Pes Anserine Bursitis: Overview
Pes anserine bursitis is an inflammatory condition of the medial (inner) knee at the anserine bursa, a sub muscular bursa, just below the pes anserinus.
Pes Anserine Bursitis: Pathology
The pes anserinus is the anatomic term used to identify the insertion of the conjoined tendons Sartorius, Gracilis, and Semitendinosus into the anteromedial proximal tibia. Theoretically, bursitis results from stress to this area (e.g. stress may result when an obese individual with anatomic deformity from arthritis ascends or descends stairs). An occurrence of pes anserine bursitis commonly is characterized by pain, especially when climbing stairs, tenderness, and local swelling.
Pes Anserine Bursitis: Pathophysiology
The etymology of the name relates to the insertion of the conjoined tendons into the anteromedial proximal tibia. From anterior to posterior, the pes anserinus is made up of the tendons of the sartorius, gracilis, and semitendinosus muscles. The tendon’s name, which literally means “goose’s foot,” was inspired by the pes anserinus’s webbed, footlike structure. The conjoined tendon lies superficial to the tibial insertion of the medial collateral ligament (MCL) of the knee.
Pes Anserine Bursitis: Muscles involved
Sartorius aids in knee and hip flexion, as in sitting or climbing; abducts and laterally rotates thigh; innervated by the femoral nerve.
Gracilis flexes and medially rotates tibia at knee; innervated by the obturator nerve.
Semitendinosus flexes knee; medially rotates tibia on femur when knee is flexed; medially rotates femur when hip is extended; counteracts forward bending at hips; innervated by tibial nerve and common fibular nerve.