The lower leg is primarily supplied by a network of arteries that branch off from the main arterial supply of the thigh. The principal arteries found directly within the lower leg are the anterior tibial artery, the posterior tibial artery, and the fibular (peroneal) artery. These vessels ensure a robust blood supply to the muscles, bones, and tissues from the knee down to the foot.
Understanding the Lower Leg's Arterial Supply
The intricate network of arteries in the lower leg originates from the popliteal artery, which is a continuation of the femoral artery from the thigh. The popliteal artery is located in the popliteal fossa (the hollow behind the knee) and gives rise to several crucial branches that supply both the knee joint and the lower leg.
The major arteries supplying the lower leg are:
- Anterior Tibial Artery
- Posterior Tibial Artery
- Fibular (Peroneal) Artery
These arteries, along with their numerous branches, ensure that the entire lower leg, including the ankle and foot, receives oxygenated blood.
Key Arteries of the Lower Leg
Let's explore each of these vital arteries in more detail:
1. Anterior Tibial Artery
The anterior tibial artery is one of the two main arteries that branch off the popliteal artery. It descends down the front (anterior compartment) of the lower leg, running between the tibia and fibula bones.
- Course and Function: It passes through a gap in the interosseous membrane and travels inferiorly with the deep fibular (peroneal) nerve. It supplies blood to the muscles of the anterior compartment, which are responsible for dorsiflexion of the foot (lifting the foot upwards).
- Key Branches:
- Anterior Tibial Recurrent Arteries: Supply the knee joint.
- Anterior Malleolar Arteries (Medial and Lateral): These branches are found around the ankle joint, supplying blood to this region.
- Continuation: As it crosses the ankle joint, the anterior tibial artery becomes the dorsalis pedis artery, which supplies the top of the foot.
2. Posterior Tibial Artery
The posterior tibial artery is the other major branch originating from the popliteal artery. It descends down the back (posterior compartment) of the lower leg.
- Course and Function: It travels inferiorly within the deep posterior compartment, providing blood to the superficial and deep muscles of this compartment, which are involved in plantarflexion (pointing the foot downwards) and inversion of the foot.
- Key Branches:
- Circumflex Fibular Artery: Aids in supplying the knee joint.
- Peroneal/Fibular Artery: This is a significant branch itself, discussed next.
- Nutrient Artery to Tibia: Supplies the bone itself.
- Posterior Malleolar Branches: Supply the ankle region.
- Continuation: Behind the medial malleolus (inner ankle bone), it divides into the medial and lateral plantar arteries, which supply the sole of the foot.
3. Fibular (Peroneal) Artery
The fibular artery, also known as the peroneal artery, is typically a large branch of the posterior tibial artery.
- Course and Function: It runs down the lateral (side) aspect of the posterior compartment, close to the fibula. It supplies blood to the lateral compartment muscles, which are responsible for eversion of the foot (turning the sole outwards), as well as muscles in the posterior compartment.
- Key Branches:
- Perforating Branch: Pierces the interosseous membrane to supply structures in the anterior compartment and ankle.
- Communicating Branch: Connects with the posterior tibial artery.
- Nutrient Artery to Fibula: Supplies the fibula bone.
- Posterior Lateral Malleolar Artery: Supplies the ankle region.
The Role of the Popliteal Artery and Genicular Branches
While not strictly within the lower leg, the popliteal artery is the direct precursor and main source of blood for all the lower leg arteries. It runs behind the knee and bifurcates at the level of the lower border of the popliteus muscle into the anterior and posterior tibial arteries.
The popliteal artery also gives rise to genicular arteries, which are crucial for the blood supply of the knee joint. These include:
- Superior Genicular Arteries (Medial and Lateral)
- Inferior Genicular Arteries (Medial and Lateral)
- Middle Genicular Artery
These arteries form an extensive anastomotic network around the knee, ensuring its robust blood supply. They are considered part of the "arteries of the knee and leg" but primarily supply the joint itself, rather than coursing down into the leg muscles.
Summary of Lower Leg Arteries
| Artery Name | Origin | Primary Location / Compartment | Main Areas Supplied | Key Branches / Continuation |
|---|---|---|---|---|
| Popliteal Artery | Femoral Artery | Behind the knee (Popliteal Fossa) | Knee joint, gives rise to lower leg arteries | Anterior Tibial, Posterior Tibial, Genicular Arteries |
| Anterior Tibial Artery | Popliteal Artery | Anterior compartment of lower leg | Anterior compartment muscles (dorsiflexion) | Anterior Malleolar, Dorsalis Pedis (continuation) |
| Posterior Tibial Artery | Popliteal Artery | Deep posterior compartment of lower leg | Posterior compartment muscles (plantarflexion, inversion) | Fibular/Peroneal, Plantar Arteries (continuation) |
| Fibular (Peroneal) Artery | Posterior Tibial Artery | Lateral aspect of posterior compartment | Lateral compartment muscles (eversion), deep posterior muscles | Perforating, Communicating, Malleolar Branches |
| Genicular Arteries | Popliteal Artery | Around the knee joint | Knee joint and surrounding structures | Superior (Medial/Lateral), Inferior (Medial/Lateral) |
Understanding these arteries is fundamental for diagnosing and treating conditions related to blood flow in the lower leg, such as peripheral artery disease or injuries. For more detailed anatomical information, refer to reputable sources like Kenhub or TeachMeAnatomy.
