Pes anserinus

Last revised by Daniel J Bell on 22 Sep 2021

Pes anserinus (rare plural: pedes anserini) is the anatomic name given to the conjoined tendons at the medial aspect of the knee that inserts onto the anteromedial aspect of the tibia

The term "pes anserinus" may also be used to describe the branching point of the facial nerve (CN-VII) within the parotid gland.   

The three tendons that form the pes anserinus (from anterior to posterior) are 1,2:

See here for mnemonics for remembering the three conjoined tendons that make up the pes anserinus.

These tendons insert onto the anteromedial proximal tibia approximately 4 cm distal to the tibial plateau 2.

The pes anserinus inserts on the medial side of the tibial tuberosity below or distal to the tibial tuberosity with significant variant anatomy 3,4, comprising mostly different accessory tendinous bands appearing from the different tendons.

The type of insertion can be classified into a short, band-shaped and fan-shaped, with fan-shaped defined as the insertion being two times the width of the tendon and band-shaped being less than two times the tendon width 3. The sartorius tendon insertion usually has a short tendon insertion, the gracilis tendon and its accessory bands show most often (ca.80%) a band-shaped attachment, whereas the semitendinosus tendon and its accessory bands are characterized by a fan-shaped insertion (ca. 80%) 3.

The pes anserinus bursa lies between the pes anserinus tendons and the more deeply located semimembranosus tendon at the level of the knee joint. This bursa can become inflamed and symptomatic: pes anserinus bursitis.

The variant anatomy is of particular clinical importance since the pes anserinus serves a harvest site for tendon grafts e.g. in anterior cruciate ligament repair 3.

In respect to the accessory bands, the majority seem to emerge from the semitendinosus tendon 3,4. Accessory bands from the sartorius and/or gracilis tendon are less frequent 3,4. The accessory bands usually insert on the gastrocnemius or popliteus fascia 3.

Some of the accessory bands of the semitendinosus muscle emerge up to 12 cm proximal to the pes anserinus insertion 3.

The name comes from the Latin for goose's foot, in view of the similarity of the structure to the webbed foot of the bird. 

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Cases and figures

  • Figure 1: annotated image
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  • Figure 2: anatomy diagram
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