Femoral artery

The femoral artery is the primary artery supplying blood to the lower limb. It is a continuation of the external iliac artery, beginning just below the inguinal ligament and extending down the thigh.

Location

The femoral artery originates from the external iliac artery as it passes under the inguinal ligament and enters the femoral triangle in the upper thigh. It runs down the anteromedial aspect of the thigh, passing deep to the sartorius muscle. In the mid-thigh region, it enters the adductor canal and continues its course toward the knee. As it exits the adductor canal, it passes through the adductor hiatus and transitions into the popliteal artery, which supplies the lower leg. The artery is located close to the femoral vein and femoral nerve within the femoral triangle.

Structure and Anatomy

Origin

The femoral artery is a continuation of the external iliac artery, which becomes the femoral artery as it passes beneath the inguinal ligament, a fibrous band that stretches from the anterior superior iliac spine to the pubic tubercle. This transition occurs at the level of the femoral triangle in the upper thigh. The femoral artery is the main blood vessel supplying oxygenated blood to the lower limb.

Course

The femoral artery descends through the femoral triangle, which is a wedge-shaped anatomical space bordered by the inguinal ligament (superiorly), the sartorius muscle (laterally), and the adductor longus muscle (medially). Within the femoral triangle, the femoral artery is located in close proximity to the femoral vein and femoral nerve, forming the neurovascular bundle that runs through the thigh.

As the artery descends into the mid-thigh region, it passes beneath the sartorius muscle and enters the adductor canal (also known as Hunter’s canal), a tunnel that extends from the apex of the femoral triangle to the adductor hiatus. The adductor canal is formed by the vastus medialis muscle (anteriorly), the adductor longus and adductor magnus muscles (posteriorly), and the sartorius muscle (medially).

At the distal end of the thigh, the femoral artery exits the adductor canal via the adductor hiatus, a gap in the adductor magnus muscle, and enters the popliteal fossa behind the knee joint. As it passes through the adductor hiatus, the femoral artery transitions into the popliteal artery, which supplies the lower leg and foot.

Branches

The femoral artery gives rise to several important branches throughout its course, which supply blood to various structures in the lower limb, including muscles, skin, and joints. The major branches of the femoral artery include:

• Superficial Epigastric Artery: This small artery arises from the femoral artery just below the inguinal ligament and travels toward the abdominal wall, supplying the skin and subcutaneous tissues of the lower abdomen.
• Superficial Circumflex Iliac Artery: This branch arises from the femoral artery and runs laterally along the inguinal ligament, supplying the skin and superficial fascia over the iliac crest.
• Superficial External Pudendal Artery: This artery arises near the inguinal region and supplies the skin of the external genitalia and lower abdominal wall.
• Deep External Pudendal Artery: A deeper branch that supplies the genital region, including the scrotum or labia majora.
• Deep Femoral Artery (Profunda Femoris): This is the largest and most significant branch of the femoral artery. It arises approximately 2-5 cm below the inguinal ligament and descends posteriorly and medially in the thigh. The deep femoral artery gives rise to several important branches, including the lateral circumflex femoral artery, the medial circumflex femoral artery, and perforating arteries that supply the deep structures of the thigh, including the muscles and bones.
• Descending Genicular Artery: This artery arises just before the femoral artery transitions into the popliteal artery. It contributes to the blood supply of the knee joint and surrounding structures.

Termination

The femoral artery terminates by passing through the adductor hiatus in the adductor magnus muscle, at which point it becomes the popliteal artery. The popliteal artery continues its course down the posterior aspect of the knee, supplying the lower leg.

Anatomical Relations

• Femoral Triangle: The femoral artery is located within the femoral triangle, where it is superficial and easily accessible. It lies between the femoral nerve (laterally) and the femoral vein (medially), making it part of the neurovascular bundle.
• Sartorius Muscle: As the artery moves distally, it is covered by the sartorius muscle, which protects it as it enters the adductor canal.
• Adductor Canal: Within the adductor canal, the femoral artery runs with the femoral vein and the saphenous nerve. The canal provides a protected pathway for the artery as it travels toward the popliteal fossa.
• Adductor Hiatus: The femoral artery passes through the adductor hiatus, a gap in the adductor magnus muscle, to transition into the popliteal artery. The adductor hiatus marks the boundary between the thigh and the lower leg.

Surface Anatomy and Palpation

The femoral artery is located relatively superficially in the femoral triangle, making it accessible for palpation. The femoral pulse can be easily felt just below the inguinal ligament, halfway between the anterior superior iliac spine and the pubic symphysis. This is a key site for assessing arterial blood flow to the lower limb.

Function

Primary Blood Supply to the Lower Limb

The femoral artery is the main artery responsible for supplying oxygenated blood to the lower limb, including the thigh, leg, and foot. As a continuation of the external iliac artery, it ensures that blood reaches the various muscles, bones, joints, and skin in the lower extremity. This function is vital for maintaining the health and function of the muscles and tissues involved in standing, walking, running, and other lower body movements.

Blood Supply to the Anterior and Medial Thigh

The femoral artery provides oxygenated blood to the muscles in the anterior and medial compartments of the thigh. These compartments contain important muscles such as the quadriceps femoris, responsible for extending the knee, and the adductor muscles, which help in the movement of the leg toward the midline of the body (adduction). The artery’s main branches that supply these compartments include the superficial epigastric artery, superficial external pudendal artery, and deep femoral artery.

