| Cranial Vault Palpation by Marc G. Pick, D.C., D.I.C.S. It appears that the majority of craniopathic disciplines employ their sutural inspections while the subject is supine on the examining table. Although this position is sanctioned during the application of facial analysis and most manipulative maneuvers, its utilization during static and motion vault palpation is not encouraged. This is primarily due to the two following reasons. 1. The sutures that rest adjacent to the examining table’s headpiece are often cumbersome to access making it unnecessarily difficult on the examiner’s palpatory attempts. 2. Gravity could conceivably initiate a compressive strain into the sutures juxtaposed to the table’s headpiece and consequently cause an incessant functional fixation throughout the cranial vault. Although the latter assumption is only theory at this time, the following exercise and facts are presented to advocate its feasibility. Gravity is a constant force compressing matter towards the earth’s core. Consequently, its effects should cause the migration of the inter-cranial contents toward the vault’s lowest site. The following exercise is designed to demonstrate this effect as the vault’s lowest site is altered and the weight of the inter-cranial contents shift to accommodate. To implement this exercise, the subject should lie supine with the examiner seated at the head of the table. Step One: Cup your hands together and place them under the subject’s occipital region. Step Two: Notice the weight of the subject’s head and whether it feels heavier on one side compared to the other. Step Three: Rotate the subject’s head so their face is turned toward the side that feels lighter. This will shift the vault’s lowest point into the lighter weight region. Notice the shift in weight as the once lighter region becomes heavier and the once heavier region becomes lighter. Step Four: Return the subject’s head to its original position and notice how the head’s weight distribution once again shifts back to its original stature. Step Five: With the subject’s head in its original position, elevate the head so as to support it upon your fingertips. Notice the increased stress and fatigue of your fingers as they attempt to support the head against the constant pressures of gravity. As suggested by the prior exercise, the shifts in the vault’s weight appears to be due to the inter-cranial contents, as they alter their position to follow gravity’s dictated course. The plausible outcome from the contents reaction would appear to be internal compression of the posterior meninges. However; if the subject’s head was resting on the examining table’s headpiece, the headpiece’s counter-resistant surface could produce an increased strain within the posterior suture’s. This increase in inter-sutural tension may then serve as a deterrent to the suture’s natural motility and consequently increase the probabilities of indirectly straining the remaining sutures through the general inter-locking beveled systems that make each suture’s response dependent upon the whole. To substantiate this, consideration should be given to the investigations of Pritchard, Scott, Girgis, Herring, Markens, Oudhof, Hicks, Cotton, Blum, Meikle, Bker, Kostopoulos and Keramid. In 1956, Pritchard, Scott and Girgis recorded the presence of connective tissue passing through the sutures articular seam to link the skull’s outer periosteal tissue layer to the periosteal dura inside (Fig. 1). This study noted the presence of five distinct tissue layers across the suture’s articular seam with the middle layer being less dense and very vasulcar.1 These findings suggest the suture’s articular seam is somewhat flexible and the softer middle zone lends itself to a higher probability that the articular union is somewhat vulnerable to compression. Herring noted that slippage of one bone upon the other would be expected if pressure was applied along the suture’s beveled axis.2 The articular beveled axis between the occiput, parietal and mastoid margins run anterolateral to posteromedial. Hence; in accordance with Herring’s notation, this would increase the probability of articular compression to the lambdoid and occipital/mastoid sutures due to the expected axial slippage from the posterior pressure of the headpiece. Markens and Oudhof divided the sutures into external and internal poritons and noted that the sutures appear to function like hinges in which the pars externa elicited the area of greatest displacement.3 Oudhof further distinguished that the fibers around the pars externa are arranged to resist forces that would either widen or narrow the suture’s articular seam.4 Consequently, the compression of the skull’s external portion and its fibers by the weight of the subject’s head could conceivably activate a resistance response that would feed into the suture’s articular seam. Hicks5 and Cotton6 concluded that one to two pounds of continuous force is all that is required to maintain a measurable separation of the maxillary segments in rhesus monkeys and humans and based upon Hicks and Cottons findings Blum7 postulated that it would not be unreasonable to assume that even low level forces might be sufficient to transmit mechanical stresses within adjacement cranial structures. Blum further postulated that short term forces exerted on the cranium can cause associated changes which seem perpetuated in the inter-sutural tissues with the formation of Type III collagenous tissue.7 Meikle, et al noted that sutures under stress have been noted to cause a significant protein accumulation within six hours of initial onset thus suggesting that mechanical stress can effectively modulate biosynthetic activities.8 He further notes with Sellers and Reynolds, that the sutures connective tissue appears to respond to stress by collagen production and affects an enzymatic activation which generates collagen hydrolysis.9 From these findings, it would appear highly probable that the amount of force generated by the weight of the supine subject’s head against the table’s headpiece is sufficient to activate an immediate intra-sutural tissue response to the sutures closest to the site of compression. In 1971 Baker EG. Noted the integrated functional relationship between sutures when he was able to record sutural movements within the cranial vault by applying alterations in width to the maxillary arch.10 Kostopoulos and Keramidas demonstrated the effects of external manipulation upon the falx cerebri of an embalmed cadaver and was able the measure changes in its elongation.11 These studies support the contention that all sutures are functionally integrated through dural association and interlocking beveled formations. Consequently, compressive stress placed on any suture has a gigh probability of reflecting changes throughout the cranium and could conceivably interfere with motion detection in distant sutures. In conclusion, a subject resting supine is subject to the influences of gravitational pressure as the weight of the head is compressed against the examining table’s headpiece. Consequently, should the subject’s head rest upon their occipital region, the weight of their brain and inter-cranial fluids will be drawn to the vault’s lowest point and exert pressure against the internal wall around the occiput and parietal/mastoid regions. As the head encounters external resistance from the surface tension of the headpiece, the compressive stress could initially generate local resistance and fixation into the sutures closest to the area. However; due to the integrated functional association of the sutural system as a whole, the functional incapacitation would probably infiltrate to the other sutures and inhibit the practitioner’s chances of performing an accurate analysis. With the subject seated, the inter-cranial substances spread across the entire floor of the cranial vault and thus evenly distributes the intracranial pressure and weight onto the embryonic cartilaginous evolved region of the cranial vault. The dural membranes are posturally suspended to eliminate accumulative strain in a particular inter-cranial region and the skull is balanced upon the occiput’s condyle surface thus eliminating any possible external counter-resistance that could place unforeseen stress into the cranial suture system. Consequently; due to the aforementioned reasons, static and motion vault examinations should be performed with the subject seated. ____________________________________________________________________ References |