Describe the boundaries and contents of the adductor canal.

Definition

• About 15 cm long; triangular in cross-section

Boundaries

• The roof is crossed by the subsartorial plexus of nerves

Contents

• Femoral artery
• Femoral vein — behind and lateral to the artery above, behind and medial below (it spirals round the artery)
• Saphenous nerve — crosses the artery from lateral to medial; does not leave through the hiatus but pierces the roof
• Nerve to vastus medialis
• Posterior and medial divisions of the obturator nerve (in the lower part)

The Adductor Hiatus

• An opening in the tendinous insertion of adductor magnus, between its adductor and hamstring parts
• Transmits the femoral artery and vein, which become the popliteal vessels beyond it
• It marks the anatomical junction between the anterior compartment of the thigh and the popliteal fossa

Adductor Magnus — a Composite Muscle

• It is the only muscle with a dual nerve supply of this kind, reflecting its composite origin from both the adductor and hamstring groups

Applied Aspects

• The adductor canal is the site of femoral artery exposure for femoropopliteal bypass grafting in peripheral vascular disease
• Adductor canal block has largely replaced the femoral nerve block for knee surgery — it provides similar analgesia while preserving quadriceps power, so the patient can mobilise safely
• Hunter's canal was named for John Hunter, who ligated the femoral artery here for popliteal aneurysm — an operation that established the principle of proximal ligation relying on collateral circulation
• Saphenous nerve entrapment where it pierces the roof causes medial knee and leg pain without motor loss, and is easily mistaken for a knee problem
• Adductor strain ("groin pull") is common in sport and affects adductor longus most often at its musculotendinous junction