Segmental drop adjusting adopts other styles to the drop table as used in the Thompson Technique

The use of drop segments on an adjusting table began with the development of the drop headpiece to aid in the toggle recoil adjusting technique first taught by B.J. Palmer, DC, in the early 1900s. In the beginning, the toggle thrust was performed on either a knee chest or side posture table without the aid of a drop piece. Then in the late 1940s, J. Clay Thompson, DC, originated the first drop headpiece while attending Palmer School of Chiropractic, Davenport, Iowa. Thompson posited that the headpiece would create a better method of delivering the thrust without the reflective force coming back into the doctor’s wrist, elbow, and shoulder.¹

The addition of the drop mechanism revolutionized the ability to deliver a more precise adjustment to the atlas vertebrae resulting in neurophysiological changes to the body. This discovery led to further development of a series of drop pieces for the dorsal, lumbar, and pelvic regions of the human body, which were incorporated into one table.

The first 12-drop adjusting tables developed by Thompson were mechanical, and the drop was initiated by stepping on a pedal to cock the individual segments on the tables. The first tables were adaptations that converted the early hi-lo tables by attaching the drop sections to the table frame.

This began the era of adjustment of the spine in a significantly different manner than was heretofore attempted by chiropractors. Until this point, adjustments were accomplished mostly by moves with the patient lying prone on a bench, and a thrust was delivered to a specific segment. Another method was to lay patients on their side, with the doctor leaning over them, and the thrust was delivered to the spine in what was characteristically termed a "long lever move."

Now, there was another adjusting option by laying the patient face down on the segmental drop table. By cocking the individual sections, doctors could adjust a specific segment of the spine in a posterior-to-anterior direction. This adjustment method became known as the Thompson Technique.

Segmental drop adjusting is a phrase that was coined in 1990 when my staff and I decided to expand on the methodology by adopting other styles of adjusting to the drop table. We found that many forms of adjusting could be adapted to the segmental drop adjusting method, including adjustment of the rib cage and the extremities.

Derifield-Thompson Analysis System
An analysis system originated by Romer Derifield, DC, of Detroit was adopted into the technique system developed by Thompson.¹ Derifield was researching the leg length inequality (LLI) when they became acquainted. Thompson embraced the LLI concept as part of his development of the Thompson Technique and further refined the concept into the five basic categories of the Derifield-Thompson analysis system still in use today.

The muscle changes used by Derifield in defining his observations of the differences noted in LLI are related to the neuronal changes controlled by the bulbo-reticular formation in the brain that affects the musculature of the body to achieve muscle balance in the human frame. The bulbo-reticular inhibitory (BRI) and the bulbo-reticular facilitory (BRF) systems, which control the balancing of the various muscle groups, achieve this balance.

The BRF tracts conduct impulses that facilitate by decreasing the resting potential of the lower motoneurons. On the other hand, the BRI tracts conduct impulses that tend to inhibit or increase the lower motoneurons. Thompson used Wells² term—contractured leg—in early manuals when describing the LLI found in many patients. Magoun and Rhines,³ in their study on spasticity, detected a neuronal connection by stimulation of Brodmann’s area four, at the anterior portion, which was found also to involve the reticular formation. Guyton, in the Textbook of Medical Physiology4 and subsequent volumes, points out the importance of understanding of the muscle control through the reticular formation.

The five categories in the Derifield-Thompson Analysis system are:

• Negative Derifield—The short leg is noted in the extended position. When the legs are flexed, the short leg stays short.

• Positive Derifield—The short leg is noted in the extended position; and when the legs are flexed, the short leg becomes even or crosses over to become longer.

• Cervical syndrome—With the legs in the extended position, the patient is asked to turn the head to the right and then the left. If the short leg becomes even or longer, this is adjusted before proceeding. A nodular mass will be palpated along the lamina pedicle junction on the opposite side to which the nose is pointed; the lowest vertebral unit is adjusted.

• X-Derifield—The legs are even in the extended position, but one of the legs goes short in the flexed position. With both legs in the flexed position, the patient is asked to turn the head first to the left and then to the right. If the short leg goes long when facing right, this is noted as a right cervical subluxation. If no change is noted in the LLI, then examine for a Negative Derifield.

• Bi-lateral cervical syndrome—Legs are even in the extended position, and when flexed are still even. Bring the legs back to extension and ask the patient to turn the head first to the right and note any change in the LLI. A positive finding will elicit a slight change in each leg when the head is turned to the left and right. This is an occipital problem with a specific adjusting procedure.

Analysis and Adjustment of the Positive Derifield
Thompson referred to the PI Ilium that involves adjustment of the posterior ilium performed in the side posture method on a bench as a Positive Derifield problem. By placing the patient in a prone position over drop sections of the table under the pelvis and a separate lumbar drop piece, the doctor can follow a specific line of correction that moves the subluxated pelvis from posterior to anterior and inferior to superior.

Using a "fencers stance" on the side of involvement, the doctor uses a thenar contact placed over the posterior superior inferior spine (PSIS) of the ilium in question (Figure 1). Standing slightly inferior with stabilization on the posterior ischium on the opposite side (Figure 2), the doctor thrusts on the involved PSIS while holding stabilization on the opposite posterior ischium. The complete set-up should look like that shown in Figure 3.

Figure 1: Thenar contact placed over the posterior superior inferior spine (PSIS).	Figure 2: Thrusts on the involved PSIS while holding stabilization on the opposite posterior ischium.	Figure 3: Complete adjustment set-up.

When applying the thrust into the involved ilium, it is important that the doctor does not thrust with the stabilization hand. There is one exception to this rule: during an examination and analysis of the films, the opposite ilium demonstrates an excessive anterior rotation. This means that the superior portion of the ilium has moved forward in relation to the posterior rotation of the opposite ilium. When this occurs, a simultaneous, moderate thrust to the stabilization side should correct the rotational aspects of the pelvis.

This brief history and overview of the Derifield-Thompson Analysis and adjusting prodecure is but a small part of the extensive informational base. The work begun by Derifield and Thompson continues in courses and seminars taught not only by me, but others who carry on the tradition of the Thompson Technique and segmental drop adjusting.

About the Author
Wayne Henry Zemelka, DC, operates the Zemelka Family Chiropractic Clinic in Davenport, Iowa, and teaches the Thompson Technique in seminars sponsored by the continuing education departments of various colleges and state organizations. He worked with J. Clay Thompson, DC, for more than 12 years developing Thompson Technique teaching tools. Zemelka can be reached at 563-386-8585 or via email: drwayne@netins.net.

References
1. Zemelka WH. The Thompson Technique: With a Special Section on Gonstead and Diversified Adjusting on the "Segmental Drop Table." Davenport, Iowa: Victoria Press; 1992.
2. Wells KF. Kinesiology: the Anatomic and Mechanical Fundamentals of Human Motion. 2nd ed. Philadelphia: Saunders; 1955.
3. Magoun HW, Rhines R. Spasticity: The Stretch Reflex and Extrapyramidal Systems. Springfield, Ill: CC Thomas; 1947.
4. Guyton AC. Textbook of Medical Physiology. 7th ed. Philadelphia: Saunders; 1986.