Subtalar joint
Encyclopedia
In human anatomy
, the subtalar joint, also known as the
talocalcaneal joint, is a joint
of the foot
. It occurs at the meeting point of the talus
and the calcaneus.
and eversion
of the foot, but plays no role in dorsiflexion
or plantarflexion
of the foot.
It is considered a plane synovial joint , also commonly referred to as uniaxial hinge joint.
The subtalar joint can also be considered a combination of the anatomic subtalar joint discussed above, and also the talocalcaneal part of the talocalcaneonavicular joint. This is the more common view of the subtalar joint when discussing its movement. When both of these articulations are accounted together, it allows for pronation
and supination
to occur.
There are two points of articulation between the two bones: one anteriorly and one posteriorly:
The subtalar joint contributes to 10% of dorsiflexion of the ankle.
of the joint is the interosseous talocalcaneal ligament
, a thick, strong band of two partially joined fibers that bind the talus and calcaneus. It runs through the sinus tarsi, a canal between the articulations of the two bones.
There are four additional ligaments that form weaker connections
between the talus and calcaneus.
A synovial membrane lines the capsule of the joint, and the joint
is wrapped in a capsule of short fibers that are continuous with the
talocalconeonavicular and calcaneocuboid joints of the foot.
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...
, the subtalar joint, also known as the
talocalcaneal joint, is a joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
of the foot
Foot
The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws...
. It occurs at the meeting point of the talus
Talus bone
-External links:* *...
and the calcaneus.
Motion
The joint allows inversionInversion (kinesiology)
Inversion is the movement of the sole towards the median plane .Tibialis anterior and tibialis posterior invert. Some sources also state that the triceps surae and extensor hallucis longus invert....
and eversion
Eversion (kinesiology)
Eversion is the movement of the sole of the foot away from the median plane. It occurs at the subtalar joint.Peroneus longus and peroneus brevis evert. Both muscles are innervated by the superficial fibular nerve....
of the foot, but plays no role in dorsiflexion
Dorsiflexion
Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
or plantarflexion
Plantarflexion
Plantarflexion is the movement which increases the approximate 90 degree angle between the front part of the foot and the shin, as when depressing an automobile pedal...
of the foot.
It is considered a plane synovial joint , also commonly referred to as uniaxial hinge joint.
The subtalar joint can also be considered a combination of the anatomic subtalar joint discussed above, and also the talocalcaneal part of the talocalcaneonavicular joint. This is the more common view of the subtalar joint when discussing its movement. When both of these articulations are accounted together, it allows for pronation
Pronation
In anatomy, pronation is a rotational movement of the forearm at the radioulnar joint, or of the foot at the subtalar and talocalcaneonavicular joints. For the forearm, when standing in the anatomical position, pronation will move the palm of the hand from an anterior-facing position to a...
and supination
Supination
Supination is a position of either the forearm or foot; in the forearm when the palm faces anteriorly, or faces up . Supination in the foot occurs when a person appears "bow-legged" with their weight supported primarily on the anterior of their feet.The hand is supine in the anatomical position...
to occur.
Relation of bones
The talus is oriented slightly obliquely on the anterior surface of the calcaneus.There are two points of articulation between the two bones: one anteriorly and one posteriorly:
- At the anterior talocalcaneal articulation, a convex area of the talus fits on a concave surface of the calcaneus.
- The posterior talocalcaneal articulation is formed by a concave surface of the talus and a convex surface of the calcaneus.
The subtalar joint contributes to 10% of dorsiflexion of the ankle.
Ligaments and membranes
The main ligamentLigament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
of the joint is the interosseous talocalcaneal ligament
Interosseous talocalcaneal ligament
The interosseous talocalcaneal ligament forms the chief bond of union between the bones.It is, in fact, a portion of the united capsules of the talocalcaneonavicular and the talocalcaneal joints, and consists of two partially united layers of fibers, one belonging to the former and the other to the...
, a thick, strong band of two partially joined fibers that bind the talus and calcaneus. It runs through the sinus tarsi, a canal between the articulations of the two bones.
There are four additional ligaments that form weaker connections
between the talus and calcaneus.
- The anterior talocalcaneal ligamentAnterior talocalcaneal ligamentThe anterior talocalcaneal ligament extends from the front and lateral surface of the neck of the talus to the superior surface of the calcaneus....
(or anterior interosseous ligament) attaches at the neck of the talus on the front and lateral surfaces to the superior calcaneus.
- The short band of the posterior talocalcaneal ligamentPosterior talocalcaneal ligamentThe posterior talocalcaneal ligament connects the lateral tubercle of the talus with the upper and medial part of the calcaneus; it is a short band, and its fibers radiate from their narrow attachment to the talus....
extends from the lateral tubercle of the talus to the upper medial calcaneus.
- The short, strong lateral talocalcaneal ligamentLateral talocalcaneal ligamentThe lateral talocalcaneal ligament is a short, strong fasciculus, passing from the lateral surface of the talus, immediately beneath its fibular facet to the lateral surface of the calcaneus....
connects from the lateral talus under the fibular facet to the lateral calcaneus, and runs parallel to the calcaneofibular ligamentCalcaneofibular ligamentThe calcaneofibular ligament is a narrow, rounded cord, running from the apex of the fibular malleolus downward and slightly backward to a tubercle on the lateral surface of the calcaneus.It is covered by the tendons of the Peronæi longus and brevis....
.
- The medial talocalcaneal ligamentMedial talocalcaneal ligamentThe medial talocalcaneal ligament connects the medial tubercle of the back of the talus with the back of the sustentaculum tali.Its fibers blend with those of the plantar calcaneonavicular ligament....
extends from the medial tubercle of the talus to the sustentaculum taliSustentaculum taliAt the upper and forepart of the medial surface of the calcaneus is a horizontal eminence, the sustentaculum tali , which gives attachment to the plantar calcaneo-navicular ligament, tibiocalcaneal ligament, and medial talocalcaneal ligament.This eminence is concave above, and articulates with the...
on the medial surface of the calcaneus.
A synovial membrane lines the capsule of the joint, and the joint
is wrapped in a capsule of short fibers that are continuous with the
talocalconeonavicular and calcaneocuboid joints of the foot.
Sources
- Calais-Germain, Blandine. "Anatomy of Movement", Eastland Press, 1993. ISBN 0-939616-17-3
- Anatomy of the Human BodyGray's AnatomyGray's Anatomy is an English-language human anatomy textbook originally written by Henry Gray. The book is widely regarded as an extremely influential work on the subject, and has continued to be revised and republished from its initial publication in 1858 to the present day...
, Henry Gray, 1918