Human Anatomy, Part 2 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2008

Special Part
Cardiovascular system, systema cardiovasculare - Special Part
Blood vessels of the systemic circulation - Arteries of the lower limb - Posterior tibial artery

The posterior tibial artery, a.tibialis posterior (Fig. 53), is a direct continuation of the popliteal artery. It originates at the lower angle of the popliteal fossa, passes beneath the tendinous arch of the soleus Muscle (m.soleus), and enters the cruropopliteal canal (canalis cruropopliteus). In the upper leg, the artery lies between the soleus and the posterior tibial muscle (m.tibialis posterior); in the middle leg, between the long flexor of toes (m.flexor digitorum longus) and the long flexor of great toe (m.flexor hallucis longus); and in the lower leg, it runs medial to the tendon of the triceps surae (m.triceps surae). Throughout its course, the a.tibialis posterior is accompanied by two posterior tibial Veins and the tibial nerve, n.tibialis (forming the posterior tibial neurovascular bundle). The projection line of the posterior tibial artery runs from the midpoint of the popliteal crease to the midpoint of the distance between the medial malleolus and the calcaneal tendon. Further distally, the artery curves behind the medial malleolus (malleolus medialis), passes beneath the flexor retinaculum (retinaculum mm. flexorum) within the malleolar canal, and reaches the medial margin of the FOOT, where it divides into the medial and lateral plantar Arteries (aa.plantares mediales et laterales). From a practical standpoint, the Topography of the posterior tibial artery is divided into three segments: the supra-malleolar segment (5–8 cm), the malleolar segment (at the level of the medial malleolus), and the infra-malleolar segment. Within these areas, the posterior tibial artery may lie anterior to the nerve, posterior and medial to the nerve, or be covered posteriorly by Muscles and nerves.

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Fig. 55. Anterior tibial artery, a.tibialis anterior

Fig. 58. Arteries of the SOLE OF THE foot

Fig. 56. Arteries of the dorsum of the foot

Fig. 56 A; B. Anatomical Variants of the dorsal (A) and plantar metatarsal arteries of the foot (B) (according to Lippert)

Branches of the posterior tibial artery:

1. R.circumflexus fibularis;

3. A.plantaris medialis;

2. A.fibularis;

4. A.plantaris lateralis.

1. The fibular circumflex branch, r.circumflexus fibularis, originates at the level of the fibular neck, which it curves around laterally, supplies the soleus (m.soleus) and long fibular (m.peroneus longus) muscles, and anastomoses with the anterior tibial artery (a.tibialis anterior) and the articular network of the knee (rete articulare genus).

2. The fibular artery, a.fibularis (Fig. 53), is the largest branch of the posterior tibial artery. It arises in the upper part of the leg, enters the musculoperoneal canal (canalis musculoperoneus) at a distance of 5–6 cm from its origin (I. Hyrtl), courses downward along the posterior surface of the posterior tibial muscle (m. tibialis posterior) and along the medial margin of the long flexor of great toe (m.fiexor hallucis longus). In the lower third of the leg, a.fibularis runs along the lateral margin of the interosseous membrane and the posterior edge of the peroneal tendons. Along its path, it supplies the triceps surae (m.triceps surae), long and short fibular muscles (m.peroneus longus et brevis), and behind the lateral malleolus, it divides into the lateral malleolar and calcaneal branches (rr.maleollaris laterales et rr.calcanei). The latter participate in supplying the capsule of the ankle joint and forming the calcaneal network (rete calcaneum). The fibular artery also gives off the nutrient artery of the Fibula (a.nutriens fibulae), a perforating branch (r.perforans) that emerges through the lower part of the interosseous membrane onto the anterior surface—where it anastomoses with branches of a.tibialis anterior—and a communicating branch (r.communicans), which forms an anastomosis in the lower third of the leg between the terminal part of the perforating artery and a.tibialis posterior.

