Talus

Talus is one of the bones of the human foot.

Subtalar Joint

Etiology

Latin = ankle-bone; hence, the tortoise-shaped tarsal of the talocrural ankle joint. The tarsus forms the lower part of the ankle joint. It transmits the entire weight of the body from the lower legs to the foot.

Joints

• The talus has joints with the two bones of the lower leg, the tibia and thinner fibula.
• These leg bones have two prominences (the lateral and medial malleoli) that articulate with the talus.
• At the foot end, within the tarsus, the talus articulates with the calcaneus (heel bone) below, and with the curved navicular bone in front; together, these foot articulations form the ball-and-socket-shaped talocalcaneonavicular joint.

Anatomy

The talus is the second largest of the tarsal bones; It is also one of the bones in the human body with the highest percentage of its surface area covered by articular cartilage. It is also unusual in that it has a retrograde blood supply, i.e. arterial blood enters the bone at the distal end.

Structure

Left talus, from above and below, with anterior side of the bone at top of image

Os trigonum on x-ray

Though irregular in shape, the talus can be subdivided into three parts.

Facing anteriorly, the head carries the articulate surface of the navicular bone, and the neck, the roughened area between the body and the head, has small vascular channels.

The body features several prominent articulate surfaces.

Body of talus

The body of the talus comprises most of the volume of the talus bone. It presents with five surfaces; a superior, inferior, medial, lateral and a posterior.

Superior surface

The superior surface of the body presents, behind, a smooth trochlear surface, the trochlea, for articulation with the tibia.

The trochlea is broader in front than behind, convex from before backward, slightly concave from side to side: in front it is continuous with the upper surface of the neck of the bone.

Inferior surface

The inferior surface presents two articular areas, the posterior and middle calcaneal surfaces, separated from one another by a deep groove, the sulcus tali.

The groove runs obliquely forward and lateralward, becoming gradually broader and deeper in front: in the articulated foot it lies above a similar groove upon the upper surface of the calcaneus, and forms, with it, a canal (sinus tarsi) filled up in the fresh state by the interosseous talocalcaneal ligament.

The posterior calcaneal articular surface is large and of an oval or oblong form.

It articulates with the corresponding facet on the upper surface of the calcaneus, and is deeply concave in the direction of its long axis which runs forward and lateralward at an angle of about 45° with the median plane of the body.

The middle calcaneal articular surface is small, oval in form and slightly convex; it articulates with the upper surface of the sustentaculum tali of the calcaneus.

Medial surface

The medial surface presents at its upper part a pear-shaped articular facet for the medial malleolus, continuous above with the trochlea; below the articular surface is a rough depression for the attachment of the deep portion of the deltoid ligament of the ankle-joint.

Lateral surface

The lateral surface carries a large triangular facet, concave from above downward, for articulation with the lateral malleolus; its anterior half is continuous above with the trochlea; and in front of it is a rough depression for the attachment of the anterior talofibular ligament.

Between the posterior half of the lateral border of the trochlea and the posterior part of the base of the fibular articular surface is a triangular facet which comes into contact with the transverse inferior tibiofibular ligament during flexion of the ankle-joint; below the base of this facet is a groove which affords attachment to the posterior talofibular ligament.

Posterior surface

The posterior surface is narrow, and traversed by a groove running obliquely downward and medialward, and transmitting the tendon of the Flexor hallucis longus.

Lateral to the groove is a prominent tubercle, the posterior process, to which the posterior talofibular ligament is attached; this process is sometimes separated from the rest of the talus, and is then known as the os trigonum.

Medial to the groove is a second smaller tubercle.

Additional images

• 

  Left talus, from below.

• 

  Left talus, medial surface.

• 

  Left talus, lateral surface.

Gray's Anatomy

• Gray's Anatomy Contents
• Gray's Anatomy Subject Index
• About Classic Gray's Anatomy
• Glossary of anatomy terms

Anatomy atlases (external)

[1] - Anatomy Atlases

This article is a medical stub. You can help WikiMD by expanding it!
Most recent articles Ongoing trials	Wikipedia

This article is a medical stub. You can help WikiMD by expanding it!
Most recent articles Ongoing trials	Wikipedia