= Sacral plexus
The <sacral plexus> is a network of anterior <spinal nerve rami>, usually incorporating L4–S4 spinal contributions, lying against the anterior surface of the <piriformis muscle>. It distributes sensory and motor fibres to much of the pelvis and lower <limb>. Major branches include the <sciatic nerve> and the <pudendal nerve>.<Anatomy and Physiology 2e by J. Gordon Betts and others>[Section 13.4, Nerve Plexuses]{ref}
Its mixed origins explain an otherwise puzzling arrangement: the <sciatic nerve> carries fibres associated with several <spinal nerves>, and fibres from one spinal level can leave through different peripheral branches. A <nerve plexus> is therefore a redistribution network, rather than a new set of <neurons> inserted into each pathway.
Back to article page
