388 MR. ST. GEORGE MIVART AND DR. J. MURIE [June 26, 



The popliteal artery is but a series of branches of the femoral, — the 

 main arterial trunk, the continuation of the femoral, being hardly 

 distinguishable by size from the numerous usual muscular and arti- 

 cular branches. The divisions commence just above the origin of 

 the gastrocnemius muscle. 



Besides the (four) superior and inferior articular branches there 

 is a middle or azygos artery of small size which pierces the fascia 

 close to the tibia. The two larger brauches, supplying the gastro- 

 cnemius and other muscles of the calf, are given off highest. 



The posterior tibial, anterior tibial, and recurrent arteries are given 

 off together from the popliteal, and about opposite the condyles of 

 the femur. The first of these runs alongside the highest and deepest 

 branch of the ischiatic nerve, and about the upper one-fifth of the 

 shaft of the tibia it pierces the deep flexor muscles of the leg, and 

 then proceeds downwards. 



The second or anterior tibial artery passes deeply over the po- 

 pliteus muscle and between the tibia and fibula, running down the 

 anterior surface of the interosseous ligament to the ankle-joint. 



The third or recurrent artery passes outwards beneath the external 

 head of the gastrocnemius. 



The continuation of the anterior tibial at the ankle-joint inoscu- 

 lates with the inferior extremity of the superficial femoral artery, and 

 then proceeds between the two inner metatarsal bones from the dor- 

 sum of the foot to the sole near their distal extremities, and there 

 supplies three digits on their plantar aspect. A branch at the mal- 

 leolus comes from the above and dips between the cuboid and external 

 cuneiform, forming a deep palmar arch of two branches. This com- 

 municates with the superficial plantar arch above described. 



Nervous System. 



The great sciatic nerve, which is large, passes beneath the pyri- 

 formis muscle. Emerging from below this and through the great 

 ischiatic notch, it passes down the back of the thigh beneath the 

 flexor muscles, but not close to the thigh-bone. Opposite the lower 

 end of the shaft of the femur it divides into the smaller (external) 

 and larger (internal) popliteal nerves. 



The external popliteal is continued as the peroneal nerve, and goes 

 beneath a small tendinous slip of the outer head of the gastrocnemius, 

 and also the peroneal muscles just below the projecting processes of 

 bone on the outer head of the fibula ; thence it descends in front of 

 the interosseous membrane alongside of the extensor muscles to the 

 ankle, and onwards to the dorsum of the foot, branches being given 

 off at the ankle-joint. 



The internal (or posterior tibial) nerve divides into two branches : 

 — one, the outermost, supplying the large superficial flexor muscles ; 

 the other dividing lower down opposite the joint into an internal 

 deep branch going to the deep flexor muscles, and a more superficial 

 one which proceeds to the inner side of the projection of the os calcis 

 and then splits into smaller branches. 





