METACARPAL BONES ANATOMY

GENERAL CHARACTERISTICS

• The metacarpal bones are five in total, numbered I to V from the thumb to the little finger
• Each metacarpal has a distinct structure consisting of:
  • Body (shaft)
  • Base at the proximal end
  • Head at the distal end
• These bones form the framework of the palm
• Contribute to hand mobility and strength

METACARPAL STRUCTURE

Base (Proximal End)

• Structure:
  • Cuboidal in shape
  • Broader at the posterior than the anterior
• Function:
  • Articulates with one or more carpal bones
  • Articulates with adjacent metacarpal bones
• Features:
  • Dorsal and volar surfaces are rough for ligament attachment

Body (Shaft)

• Structure:
  • Prismoid shape
  • Curved longitudinally:
    • Convex posterior surface
    • Concave anterior surface
• Surfaces:
  • Medial surface
  • Lateral surface
  • Dorsal surface

Head (Distal End)

• Structure:
  • Oblong in shape
  • Convex from front to back
  • Less convex transversely
• Function:
  • Articulates with the proximal phalanx

THIRD METACARPAL BONE

Size

• Smaller than the second metacarpal

Styloid Process

• Location:
  • Lateral dorsal side of the base
• Structure:
  • Pyramidal projection
• Function:
  • Attachment point for the Extensor carpi radialis brevis muscle