UC Technique #1

The following is a reprint of an article written by Dr. Molthen, published in the Journal of Chiropractic Economics. This was originally submitted to NUCCA, but they refused to print it in their Monograph. It was then submitted to Chiropractic Economics and appeared in the Nov/Dec 1980 issue.
Click here for, a reprint of Drs. Gregory and Seeman’s response.

VECTORED ADJUSTING: A CRITIQUE
by D. A. Molthen, D.C.

Vectored upper cervical adjusting is based on the hypothesis that if the mechanical configuration of the occipito-atlanto-axial subluxation can be measured accurately a force can be calculated which will mechanically align these structures.

The theory argues that if the subluxation is measured precisely with respect to direction and degree of misalignment this measurement can be integrated with a measurement of the upper cervical bone contours and, by the application of certain laws of physical science, a corrective force can be calculated.
In theory, this approach sounds plausible enough; but will it stand up to the reality of its actual application in the chiropractic office?

Vectored adjusting procedures stress the importance of X-ray alignment. This consists of aligning the focal spot with the center of the bucky so that the central ray will strike the center of the bucky at 90 degrees. The tube column is aligned with the bucky so that as the tube is moved the focal spot remains in alignment with the center of the bucky. Great care is taken in this procedure, and when properly done it results in a very close tolerance alignment. Headclamps are used to align the patient's skull and cervical region to the center of the bucky. Lateral, nasal and vertex films are made. Great care is taken to insure that the films are made with a minimum of distortion. Tube angle and tube distance are rigidly controlled. These films are then analyzed with respect to misalignment factors and bone contours. Misalignment factors are expressed in 1/4 of a degree increments. After the measurements have been made, a "Final Listing" is calculated which is the resultant angle at which a "corrective" force will be applied. The patient is placed in the side posture position, measurements are made and a force is delivered into the atlas region.

The ideal force is rectilinear in nature and has a minimum of curvilinearity. It may be applied by means of an adjusting machine, or by the employment of the musculo-skeletal framework of the doctor himself, using the pisiform bone as a contact point and aligning the various levers of his body in an attempt to deliver a rectilinear force.

(It is virtually impossible for the human body to deliver a rectilinear force; therefore it is an inefficient adjusting machine. An analogy would be attempting to play pool using a pisiform contact and the human arms, instead of a pool cue.)

All the above steps are based on the ultimate assumption that the attitudinal position of the atlas vertebra can be established with the patient lying in the side posture position.

Let's examine this assumption: The average human skull is about 22 inches in circumference. (The skull is obviously not round in shape. It would best be described as being elliptical, with the long axis being A-P. However, when it rotates it follows a roughly circular path.) As a result, each inch of circumference represents approximately 16 degrees.

360/22 = 16.3

Since each inch contains slightly more than 16 degrees, each 1/16 of an inch equals approximately one degree. A change in the position of the skull of 1/16 of an inch will cause a corresponding one degree change in the position of the atlas.

Consequently, if the measurement of the atlas rotation factor made from the vertex film showed the atlas to be rotated one degree anterior, a deviation of 1/16 on an inch in the position of the skull when the patient is in the side posture position would cause a 100 percent error. A deviation of 1/8 of an inch would cause a 200 percent error, etc. (See Figure 1.)

Figure 1: A 1/16 of an inch change in the position of the skull causes a corresponding one degree change in the position of the atlas on the atlas rotation plane.
 

If the patient were being adjusted for a right anterior atlas rotation of one degree and there were a slight deviation of the skull on the headpiece in the amount of 1/16 of an inch the 100 percent error which would result would cause the measurement taken from the vertex film to be completely obliterated. The one degree would be either completely canceled or doubled, depending on the direction of the skull rotation.
Carrying this reasoning further, a slight rotation of the head when placed on the headpiece in the amount of 1/16 or 1/8 of an inch will (based on this theory of adjusting) cause anterior rotations to be driven more anterior and posterior rotations to be driven more posterior, depending on the juxtaposition of the skull with relation to the vectored force.

Up to this point, we have discussed the error factor in only one plane, the atlas rotational plane. The adjusting vector is usually calculated in at least one other plane -- the atlas laterality plane. (See Figure 2.)
 

Figure 2. This demonstrates the error factor on the atlas laterality plane.
 

This plane is equally as sensitive to the head placement deviation. When in combination, a slight deviation in both planes causes a compounding of the error. A 1/16 of an inch deviation in each plane could easily cause a 200 percent error, a 1/8 of an inch deviation in each plane could easily cause a 400 percent error, and so on.
Obviously then, no matter how much care is taken in the preceding steps or how much calculation is involved in determining the ultimate vector, it is physically impossible to control the placement of the head on the headpiece. A slight deviation in the position of the skull in either or both planes will introduce error of such enormous proportions that all previous calculations will be rendered insignificant.