Where Is the Ulnar Styloid Process? Identification of the Absolute Location of the Ulnar Styloid Process Based on CT and Verification of Neutral Forearm Rotation on Lateral Radiographs of the Wrist
| Autor: | Jin-Woo Kang, Yong-Suk Lee, Dong-Young Noh, Yang-Guk Chung, Seung-Han Shin, Joon-Yong Jung |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Ulnar styloid process
musculoskeletal diseases Adult Male Adolescent Rotation Radiography Elbow Posture Ulna 030230 surgery Wrist Supination 03 medical and health sciences Young Adult 0302 clinical medicine Imaging Three-Dimensional Forearm medicine Humans Orthopedics and Sports Medicine Humerus Pronation Aged Aged 80 and over 030222 orthopedics business.industry musculoskeletal neural and ocular physiology Ulnar Shaft Anatomy Middle Aged musculoskeletal system body regions medicine.anatomical_structure Surgery Original Article Female Anatomic Landmarks business Tomography X-Ray Computed |
| Zdroj: | Clinics in Orthopedic Surgery |
| ISSN: | 2005-4408 2005-291X |
| Popis: | Background The location of the ulnar styloid process can be confusing because the radius and the hand rotate around the ulna. The purpose of this study was to identify the absolute location of the ulnar styloid process, which is independent of forearm pronation or supination, to use it as a reference for neutral forearm rotation on lateral radiographs of the wrist. Methods Computed tomography (CT) images of 23 forearms taken with elbow flexion of 70° to 90° were analyzed. The axial CT images were reconstructed to be perpendicular to the distal ulnar shaft. The absolute location of the ulnar styloid process in this study was defined as the position of the ulnar styloid process on the axial plane of the ulnar head relative to the long axis of the humeral shaft with the elbow set in the position for standard lateral radiographs of the wrist. To identify in which direction the ulnar styloid is located on the axial plane of the ulnar head, the angle between "the line of humeral long axis projected on the axial plane of the ulna" and "the line passing the center of the ulnar head and the center of the ulnar styloid" was measured (ulnar styloid direction angle). To identify how volarly or dorsally the ulnar styloid should appear on the true lateral view of the wrist, the ratio of "the volar-dorsal diameter of the ulnar head" and "the distance between the volar-most aspect of the ulnar head and the center of the ulnar styloid" was calculated (ulnar styloid location ratio). Results The mean ulnar styloid direction angle was 12° dorsally. The mean ulnar styloid location ratio was 1:0.55. Conclusions The ulnar styloid is located at nearly the ulnar-most (the opposite side of the humerus with the elbow flexed) and slightly dorsal aspects of the ulnar head on the axial plane. It should appear almost midway (55% dorsally) from the ulnar head on the standard lateral view of the wrist in neutral forearm rotation. These location references could help clinicians determine whether the forearm is in neutral or rotated position on an axial CT/magnetic resonance imaging scan or a lateral radiograph of the wrist. |
| Databáze: | OpenAIRE |
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