The femoral artery is a continuation of the external iliac artery and constitutes the major blood supply to the lower limb. In the thigh, the femoral artery passes through the femoral triangle, a wedge-shaped depression formed by muscles in the upper thigh. The medial and lateral boundaries of this triangle are formed by the medial margin of adductor longus and the medial margin of sartorius, respectively. Fascia lata constitutes the roof of the femoral triangle, whilst the floor is formed by pectineus and adductor longus medially as well as by iliacus and psoas major laterally. Within this triangle, the femoral artery is enclosed in a femoral sheath with the femoral vein. The femoral artery and its branches supply most of the thigh as well as the entirety of the leg and foot.
This article will discuss the anatomical course, relations and variations of the femoral artery as well as briefly talking about its branches. This will be followed by a discussion of the clinical relevance of the femoral artery.
Midway between the anterior superior iliac spine and the pubic symphysis, the external iliac artery passes under the inguinal ligament into the femoral triangle and becomes the femoral artery. The artery then travels down the anteromedial aspect of the thigh before it passes through the adductor (subsartorial) canal. When the femoral artery passes through the adductor hiatus it becomes the popliteal artery.
Inside the Femoral Triangle
Relationships of the femoral artery to other structures within the thigh can be important in clinical practice. Within the femoral triangle, the femoral artery is located deep to the:
- superficial fascia
- superficial inguinal lymph nodes
- fascia lata
- superficial circumflex iliac vein
- the femoral branch of the genitofemoral nerve
At the apex of the femoral triangle, the medial femoral cutaneous nerve crosses the artery in a lateral to medial direction.
Within the triangle, the tendons of psoas major, pectineus and adductor longus pass deep to the femoral artery. Proximally, the femoral vein is medial to the femoral artery within the sheath. At the apex of the triangle, the vein is found deep to the artery.
Inside the Adductor Canal
Within the adductor canal, the femoral artery is located deep to the:
- superficial fascia
- deep fascia
- sartorius muscle
The artery is superficial to the adductor magnus and longus muscles. Both the saphenous nerve and femoral vein vary in their location in relation to the femoral artery. The saphenous nerve is initially found lateral to the femoral artery, but is also found anterior and then medial to the nerve as it travels through the canal. Proximally, the femoral vein is found deep to the artery but is found lateral to the artery distally. The vastus medialis muscle and its nerve are located anterolateral to the femoral artery.
Distal to the origin of the profunda femoris artery, the femoral artery rarely divides into two trunks, which reunite near the adductor hiatus. Occasionally, the artery is replaced by the inferior gluteal artery, which accompanies the sciatic nerve as it travels towards the popliteal fossa. In this case, the external iliac artery ends as the profunda femoris artery.
BranchesThe femoral artery gives off five branches in the femoral triangle and one in the adductor canal, to give six in total. These branches are described below.
Superficial Epigastric Artery
The superficial epigastric artery arises from the femoral artery, 1 cm distal to the inguinal ligament. It travels through the cribiform fascia and ascends towards the umbilicus within the abdominal superficial fascia. It supplies the skin, superficial fascia and superficial inguinal lymph nodes.
Superficial Circumflex Iliac Artery
The superficial circumflex iliac artery is the smallest branch of the femoral artery. It arises near the superficial epigastric artery. Lateral to the saphenous opening, the artery passes through the fascia lata before coursing towards the anterior superior iliac spine. Like the superficial epigastric artery, it supplies the skin, superficial fascia and superficial inguinal lymph nodes.
Superficial External Pudendal Artery
The superficial external pudendal artery arises near the superficial epigastric and superficial circumflex iliac arteries. It travels through the cribiform fascia before crossing the spermatic cord deep to the long saphenous vein. It supplies the lower abdominal skin as well as the penile, scrotal or labial skin.
Deep External Pudendal Artery
The deep external pudendal artery crosses the pectineus and adductor longus muscles before traversing the fascia lata. It supplies the skin of the perineum as well as the skin of the scrotum or labium majus.
Profunda femoris, also know as the deep artery of the thigh is the largest branch of the femoral artery, which arises 3.5 cm distal to the inguinal ligament. The profunda femoris is initially found lateral to the femoral artery before it passes deep to it towards the medial aspect of the femur. It travels between the pectineus and adductor longus muscles before passing between the adductor longus and adductor brevis muscles. It then descends between the adductor longus and adductor magnus muscles before it pierces the adductor magnus to anastamose with the muscular branches of the popliteal artery. The profunda femoris is the main blood supply to the muscles that extend, flex and adduct the thigh.
Descending Genicular Artery
Descending genicular artery is the most distal branch of the femoral artery, which arises just proximal to the adductor opening within the adductor canal. It descends within the vastus medialis muscle to the medial aspect of the knee. Here, it anastomoses with the medial superior genicular artery. Branches of this artery supply the vastus medialis and adductor magnus muscles as well as the proximomedial skin of the thigh.
As the femoral artery is relatively superficial within the femoral triangle, the femoral pulse is usually easily palpated. It can be palpated midway between the anterior superior iliac spine and pubic symphysis, just inferior to the inguinal ligament. If the pulse is diminished, this may indicate partial occlusion of the common iliac artery or the external iliac artery. It may also indicate aortic coarctation, a congenital condition which causes narrowing of a segment of the aorta.
The femoral artery is a common site for cannulation as it provides access to the heart as well as to various vessels. Coronary artery angioplasty is a common intervention used in coronary artery disease, which involves cannulation of the femoral artery. A catheter is inserted into the femoral artery and is passed through the various arteries such as the common iliac artery and aorta before it reaches the coronary artery. A wire and balloon are then used to dilate the coronary artery. Angiography, or imaging of the arteries, is another common intervention involving the femoral artery. In this case, the femoral artery is cannulated and radiopaque contrast agents are injected in order to obtain radiographs of various vessels.
Due to its superficial position within the femoral triangle, the femoral artery is vulnerable to laceration. In anterior thigh wounds, the femoral vein is also commonly lacerated due to its close proximity to the femoral artery.
Peripheral vascular disease, usually caused by atherosclerosis, can lead to femoral artery occlusion. Occlusion of the femoral artery can cause intermittent claudication of the calf - cramp like pain of the calf exacerbated by movement and relieved by rest. Treatment involves pharmacological intervention with aspirin as well as an exercise programme. Angioplasty of the femoral artery may be performed but carries a small risk of thrombosis or embolisation, which can result in a loss of the leg.