Blood supply of talus was described in detail first by Wildenauer in 1950. Since then many researchers have contributed.
Talus is one of the few bones where the outcome of injury is affected due to injury to unique pattern of the blood supply.
Avascular necrosis of the talus is common after the injuries of talus bone and the arrangement of blood supply makes it vulnerable to this dreaded complication after the injury.
[Read the anatomy of talus]
The important arterial supply to the talus is described here.
Extraosseous Arterial Supply
Posterior tibial artery, anterior tibial artery and peroneal arteries are major arteries supplying the talus extraosseously through their branches.
There contribution is approximately as follows
- Anterior tibial aretery – 36%
- Posterior tibial artery – 47%
- Perforating peroneal arteries – 16%
Here is the regionwise distribution of the blood supply
From the Posterior Tibial Artery
The posterior tibial artery is one of the two branches of the tibioperoneal trunk in the lower leg. It provides blood to the posterior compartments of the leg and plantar surface of the foot. It is the main blood supplier to talar body. Following branches of posterior tibial artery are involved for supplying the talus bone.
Artery of the Tarsal Canal
This important artery usually arises from the posterior tibial artery, one centimeter proximal to the origin of the medial and lateral plantar arteries.
From that point, it passes anteriorly between the sheath of the flexor digitorum longus and the flexor hallucis longus muscles to enter the tarsal canal, in which it lies anteriorly close to the talus. Many branches enter the body of the talus from the arterial network in the tarsal canal.
Continuing through the tarsal canal into the tarsal sinus, this artery anastomoses with the artery of the tarsal sinus, a branch from anterior tibial artery forming a rich vascular sling beneath the talar neck.
Deltoid artery is responsible for supplying a portion of the medial half of the body of the talus that is close to the inner surface of the deltoid ligament of the ankle.
Deltoid artery usually arises fom the artery of the tarsal canal or directly from the posterior tibial artery. Rarely it may also arise fromthe medial plantar branch of the posterior tibial artery.
Deltoid artery is significant surgically. Most injuries of the talus occur with dorsiflexion and inversion and the medial soft tissues, including this artery, may remain intact and ensure the viability of the body of the talus.
Moreover, the medial surgical approaches to the talus may injure the vessel, thereby possibly injuring the only remaining blood supply to the talus. Hence utmost care should be taken to preserve this artery during surgery.
From the Anterior Tibial Artery
The anterior tibial artery is a branch of the popliteal artery, which supplies the anterior compartment of the leg. It supplies the talus through following branches.
Superior Neck Branches
The dorsalis pedis artery, a continuation of the anterior tibial artery,sends branches to the superior surface of the neck of the talus.
Artery of the Tarsal Sinus
This is a large artery the is always present, and always anastomoses with the artery of the tarsal canal. It is formed by an anastomosis of a branch of the dorsalis pedis artery with a branch of the perforating peroneal artery. This lateral blood supply is profuse, with many direct branches into the bone.
From the Peroneal Artery
Small perforating branches from the peroneal artery join with branches of the posterior tibial artery to form the posterior plexus around the talus. The perforating peroneal artery contributes to the artery of the tarsal sinus, but in general the peroneal supply to the talus is not considered to be important.
Intraosseous Blood Supply
Head of Talus
The head of the talus is supplied by two sources, medially by branches of the dorsalis pedis artery and laterally by branches of the arterial anastomosis in the artery of the tarsal sinus
Body of Talus
The anastomotic artery in the tarsal canal supplies most of the talar body, through four or five branches on the medial side. This vessel usually supplies almost all of the middle third of the body, except for the extreme superior aspect, and all of the lateral third, except for the posterior aspect.
The deltoid artery supplies the medial third of the body.
Rich anastomoses within the bone are present, especially between the superior neck vessels and the vessels arising from the tarsal canal. In some people, the artery of the tarsal sinus and the tarsal canal may anastomose within the bone.
Significance of Blood Supply of Talus
Thus the body of the talus has a rich blood supply through several anastomoses.
The major blood supply enters posterior to the talar neck. Thus a neck fracture that does not extend posteriorly into the body is unlikely to interfere with the blood supply. When this interference occurs, there is high risk of avascular necrosis of the talus.
Deltoid artery , in the most of the cases maintains the viability of the talar body. But it may be interfered with surgically. Hence utmost surgical care should be extended in open reduction.