Hand and finger joints
You use them every day, every day they help you with each step. Built from small joints, bones and ligaments, together they form two helping hands without which it is hard to get around. Get to know their structure and functions and learn more about prevention.
The human hand consists of 27 bones. Three segments can be distinguished:
- the wrist (carpal segment)
- the five bones of the metacarpus
- the fingers
The carpal bones are placed in two rows:
- a proximal row
- a distal row
Each of them composed of four bones.
The proximal row consists of the bones
- pisiform bone (located on the triquetral bone on palmar side)
The distal row is formed with the bones:
- the trapezium
- the trapezoid
- the capitate
- the hamate
The mechanics of the hand is quite specific. The dysfunction of one bone automatically affects the dynamics of the other bones.
The hand owes its mobility to many joints, which include:
Radial-wrist joint- it is an ellipsoidal joint formed by the combination of the radial bone with the proximal row of carpal bones. It is reinforced by a radial-wrist ligament.
Its function is inhibiting the movement of the elbow abduction of the hand
The mid-carpal joint serves as the connection between the carpal bones. The movements permitted with this joint are the palmar and dorsum flexion, radial and ulnar abduction and adduction.
- The articular connection (joints) of the proximal row of carpal bones
- The articular connections (joints) of the distal row of carpal bones
- The carpometacarpal and intermetacarpal joints are the plane joints of minimal mobility. The thumb joint is an exception, since it permits the movement of abduction and adduction, as well as deviation, opposition, flexion , extension and hyperextension.
- The finger joints (interphalengeal joints) belong to the group of spheroidal (ball and socket) joints which do not permit the rotation movement.
A few words about the ligaments of the palm
Hands consist of several ligaments that are responsible for specific movements that we can perform.
The collateral radius ligament of the wrist - is relatively short, but not too strong.
Functions: inhibiting the ulnar abduction movement of the hand
Ulnar collateral ligament of the wrist - which is longer, but much weaker than the radial wrist ligament.
Functions: inhibits movement of radial arm abduction
Palmar radial wrist ligament - broad and very strong.
Functions: inhibits the dorsal flexion and hand inversion movement
Dorsal radial-wrist ligament - less regular and slightly weaker than the previous one
Functions: limits the movement of palmar flexion and conversion
Arched arcuate ligament of the wrist - it is created by the connection of a part of the palmar-radial-wrist ligament -with ligament the palmar-wrist ligament
Functions: inhibiting movement of dorsiflexion
Curved dorsal wrist ligament - runs only between the bones of the wrist
Functions: braking movements of palmar flexion and abduction
Ligaments: Palmar metacarpal ligaments, dorsal and interosseous are designed to strengthen the metacarpal joint capsules
The most common hand disorders
The rheumatoid disorders of the hand mostly occur in the area of:
- The radiocarpal joint
- The carpometacarpal joints
- The interphalangeal joints of fingers
The degenerative changes in the radiocarpal joint occur most commonly as a result of injuries in this area. The alterations are manifested as the Heberden’s nodes, developed on the dorsolateral surface of the fingers II - V of the distal interphalangeal joints (DIP)
The nodes in the proximal interphalangeal joints area are called Bouchard's nodes.
The finger joint dislocations mostly involve the dislocations in the proximal interphalangeal joints, caused by the injuries which lead to the joint hyperthropy.
The chronic rheumatic arthritis usually develops symmetrically in the wrists and joints of the hand, including the proximal interphalangeal joints. The disease is marked by pain, inflammation, deformity and the impairment of movement, followed by degradation of the joints or even the joints atrophy. The disease belongs to the group of autoimmune disorders and it mostly affects people at the age of 30—40 or older. The occurrence of the disease if fourfold higher among women than men.
Dupuytren's contracture is the disease marked by the fixed contracture of the fingers in the flexed position, accompanied by the occurrence of the characteristic nodes in the palmar fascia. The disease is prevalent among men and it is most likely to affect the IV and V finger. It is marked by the fibrous nodes in the palmar fascia and mainly affects elderly people. It has genetic etiology.
Can the hand joints be exercised?
You can, and it's very easy. It is often recommended for example to exercise with a ball which is based on kneading it with both hands, transferring it between fingers or crushing in one hand.
Another exercise - put your hand and forearm on the table, not moving your wrist from the table move your fingers toward the wrist. Move your fingers forward to make them straight. When bending, the hand should forma distinctive peak. Repeat this exercise at least 20 times for each hand.
Regular exercise, especially when you've been diagnosed with rheumatoid arthritis or degeneration contribute to significant improvements in health. Without movement, the muscles weaken and produce contracture and the pain intensifies.