Each joint occurs between the round head of the metacarpal and the shallow base of the proximal phalanx 1, 2.
Each joint is enclosed by a fibrous capsule which attaches to the margins of the articular surfaces and is lined by a synovial membrane 2.
- two collateral ligaments
- strengthen the capsule on each side and pass from the head of the metacarpal to the base of the phalanx 1, 2
- 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 1, 2
Deep digital arteries from the superficial palmar arch
Digital nerves from the ulnar and median nerves