Formation: Ventral branches of last few lumbar + first 2 sacral spinal nerves.

In ox: L4, L5, L6, S1, S2 mainly.

Major nerves of hindlimb (from this plexus):
1. Femoral nerve (L4-L6) → quadriceps; sensation to medial leg.
2. Obturator nerve (L4-L6) → adductors.
3. Sciatic nerve (L6-S2) → biggest nerve of body; supplies all hamstrings + everything below stifle (via tibial + peroneal branches).
4. Cranial Gluteal nerve → middle/deep gluteus + tensor fasciae latae.
5. Caudal Gluteal nerve → superficial gluteus.
6. Pudendal nerve (S2-S4) → perineum, external genitalia.

LUMBOSACRAL PLEXUS — root supply of hindlimb

The lumbosacral plexus is a network of nerves formed by the ventral branches of the last few lumbar and first two sacral spinal nerves. In ox it is mainly L4-L6 + S1-S2. From this plexus all the nerves of the hindlimb arise.

MAJOR BRANCHES — what each does:
• Femoral Nerve (L4-L6): exits the abdomen via the muscular lacuna; supplies the iliopsoas + the QUADRICEPS FEMORIS. Damage = inability to bear weight (stifle collapses).
• Obturator Nerve (L4-L6): runs along medial pelvis, exits via obturator foramen; supplies the ADDUCTORS. Damage in calving = downer cow with splayed legs.
• Cranial Gluteal Nerve: Through greater sciatic foramen → middle gluteus + deep gluteus + tensor fasciae latae.
• Caudal Gluteal Nerve: → superficial gluteus.
• SCIATIC NERVE (L6-S2): The biggest nerve in the body. Exits via greater sciatic foramen, runs caudal to greater trochanter. Splits at level of stifle into:
– Tibial nerve (caudal branch).
– Common Peroneal (Fibular) nerve (cranial branch).
• Pudendal Nerve (S2-S4): To perineum and external genitalia. Site for the Pudic / Pudendal nerve block.
• Caudal Cutaneous Femoral Nerve: Skin of caudal thigh.