Sacral plexus

Last revised by Craig Hacking ◉ ◈ on 11 Oct 2022

Citation, DOI, disclosures and article data

Citation:

Knipe H, Hacking C, MacManus D, et al. Sacral plexus. Reference article, Radiopaedia.org (Accessed on 25 Sep 2023) https://doi.org/10.53347/rID-29885

DOI:

https://doi.org/10.53347/rID-29885

Permalink:

https://radiopaedia.org/articles/29885

rID:

29885

Article created:

30 Jun 2014, Henry Knipe ◉ ◈

Disclosures:

At the time the article was created Henry Knipe had no recorded disclosures.

View Henry Knipe's current disclosures

Last revised:

11 Oct 2022, Craig Hacking ◉ ◈

Disclosures:

At the time the article was last revised Craig Hacking had the following disclosures:

Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)

These were assessed during peer review and were determined to not be relevant to the changes that were made.

View Craig Hacking's current disclosures

Revisions:

27 times, by 10 contributors - see full revision history and disclosures

Systems:

Central Nervous System, Musculoskeletal

Sections:

Anatomy

Synonyms:

Sacral nerve plexus

The sacral plexus is formed by anterior rami of L4 to S4 and its branches innervate the pelvis, perineum and lower limb.

Gross anatomy

The sacral plexus forms on the anterior belly of the piriformis muscle and is formed by the lumbosacral trunk (L4-5) of the lumbar plexus, which enters the pelvis coursing medially to psoas major and unites with the ventral rami of the S1 to S4 nerve roots, which emerge from the anterior foramina of the sacrum. It forms a triangular shape with an inferiorly pointing apex.

The are a total of twelve branches⁵. The anterior sacral rami give off six branches and then divide into the anterior and posterior divisions, which provide a further three branches each (see below).

Branches

Anterior rami

nerve to piriformis (S1-S2)
perforating cutaneous nerve (S2-S3)
posterior femoral cutaneous nerve (S1-S3)
parasympathetic pelvic splanchnic nerves (S2-S4)
pudendal nerve (S2-S4)
perineal branch (S4)

See: mnemonic.

Anterior division of anterior rami

nerve to quadratus femoris and inferior gemellus muscles (L4-S1)
nerve to internal obturator and superior gemellus muscles (L5-S2)
tibial portion (L4-S3) of the sciatic nerve (L4-S3)

See: mnemonic.

Posterior division of anterior rami

superior gluteal nerve (L4-S1)
inferior gluteal nerve (L5-S2)
common peroneal portion (L4-S2) of the sciatic nerve (L4-S3)

See: mnemonic.

Relations

medial
- anterior sacral foramina
- sympathetic trunk
posterior
- piriformis
anterior
- parietal pelvic fascia
- lateral sacral arteries and veins
- common iliac vessels on top of lumbrosacral trunk
- internal iliac vessels
- ureter (in front of internal iliac vessels) lies well anterior to upper part of plexus

Variant anatomy

common peroneal and tibial parts of the sciatic nerve fail to unite and course into the lower limb separately
additional caudal nerve root contribution to the sacral plexus ⁶