- There are five metacarpal bones in the hand.
- They are named #1, #2, #3, #4, and #5, from the lateral/thumb side to the medial/little-finger side.
- A metacarpal with its associated phalanges is called a ray.
- Metacarpal #1 is within the first ray, the ray of the thumb.
- Metacarpal #5 is within the fifth ray, the ray of the little finger.
- The metacarpals articulate with:
- the phalanges distally, forming the metacarpophalangeal joints.
- the carpals proximally, forming the carpometacarpal joints.
- each other, forming the intermetacarpal joints.
NOTES:
- Each metacarpal has an expanded proximal end called the base, and an expanded distal end called the head.
- There are two sesamoid bones located on the palmar side of the head of the first metacarpal.
- The first metacarpal (the metacarpal of the thumb) may be the shortest, but is the largest metacarpal.
- The carpometacarpal joint of the thumb is known as the saddle joint of the thumb.
![Anterior view of bones of the right hand.](https://learnmuscles.com/wp-content/uploads/2020/11/08-Hand-RU-anterior-6551-fingers-down-614x1024.jpg)
Anterior view of bones of the right hand.
![Posterior view of bones of the right hand.](https://learnmuscles.com/wp-content/uploads/2020/11/08-Hand-RU-posterior-6612-1-580x1024.jpg)
Posterior view of bones of the right hand.
![Oblique (anteromedial) view of bones of the right hand.](https://learnmuscles.com/wp-content/uploads/2020/11/08-Hand-RU-medial-6658-465x1024.jpg)
Oblique (anteromedial) view of bones of the right hand.
![Bones of the wrist and hand in the posture of a fist on the right side.](https://learnmuscles.com/wp-content/uploads/2020/11/08-Hand-FDP-6776-1024x1024.jpg)
Bones of the wrist and hand in the posture of a fist on the right side.