Lecture 04 Osteology Of Hand By: A. Prof. Dr Farooq A. Khan PMC Date: 09 th Jan. 2018
HAND Distal to wrist joint Divided into three parts: Carpus Metacarpus Digits Bones Carpal bones o Prox row S L Tq P o Dist row Tm Tz C H M/Carpals Phalanges
The carpal are eight bones arranged in two rows. The proximal(near the radius and ulna), which contains the following bones. Scaphoid, Lunate, Triqutral, Pisiform. The distal row (near the metacarpal bones), which contains the following bones. Trapezium, Trapezoid, Capitate and Hamate. The formula for remembering is: She Looks Too Poor, Try To Cure Her.
Scaphoid (Greek= Boat) It is a boat shaped,and has a tubercle. Fracture of the scaphoid is through waist, by falling on outstretched hands on the tip of the fingers. It causes tenderness on the anatomical snuff box, which causes pain on the thumb and index finger.
Lunate (latin=moon) It is a half moon shaped bone, or crescentic. Dislocation of the lunate bone causes carpel tunnel syndrome, by falling on acutely dorsiflexed hand
Pisiform (Greek= Pea) It is a pea shaped,having only one facet. It is the smallest bone of the carpus. It has a groove for the ulner nerve. Triquetral (Latin= Three cornered) It is pyramidal shape.
Trapezium (Greek= Four sided Geometric figure) It is quadrangular in shape, and has acrest and groove anteriorly. It has a cancavoconvex surface distally.
Trapezoid (greek= Baby shoe) It resemble shoe of a baby.
Capitate (Latin= Head) It is the largest carpal bone, with a rounded head. It occupy the centre of the wrist.
Hamate (Latin= Hook) It is a wedge shaped, with a hook at the base. The hook is directed laterally.
Metacarpal Bones The metacarpus is the intermediate part of the hand skeleton that is located between the phalanges (bones of the fingers) and the carpus which forms the connection to the forearm. The metacarpus consists of metacarpal bones. It consist of three parts: Head. Shaft and base It is equivalent in the foot as the metatarsus.
Head The head or digital extremity (capitulum) presents an oblong surface markedly convex from before backward, and flattened from side to side; it articulates with the proximal phalanx. The dorsal surface, broad and flat, supports the tendons of the extensor muscles. The volar surface is grooved in the middle line for the passage of the flexor tendons.
Body The body (corpus; shaft) is prismoid in form, and curved. It presents three surfaces: medial, lateral, and dorsal. The medial and lateral surfaces are concave, for the attachment of the interosseus muscles. The dorsal surface presents in its distal two-thirds a smooth, triangular, flattened area which is covered in by the tendons of the extensor muscles.
Base.. The base or carpal extremity (basis) is of a cuboidal form, and broader behind than in front: it articulates with the carpus, and with the adjoining metacarpal bones. Its dorsal and volar surfaces are rough, for the attachment of ligaments.
Phalanges The phalanx bones (plural phalanges) are those that form the fingers and toes. The thumb and big toe have two phalanges, while the other fingers and toes consist of three. Phalanges are classified as long miniature bones. The phalanges do not have individual names. They are named for the digit they represent and their relative location from the center of the body (proximal or distal).
Proximal phalanges They are closest to the main part of the hand or foot and articulate with the metacarpals of the hand or metatarsals of the foot. Middle or intermediate phalanges They are between the distal and proximal. The thumb and big toe do not have middle phalanges. Distal phalanges They are at the tips of the fingers and toes. The term phalanx or phalanges refers to an ancient Greek army formation in which soldiers stand side by side, several rows deep, like an arrangement of fingers or toes.
Articulations Besides the metacarpophalangeal joints, the metacarpal bones articulate by carpometacarpal joints as follows: The first with the trapezium; The second with the trapezium, trapezoid, capitate and third metacarpal; The third with the capitate and second and fourth metacarpals; The fourth with the capitate, hamate, and third and fifth metacarpals; and The fifth with the hamate and fourth metacarpal.
Articular Facets
Congenital disorders The fourth and fifth metacarpal bones are commonly "blunted" or shortened, in pseudohypoparathyroidism and pseudopseudohypoparathyroidism. A blunted fourth metacarpal, with normal fifth metacarpal, can signify Turner syndrome. Fracture The neck of a metacarpal (in the transition between the body and the head) is a common location for a boxer's fracture.
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