Fractures and dislocations of the hand
Firstly, we’re going to address all of the anatomy of the hand as we’ll need it for other questions, and then will look at the fractures and dislocations.
A word on joint nammig within the hand:
- Carpometacarpal joint (CMC) between the carpal bones and the metacarpals
- Metacarpal phalangeal joint between the metacarpals and the proximal phalanges
- Proximal interphalangeal joint (PIP) between the proximal phalanges and middle phalanges
- Distal interphalangeal joint (DIP) between the middle phalanges and the distal phalanges
The main ligaments of the carpus and metacarpus:
- Palmer and dorsal ulnar carpal and radiocarpal ligaments
- Radial and ulnar carpal collateral ligament
- Palmar intercarpal ligament, dorsal and interosseous.
- Ligamentum carpi radiatum
- Pisohamate ligament
- Pisometacarpal ligament
- Carpometacarpal ligament, palmar and dorsal
- Metacarpal ligament, palma, dorsal and interosseous
The range of movement in the wrist joint:
- Ulnar abduction - radial abduction - 30-0-30
- Dorsal extension - palmar flexion - 60-0-60
Range of movement in the saddle joint of the thumb:
- Extension-flexion 30-0-40
- Abduction-adduction 10-0-40
The joints of the digits (metacarpophalangeal joint, PIP and DIP joints) are supported by a number of ligaments as well, these are:
- Medial and lateral collateral ligament
- Palmar ligament
- Transverse deep metacarpal ligament (connects palmar ligaments at the metacarpophalangeal joints)
The range of movement in the finger joints is as follows:
- Metacarpophalangeal joints
- Dorsal extension - palmar flexion 30-0-90
- Ulnar abduction - radial abduction 30-0-30
- Proximal interphalangeal joints
- Dorsal extension - palmar flexion 0-0-100
- Distal interphalangeal joints
- Dorsal extension - palmar flexion 0-0-90
Dorsal tendons of the hand:
- The dorsal tendons of the hand pass beneath the Retinaculum musculorum extensorum, passing under this sheat are the following tendons
- Extensor digiti minimi (has two tendons)
- Extensor digitorum
- Flatten as they reach the metacarpals and become extensor expansions which wrap around the metacarpal and proximal phalanx joining the palmar platen. This then spreads out further distally, attaching to the middle phalanx and two lateral bands which attach to the distal phalanx
- Extensor pollicis longus
Palmar tendons of the hand
- These pass beneath the flexor retinaculum (which forms the carpal tunnel)
- Flexor tendons of the superficial and deep flexors
- Flexor digitorum superficialis inserts on the base of the proximal phalanx
- Flexor digitorum profundus inserts on the distal phalanx
- Flexor pollicis longus