Vasculature of the Lower limb for MBBS exam prep

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Femoral Artery

The main artery of the lower limb is femoral artery. It is a continuation of the external iliac artery (terminal branch of the abdominal aorta). The external iliac becomes the femoral artery when it crosses under the inguinal ligament and enters the femoral triangle.

In the femoral triangle, the profunda femoris artery arises from the posterolateral aspect of the femoral artery. It travels posteriorly and distally, giving off three main branches:

  • Perforating branches– Consists of three or four arteries that perforate the adductor magnus, contributing to the supply of the muscles in the medial and posterior thigh.
  • Lateral femoral circumflex artery– Wraps round the anterior, lateral side of the femur, supplying some of the muscles in the lateral side of the thigh.
  • Medial femoral circumflex artery– Wraps round the posterior side of the femur, supplying the neck and head of the femur. In a fracture of the femoral neck, this artery can easily be damaged, and avascular necrosis of the femur head can occur.
  • After exiting the femoral triangle, the femoral artery continues down the anterior surface of the thigh, via a tunnel known as theadductor canal. During its descent the artery supplies the anterior thigh muscles.
  • The adductor canal ends at an opening in the adductor magnus, called theadductor hiatus. The femoral artery moves through this opening, and enters the posterior compartment of the thigh, proximal to the knee.  The femoral artery now known as the popliteal artery.

In addition to the femoral artery, there other vessels supplying the lower limb.

The obturator artery arises from internal iliac artery in the pelvic region.  It descends via the obturator canal to enter the medial thigh, bifurcating into two branches:

  • Anterior branch – This supplies the pectineus, obturator externus, adductor muscles and gracilis.
  • Posterior branch – This supplies some of the deep gluteal muscles.

The gluteal region is largely supplied by the superior and inferior gluteal arteries. These arteries also arise from the internal iliac artery, entering the gluteal region via the greater sciatic foramen.

The superior gluteal artery leaves the foramen above the piriformis muscle, the inferior below the muscle. In addition to the gluteal muscles, the inferior gluteal artery also contributes towards the vasculature of the posterior thigh.

The popliteal artery descends down the posterior thigh, giving off genicular branches that supply the knee joint. It moves through the popliteal fossa, exiting sandwiched between the gastrocnemius and popliteus muscles. At the lower border of the popliteus, the popliteal artery terminates by dividing into anterior and posterior tibial arteries.

The posterior tibial artery continues inferiorly, along the surface of the deep muscles (such as tibialis posterior). It accompanies the tibial nerve in entering the sole of the foot via the tarsal tunnel. During the descent of the posterior tibial artery in the leg, the fibular artery arises. This artery moves laterally, penetrating the lateral compartment of the leg. It supplies muscles in the lateral compartment, and adjacent muscles in the posterior compartment.

The other division of the popliteal artery, the anterior tibial artery, passes anteriorly between the tibia and fibula, through a gap in the interosseous membrane. It then moves inferiorly down the leg. It runs down the entire length of the leg, and into the foot, where it becomes the dorsalis pedis artery.

Arterial supply to the foot is delivered via two arteries:

  • Dorsalis pedis(a continuation of the anterior tibial artery)
  • Posterior tibial

The dorsalis pedis artery begins as the anterior tibial artery enters the foot. It passes over the dorsal aspect of the tarsal bones, then moves inferiorly, towards the sole of the foot. It then anastamoses with the lateral plantar artery to form the deep plantar arch. The dorsalis pedis artery supplies the tarsal bones and the dorsal aspect of the metatarsals. Via the deep plantar arch, it also contributes to the supply of the toes.

The posterior tibial artery enters the sole of the foot through the tarsal tunnel. It then splits into the lateral and medial plantar arteries. These arteries supply the plantar side of the foot, and contributes to the supply of the toes via the deep plantar arch

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