CCD angle

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CCD angle

The CCD angle (abbreviation for Centrum-Collum-Diaphysen-Winkel) describes the angle between the neck and the shaft of the thighbone .

The projected CCD angle is determined on the classic x-ray image ( anterior-posterior ) of both hip joints. This is only the projected angle and not the actual angle, as the anteversion of the femoral neck (standard 12 °), which is also present , is not the actual anatomical angle (e.g. on a skeleton or during an operation) Angle acts. The reason lies in the two-dimensional image of an actually three-dimensional structure through the X-ray image. Since the hip is in anteversion and this causes the angle to increase, the radiographically measured angle is always larger than the real one. External rotation of the hip, i.e. strengthening the anteversion, increases this angle even further.

Therefore, recordings can also be made with a slight internal rotation in order to determine the approximately real angle. To do this, the leg is turned inwards until the large roll hillock ( greater trochanter ) can be felt most prominently on the outside, analogous to the clinical examination of the anteversion position.

determination

To determine the exact CCD angle , a circle is drawn around the center of the femoral head on an X-ray image of the hip joint in the frontal plane , an "ap" image , which intersects the medial and lateral femoral neck contours. These intersections are connected; the line through the middle of this connecting line and the femoral head center corresponds to the femoral neck axis. To determine the femoral shaft axis, two transverse diameters of the shaft are drawn below the lesser trochanter. The connecting line through the center points of these gives the shaft axis.

In order to approximately determine the real, i.e. actually present angle, one uses a table (Müller from 1957), with the help of which one can use the projected values ​​for CCD angle and antetorsion angle to determine the respective real values ​​with an error rate of approx. 5% can determine. The projected anteversion angle is determined in the Rippstein image with the hip joint in 90 ° flexion and 20 ° abduction .

Standard values

Normal values ​​of projected center-collum-diaphyseal angles
Standard values ​​of projected anteversion angle

Individual evidence

  1. ↑ Michael Schünke: Functional Anatomy - Topography and Function of the Movement System , Thieme Georg Verlag, 2000, ISBN 978-3-131-18571-6 , p. 320
  2. ^ Wolfgang Dihlmann: Gelenke - Wirbelverbindungen , Thieme, Stuttgart, 3rd edition 1987, p. 281
  3. ↑ Hans U. Debrunner, Wolfgang Rüdiger Hepp: Orthopädisches Diagnostikum , Thieme, Stuttgart, edition: 7th, 2004, ISBN 978-3-133-24007-9 , p. 145