| Pivot joint | |
|---|---|
 | |
| Details | |
| Identifiers | |
| Latin | articulatio trochoidea |
| TA98 | A03.0.00.045 |
| TA2 | 1557 |
| FMA | 75294 |
| Anatomical terminology | |
Inanimal anatomy, apivot joint (trochoid joint,rotary joint orlateral ginglymus) is a type ofsynovial joint whosemovement axis is parallel to thelong axis of the proximal bone, which typically has a convexarticular surface.
According to one classification system, a pivot joint like the othersynovial joint—thehinge joint has onedegree of freedom.[1] Note that thedegrees of freedom of a joint is not the same as a joint'srange of motion.
Pivot joints allowrotation, which can be external (for example when rotating an arm outward), or internal (as in rotating an arm inward). When rotating the forearm, these movements are typically calledpronation andsupination. In thestandard anatomical position, the forearms are supinated, which means that the palms are facing forward, and the thumbs are pointing away from the body. In contrast, a forearm in pronation would have the palm facing backward and the thumb would be closer to the body, pointing medially.
Examples of a pivot joint include:
In contrast, spherical joints (orball and socket joints) such as thehip joint permit rotation and all other directional movement, while pivot joints only permit rotation.
This article incorporates text in thepublic domain frompage 285 of the 20th edition ofGray's Anatomy(1918)