The quadriceps muscles play a crucial role in knee extension, while the adductors stabilize the hip and pelvis during movement. Proper blood flow to these muscle groups ensures their efficiency in performing daily activities such as walking, climbing, and running.

Deep Supply Through the Deep Femoral Artery (Profunda Femoris)

The deep femoral artery (profunda femoris), a major branch of the femoral artery, is responsible for supplying blood to the deep muscles and tissues of the thigh, including the hamstring muscles in the posterior compartment. The deep femoral artery also gives rise to the medial circumflex femoral artery and the lateral circumflex femoral artery, which supply the hip joint and contribute to the blood supply of the proximal femur, including the femoral head and neck. This deep blood supply supports thigh movements and joint stability, allowing for a wide range of motion at the hip and knee joints.

Blood Supply to the Hip Joint

The femoral artery, through its branches—particularly the medial circumflex femoral artery—provides an important blood supply to the hip joint and the head of the femur. This blood supply is crucial for maintaining the health of the femoral head and neck, which are essential for proper hip function. The hip joint allows for a wide range of movements, including flexion, extension, abduction, adduction, and rotation. The femoral artery ensures that the tissues and cartilage within the hip joint remain well-nourished, preventing degeneration and supporting joint mobility.

Blood Supply to the External Genitalia and Lower Abdomen

The femoral artery gives rise to the superficial external pudendal artery and the deep external pudendal artery, which provide blood to the external genitalia and parts of the lower abdomen. These arteries supply blood to the scrotum in males and the labia majora in females, as well as the skin and soft tissues in the surrounding regions. This blood supply ensures the health and function of the external genitalia and contributes to the vascular network in the lower abdominal region.

Contribution to the Blood Supply of the Knee

The femoral artery, through its descending genicular artery, contributes to the blood supply of the knee joint and surrounding tissues. The descending genicular artery participates in the formation of the genicular anastomosis, a network of arteries that ensures continuous blood flow to the knee joint, especially during flexion and extension of the leg. This collateral circulation is essential for supporting knee stability and movement, allowing for activities such as walking, running, and squatting.

Supply to the Leg and Foot via the Popliteal Artery

As the femoral artery continues down the thigh and passes through the adductor hiatus, it transitions into the popliteal artery behind the knee. The popliteal artery is responsible for supplying blood to the lower leg and foot through its branches, including the anterior tibial, posterior tibial, and fibular arteries. By transitioning into the popliteal artery, the femoral artery ensures that oxygenated blood reaches the muscles and tissues of the leg, supporting activities like walking, running, and standing.

Support for Oxygenation and Metabolic Needs

As with all arteries, the femoral artery plays a key role in delivering oxygenated blood to the muscles, bones, and soft tissues of the lower limb. Oxygen is essential for cellular respiration, which allows cells to produce energy for muscle contraction and tissue maintenance. By delivering oxygen and nutrients to these structures, the femoral artery supports the metabolic needs of the lower limb, allowing for sustained movement, muscle repair, and recovery after physical exertion.

Removal of Metabolic Waste Products

The femoral artery facilitates the removal of metabolic waste products from the lower limb by maintaining proper blood circulation. By delivering oxygenated blood and allowing deoxygenated blood to be carried away by the femoral vein, the artery helps clear waste products such as carbon dioxide and lactic acid from the muscles. This function is crucial for preventing muscle fatigue, especially during physical activities like walking, running, and climbing.

Collateral Circulation and Protection Against Ischemia

The femoral artery and its branches play a significant role in collateral circulation, which is the development of alternative pathways for blood flow in the event of arterial blockages or constriction. Through its connection with the deep femoral artery, circumflex arteries, and the genicular anastomosis around the knee, the femoral artery ensures that blood can still reach critical areas of the lower limb even if the primary arterial pathway is compromised. This collateral circulation helps protect against ischemia (lack of blood supply), which can lead to tissue damage or muscle weakness.

Maintenance of Muscle and Tissue Viability

By supplying the muscles, bones, and skin of the lower limb with a steady flow of oxygenated blood, the femoral artery supports the viability of the muscles and soft tissues. This is particularly important for recovery after injury or surgery, as well as for maintaining muscle strength, skin health, and overall function of the lower limb. The femoral artery’s role in tissue oxygenation and nutrient supply ensures that the structures of the lower limb can repair themselves, recover from physical stress, and function optimally.

Clinical Significance

The femoral artery is a major blood vessel supplying oxygenated blood to the lower limb, and its clinical importance is substantial. It is commonly used for vascular access during diagnostic procedures like angiography or cardiac catheterization due to its large size and accessibility in the groin region.

Conditions like femoral artery occlusion or atherosclerosis can lead to reduced blood flow to the leg, causing pain (claudication), weakness, or critical limb ischemia. The femoral artery is also prone to aneurysms, which can cause life-threatening complications if they rupture. Additionally, during surgeries such as coronary artery bypass grafting (CABG), the femoral artery may be used as a source for harvesting graft material or as an access point for bypassing occluded vessels. Palpation of the femoral pulse is an important clinical diagnostic tool for assessing blood flow and circulation to the lower extremities.