Femoral triangle

Last revised by Yoshi Yu on 17 Mar 2023

The femoral triangle is an anatomical space in the anterior upper thigh that contains several palpable structures.

Gross anatomy

Boundaries

The major boundaries can be recalled with the mnemonic SAIL 1,2:

Contents

From lateral to medial 1:

  • femoral nerve

  • femoral sheath (thickening of the deep fascia of the thigh) which has three compartments (from lateral to medial):

    • femoral artery and its branches (within the lateral compartment of the femoral sheath) and the femoral branch of the genitofemoral nerve

    • femoral vein (within the intermediate compartment of the femoral sheath) and deep lymph nodes

    • femoral canal (the medial compartment of the femoral sheath) which contains fat and lymph nodes (of Cloquet)

The basic order can be recalled with the mnemonics seen here.

Radiographic features

CT

The femoral triangle is best seen on coronal reformats but because of its curved nature around the anterior thigh it cannot always be fully seen. Cherian and Parnell 2 have proposed a radiologic femoral triangle (as opposed to the above described anatomic femoral triangle) with the following boundaries:

  • laterally: femoral vein

  • medially: pectineus muscle

  • superiorly: inguinal ligament

Cherian and Parnell state that the importance of the radiologic femoral triangle is that it is a site for femoral hernias identifiable on MDCT and acts as a surrogate site for the femoral canal 2

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