Anatomy Atlas

Femoral triangle

Trigonum femorale
Also: Scarpa triangle
Space / regionHigh-yielddraftCardioMSK

Triangular region of the upper anterior thigh containing the femoral nerve, artery, vein and canal. It is the site of the femoral pulse, arterial and venous access, and femoral hernias.

Core anatomy

Location

Upper anterior thigh, just below the inguinal ligament.

Boundaries
superior (base)
Inguinal ligament
lateral
Medial border of sartorius
medial
Medial border of adductor longus
floor
Iliopsoas (laterally) and pectineus (medially), with adductor longus
roof
Fascia lata with the saphenous opening (cribriform fascia)
apex
Where sartorius crosses adductor longus, continuing as the adductor canal
Contents
  • Lateral to medial — NAVEL: Femoral nerve (outside the sheath), femoral artery, femoral vein, empty space/femoral canal, lymphatics (deep inguinal nodes, node of Cloquet)
  • Femoral sheath: a fascial sleeve (from transversalis and iliac fascia) around the artery, vein and canal — not the nerve
  • Deep femoral artery and vein; the termination of the great saphenous vein through the saphenous opening
  • Femoral branch of the genitofemoral nerve
Communications

Above: the femoral ring (the mouth of the femoral canal) opens into the abdomen — bounded by the inguinal ligament (anterior), pectineal ligament (posterior), lacunar ligament (medial) and femoral vein (lateral). Below: continuous with the adductor canal.

Mentioned in

Generated automatically from links in other entries.

Femoral triangle (right, anterior view)The femoral triangle of the right thigh, with lateral on the left. Its base is the inguinal ligament, from the anterior superior iliac spine to the pubic tubercle; its lateral border is sartorius and its medial border adductor longus, which meet at the apex, where the adductor canal begins. The floor is iliopsoas laterally and pectineus medially. From lateral to medial lie the femoral nerve outside the femoral sheath, then inside the sheath the femoral artery, the femoral vein and the femoral canal, with the deep inguinal lymph nodes most medially (NAVEL). The great saphenous vein joins the femoral vein through the saphenous opening, below and lateral to the pubic tubercle. The deep femoral artery leaves the femoral artery a few centimetres below the ligament and runs posteriorly.ASISInguinal ligamentFemoral nerveDeep femoral arteryIliopsoas (floor)SartoriusApex → adductor canalPubic tubercleFemoral arteryFemoral veinFemoral canal (ring)Deep inguinal nodesSaphenofemoral junctionPectineus (floor)Adductor longusGreat saphenous veinLateral ←→ MedialNAVEL, lateral → medialDashed outline = femoral sheath

Swipe sideways to see the whole diagram →

Femoral triangle (right, anterior view). Lateral on your left. The base is the inguinal ligament, the borders are sartorius (lateral) and adductor longus (medial), and the floor is iliopsoas and pectineus. Lateral to medial: Nerve (outside the femoral sheath), Artery, Vein, Empty space (femoral canal), Lymphatics. The pulse is felt just below the mid-inguinal point, with the vein just medial to it; a femoral hernia comes through the femoral canal.
Original schematic, created for this atlas.
Dissection of the femoral triangle showing the femoral nerve, artery and vein, sartorius, adductor longus and the great saphenous vein
Dissection of the femoral triangle: femoral nerve, artery and vein between sartorius and adductor longus.
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 549. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))
Surface projection of the femoral artery and femoral nerve on the front of the thigh from the inguinal ligament to the adductor tubercle
Surface markings of the femoral artery and nerve.
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 1245. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))

Clinical correlations

Femoral hernia PANCE

Mechanism / lesion

Herniation through the femoral ring into the femoral canal, below the inguinal ligament and medial to the femoral vein; more common in women.

Classic presentation

A small groin bulge below and lateral to the pubic tubercle; highest risk of incarceration and strangulation of groin hernias (narrow, rigid ring), so repair is recommended. See inguinal canal.

Femoral vascular access PANCE

Mechanism / lesion

Arterial puncture for angiography/PCI; central venous access into the femoral vein.

Classic presentation

Palpate the arterial pulse below the mid-inguinal point; the vein is just medial. Puncture below the inguinal ligament — a high puncture can cause retroperitoneal hemorrhage.

Inguinal lymphadenopathy

Mechanism / lesion

Drainage of the lower limb, perineum, lower abdominal wall and anal canal below the pectinate line (see pelvic and inguinal lymph drainage).

Classic presentation

Enlarged nodes in the triangle; examine the whole drainage area.

High-yield PANCE pearls

  • NAVEL lateral → medial: Nerve, Artery, Vein, Empty space, Lymphatics.
  • Femoral hernia: women, below the inguinal ligament, medial to the femoral vein, highest strangulation risk.
  • Femoral venous line: vein is medial to the pulse.
  • The femoral nerve lies outside the femoral sheath.

Imaging anatomy

CT

Femoral hernias with bowel obstruction; hematomas after catheterization.

Ultrasound

Guides femoral arterial and venous access and nerve blocks; distinguishes hernia, lymph node, pseudoaneurysm and saphena varix.

Physical exam

Surface landmarks

Inguinal ligament from the ASIS to the pubic tubercle; the femoral pulse just below its midpoint (mid-inguinal point).

Palpation

Femoral pulse; lymph nodes; groin masses (a femoral hernia lies below and lateral to the pubic tubercle; an inguinal hernia above and medial). A saphena varix has a cough thrill and disappears on lying down.

Strength / function testing

Cough impulse over any groin mass.

Self-quiz

Q1.

Which structure lies immediately medial to the femoral vein in the femoral triangle?

Show answer

C

Lateral to medial: nerve, artery, vein, femoral canal (empty space), lymphatics. Femoral hernias pass through the canal, just medial to the vein.

Q2.

A 70-year-old woman has vomiting and a tender, irreducible lump in the groin below the inguinal ligament and lateral to the pubic tubercle. What is the most likely diagnosis?

Show answer

C

A lump below the inguinal ligament and inferolateral to the pubic tubercle in an older woman with bowel obstruction is an incarcerated femoral hernia — the groin hernia most prone to strangulation, needing urgent surgery.

Q3.

Which muscle forms the medial boundary of the femoral triangle?

Show answer

A

The femoral triangle is bounded by the inguinal ligament (base), the medial border of sartorius (lateral) and the medial border of adductor longus (medial). Iliopsoas, pectineus and adductor longus form its floor.

Q4.

Which structure forms the medial boundary of the femoral ring, the opening of the femoral canal?

Show answer

C

The femoral ring is bounded by the inguinal ligament (anterior), the pectineal ligament (posterior), the lacunar ligament (medial) and the femoral vein (lateral). The rigid, narrow ring explains why femoral hernias strangulate so often.

Q5.

Where should the needle be placed to cannulate the femoral vein?

Show answer

D

From lateral to medial the triangle contains the Nerve, Artery, Vein, Empty space (femoral canal) and Lymphatics (NAVEL). The vein lies just medial to the arterial pulse, and puncture should be below the inguinal ligament.

Flashcards

See also