Each joint occurs between the round head of the metacarpal and the shallow base of the proximal phalanx .
Each joint is enclosed by a fibrous capsule which attaches to the margins of the articular surfaces and is lined by a synovial membrane .
- two collateral ligaments
- strengthen the capsule on each side and pass from the head of the metacarpal to the base of the phalanx
- palmar ligament (volar ligament)
- a thick, fibrocartilaginous plate that connects the collateral ligaments and attaches firmly to the base of the proximal phalanx and attaches loosely to the head of the metacarpal
Deep digital arteries from the superficial palmar arch
Digital nerves from the ulnar and median nerves