Trapezium (bone)

The trapezium bone, also called the greater multangular bone, is one of the small bones in the hand. It sits on the thumb side of the wrist. The trapezium helps form the radial edge of the carpal tunnel, a narrow space in the wrist that keeps nerves and tendons safe. This bone is important for making the hand flexible and strong. It helps us grip, twist, and do many things easily each day. Learning about the trapezium bone shows us how our hands are built for many different tasks.

Structure

The trapezium is a small bone in the wrist on the thumb side. It sits between the scaphoid and the bone connected to the thumb. This bone helps the thumb move.

The trapezium has several surfaces that connect to other wrist bones and muscles. Its top surface links with the scaphoid. Its bottom surface matches the base of the bone connected to the thumb. The side facing the palm has a deep groove that helps a wrist muscle work properly.

Function

The carpal bones help give the hand its strong shape. The trapezium bone is the bone farthest out around the carpal tunnel. It helps the thumb move.

Clinical relevance

The trapezium bone can sometimes develop arthritis where it joins the bone of the thumb. This often happens because the hand is used a lot over time.

Etymology

The word "trapezium" comes from the Greek word trapezion, which means "a little table". This comes from an even older Greek word, trapeza, meaning "table". The term was first used in 1840.

Additional images

The trapezium bone, also called the greater multangular bone, is one of the small bones in the wrist. Below are some pictures showing where it is and how it looks from different angles:

• Position of trapezium (shown in red). Left hand. Animation.
• Trapezium of the left hand.
• Trapezium bone.
• Right hand back view (dorsal view). Thumb on bottom.
• Right hand front view (palmar view). Thumb on top.
• Bones of the left hand. Front surface. Trapezium shown in yellow.
• Bones of the left hand. Back surface. Trapezium shown in yellow.
• Trapezium shown in red (labelled as "Greater Multang"). Cross section of wrist (thumb on left). Trapezium shown in red (labelled as "Greater Multang").
• Cross section across the wrist and fingers. Trapezium is shown in yellow (labelled as "Greater Multang").
• Ligaments of wrist. Front view
• Tendons of forefinger and vincula tendina.