ulna
Definition
The ulna is a long bone in the forearm. It is the larger of the two bones in the forearm, and it is located on the side of the forearm that is opposite the thumb.
The ulna has a proximal end, a shaft, and a distal end. The proximal end articulates with the humerus at the elbow joint. The shaft is the longest part of the bone. The distal end articulates with the radius and the wrist bones.
The ulna helps to stabilise the elbow joint and to move the forearm. It also helps to support the wrist and hand.
The ulna is a common site for fractures. This is because it is exposed to a lot of stress when the arm is used.
How can the word be used?
The ulna is the bone that forms the elbow joint.
Different forms of the word
Noun:
- ulna (the longer of the two bones in the forearm, located on the little-finger side).
- ulnar (of or relating to the ulna).
- ulnar nerve (a nerve that runs along the ulna).
Etymology
Noun:
- ulna (the longer of the two bones in the forearm, located on the little-finger side).
- ulnar (of or relating to the ulna).
- ulnar nerve (a nerve that runs along the ulna).
The word "ulna" comes from the Latin word "ulna", which means "elbow". The Latin word "ulna" is related to the Greek word "olecranon", which also means "elbow".
The word "ulna" is first attested in English in the 14th century. It was originally used to refer to the elbow joint, but it soon came to be used to refer to the bone itself.
Question
Where can you find your ulna?
AQA Science Exam Question and Answer
Question:
Define the ulna bone and its role in the human arm's skeletal structure. Explain how the ulna's distinct features contribute to its functions and interactions with other bones. Provide an example of a movement or action that involves the ulna bone.
Answer:
The ulna is one of the two long bones in the human forearm, alongside the radius. It plays a crucial role in forming the forearm's skeletal framework and facilitating various arm movements.
The ulna's distinct features contribute to its functions and interactions within the arm. At its proximal end, the olecranon process forms the bony prominence of the elbow, allowing the ulna to articulate with the humerus. The trochlear notch articulates with the trochlea of the humerus, enabling forearm flexion and extension. The ulnar head forms the distal part of the forearm joint with the wrist's radius bone, aiding in wrist rotation.
One notable movement involving the ulna is pronation and supination of the forearm. During pronation, the ulna and radius rotate, causing the palm to face downward. In contrast, during supination, the rotation of the bones causes the palm to face upward. This movement is vital for various activities, such as turning a doorknob or using a screwdriver.