Measurement of the wrist in posteroanterior radiographs and its clinical significance

Abstract

Objective To obtain normal values of parameters of the wrist joint by measuring posteroanterior X-rays of normal wrist joints and provide basis of using these parameters for judgment of pathological conditions of the wrist. Methods Standard postereanterior X-rays of 40 normal wrists were taken.The Pacs System software was used to measure 9 parameters in these radiographs, including 7 new parameters:the ulnar styloid length (USL), ulnar head length (UHL), ulnar head diameter (UHD), maximal distal radius width (MDRW), proximal distal radius width ( PDRW), sigmoid notch width (SNW) and sigmoid notch length (SNL). The respective indices were defined by the ratio of these parameters to the length of the third metacarpus. Results The values and indices of USL, UHL, UHD, MDRW and PDRW are (3.01±1.65) mm,(0.05±0.03), (9.11±1.54) mm, (0.15±0.02), (18.56±1.96) mm, (0.30±0.03),(29.60±2.70) mm, (0.48±0.04), (27.60±2.00) mm and (0.45±0.03), respectively. Four types (Ⅰ toⅣ) of sigmoid notch were identified, with types Ⅰ, Ⅱ and Ⅳ present dominantly. The SNW of types Ⅰ, Ⅱ, and Ⅳ are (3.32±1.61) mm, (3.53±1.15) mm and (1.55±1.01) mm, respectively. The SNL of types Ⅰ, Ⅱ,and Ⅳ are ( 10.15±1.61 ) mm, ( 10.96 ± 2.33) mm and ( 10.32 ± 1.57) mm, respectively. Correspondingly,the SNW indexes were (0.05±0.02), (0.06±0.02), and (0.03±0.02); the SNL indexes were (0.16±0.02), (0.18±0.03) and(0.17±0.02). Conclusion The study presents a number of new indices which may be useful in quantifying the changes of wrists in radiograph. The measured normal values provide a basis for evaluation of changes in wrist disorders. Key words: Carpal joints; X-ray film; Parameter