3. The lateral plantar artery, a.plantaris lateralis (Fig. 58), is the largest terminal branch of the tibial artery. It runs anterior to the lateral tuberosity of the calcaneus (tuber calcanei), beneath the tendon of the adductor hallucis muscle (m.adductor hallucis), and then penetrates between the short flexor of toes (m.fiexor digitorum brevis) and the square muscle of the sole (m.quadratus plantae). Reaching the lateral margin of the foot, the artery passes between m.quadratus plantae and the short flexor of the little toe (m.fiexor digiti minimi brevis). Near the Base of the fifth metatarsal bone, it turns medially to form the plantar arch (arcus plantaris). In the first intermetatarsal space, the plantar arch anastomoses with the arcuate artery (a.arcuata) via the deep plantar branch (r.plantaris profundus, a branch of the dorsal artery of the foot). Four plantar metatarsal arteries (aa.metatarsales plantares*) arise from the plantar arch. In the interosseous spaces, these arteries receive perforating branches from the dorsal metatarsal arteries.

Fig. 57. Diagram of the arteries, arterial arches, and anastomoses of the foot (according to I. Ye. Kefeli)

The plantar metatarsal arteries, aa.metatarsales plantares (Fig. 58), also send perforating branches (rr.perforantes) to the dorsal metatarsal arteries. These anastomoses maintain the Blood supply to the foot during prolonged standing when the lateral plantar artery (a.plantaris lateralis) is compressed. The plantar metatarsal arteries continue into the common plantar digital arteries (aa.digitales plantares communes), which course distally to the interdigital spaces, where they divide into two proper plantar digital arteries (aa.digitales plantares рrорriае). These anastomose with one another in the finger/toe pads (Fig. 57).

The first common plantar digital artery branches into three proper plantar digital arteries: two of them run along the sides of the big toe, while the third runs along the side of the second toe. The remaining proper plantar digital arteries (second, third, and fourth) supply the medial surfaces of the toes (II, III, IV, and V). Near the heads of the Metatarsal Bones, perforating branches pass from the aa.digitales plantares communes to the dorsal digital arteries.

4. The medial plantar artery, a.plantaris medialis (Fig. 58), is a slender terminal branch of the posterior tibial artery. It runs beneath m.adductor hallucis, lies within the medial groove of the sole, and divides into a superficial branch (r.superficialis) and a deep branch (r.profundus). The superficial branch supplies m.adductor hallucis and the medial side of the hallux. The deep branch supplies m.adductor hallucis and the digital flexors. The medial plantar artery anastomoses with the first dorsal metatarsal artery.

Thus, due to the presence of an anastomosis between a.plantaris lateralis and a.plantaris medialis (branches of a.tibialis posterior), the plantar arch (arcus plantaris) is formed in the horizontal plane of the foot (see Fig. 57). The second arterial arch of the foot lies in the vertical plane. It is formed by the junction of the plantar arch (arcus plantaris) with the deep plantar branch (r.plantaris profundus, a branch of the dorsal artery). Alongside the arterial arches, perforating branches form anastomoses between the plantar metatarsal arteries (aa.metatarsea plantares) and dorsal metatarsal arteries (aa.metatarsea dorsales). The presence of these anastomoses ensures optimal blood supply to the foot and provides collateral Circulation in certain diseases affecting the tunica intima of the arteries (such as angiopathy, endarteritis, and Diabetes Mellitus).

* In 27% of individuals, the IV plantar metatarsal arteries (aa.metatarsales plantares) are supplied by the deep plantar branch of the dorsal artery of the foot (a.dorsalis pedis), whereas in 26% of cases, the plantar arch is formed entirely by branches of the deep plantar branch (r.plantaris profundus). In 19% of cases, the IV plantar metatarsal artery originates from the deep branch of a.plantaris lateralis; in 13% of cases, the III plantar metatarsal artery also originates there, while the others stem from r.plantaris profundus. In only 7% of cases do all plantar metatarsal arteries arise from the plantar arch originating exclusively from the deep branch of a.plantaris lateralis. In 6% of cases, the II–IV plantar metatarsal arteries originate from the plantar arch (arcus plantaris), whereas the I plantar metatarsal artery arises from r.plantaris profundus (Lippert) (see Fig. 56 A, B).