Nerve & Blood Supply Nerve & Blood Supply of the Lower of the Lower ExtremitiesExtremities

Reynaldo V. Lopez, M.D.Senior LecturerDepartment of AnatomyAngeles University School of Medicine

The Lumbar Plexus and Innervation of the The Lumbar Plexus and Innervation of the Lower LimbLower Limb

• Lumbar plexus

• Arises from L1-L4

• Smaller branches innervate the posterior abdominal wall and psoas muscle

• Main branches innervate the anterior thigh

•Femoral nerve – innervates anterior thigh muscles

•Obturator nerve – innervates adductor muscles

The Lumbar PlexusThe Lumbar Plexus

The Sacral PlexusThe Sacral Plexus

• Arises from spinal nerves L4-S4

• Caudal to the lumbar plexus

• Often considered with the lumbar plexus

• Lumbosacral plexus

Innervation of the Lower LimbInnervation of the Lower Limb

• Sciatic nerve – the largest nerve of the sacral plexus• Actually two nerves in one sheath

•Tibial nerve – innervates most of the posterior lower limb

•Common fibular (peroneal) nerve – innervates muscles of the anterolateral leg

Innervation of the Lower LimbInnervation of the Lower Limb

• Superior and inferior gluteal nerves – innervate the gluteal muscles

• Pudendal nerve – innervates muscles of the perineum

The Sacral PlexusThe Sacral Plexus

Innervation of the Skin: DermatomesInnervation of the Skin: Dermatomes

• Dermatome – an area of skin

• Innervated by cutaneous branches of a single spinal nerve

• Lower limb

• Lumbar nerves – anterior surface

• Sacral nerves – posterior surface

Map of Dermatomes – Anterior ViewMap of Dermatomes – Anterior View

Map of Dermatomes – Posterior ViewMap of Dermatomes – Posterior View

Nerves of the HipNerves of the Hip

• All of the nerves that travel down the thigh pass by the hip.

• The main nerves are the femoral nerve in front and the sciatic nerve in back of the hip.

• The obturator nerve, also goes to the hip.

Nerves of the KneeNerves of the Knee

• The most important nerve around the knee is the popliteal nerve in the back of the knee.

• The nerve splits just above the knee to form the tibial nerve and the common peroneal nerve.

Nerves of the FootNerves of the Foot

• The main nerve to the foot, the tibial nerve, enters the sole of the foot by running behind the medial malleolus.

• Supplies sensation to the toes & sole of the foot & controls the muscles of the sole of the foot.

Nerves of the FootNerves of the Foot

• Several other nerves run into the foot on the outside of the foot and down the top of the foot.

• These nerves primarily provide sensation to different areas on the top and outside edge of the foot.

Arteries of the Pelvis and Lower LimbsArteries of the Pelvis and Lower Limbs

• Internal iliac arteries

• External iliac artery

• Femoral artery

• Popliteal artery

• Anterior tibial artery

• Posterior tibial artery

Internal Iliac ArteryInternal Iliac Artery

Figure 19.15

Arteries of the HipArteries of the Hip

•The large femoral artery begins deep within the pelvis & passes by the front of the hip area and goes down toward the inner edge of the knee. •The femoral artery has a deep branch, called the profunda femoris that sends 2 vessels that go through the hip joint capsule. •These are the main blood supply for the femoral head.

Arteries of the HipArteries of the Hip

• The ligamentum teres contains a small blood vessel that gives a very small supply of blood to the top of the femoral head.

Arteries of the KneeArteries of the Knee

•The major blood vessels around the knee travel with the popliteal nerve down the back of the leg. •The popliteal artery and popliteal vein are the largest blood supply to the leg and foot. •If the popliteal artery is damaged beyond repair, it is very likely the leg will not be able to survive.

Arteries of the FootArteries of the Foot

•The main blood supply to the foot, the posterior tibial artery, runs right beside the nerve of the same name.• Other less important arteries enter the foot from other directions.

Arteries of the FootArteries of the Foot

•One of these arteries is the dorsalis pedis that runs down the top of the foot. •You can feel your pulse where this artery runs in the middle of the top of the foot.

Major Veins of the Systemic CirculationMajor Veins of the Systemic Circulation