Lumbar Plexus

This plexus is situated in the posterior part of the psoas major muscle, anterior to the transverse processes of the lumbar vertebrae. It is formed by the ventral branches of the first three lumbar nerves and most of the fourth lumbar nerve (L1, L2, L3 and L4) and an anastomotic branch of T12, giving a branch to the sacral plexus.

L1 receives the anastomotic branch from T12 and then supplies three branches which are the Iliohypogastric Nerve, the Ilioinguinal Nerve and the Superior Root of the Genitofemoral Nerve.

L2 trifurcates giving the inferior root of the Genitofemoral Nerve , the Superior Root of the Lateral Cutaneous Nerve of the Thigh and the Superior Root of the Femoral Nerve.

L3 grants the Lower Root of the Lateral Cutaneous Nerve of the Thigh , the Middle Root of the Femoral Nerve and the Upper Root of the Obturator Nerve.

L4 supplies the anastomotic branch to L5 and then bifurcates giving the Inferior Root of the Femoral Nerve and the Inferior Root of the Obturator Nerve.

LUMBAR PLEXUS

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.

LUMBAR PLEXUS

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.

OBTURATORY NERVE

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.

FEMORAL NERVE AND LATERAL CUTANEOUS THIGH

Source: NETTER, Frank H.. Atlas of Human Anatomy. 2nd edition Porto Alegre: Artmed, 2000.