Sacral plexus

 ( Nerve Plexus ) 

In human anatomy, the sacral plexus is a nerve plexus which provides motor and sensory nerves for the posterior thigh, most of the lower leg and foot, and part of the pelvis. It is part of the lumbosacral plexus and emerges from the lumbar vertebrae and sacral vertebrae (L4-S4). Thieme Atlas of Anatomy (2006), pp 470-471 A sacral plexopathy is a disorder affecting the nerves of the sacral plexus, usually caused by trauma, nerve compression, vascular disease, or infection. Symptoms may include pain, loss of motor control, and sensory deficits.

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Structure The sacral plexus is formed by:

• the lumbosacral trunk
• the anterior division of the first sacral nerve
• portions of the anterior divisions of the second and third sacral nerves

The nerves forming the sacral plexus converge toward the lower part of the greater sciatic foramen, and unite to form a flattened band, from the anterior and posterior surfaces of which several branches arise. The band itself is continued as the sciatic nerve, which splits on the back of the thigh into the tibial nerve and common fibular nerve; these two nerves sometimes arise separately from the plexus, and in all cases their independence can be shown by dissection. Often, the sacral plexus and the lumbar plexus are considered to be one large nerve plexus, the lumbosacral plexus. The lumbosacral trunk connects the two plexuses.

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Relations The sacral plexus lies on the back of the pelvis in front of the piriformis muscle and the pelvic fascia. In front of it are the internal iliac artery, internal iliac vein, the ureter, and the sigmoid colon. The superior gluteal artery and vein run between the lumbosacral trunk and the first sacral nerve, and the inferior gluteal artery and vein between the second and third sacral nerves.

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Nerves formed All the nerves entering the plexus, with the exception of the third sacral, split into ventral and dorsal divisions, and the nerves arising from these are as follows of the table below:

+ Nerves of the sacral plexus Thieme Atlas of Anatomy (2006), pp 476, 478, 482
! Nerve !! Segment !! Innervated muscles !! Cutaneous branches
Superior gluteal	L4-S1	Gluteus medius Gluteus minimus Tensor fasciae latae
Inferior gluteal	L5-S2	Gluteus maximus
Posterior cutaneous femoral Inferior cluneal nerves Perineal branches	S1-S3
Perforating cutaneous	S2-S3
Direct branches from plexus
Piriformis S1-2	Piriformis
Obturator internus L5, S1-2	Obturator internus and Superior gemellus
Quadratus femoris L4-5, S1	Quadratus femoris and Inferior gemellus
Sciatic nerve	L4-S3	Semitendinosus (Tib) Semimembranosus (Tib) Biceps femoris Long head (Tib) Short head (Fib) Adductor magnus (medial part, Tib)
Common fibular	L4-S2		Lateral sural cutaneous Communicating fibular
Superficial fibular	[[Fibularis longus]] [[Fibularis brevis]]	Medial dorsal cutaneous Intermediate dorsal cutaneous
Deep fibular	Tibialis anterior Extensor digitorum longus Extensor digitorum brevis Extensor hallucis longus Extensor hallucis brevis Fibularis tertius	Lateral cutaneous nerve of big toe Intermediate dorsal cutaneous
Tibial nerve	L4-S3	[[Plantaris>Plantaris muscle]] Tibialis posterior Flexor digitorum longus Flexor hallucis longus	Medial sural cutaneous Medial calcaneal Lateral dorsal cutaneous
Medial plantar	Abductor hallucis Flexor digitorum brevis Flexor hallucis brevis (medial head) Lumbrical (first and second)	Proper digital plantar
Lateral plantar	Flexor hallucis brevis (lateral head) Quadratus plantae Abductor digiti minimi Flexor digiti minimi Lumbrical (third and fourth) Plantar interossei (first to third) Dorsal interossei (first to fifth) Adductor hallucis	Proper plantar digital
! colspan=4 >Pudendal and coccygeal
Pudendal nerve (Pudendal plexus)	S2-S4	Muscles of the [[pelvic floor]]: [[Levator ani]] Superficial transverse perineal Deep transverse perineal Bulbospongiosus Ischiocavernosus Sphincter anus externus Urethral sphincter	[[Perineal>Perineal nerve]] Posterior scrotal/labial Dorsal penis/clitoris prostatic urethra./vagina
Coccygeal nerve (Coccygeal plexus)	S5-Co1	Coccygeus muscle]]	Anococcygeal Dorsal branches

==Additional images==

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See also

• Cervical plexus
• Brachial plexus
• Lumbar plexus
• Coccygeal plexus
• Lumbosacral plexus
• Nerve plexus
• Sciatic nerve
• Pudendal nerve
• Posterior femoral cutaneous nerve
• Superior gluteal nerve
• Inferior gluteal nerve

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Notes

• (2025). 9781588904195, Thieme. ISBN 9781588904195

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External links

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