Femoral Triangle and Adductor Canal

The femoral triangle is a significant anatomical structure located in the upper medial aspect of the thigh, directly below the inguinal ligament. This triangular region serves as a critical pathway for various important neurovascular structures.

Structure of the Femoral Triangle

The key boundaries of the femoral triangle are:

Superiorly: Inguinal ligament, which forms the base of the triangle.
Laterally: Medial border of the sartorius muscle.
Medially: Medial border of the adductor longus muscle.
Apex: Formed by the intersection of the sartorius and the adductor longus, directed inferiorly.

The floor of the femoral triangle is gutter-shaped and consists of four muscles arranged from lateral to medial:

Iliacus
Psoas
Pectineus
Adductor longus

The roof is formed by three layers starting from superficial to deep:

Skin
Superficial fascia with its contents
Deep fascia containing the saphenous opening

Contents of the Femoral Triangle

Within the femoral triangle, several important structures can be found:

Nerves: Includes the femoral nerve and the femoral branch of the genitofemoral nerve, along with the lateral cutaneous nerve of the thigh.
Arteries: The femoral artery and its branches are located here.
Veins: The femoral vein and its tributaries can be found in this area.
Lymphatic Structures: Deep inguinal lymph nodes and lymphatic vessels.
Fascia: The femoral sheath surrounding the femoral vessels.

Understanding the Femoral Sheath

The femoral sheath is a funnel-shaped fascial structure that encases the upper 1.5 inches of the femoral vessels:

Anterior Wall: Formed by a downward prolongation of the transversalis fascia of the abdominal wall.
Posterior Wall: Comprised of a downward prolongation of the iliac fascia from the abdominal wall.

The femoral sheath is divided into three compartments:

Lateral compartment: Houses the femoral artery and the femoral branch of the genitofemoral nerve.
Intermediate compartment: Contains the femoral vein.
Medial compartment (femoral canal): Contains lymph vessels and one of the deep inguinal lymph nodes.

The Femoral Canal

The femoral canal is the small medial compartment of the femoral sheath, measuring about 0.5 inches in length. It serves two primary functions:

Provides a dead space for the distended femoral vein.
Acts as a lymphatic pathway from the lower limb to the external iliac nodes.

Notably, the femoral ring, which is the base of the femoral canal, is wider in females due to a wider pelvis, making femoral hernias more common among females.

Hernias and Clinical Significance

A femoral hernia occurs when a portion of the abdominal peritoneum protrudes through the femoral canal. The neck of the hernial sac is typically located below and lateral to the pubic tubercle. This condition is serious and requires surgical intervention due to the potential for strangulation of the herniated tissue.

Inguinal Canal and Differential Diagnosis of Hernias

The inguinal canal is another critical anatomic area where hernias can occur. In contrast to femoral hernias, inguinal hernias occur above and medial to the pubic tubercle. It's essential to differentiate between these conditions, as their presentation can overlap.

Inguinal hernia: The swelling is above and medial to the pubic tubercle.
Superficial inguinal lymph nodes: Enlargement usually involves multiple nodes, often associated with lymphadenitis.
Great saphenous vein: Swelling can indicate a localized dilatation known as saphenous varix.
Psoas sheath: Pathologies such as tuberculous infections can manifest here.
Femoral artery: Aneurysms may also present similar symptoms.

Adductor Canal

The adductor canal, also known as Hunter’s canal, is an intermuscular space located on the medial aspect of the thigh, specifically beneath the sartorius muscle. This canal begins at the apex of the femoral triangle and ends at the adductor hiatus.

Structure of the Adductor Canal

The adductor canal is triangular in cross-section, featuring:

Anteromedial wall: Formed by the sartorius and fascia.
Posterior wall: Composed of the adductor longus and adductor magnus muscles.
Anterolateral wall: Made up of the vastus medialis muscle.

The contents of the adductor canal include:

Femoral artery and its branches
Femoral vein
Saphenous nerve
Nerve to vastus medialis
Obturator nerve
Subsartorial plexus of nerves

The subsartorial plexus consists of neural branches from the medial cutaneous nerve of the thigh, saphenous nerve, and obturator nerve.

Branches of the Femoral Artery

The femoral artery, a continuation of the external iliac artery, enters the thigh and has several important branches:

Superficial branches: These include the superficial circumflex iliac artery, superficial epigastric artery, and superficial external pudendal artery, which supply the upper thigh, lower abdomen, and perineum.
Deep branches: This includes the profunda femoris artery, which gives rise to medial and lateral femoral circumflex arteries and perforating arteries.

The femoral vein lies medial to the femoral artery, playing a vital role in venous return from the lower limb. It connects to the external iliac vein as it exits the thigh.

Finally, the profunda femoris artery is critical for supplying blood to the deep structures of the thigh and branches just below the inguinal ligament.

Test Your Knowledge

To reinforce your understanding of the femoral triangle and adductor canal, consider these questions:

What are the branches of the femoral artery?
What are the boundaries of the adductor canal?
What are the branches of the femoral nerve?

Anatomical Study of the Femoral Triangle and Adductor Canal

Anatomical Study of the Femoral Triangle and Adductor Canal