First, the proximal row is removed and the distal row is fastened to the metacarpals.Then, one side of the arthroplasty is placed upon the distal row and the other side on the distal radius.Additionally, the head of the ulna is removed.…
The scaphoid contributes to the stability of the midcarpus as it articulates distally with the trapezium and the trapezoid.The distal row is more rigid as its transverse arch moves with the metacarpals.Biomechanically and clinically, the carpal bones are better understood as arranged in three longitudinal columns: In this context the pisiform is regarded as a sesamoid bone embedded in the tendon of the flexor carpi ulnaris.…
The trapezoid is a four-sided carpal bone found within the hand.The trapezoid is found within the distal row of carpal bones.The superior surface, quadrilateral, smooth, and slightly concave, articulates with the scaphoid.…
The capitate is the largest carpal bone found within the hand.The capitate is found within the distal row of carpal bones.…
The procedure exists of a couple of elements.First, the proximal row is removed and the distal row is fastened to the metacarpals.Then, one side of the arthroplasty is placed upon the distal row and the other side on the distal radius.…
These extensions reach almost to the proximal surface of the bones in the proximal row and are separated from the cavity of the radiocarpal joint by the thin interosseous ligaments.There are three distal prolongations of the midcarpal joint cavity between the four bones of the distal row.The joint space between trapezium and trapezoid, or that between trapezoid and capitate, may communicate with cavities of the carpometacarpal joints, most commonly the second and third.…
The hamate is an irregularly-shaped carpal bone found within the hand.The hamate is found within the distal row of carpal bones, and abuts the metacarpals of the little finger and ring finger.Adjacent to the hamate on the ulnar side, and slightly above it, is the pisiform bone.…
The trapezium is an irregularly-shaped carpal bone found within the hand.The trapezium is found within the distal row of carpal bones, and is directly adjacent to the metacarpal bone of the thumb.On its ulnar surface are found the trapezoid and scaphoid bones.…
The function of the finger CMC joints and their segments overall is to contribute to the palmar arch system together with the thumb.The proximal transverse arch of the palm is formed by the distal row of carpal bones.The concavity of this arch is augmented at the level of the metacarpal heads by the flexibility of the first, fourth, and fifth metacarpal heads around the fixed second and third metacarpal heads; a flexible structure called the distal transverse arch.…
The trapezoid bone (lesser multangular bone) is a carpal bone in tetrapods, including humans.It is the smallest bone in the distal row.It may be known by its wedge-shaped form, the broad end of the wedge constituting the dorsal, the narrow end the palmar surface; and by its having four articular facets touching each other, and separated by sharp edges.…
On the palmar side, the carpus is concave, forming the carpal tunnel which is covered by the flexor retinaculum.Because the proximal row is simultaneously related to the articular surfaces of the radius and the distal row, it adapts constantly to these mobile surfaces.The bones of this row - scaphoid, lunate, and triquetrum - have their individual movements.…
The cavity of the midcarpal joint is very extensive and irregular.The major portion of the cavity is located between the distal surfaces of the scaphoid, lunate, and triquetrum and proximal surfaces of the four bones of the distal row.Proximal prolongations of the cavity occur between the scaphoid and lunate and between the lunate and triquetrum.…
The bones in each carpal row interlock with each other and each row can therefore be considered a single articular body.In the proximal row a limited degree of mobility is possible, but the bones of the distal row are connected to each other and to the metacarpal bones by strong ligaments that make this row and the metacarpus a functional entity.The joints of the proximal row are arthrodial joints, The scaphoid, lunate, and triangular are connected by dorsal, volar, and interosseous ligaments.…
The structure of the carpus varies widely between different groups of tetrapods, even among those that retain the full set of five digits.In primitive fossil amphibians, such as Eryops, the carpus consists of three rows of bones; a proximal row of three carpals, a second row of four bones, and a distal row of five bones.The proximal carpals are referred to as the radiale, intermediale, and ulnare, after their proximal articulations, and are homologous with the scaphoid, lunate, and triquetal bones respectively.…
The carpometacarpal (CMC) joints are five joints in the wrist that articulate the distal row of carpal bones and the proximal bases of the five metacarpal bones.The CMC of the thumb or the first CMC, also known as the trapeziometacarpal joint (TMC), differs significantly from the other four CMCs and is therefore described separately.…
The intercarpal articulations (articulations of the carpus) can be subdivided into three sets of articulations: Those of the proximal row of carpal bones, those of the distal row of carpal bones, and those of the two rows with each other.The bones in each carpal row interlock with each other and each row can therefore be considered a single articular body.…
The midcarpal joint is formed by the scaphoid, lunate, and triquetral bones in the proximal row, and the trapezium, trapezoid, capitate, and hamate bones in the distal row.The distal pole of the scaphoid articulates with two trapezial bones as a gliding type of joint.…
During palmar flexion the proximal carpal bones are displaced towards the dorsal side and towards the palmar side during dorsiflexion.While flexion and extension consist of movements around a pair of transverse axes -- passing through the lunate bone for the proximal row and through the capitate bone for the distal row -- palmar flexion occurs mainly in the radiocarpal joint and dorsiflexion in the midcarpal joint.Dorsiflexion is produced by (in order of importance) extensor digitorum, extensor carpi radialis longus, extensor carpi radialis brevis, extensor indicis, extensor pollicis longus, and extensor digiti minimi.…
