Adductor Canal: Boundaries, Contents and Clinical Anatomy

By Dr Richard Miller, MBChB FRCS · Reviewed 1 October 2026

The adductor canal is a narrow tunnel in the middle third of the thigh that carries the femoral vessels from the femoral triangle to the back of the knee. It lies under sartorius, between vastus medialis and the adductor muscles, and contains the femoral artery and vein, the saphenous nerve and the nerve to vastus medialis.

Adductor Canal · key facts

Boundaries: Apex of femoral triangle to adductor hiatus; vastus medialis anterolaterally
Roof: Sartorius over a fibrous vastoadductor membrane
Floor: Adductor longus above, adductor magnus below
Contents: Femoral artery and vein, saphenous nerve, nerve to vastus medialis, lymphatics
Clinical relevance: Adductor canal block, femoral artery occlusion, femoropopliteal bypass

Boundaries

The adductor canal is a triangular intermuscular tunnel that begins at the apex of the femoral triangle and ends at the adductor hiatus in adductor magnus, just above the knee. It is also called the subsartorial canal or Hunter's canal, after the surgeon John Hunter.

Wall	Formed by
Anterolateral wall	Vastus medialis
Posterior wall (floor)	Adductor longus in the upper part, adductor magnus in the lower part
Anteromedial wall (roof)	A tough fibrous sheet, the vastoadductor membrane, bridging vastus medialis and the adductors, covered by sartorius
Entrance	Apex of the femoral triangle, where the medial border of sartorius crosses the medial border of adductor longus
Exit	Adductor hiatus, a gap between the adductor and hamstring parts of adductor magnus, above the adductor tubercle

In cross-section the canal is triangular. Sartorius lies on the roof along its whole length, which is why it is called the subsartorial canal.

The adductor canal contains the femoral artery and vein and two branches of the femoral nerve.

Femoral artery: enters at the apex of the femoral triangle and leaves through the adductor hiatus, where it becomes the popliteal artery. Clinicians call this segment the superficial femoral artery. Just above the hiatus it gives the descending genicular artery, which joins the anastomosis around the knee.
Femoral vein: lies behind the artery throughout the canal and becomes the popliteal vein at the hiatus.
Saphenous nerve: lies lateral to the artery at the top of the canal, crosses in front of it, and is medial to it at the bottom. It does not pass through the hiatus; it leaves by piercing the roof with the saphenous branch of the descending genicular artery.
Nerve to vastus medialis: runs in the upper part of the canal on the lateral side of the artery before entering the muscle.
Lymphatic vessels: deep lymphatics from the leg and popliteal nodes, running up alongside the femoral vessels to the deep inguinal nodes.

Relations

The adductor canal is a conduit between two spaces: the femoral triangle above and the popliteal fossa below.

Above: in the femoral triangle the femoral vein lies medial to the artery; it has moved behind the artery by the time both enter the canal.
Below: through the adductor hiatus the vessels reach the popliteal fossa, where the vein lies superficial to the artery.
On the roof: a fine subsartorial plexus of nerves, from the medial cutaneous nerve of thigh, the saphenous nerve and the anterior division of the obturator nerve, supplies the overlying skin.
Medially: the great saphenous vein runs in the superficial fascia, well away from the canal, and is not one of its contents.

Clinical relevance

The adductor canal matters clinically as a site for regional anaesthesia, a common site of arterial occlusion and a route for vascular surgery.

Adductor canal block

Local anaesthetic injected around the femoral artery under sartorius, guided by ultrasound, blocks the saphenous nerve and some fibres to the knee. It gives analgesia after knee replacement and anterior cruciate ligament reconstruction. Compared with a femoral nerve block it largely spares quadriceps strength, which helps early mobilisation, although the nerve to vastus medialis can be affected by high injections.

Arterial disease

The femoral artery in the lower canal, near the adductor hiatus, is one of the commonest sites of atherosclerotic occlusion in the lower limb. Patients present with calf claudication. The descending genicular and other collaterals around the knee may keep the leg viable. Surgical access to this segment for femoropopliteal bypass is gained by retracting sartorius.

Historical note

In the eighteenth century John Hunter treated popliteal aneurysm by tying the femoral artery in this canal, well above the aneurysm, relying on collateral flow to preserve the limb. The canal carries his name for that reason.

Saphenous nerve entrapment

The saphenous nerve can be compressed where it pierces the roof of the canal, giving pain along the medial knee and leg.

How it is examined

On a cadaveric spotter, in an OSPE and in MRCS Part B anatomy.

A pin on the muscle forming the roof of the canal is sartorius; the muscle on its lateral side is vastus medialis, and the floor is adductor longus above and adductor magnus below.
The thin nerve lying on the front of the femoral artery in the canal is the saphenous nerve. The nerve heading laterally into vastus medialis is the nerve to vastus medialis.
Expect the follow-up: what the femoral artery becomes after the adductor hiatus (popliteal artery), and which content of the canal does not pass through the hiatus (the saphenous nerve).
Viva favourite: why an adductor canal block is preferred to a femoral block after knee replacement (it spares quadriceps power).
Do not list the great saphenous vein as a content; it is superficial, in the subcutaneous tissue.

Key points

The adductor canal runs from the apex of the femoral triangle to the adductor hiatus in the middle third of the thigh.
Its walls are vastus medialis, adductor longus and magnus, and a fibrous roof under sartorius.
It contains the femoral artery and vein, the saphenous nerve and the nerve to vastus medialis.
The saphenous nerve crosses the artery from lateral to medial and leaves by piercing the roof.
It is used for the adductor canal block and is a common site of femoral artery occlusion.

Common questions

What passes through the adductor canal?

The adductor canal contains the femoral artery, the femoral vein, the saphenous nerve and the nerve to vastus medialis, along with deep lymphatic vessels. The artery and vein continue through the adductor hiatus to become the popliteal vessels. The saphenous nerve leaves the canal by piercing its fibrous roof near the knee, and the nerve to vastus medialis leaves laterally to enter that muscle.

Where is the adductor canal?

The adductor canal lies in the middle third of the medial thigh, deep to sartorius. It begins at the apex of the femoral triangle and runs down to the adductor hiatus, an opening in adductor magnus just above the adductor tubercle of the femur. Vastus medialis forms its lateral wall and the adductor longus and adductor magnus muscles form its floor.

What does an adductor canal block numb?

An adductor canal block mainly anaesthetises the saphenous nerve, numbing the skin of the medial knee, leg and ankle, and also reaches some articular nerves to the knee. It is used for pain relief after knee replacement and knee ligament surgery. Because it largely spares the motor branches of the femoral nerve, quadriceps strength is better preserved than with a femoral nerve block.

Why is it called Hunter's canal?

The adductor canal is called Hunter's canal after John Hunter, the eighteenth-century British surgeon and anatomist. He treated popliteal artery aneurysms by tying off the femoral artery within this canal, some distance above the aneurysm, rather than amputating the leg. The collateral circulation around the knee kept the limb alive, and the canal became linked with his name.

References

Gray's Anatomy: The Anatomical Basis of Clinical Practice. Standring S (ed). Elsevier. 42nd edition, 2020.
Moore's Clinically Oriented Anatomy. Moore KL, Dalley AF, Agur AMR. Wolters Kluwer. 9th edition, 2022.
Last's Anatomy: Regional and Applied. Elsevier.