676 BLOOD-VASCULAR SYSTEM OF THE HORSE 



thigh. In company with the large saphenous vein and the- saphenous nerve it 



descends superficiallj' on the anterior part of the gracilis, continues on the deep 



fascia of the leg, and di\'ides aljove the hock into two branches, which accompany 



the radicles of the vein. It gives off cutaneous twigs and anastomoses with the 



recurrent tibial artery-. 



In some cases this anastomosis does not occur. The artery may be larger and directly con- 

 tinuous with the medial tarsal arterj^ 



6. The articular branch (A. genu suprema) is a slender artery which arises 

 from the femoral just before it passes through the adductor. It descends along the 

 posterior border of the vastus medialis to the medial surface of the stifle joint, 

 where it ramifies. 



7. The nutrient artery of the femur (A. nutritia femoris) is given off at the 

 middle of the femur and enters the nutrient foramen. 



8. The posterior femoral artery (A. femoris caudalis)^ is a large vessel which 

 arises from the posterior face of the femoral just before or as the trunk passes be- 

 tween the two heads of the gastrocnemius (Fig. 584) . It is very short and divides 

 into two branches. The ascejiding branch passes upward and outward between 

 the adductor (in front) and the semimembranosus (behind), and ramifies in the 

 biceps femoris, vastus lateralis, adductor, and semitendinosus. The descending 

 branch passes downward and backward on the lateral head of the gastrocnemius, 

 then curves upward between the biceps femoris and semitendinosus (crossed 

 laterd,lly by the tibial nerve) and divides into branches to these muscles. A branch 

 descends between the heads of the gastrocnemius, gives branches to that muscle 

 and the superficial digital flexor, and is continued by a slender artery which ac- 

 companies the tibial nerve and unites with the recurrent tibial artery. A small 

 branch often ascends alongside of the sciatic nerve, between the biceps and semi- 

 tendinosus and anastomoses with a descending branch of the obturator. 



This branch is frequently absent, but the large vein which it accompanies when present, is 

 constant and connects the obturator and posterior femoral veins. 



The Popliteal Artery 



This' artery (A. poplitea) is the direct continuation of the femoral. It lies 

 between the two heads of the gastrocnemius, at first on the posterior face of the 

 femur, then on the femoro-tibial joint capsule. It descends through the popliteal 

 notch under cover of the popliteus, inclines outward, and divides near the proximal 

 part of the interosseous space into anterior and posterior tibial arteries. The 

 satellite vein lies along its medial side at the stifle joint. Collateral branches are 

 supplied to the stifle joint and the gastrocnemius and popliteus. 



One of the articular branches (A. genu media) runs directly forward, passes through the 

 posterior part of the capsule of the femoro-tibial joint, and supplies the cruciate ligaments, syno- 

 vial membrane, etc. Another branch (A. genu lateralis distalis) passes outward under the lateral 

 head of the gastrocnemius, and concurs with the articular branch of the femoral artery in forming 

 a plexus on the stifle. 



POSTERIOR TIBIAL ARTERY 



The posterior tibial artery (A. tibialis posterior) is much the smaller of the two 

 terminals of the popliteal. It lies at first between the tibia and the popliteus, 

 then between that muscle and the deep and inedial heads of the deep digital flexor. 

 Lower down it descends along the tendon of the flexor longus, becomes superficial 

 in the distal third of the leg, and divides into lateral and medial tarsal branches.^ 

 The collateral branches include the nutrient artery of the tibia (A. nutritia tibiae) 

 and muscular branches (Rami musculares) to the muscles on the posterior surface 

 of the tibia. 



' Also termed the femoro-popliteal artery. 



^ Instead of dividing thus, the posterior tibial may be continued by the lateral tarsal. The 

 medial tarsal may be a continuation of the saphenous artery. 



