42.2 Anatomy

Innervation of the posterior knee is provided by articular branches that originate from the sciatic, tibial nerve (TN), common peroneal (CPN), and the posterior division of the obturator nerve. 

The articular branches from the TN are the main source of innervation to the posterior knee joint capsule. They originate either proximal or distal to the superior border of the medial femoral condyle, and course transversely to the intercondylar region, between the medial and lateral femoral condyles, where they further branch. 

The articular branches from the sciatic and/or the CPN further divide into anterior and posterior branches to innervate the anterolateral and posterolateral capsule, respectively.  

Finally, the articular branch from the posterior obturator nerve courses through the adductor hiatus, together with the femoral artery and vein, and enters the popliteal fossa. At the level of the femoral condyles, it divides into two to three terminal branches that supply the superomedial aspect of the posterior capsule.