This is the larger of the two popliteal nerves, and passes down the middle of the popliteal space as far as the lower border of the popliteal muscle, where it becomes the posterior tibial nerve. At first it lies away from, and to the lateral side of, the popliteal artery, but becomes superficial to that vessel in the middle of the popliteal space, finally reaching its medial side.

Branches

(a) Muscular, to the gastrocnemius, soleus, plantaris, and popliteus.

(b) Articular, two or three in number, accompany the superior medial, inferior medial, and azygos, articular arteries to the knee-joint.

(c) Cutaneous, ramus communicans tibialis. It descends between the two heads of the gastrocnemius to join the ramus communicans fibularis of the external popliteal.