Lumbar Plexus and Nerve Anatomy

The ilioinguinal nerve is a sensory and motor nerve that emerges from the lumbar plexus and travels through the inguinal canal. It supplies various areas in the groin and thigh.

The ilioinguinal nerve provides sensation to the anterior labial or scrotal skin, pubic region, and superior antero-medial thigh.

The ilioinguinal nerve innervates the internal and transversal abdominal muscles.

Damaging the ilioinguinal nerve often results from surgical trauma to the abdominal muscles. It can also occur during inguinal hernia repairs and pregnancy.

The genitofemoral nerve emerges from the lumbar plexus and divides into femoral and genital branches.

The femoral branch of the genitofemoral nerve provides sensation to the anterior, upper, and medial regions of the thigh, while its genital branch innervates the anterior scrotal skin in men and the mons pubis and labia majora in women.

The genital motor branch of the genitofemoral nerve controls the cremaster muscle in men, responsible for raising the testicles.

The lateral femoral cutaneous nerve emerges from the lumbar plexus, runs near the iliac fossa, and eventually provides sensation to the anterior and posterior lateral thigh, down to the knee.

A mixed nerve that innervates the thigh and leg, providing both sensory and motor functions.

A branch of the femoral nerve, it provides sensory innervation to the skin of the anteromedial thigh, medial leg, and foot.

A nerve that originates from the lumbar plexus (L2-L4), entering the medial thigh through the obturator canal.

This nerve primarily provides motor control to the adductor muscles, which are responsible for drawing the thighs towards the midline.

The obturator nerve provides sensory innervation to the medial thigh, ensuring we feel sensations from that area.

The sacral plexus is a complex network of nerves found on the posterior pelvic wall, formed by the ventral rami of spinal nerves L4-L5 and S1-S4.

Originating from the sacral plexus (L4-S1), this nerve primarily controls the tensor fasciae latae, gluteus medius, and gluteus minimus, assisting in hip abduction and external rotation.

Originating from the sacral plexus (L5-S2), it provides motor innervation to the gluteus maximus muscle, which helps with hip extension and external rotation.

The iliohypogastric nerve is formed from spinal nerves T12 and L1. It emerges from the lumbar plexus and travels through the abdominal muscles, providing sensation to the skin of the gluteal region and suprapubic area, and motor control to the abdominal wall muscles.

The iliohypogastric nerve travels anterolaterally, crossing the psoas major muscle, passing in front of the quadratus lumborum muscle, and then piercing the transversus abdominis muscle.

The iliohypogastric nerve has two branches, the lateral cutaneous branch and the anterior cutaneous branch. The lateral cutaneous branch provides sensation to the skin of the posterolateral gluteal region, while the anterior cutaneous branch supplies sensation to the skin of the suprapubic region.

The iliohypogastric nerve provides motor innervation to the transversus abdominis muscle, internal oblique muscle, and the conjoint tendon, which helps stabilize the abdominal wall.

Damage to the iliohypogastric nerve can occur due to surgical trauma, sports injuries, or pregnancy-related abdominal expansion. Clinical signs include burning pain in the suprapubic and inguinal regions.

The ilioinguinal nerve is formed from the L1 spinal nerve and originates from the lumbar plexus.

The ilioinguinal nerve emerges from the lumbar plexus, courses posterior to the psoas major muscle, and then runs along the anterior surface of the quadratus lumborum muscle. It passes through the transversus abdominis muscle and then through the internal oblique muscle.

The ilioinguinal nerve provides sensory innervation to the skin of the upper medial thigh, the scrotum in males, and the mons pubis and labia majora in females.

A nerve arising from spinal segments S2-S3 that provides cutaneous innervation to the inferior medial part of the buttock.

A nerve originating from spinal segments S1-S3 that exits the pelvis through the greater sciatic foramen and travels along the back of the thigh to the knee.

A nerve arising from spinal segments L4-S1 that leaves the pelvis through the greater sciatic foramen, enters the gluteal region, and innervates the quadratus femoris, inferior gemellus muscles, and the hip joint.

A nerve originating from spinal segments L5-S2 that exits the pelvis via the greater sciatic foramen, enters the lesser sciatic foramen, and innervates the obturator internus and superior gemellus muscles.

A mixed nerve arising from spinal segments S2-S4 that provides motor and sensory innervation to the perineum.

The largest nerve in the body, formed by the union of the tibial and common fibular nerves.

A branch of the sciatic nerve that supplies the posterior muscles of the leg (hip extensors and knee flexors).

Branches off the tibial nerve that innervate the muscles and provide sensory function to the knee joint.

The medial sural cutaneous nerve provides sensory innervation to a portion of the calf, specifically the medial aspect.

The tibial nerve branches into these nerves, which innervate the sole of the foot.

A branch of the tibial nerve, responsible for providing sensation to the medial aspect of the heel.

This nerve is responsible for motor function in the posterior compartment of the leg, controlling muscles like plantaris, soleus, and gastrocnemius.

This nerve innervates deep muscles in the posterior compartment of the leg, including popliteus, flexor hallucis longus, flexor digitorum longus, and tibialis posterior.

The common fibular nerve branches into two nerves, the superficial fibular and the deep fibular nerve.

This nerve innervates muscles involved in eversion (turning the sole of the foot outward).

This nerve innervates muscles in the anterior compartment of the leg, responsible for dorsiflexion (lifting the foot up).

This nerve forms from the combination of branches from the tibial and common fibular nerves and provides sensory innervation to the lateral side of the leg and foot.