DE2012800A1 - Measuring device for determining the true femoral neck shaft angle and the true twisting angle of the femoral neck - Google Patents

Description

Measuring device for determining the true femoral neck angle and the true twist angle of the femoral neck.

Name of the device: Femur calculator Area of application: Orthopedics. The device simplifies the determination of the angle.

It is specially invented for an X-ray method that the author himself has developed. If an operative correction of the above mentioned angles is necessary, so their previous calculation is a prerequisite.

This device was built according to your own ideas, as it is from the X-ray technology developed by with. It's not a reliance to any other device. The X-ray bischiometer according to M..MUller determined projected Angles that are converted into real angle values using conversion tables.

Description of the femoral calculator: It is pocket size size of W x 15 cm and is made of 2 mm thick Plexiglas.

The plate is engraved with: 1. A protractor 2. Seven circles with a radius of 0.5 cm to 3.5 cm.

The distance between the circles is 0.5 cm.

From the intersection of the circles with the horizontal run parallel downward stretches of 7 cm in length, which are delimited transversely at their lower end.

The middle straight is slotted continuously to a width of 1.5.

3. A cm measurement with mm subdivisions is attached to the side.

I. Explanations of the anatomy of a thigh bone: On his upper end is the femur angled @ t. The angle between the femoral neck and femoral shaft is called the femoral neck shaft angle.

The femoral neck with the femoral head protrudes upwards, from through it rotates out of the contact surface of the rest of the bone. The angle between In medical parlance, the contact surface and the femoral neck axis are or Antetorsia angle of the femoral neck called.

With the X-ray technology developed by me and the application of the Femur calculator, both angles can be determined on simple tracks.

II. Explanation of the attached drawings: Right and left drawing on sheet 3 there are breaks from an X-rayed femur. The left picture shows the bone in plan view and the right one in side view. Femoral neck stem and antetorsion angles are solid angles that are here in two perpendicular to each other Levels are mapped.

1. The angle between the segment AB and the shaft axis @ is the true one Femoral neck shaft angle.

2. Angle between the line AC and the shaft axis will referred to as the projected femoral neck shaft angle.

3. The angle BAC in the right triangle is the true antetorsion angle of the femoral neck.

4th

4a = shaft axis viewed from above. 4b = shaft axis viewed from the side 5. Tangent, which is the posterior portion of the great rolling mound and the posterior portion the thigh rolls touches.

III. Using the femur calculator: 1. Determine the center of the head.

One of the circles is brought into agreement with the contour of the head and then-the femoral head center is marked. In the left picture carries the head center the designation C and in the right B. The different letters depends on the different projection of the femoral head in the two at right angles to each other standing X-ray planes together. As the size of the hip head of the individual Different circles are required depending on the individual.

2. Draw in the axis of the handle neck.

The distance AC is a projection of the true distance AB of the femoral neck. After determining the center of the Hüttkopf, the parallel routes become the Femoral neck moves that number and distance of the lines from the upper and lower Femoral neck limits are the same.

The slot is now exactly in the middle of the femoral neck and the Axis AC can be drawn in.

3. Determination of the shaft axis in the drawing on the left.

It will be the middle of the femoral shaft as two different Points are marked and the axis is drawn.

4. Drawing of the shaft axis in the side image.

A horizontal line becomes at the level of the point of contact of the tangent DF, which intersects the tangent at the rear of the large rolling hill (F). To mark the center of the shaft, the distance DF must be halved.

Then it is parallel to the tangent and perpendicular through the center point the shaft axis is drawn.

5. Determination of the route BC.

The perpendicular is dropped from the center point B onto the shaft axis.

The point of intersection is C in the right-angled triangle.

6. Determination of the antetorsion angle.

There are now the two legs AC and BC of the right triangle drawn and then the segment AB.

The true angle of antetorsion is the angle BAC in the right-angled Triangle.

7. Determination of the true femoral neck shaft angle.

To do this, the perpendicular must be made from point C to the shaft axis you take the line AB and transfer it from the intersection point A to the left The point of intersection with the perpendicular is point B of our rec'rt ':' inkligen Triangle.

The whole principle of the method has to be imagined in three dimensions. The segment AC is the perpendicular projection of AB if the anteversion angle is not zero. To the real one To be able to draw the femoral neck shaft, you simply have to fold the line AB into the same plane.

Proof of the correctness of this method is the fact that the true femoral neck shaft angle alwaysxg: Miiiz is smaller than the projected angle; both are only equal if the antetorsion angle is zero.

I ask you to treat all the documents confidentially, since the method has not yet been published.

Please send your correspondence to the following address by April 20th Dr. Guido König 25 Twmpath Gbowen, Shropshire, England Then the correspondence to my home address 7401 Unterjesingen Saar- Str.PO

Claims (1)

Generic term: measuring device for determining angles on a thigh bone on x-rays. Characteristic part: characterized in that the measuring device is composed of a protractor, several circles, several parallel lines, the innermost of which is continuously slotted and a centimeter measure. 1i.aiifgebiet The discovery concerns a measuring device stiffening of the femoral neck shaft angle and the Twist angle of the pouring ice to e er special X-ray method is used The method is used in the »hopEdiO. Task: The invention is based on the task of providing Achaen in one on one. X-ray image of the thigh kelknocheu oinsuzeicheo Str kei abiesson and To irradiate angles. Solution: The task is ingeniously solved in that the NEAS device contains all the devices that are necessary for the Wi kelbesti + rfordorlich are. Description of the X so ites: Ee ha aechenfornat size of 10 s 15 ci fld is off 2+ strong plexiglass made. On the plate are engraved: 1. Bil angle eater 2. Seven circles with a radius of 0.5 to 3.5 ci. From the intersection of the circles with the xorisontals run n-rrlll down Strockei from 7 on L eerseite