4/4/2024 0 Comments Xray normal hip lat![]() An angle less than 125 degrees is classified as coxa varus. This angle is normally between 125 and 140 degrees. ![]() One line is drawn down the anatomic axis of the femoral neck, and the other is drawn down the anatomic axis of the femur. The NSA is defined by the angle formed by the longitudinal axes of the femoral neck and the proximal femoral diaphyseal axis. A discrepancy greater than 2.0 cm corresponds with a functional leg length discrepancy and can have an adverse effect on the kinematic function of the hip. Ideally this line should be symmetrical to the contralateral hemipelvis. By combining all views, we should be able to define the following parameters for each patient: leg length inequalities, NSA, femoral neck trabecular patterns, lateral and anterior center edge angles, acetabular inclination, joint space width, lateralization, head sphericity, acetabular cup depth, and anterior and posterior wall orientation.įunctional leg lengths may be assessed on an AP pelvis radiograph by constructing a line horizontally off the superiormost portion of the iliac crest. Interpretation of both the false-profile and AP pelvic views generally helps to characterize the acetabular morphology, whereas the other views better describe the proximal femoral anatomy. Interpretation of Plain Radiographic Images The crosshairs of the beam should be directed at a point midway between the anterior superior iliac spine (ASIS) and the pubic symphysis, and the tube-to-film distance should be approximately 40 inches in a line directed perpendicular to the table. Each leg should be abducted 15 to 20 degrees from the midline, and the pelvis and tibia should be parallel to the long axis of the body (neutral rotation). For both views, the film cassette is placed beneath the pelvis and the tube is centered over the upper border of the pubic symphysis. The 90-degree Dunn view assesses the patient with 90-degree hip flexion, whereas the 45-degree Dunn view (“modified Dunn view”) assesses the patient with 45 degrees of hip flexion ( Fig. It was originally described as a technique to measure femoral neck anteversion in children. The Dunn view is commonly used for assessment of femoral head sphericity in patients believed to have cam-type femoroacetabular impingement (FAI). (From Clohisy JC, Carlisle JC, Beaulé PE, et al: A systematic approach to the plain radiographic evaluation of the young adult hip. The standing AP radiograph assesses (1) functional leg length inequalities (2) neck shaft angle (NSA) (3) femoral neck trabecular patterns (4) lateral and anterior center edge angles (5) acetabular inclination (6) joint space width (7) lateralization (8) head sphericity (9) acetabular cup depth and (10) anterior and posterior wall orientation ( Figs. A standing rather than a supine AP radiograph is obtained because acetabular roof obliquity, center edge angle, and minimum joint space width may vary between weight-bearing and supine positions. A 1- to 3-cm gap should be seen between the apex of the coccyx and the superior border of the pubic symphysis for proper pelvic inclination. The radiographic teardrops, iliac wings, and obturator foramina should be symmetrical in appearance. The coccyx should be centered in line with the pubic symphysis. The crosshairs of the beam should be centered on a point half the distance between the superior border of the pubic symphysis and on a line drawn connecting the anterior superior iliac spine. Both lower extremities should be internally rotated by 15 degrees to account for normal anatomic anteversion, and this position helps maximize the view of the femoral neck. ![]() The x-ray tube–to-film distance should be approximately 120 cm, and the x-ray tube should be aimed perpendicular to the film. Descriptions of each view are provided in the following sections.Ī proper AP view should be taken with the patient standing. All views are technique dependent, and each demonstrates a different anatomic perspective of the hip joint. Among these, the most commonly referenced include the AP view of the pelvis (AP pelvic view), a cross-table lateral view, a 45-degree or 90-degree Dunn view, a frog-leg lateral view, and a false-profile view. Several radiographic views are important for proper evaluation of the hip. Traditionally, the lateral hip radiograph demonstrates details of the femoral neck and helps identify cam impingement pathology, whereas the anteroposterior (AP) view demonstrates the acetabular version. This chapter describes the key imaging studies used when examining a skeletally mature patient with a pathologic hip, as well as a systematic approach to interpretation of these studies. Although the history and physical examination play a critical role in determining the diagnosis, it is also important to have a systematic approach to help diagnose these disorders radiographically. A multitude of structural hip disorders can occur in athletes with hip pain. ![]()
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