Radiological Anatomy of the Hand Bones PDF

RADIOLOGICAL ANATOMY OF THE HAND BONES The bones of the hand are grouped into three categories: Carpal bones (8 bones ) - most proximal part Metacarpal (5 bones ) middle part Phalanges (14 bones ) - most distal The carpal bones The carpal bones are arranged in two rows ,each row composed of four...

RADIOLOGICAL ANATOMY OF THE HAND BONES The bones of the hand are grouped into three categories: Carpal bones (8 bones ) - most proximal part Metacarpal (5 bones ) middle part Phalanges (14 bones ) - most distal The carpal bones The carpal bones are arranged in two rows ,each row composed of four bones. In the proximal row, from lateral to medial, are the scaphoid, lunate and triquetral bones, with the pisiform on the anterior surface of the triquetral In the distal row from lateral to medial are the trapezium, trapezoid, capitate and hamate bones ( hamate bone has a projection on its palmar surface, known as the ‘hook of hamate’) In the proximal row, the scaphoid and lunate articulate with the radius to form the wrist joint (radiocarpal joint). The distal row of carpal bones articulate with the metacarpals at the carpometacarpal joints. Intercarpal joints: are joints between the carpal bones of the hand Midcarpal joint: between the scaphoid, lunate and triquetrum proximally and the trapezium, trapezoid, capitate and hamate distally The carpal bones collectively form an arch in the coronal plane. A membranous band, named the flexor retinaculum, spans between the medial and lateral edges of the arch, forming a tunnel named the carpal tunnel where flexor tendons and median nerve pass through it.  Radiological features of the carpal bones CT,MRI and XRAY can be used for medical imaging of the bones of the hands The carpals can be radiographed in the anteroposterior, lateral and oblique positions Xray of elbow joint AP view illustrating carpal bones Xray of wrist lateral view illustrate the carpal bones Ossification of the carpal bones These ossify from a single center each.The capitate ossifies first and the pisiform last. Excluding the pisiform, they ossify in a clockwise direction from capitate to trapezoid as follows: the capitate at 4 months the hamate at 4 months the triquetral at 3 years the lunate bone at 5 years and the scaphoid, trapezium and trapezoid at 6 years The pisiform ossifies at 11 years of age THE METACARPALS The five metacarpals are numbered from the lateral to the medial side Each has a base proximally that articulates with that of the other metacarpals, except in the case of the first metacarpal. Each metacarpal has a rounded head distally, which articulates with the proximal phalanx. Carpometacarpal (CMC) joints: between the distal row of carpal bones and the proximal bases of the five metacarpal bones. Intermetacarpal joints: between the bases of the second, third, fourth and fifth metacarpal bones articulate with one another by small surfaces covered with cartilage. The phalanges ; are 14 in number, three for each finger and two for the thumb. Like the metacarpals, each has a head, a shaft and a base The distal part of the distal phalanx in bones of the hand expanded as the tuft of the distal phalanx Articulations of the phalanges Metacarpophalangeal joint: between the metacarpals and proximal phalanges. Proximal interphalangeal joint: between the proximal and middle phalanges. Distal interphalangeal joint: between the middle and distal phalanges. The thumb only has a single interphalangeal joint. Radiological features of the metacarpals and phalanges Bone age xray A radiograph of the left hand is used in the determination of bone age.Standards of age determined by epiphyseal appearance and fusion of left hand bones and wrist bones has been done. Bone age xray(ap xray of left hand) Sesamoid bones: A sesamoid bone is a small bone commonly found embedded within a muscle or tendon near joint surfaces Two sesamoid bones are found related to the anterior surface of the metacarpophalangeal joint of the thumb in the normal radiograph. A single sesamoid bone in relation to this joint in the little finger is seen in 83% of radiographs, and at the interphalangeal joint of the thumb in 73%. sesamoids can be occasionally found at other metacarpal and distal interphalangeal joints Ossification of the metacarpals and phalanges These ossify between the ninth and twelfth fetal weeks Secondary ossification centers appear in the distal end of the metacarpals of the fingers at 2 years and fuse at 20 years of age Secondary centers for the thumb metacarpal and for the phalanges are at their proximal end appear between 2 and 3 years, and fuse between 18 and 20 years of age