are: the sciatic nerve which branches into the tibial and fibular nerves, the posterior femoral cutaneous nerve, the pudendal nerve, and the superior and inferior gluteal nerves. The collateral branches are the superior and inferior gluteal, and the posterior femoral cutaneous nerve. The terminal branches are the sciatic nerve and the pudendal nerves.


Superior gluteal nerve
Inferior gluteal nerve
Sciatic nerve
Posterior femoral cutaneous nerve
Nerve to quadratus femoris
Nerve to gemellus inferior
Nerve to obturator internus
Nerve to piriformis
Branch of sacral nerve plexus to levator ani
Branch of sacral nerve plexus to coccygeus
Branch of sacral nerve plexus to external anal sphincter


Plexus sacralis


Plexus sacral


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