THE ARTERIES. 313 
anterior and passes distad along the dorsal (anterior) border 
of the fibula. 
Branches of the popliteal artery: 
1. A. suralis.—This is a large branch which passes distad 
from the caudal side of the popliteal artery. It sends branches 
to the biceps and to the fat in the popliteal space, and passes 
onto the ventral border of the lateral head of the gastrocnemius. 
It sends branches to both heads of the gastrocnemius and to 
the popliteus, passes distad onto the lateral surface of the ten- 
don of Achilles, and may be traced to the proximal portion of 
the dorsolateral side of the foot, where it sends many branches 
to the integument about the ankle-joint. It then passes along 
the lateral side of the foot and supplies the artery on the lateral 
side of the fifth digit. 
2. Aa. genu posteriores.—Several small arteries which 
pass to the knee-joint. 
3. Rami musculares.—Numerous small branches to the 
muscles about the popliteal space. 
4. A. tibialis posterior.—This is the largest branch of the 
popliteal artery, which it leaves just before the latter passes 
beneath the popliteal muscle. The tibialis posterior passes at 
first mediad, then turns distad, passes across the popliteus 
muscle onto the surface of the flexor longus hallucis, and 
ramifies in the substance of this muscle and its tendon. It 
gives branches also to the gastrocnemius and soleus. (It does 
not pass into the foot as does the corresponding artery in 
man.) 
5. A. tibialis anterior.—The anterior tibial artery is the 
continuation of the popliteal after its passage through the inter- 
osseous membrane between tibia and fibula to the dorsal side of 
the lower leg. Here it passes distad, lying against the inter- 
osseous menibrane, between the extensor longus digitorum and 
the tibialis anterior muscle, or partly imbedded in the substance 
of the latter. It passes, lying beneath the tendons of these 
muscles, through the transverse ligament proximad of the 
malleoli, thus reaching the dorsum of the foot. It extends dis- 
tad across the tarsus to the space between the second and third 
metatarsals, and through this space to the plantar side of the 
