by Matthew Law

The Bones of the Hand

Picture: Matthew Law 

The carpals are arranged in two rows of 4 bones. On the proximal row there is a joint between the scaphoid and the radius.

Scaphoid – Lunate – Triquetral – Pisiform

Trapezium – Trapezoid – Capitate – Hamate

 (a good mnemonic for these is Some Lovers Try Positions That They Can't Handle)

The hamate is easily identified by its hook.

The carpal tunnel passes between the carpals and flexor muscles.

Above: right scaphoid. Palmar is down. 

Picture: Matthew Law

Distal to the carpals are the metacarpals. These articulate with the phalanges (proximal phalanx, middle or intermedial phalanx, and distal phalanx). The distal phalanx ends in a tuberosity. There are a huge number of nerves on the distal phalanx. The thumb is different in shape to the others. The palmar surface is distinguished by a big indentation on the palmar side for the opponens polaris. It is not always easy to separate left from right.

The 5^th metacarpal only has one articulation. The 2^nd has a saddle joint in an inverted V-shape. 3^rd has a styloid process. Nothing really distinguishes the 4^th.

Phalanges: the 1^st proximal is very robust. 1^st distal is larger than the other distals.

Joints: Distal Inter-Phalangeal Joints (DIPs); Proximal Inter-Phalangeal Joints (PIPs); Metacarpal-Phalangeal Joints (MCPs) and Carpo-Metacarpal Joints (CMCs)

Arthritic disease in the hand tends to affect the radial side.  

FURTHER READING

White, T.D., and Folkens, P.A., 2005, The Human Bone Manual (San Diego: Academic Press) Chapter 13 is on the hands.

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