MCP and IP Joints Flashcards
MCP articulations
heads of metacarpals with bases of proximal phalanges
IP articulations
head of proximal phalanx with base of distal phalanx
what type of joints are the MCP joints?
condyloid synovial joint
what type of joints are the IP joints?
hinge synovial joint
what do the collateral ligaments of the MCP joints do?
- attach from head of metacarpal to base of proximal phalanx
- slack/loose when extended, taught when flexed
- allow ABD/ADD when extended
- flexion does not allow same ROM as extension
what do the palmar ligaments of the MCP joints do?
- CT plate located on anterior surface of joints
- connect head of metacarpal to base of proximal phalanx
- form groove for flexor tendons
- act as attachment for collateral ligaments
- resist hyperextension
why isn’t there a dorsal equivalent to the palmar ligaments of the MCP joints?
- because of the extensor expansion
- this design allows for minimal resistance to gripping
what do the collateral ligaments of the IP joints do?
- attach from head of proximal phalanx to base of distal phalanx
- always tight, whether flexed or extended, so no ABD/ADD like the MCP joints
what do the palmar ligaments of the IP joints do?
- CT plate located on anterior surface of joints
- connect head of prox phalanx to base of distal phalanx
- form groove for flexor tendons
- act as attachment for collateral ligaments
- act as attachment for extensor muscles (extensor expansion)
- resist hyperextension
what movements are possible at the MCP joints?
flexion/extension
ABD/ADD when digits are extended
what movements are possible at the IP joints?
flexion/extension
can’t ABD/ADD bc collateral ligaments are always tight and restrictive
what do the retinacular ligaments do?
- attach fibrous sheath of proximal phalanx (anterior) to extensor expansion of distal phalanx (posterior)
- cause proximal and distal IP joints to flex and extend together
