Femoral canal

Deep femoral ring

The deep femoral ring (anulus femoralis) is the deep opening of the canal. It is through this opening that a hernial protrusion penetrates from the abdominal cavity. The opening is located in the most medial part of the vascular lacuna.

It is bounded by four structures:

• Anteriorly: inguinal ligament.
• Posteriorly: pectineal ligament (lig. pectineale or Cooper's ligament), resting on the pecten of the pubic bone.
• Medially: lacunar ligament (lig. lacunare or Gimbernat's ligament), located in the angle between the inguinal ligament and the pubic crest.
• Laterally: femoral vein.

Topography and walls of the canal

The femoral canal lies beneath the fascia lata. Anteriorly, it is covered by the sartorius muscle (m. sartorius). The middle of the canal is located approximately 15–20 cm from the adductor tubercle of the femur.

The canal has three walls:

1. Medial: adductor magnus muscle (m. adductor magnus).
2. Lateral: vastus medialis muscle (m. vastus medialis).
3. Anterior: vasto-adductor intermuscular septum (septum intermusculare vastoadductoria), which spans between the two aforementioned muscles.

Openings of the canal

There are three openings of the femoral canal:

• Upper opening: serves as the entrance from the anterior femoral sulcus. The femoral vessels and saphenous nerve (n. saphenus) pass through it.
• Lower opening: a cleft between the muscle bundles of the adductor magnus muscle (or between its tendon and the bone). Through it, the femoral vessels head toward the posterior surface of the thigh — into the popliteal fossa.
• Anterior opening: is located in the vasto-adductor intermuscular septum and leads to the subcutaneous tissue beneath the sartorius muscle. The descending genicular artery and vein (a. et v. descendens genus) as well as the saphenous nerve emerge here. Sometimes these structures pierce the septum through a single common opening, and sometimes through several isolated ones.

Communications of the canal

Knowledge of the pathways of communication of the femoral canal is critical for understanding the spread of purulent processes in the lower extremity:

• Proximally: the canal communicates with the cellular tissue of the femoral triangle (trigonum femorale).
• Distally: opens into the popliteal fossa (fossa poplitea) via the hiatus adductorius.
• Along the vessels and nerve (descending genicular artery and vein, saphenous nerve): pus can descend into the subcutaneous tissue of the medial surface of the knee joint and lower leg.

Hernia anatomy

Abdominal hernias are divided into external (protruding under the skin) and internal (forming in peritoneal pockets inside the abdominal cavity). Any hernia necessarily consists of three elements:

1. Hernial ring (gates) — an anatomical defect or natural opening in the musculo-aponeurotic layer of the abdominal wall.
2. Hernial sac — the displaced parietal layer of the peritoneum. It is divided into the neck (in the region of the ring), body, and fundus.
3. Hernial contents — abdominal organs that end up inside the sac (most commonly the greater omentum or loops of the small intestine).

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Layer-by-layer topography of tissues superficial to the canal (skin, subcutaneous tissue, superficial nerves)
• Topography of superficial nerves (branches of the femoral and obturator nerves)
• Features of the localization of the great saphenous vein
• Variant anatomy of the anterior opening of the canal

Other topics in the "Lower Limb" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.