Usually the ilia are both normally articulated; this is one of the most difficult joints to weaken and is seldom affected except by the most extreme force. When iliac subluxation exists one side is affected alone nine times out of ten. The tenth case may show double subluxation. Movement Nine-tenths of the so-called “iliac adjustments” are quite amusingly ineffective. The force required really to _move_ an ileum (save in joint disease or in children) is tremendous and not to be commanded by the ordinary adjuster. The light jars applied as a routine procedure by so many Chiropractors are in reality nothing more than single percussion strokes which stimulate the sacral nerves. Place patient in position B and apply the hands to a posterior ilium as to a posterior sacrum, making contact with the most prominent portion of crest or posterior border and driving in a direction which would represent a part of the circumference of a circle of which the transverse sacral axis of rotation touches the center, or the center of fixation in the sacroiliac joint. COCCYGEAL ADJUSTMENTS Examination Place patient on an angle table, i. e., one which rises in the center and slopes away toward either end. Separate the thighs slightly, patient lying face down, and insert the rubber-covered second finger, palmar surface upward, very carefully into the rectum. The tip of the coccyx may then be felt and its movability and position determined. Unless it is immovably fixed in an abnormal position it should not be molested; the movable coccyx responds to mere muscle tension by changes of position and cannot act as a primary cause of nerve impingement. Usually this examination will be rendered unnecessary by the external palpation which may disclose the movability of the coccyx and at once render further exploration superfluous. When the coccyx is anteriorly subluxated and ankylosed in that position it may be a factor in producing constipation, hemorrhoids, etc., but its influence in other diseases, especially of the nervous system, has been greatly overrated by those who have not yet fully accepted the doctrine that nerve impingement is the primary cause of all disease. [Illustration: Fig. 30. Edge contact with “Roll,” q. v. Attitude of patient for coccygeal adjustment.] Movement When it has been decided that the coccyx must be moved, the position and use of hand is the same as for the palpation. The finger hooks under the tip of the coccyx, draws upon it until a tight contact is secured and then jerks sharply backward upon it with a view to its abrupt fracture. No mitigation of the jerk in the hope of previously loosening or gradually replacing the bone is of value for _osseous tissue_ must be broken before any movement may take place. This movement is painful and the region of the newly fractured coccyx may remain sore for a period ranging from a few days to several weeks. It is wise to warn the patient of the facts before proceeding.