Synonym
Articulatio phalangea;
Definition
The finger joint forms the articulated connection between the individual bony phalanges. It connects proximally (close to the body) the phalanges with the metacarpal bone, distally (far from the body) the individual phalanges with each other. A distinction is made between the metacarpophalangeal joint, the metacarpophalangeal joint and the distal joint.
Structure of the finger joint
The following bones are involved in the construction of the finger:
- Metacarpal bone (Os metacarpale)
- Phalanx proximalis ossis digiti
- Middle phalanx (Phalanx media ossis digiti)
- Phalanx distalis ossis digiti
Basic Finger Joint
The metacarpophalangeal joint (Articulatio metacarpophalangealis) is the connection between the metacarpal bone and the proximal phalanx. It is a limited ball-and-socket joint and therefore functionally seen a so-called egg joint (ellipsoid joint, Articulatio ellipsoidea). It allows movement in two axes: lateral movement (abduction and adduction) as well as flexion and extension.
An exception is the metacarpophalangeal joint (Art. metacarpophalangealis I). It is a hinge joint that allows movement in only one main axis, namely flexion and extension. Externally, one sees the basic joints as colloquially called knuckles.
Middle finger joint
The middle finger joint (Articulatio interphalangealis proximalis, PIP) connects the base and middle phalanx. It is a hinge joint and therefore only allows flexion and extension. Again, the thumb is an exception. It does not have a middle joint, as it only has two phalanges.
Finger End Joint
The Articulatio interphalangealis distales (DIP), the distal finger joint, is the connection between the middle and distal phalanx. Like the middle finger joint, it is a hinge joint and has the same range of motion.
Tapes
Each finger joint is secured by a strap system. 1. ligamenta collateralia: Each finger joint, i.e. three per finger, has two of these ligaments. When the finger is bent, they restrict its spreading, while in the extended position they are relaxed and thus allow movement.
2nd Ligamentum collaterale accessorium and Ligamentum phalangoglenoidale: Lying on the back of the hand. Due to their constant tension, they limit, for example, the extension. 3rd Ligamenta palmaria digiti: Lying on the inside of the hand. Protect the tendons of the finger flexors (flexors) from the bone through their fibrous cartilage as a cushion. There are also ligaments that strengthen the tendon sheaths in which the tendons are located and ligaments that create a connection between the adjacent finger base joints through their cross-linking.
