Collateral Ligaments of the 1st MCP

Proximal/Superior Attachment

• Head of 1st Metacarpal - Tubercle and Adjacent Depression on the side of the Metacarpal Head

Distal/Inferior Attachment

• Base of Proximal Phalanx of the Thumb - Palmar Aspect of the side

Joints

• 1st Metacarpophalangeal Joint (1st MCP)