The metacarpals are bones in the human hand. The hand consists of the carpals (wrist bones), the metacarpals (palm bones), and the phalanges (four fingers and thumb). There are in total 27 bones in hand. Eight carpal bones make up the wrist. They are arranged roughly in two rows. In the row nearest the forearm, starting from the thumb side, are the scaphoid, lunate, triquetrum, and pisiform bones. In the second row are the trapezium, trapezoid, capitate, and hamate bones. Five long metacarpal bones make up the palm. They connect the wrist with the fingers and thumb. Each of the four fingers contains three slender phalanges. However, the thumb contains only two phalanges.

Fact File

Muscles can’t push, they can only pull. Muscles are pulling gently against each other most of the time.This keeps them firm and stops them from becoming floppy. Muscles get bigger and stronger if you exercise them. Muscles are joined to bones by tough ‘bands’ called tendons.

Anatomy of Metacarpals

The hand bones function is to provide flexibility and support to our soft tissues. The bones in our hand are of 3 types:

  • Carpal bones (Proximal) – A pair of eight irregularly shaped bones in the wrist region.
  • Metacarpals – You will find five metacarpals in the middle part of the palm, each one connected to a finger
  • Phalanges (Distal) – It is the bones of the fingers.

In human anatomy, the metacarpal bones are in the middle area of the hand situated between the phalanges and the carpal bones of the wrist. The middle part of the hands is made up of five bony structures called the metacarpals. They include a shaft, a base, and a distal head.

First metacarpal

It is the shortest and also the most mobile of all of the metacarpals. It’s positioned on a more anterior plane, and it is also rotated medially at an ideal angle. It is saddle-shaped and articulates with the trapezium bone of the distal row of carpal bones in addition to distally using the first proximal phalanx.

Second metacarpal

It has a notch formed proximal base and is connected to trapezium bone, the capitate bone of the distal carpal row. It articulates distally during its head with the second proximal phalanx.

Third metacarpal

It includes a complex proximal bottom, articulates with different bones of the hands, the second metacarpal bone, and the fourth metacarpal bone. As a whole, the foundation is formed as a styloid process on its dorsomedial aspect. It has an articular aspect that communicates with all the capitate bone of the distal carpal row.

Fourth metacarpal

This bone contains two proximal facets at its base that allow it to articulate with the capitate and hamate bones of the distal carpal row and the two little facets medially and laterally for the third and fifth metacarpal bones.

Fifth metacarpal

The fifth metacarpal bone articulates proximally with the hamate bone of the distal carpal row and medially with the fourth metacarpal bone.

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