Sacral spinal nerve 4

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The sacral spinal nerve 4 (S4) is a spinal nerve of the sacral segment.^[1].

It originates from the spinal column from below the 4th body of the sacrum

[edit] Muscles

S4 supplies many muscles, either directly or through nerves originating from S4. They are not innervated with S4 as single origin, but partly by S4 and partly by other spinal nerves. The muscles are:

• iliococcygeus
• puborectalis
• coccygeus
• Sphincter ani externus muscle
• sphincter urethrae membranaceae

[edit] References

v • d • e Nerves: spinal nerves Cervical (8) C1, C2, C3, C4, C5, C6, C7, C8 anterior (Cervical plexus, Brachial plexus) - posterior (Posterior branches of cervical nerves, Suboccipital - C1, Greater occipital - C2, Third occipital - C3) Thoracic (12) T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12 anterior (Intercostal, Intercostobrachial - T2, Thoraco-abdominal nerves - T7-T11, Subcostal - T12) - posterior (Posterior branches of thoracic nerves) Lumbar (5) L1, L2, L3, L4, L5 anterior (Lumbar plexus, Lumbosacral trunk) - posterior (Posterior branches of the lumbar nerves, Superior cluneal L1-L3) Sacral (5) S1, S2, S3, S4, S5 anterior (Sacral plexus) - posterior (Posterior branches of sacral nerves, Medial cluneal nerves) Coccygeal (1) anterior (Coccygeal plexus) - posterior (Posterior branch of coccygeal nerve)