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

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

end of the

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

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 used to describe the entire appendage of the upper limb, but which in anatomy, techn ...

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, and behind, by a shallow groove for the

tendon A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tensi ...

of the

extensor carpi ulnaris muscle In human anatomy, the extensor carpi ulnaris is a skeletal muscle located on the ulnar side of the forearm. The extensor carpi ulnaris acts to extend and adduct at the carpus/wrist from anatomical position. Being an extensor muscle, extensor car ...

. The styloid process of the ulna varies from 2 to 6 mm in length.

Function

The rounded end of the styloid process of the ulna connects to the

ulnar collateral ligament Ulnar collateral ligament (or UCL) may refer to: * Ulnar carpal collateral ligament * Ulnar collateral ligament of elbow joint The ulnar collateral ligament (UCL) or internal lateral ligament is a thick triangular ligament at the medial aspec ...

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 The triquetral bone (; also called triquetrum, pyramidal, three-faced, and formerly cuneiform bone) is located in the wrist on the medial side of the proximal row of the carpus between the lunate and pisiform bones. It is on the ulnar side of th ...

in the

, known as ulnar styloid impaction syndrome.

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

is used to diagnose it.

Conservative management Conservative treatment 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, conservati ...

involves

injection Injection or injected may refer to: Science and technology * Injective function, a mathematical function mapping distinct arguments to distinct values * Injection (medicine), insertion of liquid into the body with a syringe * Injection, in broadca ...

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 chronic obstructive pulmonary disease (COPD). It can be taken in variou ...

, while

surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...

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 Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

References

External links

* Upper limb anatomy Ulna {{musculoskeletal-stub