Lower Limb Arterial Supply

Overview of Arterial Supply

• The video highlights similarities in arterial arrangements between the upper and lower limbs by tracing arteries down the leg from the aorta, similar to how the upper limb was covered in the previous video.

Aorta and Iliac Arteries

• The abdominal aorta descends deeply within the abdomen.
• At the level of the inferior mesenteric artery, the aorta splits into the left and right common iliac arteries.
• Each common iliac artery further divides into:
  • An internal iliac artery supplies blood to the pelvic viscera.
  • An external iliac artery runs towards the lower limb.
• There is no single "iliac artery"; the correct terminology includes common, internal, and external iliac arteries.

Femoral Artery

• The external iliac artery changes its name to the femoral artery as it passes beneath the inguinal ligament.
• The femoral artery is the main artery of the thigh, located in the anterior compartment.
• It runs deep to the sartorius muscle within the subsartorial canal, alongside the femoral vein and nerve.
• There are deep branches of the femoral artery (profunda femoris) that supply blood to the femur and quadriceps muscles.
• The femoral artery courses medially towards the adductor compartment.

Adductor Hiatus and Popliteal Artery

• The femoral artery passes through the adductor hiatus, a gap in the adductor muscles, to reach the popliteal fossa behind the knee.
• After passing through the adductor hiatus, the femoral artery becomes the popliteal artery.
• Lateral and medial circumflex femoral arteries loop around the femur, arising from the femoral artery.
• Circumflex arteries from the external iliac artery also contribute to anastomoses around the hip joint, providing collateral circulation.

Genicular Arteries

• The popliteal artery sends off branches to supply the knee and establish collateral circulation; these are called genicular arteries.
• The Latin word for knee is "genu," hence the term "geniculate."
• These branches include:
  • Superior lateral genicular artery
  • Inferior lateral genicular artery
  • Superior medial genicular artery
  • Inferior medial genicular artery
  • Middle genicular artery
• These arteries interconnect with anastomoses both superior and inferior to the knee joint, which is crucial for collateral circulation if the popliteal artery is occluded.

Tibial Arteries

• The popliteal artery splits:
  • Posterior tibial artery descends down the calf in the posterior compartment, deep to the gastrocnemius and soleus muscles.
  • Anterior tibial artery passes through the interosseous membrane to reach the anterior compartment of the leg.
• The anterior tibial artery runs down anteriorly on the interosseous membrane, supplying the anterior compartment muscles.
• The posterior tibial artery gives off a fibular (peroneal) branch.
• The fibular artery runs down with the fibula, supplying blood to the bone and nearby structures.

Arterial Supply to the Foot

• The posterior tibial artery runs around the medial malleolus to enter the foot.
• The fibular artery runs around the lateral malleolus.
• Anteriorly, the anterior tibial artery becomes the dorsalis pedis as it enters the dorsum (top) of the foot.
• The Posterior tibial artery ends as:
  • Medial plantar artery
  • Lateral plantar artery
• These arteries form a deep plantar arch, along with the deep plantar artery.
• There are sometimes superficial and deep plantar arches, or just a single plantar arch (referred to as the deep plantar arch).
• The plantar arch gives off metatarsal and digital branches to supply the toes and metatarsals.

Dorsalis Pedis and Anastomoses

• The anterior tibial artery becomes the dorsalis pedis after passing between the malleoli.
• The dorsalis pedis gives off the deep plantar artery, which dives down through the foot between the first and second metatarsals to join the plantar arch.
• Therefore, the plantar arch receives blood from both the posterior tibial (via medial and lateral plantar arteries) and anterior tibial arteries (via dorsalis pedis).
• The fibular artery ends by giving off calcaneal and malleolar branches.
• The dorsalis pedis continues around, giving off branches to the toes, and forms the arcuate artery.
• The arcuate artery may or may not anastomose with branches from the fibular artery.

Palpable Pulses in the Lower Limb

• Femoral pulse is palpable just inferior to the inguinal ligament.
• Popliteal pulse is palpable in the popliteal fossa behind the knee (superficial when the knee is bent).
• Posterior tibial pulse is palpable posterior to the medial malleolus.
• Dorsalis pedis pulse is palpable on the dorsum of the foot.

Summary of Key Concepts

• Arteries change names as they pass through different anatomical regions.
• Arterial branches at joints and anastomoses provide potential collateral circulation around:
  • Hip joint
  • Knee joint
  • Ankle joint
• Blood supply in the foot is complex, involving medial and lateral plantar arteries, dorsalis pedis, and various branches that link up.
• Knowledge of foot and ankle bone names is helpful for understanding arterial nomenclature in the region.