This site uses cookies to improve performance. If your browser does not accept cookies, you cannot view this site. Show
Setting Your Browser to Accept CookiesThere are many reasons why a cookie could not be set correctly. Below are the most common reasons:
Why Does this Site Require Cookies?This site uses cookies to improve performance by remembering that you are logged in when you go from page to page. To provide access without cookies would require the site to create a new session for every page you visit, which slows the system down to an unacceptable level. What Gets Stored in a Cookie?This site stores nothing other than an automatically generated session ID in the cookie; no other information is captured. In general, only the information that you provide, or the choices you make while visiting a web site, can be stored in a cookie. For example, the site cannot determine your email name unless you choose to type it. Allowing a website to create a cookie does not give that or any other site access to the rest of your computer, and only the site that created the cookie can read it.
The standard radiographic projections used to evaluate injury to the pelvic girdle and proximal femur include the anteroposterior (AP) pelvis (bilateral hips) and AP unilateral hip. AP oblique pelvis (the “frog leg”) projections are commonly performed on non-trauma patients to evaluate congenital hip dislocation. The AP view is frequently not sufficient to provide adequate evaluation of the entire sacral bone, the sacroiliac (SI) joints, and the acetabulum. Special radiographic projections are performed to evaluate the SI joints, sacral bones, and acetabulum. AP pelvis (bilateral hips) projection The standard radiographic view for the pelvis is obtained in an AP position with the patient supine. Most traumatic conditions involving the sacral wings, the iliac bones, ischium, the pubis, and the femoral head and neck can sufficiently be evaluated on the AP projection of the pelvis and hip. This view also demonstrates an important anatomical relationship in the longitudinal axes of the femoral neck and shaft. Normally, the angle formed by these axes ranges from 125°-135°. Varus and valgus configuration of a femoral neck fracture is said to occur if there is decrease or increase, respectively, in this angle. Technical factors
AP unilateral hip projection An AP unilateral hip study is usually a postoperative or a follow-up exam to demonstrate the acetabulum, femoral head and neck, and the greater trichinae, as well as the condition and placement of any existing orthopedic appliance. Technical factors and patient positioning are the same as for an AP pelvis (bilateral hips) exam. The CR is placed perpendicular to the femoral neck in question, approximately 2 ½ inches (6.4 cm) distal on a line drawn perpendicular to the mid point of a line between the ASIS and the pubic symphysis. In other words, the CR is directed 1-2 inches (2.5-5 cm) distal to mid femoral neck. The femoral neck can be located about 1-2 inches (3-5 cm) medial and 3-4 inches (8-10 cm) distal to the ASIS. The collimated field should demonstrate the femoral head and neck, trochanters, the proximal third of the femur shaft, regions of the ilium, and the pubic bones adjoining the pubic symphysis. The greater trochanter and femoral head and neck should be in full profile without foreshortening. The lesser trochanter should not project beyond the medial border of the femur. Optimal exposure should ensure visualization of the femoral head through the acetabulum. AP oblique pelvis projection x-ray positioning techniques This projection is also called the bilateral “frog leg” position. It is useful for demonstration of a non-trauma hip or developmental dysphasia of the hip, also known as congenital hip dislocation (CHD). It shows an AP oblique projection of the femoral heads, necks, and the trochanteric areas projected onto one radiograph for comparative purposes. Technical factors
Evaluation criteria
Other special radiographic projections to evaluate injury to the pelvic girdle include the AP axial outlet projection, AP axial inlet projection, oblique projections for acetabulum, groin projections (axiolateral), and posterior oblique projections for SI joints. These are usually requested in trauma patients after a routine AP projection shows some pathology, or in postsurgical patients who need follow-up evaluation. AP axial pelvic outlet and AP axial pelvic inlet projections The AP axial outlet projection shows an elongated projection of the pubic and ischial rami. This projection provides an excellent view of the bilateral pubes and ischia to assess pelvic bones for fractures and displacements. The AP axial inlet projection provides assessment of the pelvic ring. The technical factors and patient positioning for these projections are the same as for an AP pelvis projection. The main difference lies in the CR angulations. For an AP axial outlet projection, the CR is angulated cephalad 20°-35° for males and 30°-45° for females and is centered to a point 2 inches (5 cm) distal to the superior border of the pubic symphysis. For an AP axial inlet projection, the CR is angulated caudad 40° and is centered to a midline point at the level of both ASIS. Oblique projections of the acetabulum Oblique projections, known as Judet’s views, are necessary to evaluate the acetabulum. The anterior (internal) oblique projection helps delineate the anterior column and the posterior rim of the acetabulum. The posterior (external) oblique projection delineates the posterior column and the anterior acetabular rim. For a posteroanterior (PA) oblique projection the patient lies in a semi-prone position on the affected side. The unaffected side is elevated so that the anterior surface of the body forms a 38° angle from the table. The CR is directed 12° cephalic to the side being examined, approximately 2 inches (5 cm) lateral to the midsagittal plane at the inferior level of coccyx, permitting the CR to be directed through the acetabulum.
Axiolateral projection of the hip and proximal femur (groin projection) The groin projection is particularly useful in evaluating anterior and posterior displacement of fracture fragments in proximal femoral fractures, as well as the degree of rotation of the femoral head. This projection provides a true lateral image of the proximal femur and also demonstrates an important anatomic feature, the angle of the anteversion of the femoral neck, which normally ranges from 25°-30°. It may be done on a stretcher or at bedside if the patient cannot be moved. The unaffected leg is elevated and flexed so that the unaffected thigh is outside the collimation field. The IR is placed in a crease above the iliac crest so that it is parallel to the femoral neck and perpendicular to the CR. If the limb can be safely moved, internally rotate the foot about 15° by grasping the heel to overcome the anteversion of the femoral neck. The CR is directed to the femoral neck and to IR. Oblique projection for the SI joints Various methods have been used to examine the sacroiliac joints; however, none is ideal as the normal undulating articular surfaces make evaluation of these joints extremely difficult. An angled AP radiograph can be taken with the tube angulated 30°-35° in a cephalad direction. This projection is known as a Ferguson view. It not only shows the SI joints to a better advantage but also helps in more effectively evaluating injury to the sacral bone, the pubis, and the ischial rami. Some radiologists prefer a PA radiograph with 25°-30° of caudal angulation of the tube to evaluate the SI joints. In either case, both sacroiliac joints are exposed on a single film, facilitating a comparative evaluation. By Dr. Naveed
Ahmad Related Reading The lowdown on lumbar spine positioning, June 19, 2003 Radiographic positioning techniques for the cervical spine, March 26, 2003 Boning up on humerus, clavicle, and AC joint positioning, February 18, 2003 Getting the most from shoulder positioning, December 24, 2002 The bends and flexures of forearm and elbow x-ray positioning, November 21, 2002 Copyright © 2003 AuntMinnie.com How is the patient positioned for an AP projection modified Cleaves method of the pelvis to demonstrate the femoral neck without foreshortening?How is the patient positioned for an AP oblique projection (modified Cleaves method) of the pelvis to demonstrate the femoral neck without foreshortening? . Abduct the femurs to 20-30 degrees from vertical.
Where is the central ray directed for the AP oblique projection modified Cleaves of the femoral necks?Positioning chpt7. |