Which one is not part of the carpal bones?
A. Hamate
B. Trapezid
C. Trapezium
D. Lunate
The correct answer and explanation is:
The correct answer is B. Trapezid.
The carpal bones are a group of eight small bones located in the wrist, which form two rows. These bones allow for flexibility and a wide range of motion in the hand. The bones of the wrist are as follows:
Proximal row (closer to the forearm):
- Scaphoid
- Lunate
- Triquetrum
- Pisiform
Distal row (closer to the hand):
- Trapezium
- Trapezoid
- Capitate
- Hamate
Among the options given:
- Hamate, Trapezium, and Lunate are indeed part of the carpal bones.
- Trapezid, however, is not a valid carpal bone. It seems to be a misspelling or confusion with Trapezoid, which is the correct name for one of the carpal bones in the distal row, situated between the trapezium and the capitate.
The trapezium is located in the distal row and is positioned at the base of the thumb, forming the important thumb joint with the first metacarpal bone. The trapezoid is located next to it, a bit further towards the palm, and it helps with the articulation of the second metacarpal bone.
Understanding the carpal bones is crucial for identifying wrist injuries or disorders. Knowledge of these bones helps in diagnosing fractures, dislocations, or arthritis that affect the wrist, which is a highly mobile and complex joint in the body.