Carpus

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

In tetrapods, the carpus is the 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 (or toes in quadrupeds), whereas those of the metacarpus do. (The corresponding part of the foot is the tarsus.) Carpal bones are not considered part of the hand but are part of the wrist. The carpal bones allow the wrist to move and rotate vertically and horizontally.

Variations

In some macropods, the scaphoid and lunar bones are fused into the scapholunar bone.

The carpus

Row	Name	Proximal/radial articulations	Distal articulations	Metacarpal articulations
Proximal	Scaphoid	radius, lunate	trapezium, trapezoid, capitate	-
Proximal	Lunate	radius, scaphoid, triquetral	capitate, hamate	-
Proximal	Triquetral	lunate, pisiform (but NOT ulna)	hamate	-
Proximal	Pisiform (sesamoid bone)	triquetral	-	-
Distal	Trapezium	scaphoid	trapezoid	#1 and #2
Distal	Trapezoid	scaphoid	trapezium, capitate	#2
Distal	Capitate	scaphoid, lunate	trapezoid, hamate	#2, #3 and #4
Distal	Hamate	triquetral, lunate	capitate	#4 and #5

Mnemonics

There exist several mnemonics to remember these bones:

• Some Lovers Try Positions That They Can't Handle.
• Sally left the party / to take Cathy home.

Common characteristics of the carpal bones

Each bone (excepting the pisiform) presents six (6) surfaces.

Of these the palmar or anterior and the dorsal or posterior surfaces are rough, for ligamentous attachment; the dorsal surfaces being the broader, except in the lunate.

The superior or proximal, and inferior or distal surfaces are articular, the superior generally convex, the inferior concave; the medial and lateral surfaces are also articular where they are in contact with contiguous bones, otherwise they are rough and tuberculated.

The structure in all is similar: cancellous tissue enclosed in a layer of compact bone.

See also

• Bone terminology
• Terms for anatomical location
• Carpal tunnel
• Carpal tunnel syndrome

Additional images

• 
  Human hand bones
• 
  Bones of the left hand. Palmar surface.
• 
  Bones of the left hand. Dorsal surface.
• 
  Vertical section through the articulations at the wrist, showing the synovial cavities.

External links

• Template:SUNYAnatomyLabs - "Palm of the Hand: Carpal bones"
• Template:KansasHandKinesiology