Hand & Wrist

A normal human hand and wrist is made up of a total of 27 bones.  The hand wrist account for a total of 54 (roughly 26%) bones out of 206 bones that comprise the adult human body.  Each wrist is made up of eight bones including the scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, and hamate.  Each hand has 19 bones which consists of 5 metacarpal bones and 14 phalanges (finger bones).

Find high quality Skeleton & Bone Models and Skeleton & Bone Posters at VisuMedical.com!

Select a Bone or area to View Below

Directions: Hover over an area on the image and the name of that bone or area will be displayed.  You can then click that area to obtain more information.  Hover over the middle finger for more detailed information.

  

Additional Information

Wrist

General information
The wrist area is composed of eight carpal bones, each held to adjacent carpals by volar, dorsal, and interosseous ligaments. The eight carpal bones are arranged in two rows: the proximal row includes the scaphoid, lunate, triquetrum, and pisiform; and the distal row consisting of the trapezoid, trapezium, capitate, and hamate (all lateral to medial in anatomical position).

Articulations
Bones of the proximal row of carpals articulate with the radius while bones of the distal row articulate with the metacarpals. The area considered the wrist joint (the radiocarpal joint) includes the radius and the triangular fibrocartilage with the scaphoid, lunate, and triquetrum. The joint between proximal and distal rows of carpals is called the midcarpal joint. On the thumb side (radial side) of the wrist the joint, between the first metacarpal and the trapezium, is the carpometacarpal joint of the thumb.

Muscle attachments
Flexor carpi ulnaris and abductor digiti minimi attach to the volar surface of the pisiform. On the same side of the hand, flexor digiti minimi and opponens digiti minimi can be found on the volar side of the hamate. The volar surface of the capitate serves as a point of attachment for adductor pollicis. Flexor pollicis brevis, opponens pollicis, and abductor pollicis longus, as well as a small slip of abductor pollicis brevis, find attachment to the volar surface of the trapezium.
BACK TO TOP

Metacarpals

General information
There are five metacarpals of the hand, one associated with each of the digits. The first metacarpal can be distinguished from the others due to its thicker and shorter appearance. The other four metacarpals are quite similar in appearance with the third metacarpal usually being the longest and the fifth being the shortest. Each metacarpal has a distal end called the head and a proximal end called the base with the shaft of the bone between the two ends.

Articulations
Each metacarpal articulates proximally with one or more carpal bones and sometimes with the adjacent metacarpal(s). Distally, each metacarpal articulates with a proximal phalanx. The first metacarpal often has a sesamoid bone associated with the metacarpal head.

Muscle attachments
The palmar and dorsal interossei attach along the shaft of the metacarpals in respective positions for their actions. In addition to the finger abductors and adductors, adductor pollicis attaches on the bases of the second and third metacarpals and the shaft of the third. Along the first metacarpal, one can find opponens pollicis, abductor pollicis longus, adductor pollicis, and the first dorsal interosseous.
BACK TO TOP

Phalanges

General information
Each finger consists of three phalanges while the thumb has only two, making a total of 14 phalanges in each hand. The phalanges are named according to their position and relationship to the others: proximal, intermediate, and distal.

Articulations
The base of the proximal phalanx articulates with its companion metatarsal head. The four intermediate phalanges articulate with the distal end of the proximal and the proximal end of the distal phalanges of the same finger. The proximal phalanx of the thumb articulates proximally with the first metatarsal and distally with the proximal end of the distal phalanx.

Muscle attachments
The palmar and dorsal interossei attach on the appropriate side of the base of the proximal phalanx to achieve their function. Extensor pollicis brevis, the first dorsal interosseous, and adductor pollicis attach on the proximal phalanx of the thumb, while the distal phalanx serves as a point of attachment to flexor pollicis longus and extensor pollicis longus. The dorsal side of the phalanges of the fingers finds extensor digitorum longus attaching via its central slip to the base of the intermediate phalanx and the lateral bands attaching on the base of the distal phalanx of the four fingers.
BACK TO TOP