The styloid process of the ulna is a bony prominence found at

distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

end of the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

in the

forearm The forearm is the region of the upper limb between the elbow and the wrist. The term forearm is used in anatomy to distinguish it from the arm, a word which is most often used to describe the entire appendage of the upper limb, but which in ...

Structure

The styloid process of the ulna projects from the medial and back part of the ulna. It descends a little lower than the head. The head is separated from the styloid process by a depression for the attachment of the apex of the

triangular articular disk The triangular fibrocartilage complex (TFCC) is formed by the triangular fibrocartilage discus (TFC), the radioulnar ligaments (RULs) and the ulnocarpal ligaments (UCLs). Structure Triangular fibrocartilage disc The triangular fibrocartilage ...

, and behind, by a shallow groove for the

tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...

of the extensor carpi ulnaris muscle. The styloid process of the ulnar varies in length between 2 mm and 6 mm.

Function

The rounded end of the styloid process of the ulna connects to the ulnar collateral ligament of the

wrist In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; "The wrist contains eight bones, roughly aligned in two rows, known as the carpal ...

. The radioulnar ligaments also attaches to the base of the styloid process of the ulna.

Clinical significance

Fractures of the styloid process of the ulna seldom require treatment when they occur in association with a distal radius fracture. The major exception is when the joint between these bones, the

distal radioulnar joint The distal radioulnar articulation (also known as the distal radioulnar joint, or inferior radioulnar joint) is a synovial pivot joint between the two bones in the forearm; the radius and ulna. It is one of two joints between the radius and ulna, ...

(or DRUJ), is unstable. When the DRUJ is unstable, the ulnar styloid may require independent treatment. An excessively long styloid process of the ulna can cause painful contact with the triquetral bone in the

, known as ulnar styloid impaction syndrome.

Radiology Radiology ( ) is the medical discipline that uses medical imaging to diagnose diseases and guide their treatment, within the bodies of humans and other animals. It began with radiography (which is why its name has a root referring to radiati ...

is used to diagnose it.

Conservative management Conservative management is a type of medical treatment defined by the avoidance of invasive measures such as surgery or other invasive procedures, usually with the intent to preserve function or body parts. For example, in appendicitis Appendi ...

involves injection of

triamcinolone Triamcinolone is a glucocorticoid used to treat certain skin diseases, allergies, and rheumatic disorders among others. It is also used to prevent worsening of asthma and COPD. It can be taken in various ways including by mouth, injection int ...

, while surgery involves shortening of the styloid process of the ulna via resection. The position of the styloid process of the ulna in relation to the wrist must be considered when applying a wrist splint. This is important in preventing pressure ischaemia.

References

External links

* Upper limb anatomy Ulna {{musculoskeletal-stub