Lower Limb

Femoral Triangle

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The femoral triangle is first described by Antonio Scarpa (see Scarpas’ Fascia). It is a triangular subfascial space located in the anterio-medial aspect of the proximal thigh. As this anatomical region allows for easy access to major vessels, it is therefore often used for endovascular procedures such as coronary/peripheral angiography, and endovascular surgical procedures.

Gross Anatomy

The Femoral Triangle



Fascia Lata

Floor (Lateral to Medial)



Psoas Tendon




Adductor Longus


Medial: Medial Border of Adductor Longus


Lateral: Medial Border of Sartorius


Superior: Inguinal Ligament

Contents (Lateral to Medial)

Femoral Nerve


Femoral Artery


Femoral Vein – also saphenous opening


Deep Inguinal Lymph Nodes


Fascia Lata

Fascia lata is the deep fascia of the thigh and forms the roof of the femoral triangle. It is a layer of fibrous connective tissue that encapsulates the muscles of the thigh, with intermuscular septa separating each individual compartment of muscle groups. On the anteromedial aspect of the fascia, around 3-4 cm inferior and lateral to the pubic tubercle, lies an oval defect called saphenous opening. This is where the long/great saphenous vein (LSV/GSV) feeds into the femoral vein, forming the saphenofemoral junction (SFJ). Superficial inguinal lymphatics also pass through this opening and join deep inguinal lymphatics here.


Contents of the Femoral Triangle

Femoral Nerve

The Femoral nerve (L2-L4) is the most lateral lying structure, and is the largest branch of the lumbar plexus. Its motor innervation supplies the hip flexor and knee extensor muscles. The Femoral nerve also supplies sensation to the anterior and medial aspect of the thigh via anterior cutaneous branches.


Femoral Sheath

Medial to the femoral nerve is the femoral sheath, an extension of transversalis and iliopsoas fascia. Inside this sheath, it is divided into three compartments. The most lateral compartment contains the femoral artery, medial to the artery lies the femoral vein, with the femoral canal being the most medial compartment of the femoral sheath.


Femoral Artery

The femoral artery, otherwise known as the common femoral artery, is a continuation of the external iliac artery. This subsequently splits into a deeper branch (profunda femoris, which supplies the thigh) and a superficial branch (superficial femoral artery, which supplies the leg) within the femoral triangle before entering the adductor canal.


Femoral Vein

Femoral vein accompanies the femoral artery along its course in a similar distribution. It receives the LSV at the SFJ.

Clinical Anatomy

Femoral Pulse and Access

At the level of the inguinal ligament, the femoral artery crosses underneath at the mid-inguinal point (midpoint between the anterior superior iliac spine and the pubic symphysis). The femoral pulse can therefore be palpated at this point. Arterial puncture at this point allows access for angiography and endovascular procedures. In the absence of femoral pulsation in peripheral vascular disease, the femoral artery can be identified in thinner individuals by rolling one’s fingers over the mid-inguinal point - a calcified tube may be palpable here indicating a severely atherosclerotic femoral artery.


The femoral artery is a relatively superficial large calibre vessel, which allows relatively easy puncture for procedures such as coronary/peripheral angioplasty. Furthermore, in patients who are peripherally shutdown, or in resuscitation situations, femoral arteries can be accessed for arterial blood gases/blood samples reliably.


Femoral hernia

A Femoral hernia occurs when intraabdominal contents herniates through the femoral canal. Clinically, the patient with a femoral hernia would complain of a lump (sometimes tender) in their groin. Examination would reveal a lump below the inguinal ligament and lateral to the pubic tubercle. This differs to an inguinal hernia, which are typically found above the inguinal ligament and medial to the pubic tubercle.


Femoral hernias are more common in elderly females. This is often due to atrophy of adipose tissue around the femoral canal, leaving a space for herniation to occur. Treatment of a femoral hernia is surgical, requiring a repair. This is often performed on an urgent/emergency basis due to the high risk of hernia strangulation which comes from the tight confines of the femoral canal.


Saphenous Varix

Otherwise known as saphena varix, is a localised dilatation of the proximal LSV at the SFJ due to venous valvular incompetence. It can be associated with varicose veins elsewhere within the superficial venous system. Clinically it can be confused with a hernia as it can exhibit a cough impulse (a transmitted wave of pressure down the vein induced by coughing). However, a saphena varix disappears immediately when the patient is supine, and can have a bluish appearance. Auscultation may reveal a venous hum. Diagnosis is usually made with venous duplex ultrasonography and treatment by surgical ligation of the SFJ.


Femoral Artery Pseudoaneurysm

Femoral artery pseudoaneurysms occur as a consequence of arterial injury. It typically presents as a painful and gradually expanding pulsatile mass within the femoral triangle, with a history of previous vascular interventional procedures, or repeated puncture from intravenous drug use. Erroneous diagnosis of localised abscess is occasionally made if the overlying skin appears erythematous. Radiological investigation to determine the nature of the lump is essential. Disastrous consequences can occur if one proceeds with incision and drainage with a presumed diagnosis of groin abscess without excluding the possibility of pseudoaneurysm. Treatment options for femoral pseudoaneursysms include surgical repair/ligation and endovascular sealing. 

Quick Anatomy

Key Facts

Femoral Nerve:

  • L2-L4
  • Motor Supply - Hip Flexors and Knee Extenders
  • Sensory Supply – Anteromedial Thigh

Femoral Artery:

  • Origin: External Iliac Artery
  • Branches: Superficial Circumflex Iliac Artery, Superficial Epigastric Artery, Superficial/Deep External Pudendal Artery, Profunda Femoris, Descending Genicular Artery
  • Corresponding Veins: Femoral Vein


The Borders of the Femoral Triangle





Adductor Longus


Inguinal Ligament


The Contents of the Femoral Triangle



Femoral Nerve


Femoral Artery


Femoral Vein


Empty Space (allows expansion of veins and lymphatics)


Lymphatics (deep inguinal lymph nodes)


The Floor of the Femoral Triangle




Pierced The

Psoas Tendon



Artery Laboriously

Adductor Longus


The femoral triangle is somewhat of a favourite for examiners and frequently tested in clinical anatomy examination. Located in the anterior aspect of proximal thigh, it is a triangular subfascial space of great anatomical and clinical importance. It provides easy access to the femoral neurovascular bundle and is therefore frequently utilised for surgical and endovascular procedures where vascular access is required. Groin lumps within the femoral triangle can be due to many underlying pathologies as the region contains multiple different structures, good understanding of anatomy is therefore essential to the diagnostic process. 


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