SITUACIÓN ACTUAL

In order to effectively apply cranial manipulative techniques, subtle or orthopedic, it is essential that the anatomy of the skull, the 22 individual bones, their sutures and other articulations, as well as surface landmarks be intimately studied. This knowledge can best be achieved by obtaining and becoming familiar with an intact human skull.

Most plastic models offer accurate representations of the shape and articular characteristics of the skull, with many showing quite adequate detail as

to attachments and surface markings. Plastic is, however, a poor substitute for the feel of real bone, even dead bone, but because of expense and the lack of availability of human skulls, plastic may have to suffice. A real specimen skull, superior though it undoubtedly is to a plastic version, will still fail to provide the degree of pliability present in the living skull.

As Magoun (1966) explains:

Osteopathic findings are based on living tissues, not cadaveric anatomy. They are concerned with the dynamic rather than the static. The tree that is alive and full of sap sways in the wind but the telephone pole does not. There is [just] as much difference between the normal physiological state of living bone and the dry, defatted condition of laboratory specimens from which anatomic descriptions for the average text are derived.

A further important learning aid is a disarticulated skull, which for preference should also be real, although plastic is cheaper (but not inexpensive) and more readily available. A good-quality atlas of human anatomy (Churchill Livingstone's Gray's Anatomy is highly recommended) is another absolute requirement.

In addition, as many living heads as possible, of all ages, including your own, should be palpated as frequently as possible, so that your hands can familiarize themselves with the numerous land-marks and patterns of movement which you need to be able to 'read', long before therapeutic application of these methods can commence.

Magoun (1966) once again has found the words which summarize palpation (and treatment) requirements, especially of the cranium: 'To employ other than a skilful and delicate sense perception is to lose the shades of physiological reaction so necessary for success. Living cells prefer persuasion to force, consideration to trauma, intelligence to ill-expended energy. One must work with the tissues not against them'.

This text will not attempt a complete description of all that it is necessary to know in terms of cranial anatomy and physiology in order to safely perform cranial therapy; it will, however, summarize what that knowledge should include, using lists, brief discussion and illustrations (see Figs 6.1A-E and Fig. 6.2).

Additional texts, suitable for further study, will also be indicated, with Pick's Cranial Sutures (1999) in particular being a highly recommended source of information. Exercises will be suggested, involving the previously mentioned whole and disarticulated skulls as well as living heads, in order to facilitate achievement of the degree of palpatory literacy necessary to allow intelligent assessments to be made of functional and structural patterns, well before beginning to safely apply cranial therapy in an effective manner.

Note: It is necessary to restate the widespread belief (including the author's) that the skills required for safe and effective cranial therapy application cannot be acquired from books alone, without accompanying hands-on demonstration and lengthy practice, supervised by a skilled tutor.

The trainee cranial therapist needs to have available:

• a disarticulated skull (authentic if possible)

• a whole skull (authentic if possible)

• a high-quality illustrated anatomy text (Gray's Anatomy is recommended - Churchill Livingstone edition).

• time to practice on numerous volunteers (friends, family) who can loan their heads for up to an hour regularly, ideally daily.

Palpation pressure considerations

How much pressure should be used when palpating and when treating cranial structures?

There are various answers to this question, some simple, some complex.

In the discussion, later in this chapter, of the proposed flexibility into adult life of the junction between the occipital bone and the sphenoid (the sphenobasilar synchondrosis), there is mention of the extremely light degrees of force/pressure suggested by different experts. These include 5-10 grams (Milne 1995, Upledger 1996) and 'half an ounce' (14 grams) (Ettlinger & Gintis 1991).

Kostopoulos & Keramides (1992) demonstrated in their study on a recently deceased cadaver a need for 4 ounces (140 g) of traction force to begin the process of elongating the falx cerebri.

Pick (1999) has suggestions regarding pressure in cranial assessment and treatment that he describes as:

Figure 6.1 A Lateral view of cranium and its major landmarks and sutures.

Figure 6.1 B Frontal view of cranium and its major landmarks and sutures.

Figure 6.1 C Inferior view of cranium and its major landmarks and sutures.

• surface level: first contact, molding to the contours of the structure, no actual pressure

• working level: 'The working level.... Is the level at which most manipulative procedures begin.

Within this level the practitioner can feel pliable counter-resistance to the applied force. The contact feels noninvasive ... and is usually well within the comfort zone of the subjects. Here the practitioner will find maximum control over the intracranial structures' (Pick 1999, pp xx-xxi)

• rejection levels: Pick suggests these levels are reached when tissue resistance and/or discomfort/pain are noted. Rejection will occur at different degrees of pressure, in different areas and in different circumstances and is not recommended in the therapeutic setting.

So how much pressure should be used? Not enough to hurt and yet enough to be effective.

Time suggested at least 5 minutes

Whichever cranial bone is used in Exercise 6.1a, this should be followed by a blindfolded palpation of the same bone in a live subject, with its contours, sutures, resilience and observed (intrinsic, not initiated) motion being felt for and described.

• When comparison is made with the same bone in a living skull in this way, similarities and differences should gradually become apparent.

• The differences between the dead and live bone should be described and defined, ideally into a tape recorder.

• Clearly the living bone cannot be palpated directly but must be palpated through superficial tissue. This requires that the palpation become discriminating, filtering out information offered by the soft tissues which overlie the bone being assessed.

• By applying full attention to what is being palpated (for not less than 5 minutes in the early stages), subtle awareness of motion inherent in the live bone may also become apparent.

• There are a number of possible rhythms which may be noted when palpating a living skull - including pulsation, respiration and a slower rhythmic motion. It should be possible to gradually focus on one or other of the first two of these at will. In time the third may become evident.

• For at least some of the time the palpating hand(s) should be absolutely still, allowing movement to be evaluated. Compare your findings regarding the living bone with what you noted when handling the real or plastic version.

Time suggested 5 minutes

• Sit with your eyes closed while palpating one of the cranial bones, real or plastic (in time each of the cranial bones should receive this palpation attention many times).

• Articular structures should be felt for bevels, interdigitations, landmarks and features and described in some detail (perhaps with some-one else handing the bsome-one to you and with your findings spoken into a tape recorder for re-evaluation when the bone is studied with eyes open).

• The bone should be named, sided and as many as possible of its particular features discussed.

• Reflect on what the difference might be in the feel of plastic as opposed to bone.

• Bone, albeit no longer living, has a slight compressive resilience which plastic never has, nor can plastic achieve the detail of sutural interdigitation which bone demonstrates.

• The whole process of palpating is enhanced, suggests Frymann (1963), if the arms are supported on a table surface, so that the hands and fingers are unaffected by the weight of the arms (Frymann 1963).