External Plantar Artery

The larger of the two terminal branches runs outwards and forwards between flexor brevis digitorum on the inner side and accessorius and abductor minimi digiti on the outer side to the base of the fifth metatarsal bone. It then passes inwards across the bases of the metatarsal bones, where on the outer side of the first one it terminates by anastomosing with the dorsalis pedis artery, thus forming the plantar arch (see Fig. 24).

Branches

1. Internal calcaneal.

2. Muscular.

3. Cutaneous. From the arch4. Digital branches - four in number-running on the outer side of the little toe and the plantar surfaces of the interosseous muscles.

5. Perforating arteries - three in number-anastomosing with the dorsal arteries.

6. Articular to the tarsal joints.

Anterior Tibial Atery

The smaller of the two terminal branches of the popliteal artery passes forward above the interosseous membrane and runs down the front of the leg and terminates by becoming the dorsal artery of the foot from the lower border of popliteus to the front of the ankle. It lies on, successively, anterior surface upper two-thirds of interosseous membrane, shaft of tibia, anterior ligament of ankle-joint.

On the inner side of the upper two-thirds lies the tibialis-anticus, and in the lower third the extensor longus hallucis crosses over and lies on the inner side. On the outer side of the upper two-thirds lie respectively extensor longus digitorum and extensor longus hallucis, and the last part of the artery lies between the tendons of these two muscles.

The anterior tibial nerve lies on the outer side of the artery, and at the ankle lies between it and the outermost tendon of extensor longus digitorum. The artery is accompanied by venae comites.

Branches

1. Muscular to adjacent parts.

2. Cutaneous to skin of front of leg.

3. Internal malleolar anastomoses with posterior tibial.

4. External malleolar anastomoses with peroneal. Dorsalis Pedis artery is the direct continuation of the anterior tibial artery from the front of the ankle-joint to the posterior extremity of the first interosseous space, where it anastomoses with the external plantar artery to form the plantar arch. It lies on, successively, anterior ligament of the ankle-joint, head of the astragalus, navicular bone, intercuneiform ligaments.

It is covered by skin and fascia and the lower part of the anterior annular ligament.

The internal terminal branch of the anterior tibial nerve lies on the outer side of the artery, between it and the extensor brevis digitorum.

The tendon of extensor proprius hallucis lies on the inner side.

Branches

1. Cutaneous to skin of dorsum of foot.

2. Dorsalis hallucis runs on first interosseus muscle and supples first and second toes.

3. Metatarsal arises just before termination of artery, and, running outwards, gives off branches to supply the digital clefts.

Veins of the Lower Limb.

The veins of the lower limb are arranged in a similar manner to those of the upper limb, in two groups-superficial and deep.

The Deep veins consist of venae comites accompanying all the arteries in the leg, which unite to form the Popliteal vein at the lower border of popliteus. The popliteal vein passes upwards through the popliteal space, at first on the inner side of the artery and above on the outer side; it then passes through the opening in adductor magnus and becomes the femoral vein.

Femoral Vein

The Femoral vein is the direct continuation of the popliteal vein. It ascends through Hunter's canal and Scarpa's triangle, and, passing under Poupart's ligament on the inner side of the femoral artery, becomes the external iliac vein.

The Superficial veins of the lower limb are two in number - the internal or long saphenous vein and the external or short saphenous vein.

The veins on the toes are arranged similarly to those of the fingers, and form plexuses on the sole and dorsum of the foot, which enter the external and internal saphenous veins respectively.

The Internal Saphenous vein is formed by the veins on the inner side of the sole and dorsum of the foot. It passes upwards in front of the internal malleolus, and, passing behind the inner border of the tibia, it runs up the leg to a point behind the internal condyle of the femur. Then, coursing outwards and forwards, it passes up the inner side of the thigh and terminates in the upper part of Scarpa's triangle in the femoral vein.

The External Saphenous vein is formed by the veins on the outer side of the sole and dorsum of the foot. It passes behind the external malleolus and up the back of the leg to the lower part of the popliteal space, where it enters the popliteal vein.