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Metacarpal bones

life science Maturity 11-13 Next article →

The metacarpal bones are the bones that make up your palm.

Metacarpus (left hand) dorsal view
Metacarpus (left hand) dorsal view

Scientists call this group of bones the metacarpus. They sit in the middle of your hand. They are located between your wrist bones and your finger bones. These bones are very important for how your hand works. They help shape the palm of your hand. They also help you grab and hold objects.

Evolution pl
Evolution pl

Each metacarpal bone has three main parts. The first part is the base, which is near your wrist. The second part is the body, which is the long middle section. The third part is the head, which is near your fingers. The body is shaped like a prism and is curved. It has a ridge that helps muscles attach to it. The head has a wide surface to connect to your finger bones. The base is a blocky shape that connects to the carpal bones of the wrist.

These bones do not all move in the same way. The thumb metacarpal is very special because it moves independently. It connects to a bone called the trapezium. The other bones are more fixed in place. The index metacarpal is the most firmly fixed bone of all. The middle bones are tightly joined to the wrist by interlocking parts. The ring and little finger bones have a bit more movement. This variety helps your hand perform many different tasks.

Many people experience bone injuries during their lives. About 2.5% of people will break a metacarpal bone at some point. One common injury is called a boxer's fracture. This happens at the neck of the fifth metacarpal. Another common break is called a Bennett's fracture. This type of break happens at the base of the thumb. Doctors can treat these breaks with rest or sometimes with surgery. They may use a method called ORIF to fix the bone.

Metacarpal bones are also found in many other animals. These bones are homologous to the metatarsal bones in the foot. This means they are similar structures used for different jobs. In birds and bats, these bones help form the wing. In some four-legged animals, they form part of the foot. Some animals have long, strong metacarpals to help them run fast. The name comes from Greek words meaning "beyond the wrist."

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File:Metacarpus (left hand) dorsal view.png
Metacarpus (left hand) dorsal view.png
File:Evolution pl.png
Evolution pl.png
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