The canine lumbosacral plexus, the source of multi-segmental nerves that innervate the pelvic limb and pelvis, is formed by ventral branches L4 though S3. The plexus gives rise to three major nerves that innervate the pelvic limb (femoral, obturator and sciatic) and two major nerves to the pelvis (pudendal and pelvic). Other nerves from the plexus innervate gluteal and pelvic diaphragm muscles and several cutaneous nerves.
The femoral n. (blue) innervates cranial muscles of the thigh. The obturator n. (orange) innervates adductor musculature. The sciatic n. (dark green) innervates the remaining limb muscles: hamstring and crus muscles. The pudendal n. (purple) conveys somatic innervation and the pelvic n. (yellow) conveys visceral innervation to the pelvis