page_title: Carpal bones
section_title: Radial abduction/ulnar adduction
hierarchical_section_title: Carpal bones / Function / Movements / Radial abduction/ulnar adduction
caption_attribution_description: English: An anatomical illustration from the 1921 German edition of Anatomie des Menschen: ein Lehrbuch für Studierende und Ärzte with latin terminology.
context_page_description: The carpal bones are the eight small bones that make up the wrist that connects the hand to the forearm. The term "carpus" is derived from the Latin carpus and the Greek καρπός, meaning "wrist". In human anatomy, the main role of the wrist is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, and the mobility of individual carpal bones increase the freedom of movements at the wrist.
  In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers, whereas those of the metacarpus do. The corresponding part of the foot is the tarsus. The carpal bones allow the wrist to move and rotate vertically.
context_section_description: During radial abduction the scaphoid is tilted towards the palmar side which allows the trapezium and trapezoid to approach the radius. Because the trapezoid is rigidly attached to the second metacarpal bone to which also the flexor carpi radialis and extensor carpi radialis are attached, radial abduction effectively pulls this combined structure towards the radius. During radial abduction the pisiform traverses the greatest path of all carpal bones.
  
  Radial abduction is produced by (in order of importance) extensor carpi radialis longus, abductor pollicis longus, extensor pollicis longus, flexor carpi radialis, and flexor pollicis longus.
  Ulnar adduction causes a tilting or dorsal shifting of the proximal row of carpal bones.
  It is produced by extensor carpi ulnaris, flexor carpi ulnaris, extensor digitorum, and extensor digiti minimi.
  Both radial abduction and ulnar adduction occurs around a dorsopalmar axis running through the head of the capitate bone.
caption: Left: Dorsiflexion
  Right: Palmar flexion
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