PINS is most closely related to the osteopathic modality of inhibition. According to the Glossary of Osteopathic Terminology (American Osteopathic Association 1998), inhibition is ‘a term that describes steady pressure to soft tissues to effect relaxation and normalize reflex activity.’ Inhibition, or this use of ‘steady pressure to soft tissues’, is perhaps one of the oldest methods of manual treatment, regardless of the name applied. Typically, inhibition is performed by pressing the fingers or other body parts at a constant mild-to-moderate amount of force on regions of persistent hypertonic muscle. Even though the patient may complain of pain or decreased function, the objective of the treatment is to decrease the tonicity of the muscles. The symptoms that the patient has are directly related to this increased dysfunctional muscular tone (Dowling & Scariati 2005).

Large superficial muscles are most easily identified in both the normal relaxed and hypertonic states. A series of regional muscles can be identified and treated in pairs or individually. The supine or prone positions may facilitate the process as the patient will not need to use some of these muscles for postural support of the trunk and neck. With the patient in the supine position, a muscle, such as the trapezius, can easily be located in the cervical, shoulder and upper thoracic regions. The body of the muscle can be grasped, pressed or pinched. A hypertonic muscle is usually found to be firmer, but not necessarily larger, than its counterpart on the other side. An initial response of the tissue to pressure may be an increase in tonus and perhaps sensitivity. Gradually, with sustained pressure, the structures relax.

Another consideration is the relationship between musculoskeletal structures and the underlying organs. The viscera receive innervation from the spinal cord via nerves that originate from the same segments as the nerves that service the more superficial structures. As the sympathetic chain lies just anterior to the rib heads, dysfunction of the vertebra may result in increased sympathetic activity, or stimulation, to the innervated visceral target organs and the segmental musculoskeletal region (Ehrenfeuchter 1997).

The sympathetic system is often referred to as the ‘flight or fight’ response mechanism. It allows for rapid response to perceived danger or injury. The organism’s reactions are channelled towards self-preservation. The heart rate increases, pupils dilate, blood is shunted to the skeletal muscles and away from the internal organs, and the respiratory rate increases. Gastrointestinal activity, among other visceral concerns, effectively shuts down. This normal reaction to stresses becomes abnormal when it does not abate. Inhibition also has a specialized purpose in the thoracic region. In theory, constant pressure to an area, which is the source of increased sympathetic activity, will result in reduction of the autonomic activity. Raised blood pressure, ischaemic changes, arrhythmias, tachycardias or myocardial infarction secondary to vasospasm of a congested coronary artery may result from the effect of the stimulation on a visceral organ such as the heart. Musculoskeletal response includes spasm, decreased circulation due to vasoconstriction, impaired drainage of waste products, sensitivity changes and trophic alterations. Acute responses to this activity are the same as those to any new injury: redness (rubor), pain (dolor), swelling (tumor), heat (calor) and decreased function (functio laesa) (Robbins et al 1984).

• The skin and subcutaneous tissue may have a ‘doughy’ consistency and the pain sharp and throbbing.

• As the state persists without relief, the alterations reflect the chronicity of the dysfunction. Muscles and the surrounding fascia become more fibrotic (‘ropy’).

• The skin responds to the chronicity of the dysfunction by becoming thinner, paler and cooler.

• Pain responses may be more variable from insensitivity (‘anaesthetic’) to altered sensitivity (‘paraesthesia’) to hypersensitivity.

External pressure, such as is provided by inhibition, may initially result in a transitory increase in spasm or sensitivity. However, subsequent reduction of some or all of these components can be readily appreciated. Research regarding the visceral responses has indicated reduction of the undesirable autonomic responses (Hermann 1965). However, the persistence may be more dependent on the aetiology. If the visceral organ’s structure or function were somehow altered, either primarily or secondarily, then the benefits of surface inhibition might be short lived. The more observable musculoskeletal signs and symptoms might represent a viscerosomatic reflex. When a musculoskeletal injury is the origin, a somatovisceral reflex may occur. Manipulative treatment of the musculoskeletal structures may result in a more persistent reduction of all elements.

In the suboccipital and sacral regions, the intention switches from the sympathetic half of the autonomic system towards resetting parasympathetic activity, the other half of the autonomic nervous system. Rather than being reactive to external danger such as the sympathetic system, the parasympathetics comprise nerves affecting the modifying reconstructive processes. Upgrading of parasympathetic activity coordinates increased gastrointestinal motility, decreased sphincter closure, reduction of heart rate, constriction of pupils, and sleepiness, to name just a few of the reactions.

Parasympathetic fibres travel only to the head and trunk, not to the extremities. Any region that has a visceral organ will have parasympathetic innervation. Although there are other cranial nerves (III, V, VII and IX) with some parasympathetic fibres, the vagus nerve (cranial nerve X) is the major influence to the head, neck, and thoracic and abdominal cavities. The origin of the vagus nerve is in the upper spinal cord and lower brainstem. The pelvic organs and the terminal portions of the gastrointestinal system are influenced by branches of nerves originating from the terminus of the spinal cord and exiting from foramen in the sacrum (S2, S3 and S4). The parasympathetic centres also receive sensory information from the target organs.

Persistent conditions such as nausea, vomiting, diarrhoea, dysmenorrhoea and dyspepsia are parasympathetic in nature. Dysfunction of the upper cervical, occipital and sacral regions may reflect or result in inappropriate parasympathetic activity. Inhibitory treatment results in reduction of the more superficial representation (increased musculoskeletal tone and congestion) and theoretically downregulates the more internal mechanisms. A thorough understanding of the structure and function of all of the factors related to dysfunction should guide accurate treatment.

Andrew Taylor Still first developed the concepts of osteopathy in 1874. An American medical practitioner primarily trained through apprenticeship with his father, a Methodist missionary and itinerant practitioner, Dr. Still practised what could be called conventional medicine until he suffered personal loss as a result of its inadequacy. Despite calling in other practitioners to assist, he watched as members of his family succumbed to meningitis. Realizing that the approaches utilized in the ‘heroic’ era of medicine, which were the primary tools of the allopathic profession at that time, were often more dangerous than the diseases they were meant to combat, and seeking other means, Still began using manipulative treatments. He found these were quite effective in managing or facilitating his patients’ health.

Theorizing that the body was a unit, structure and function were interrelated, and the body had the ability to heal and defend itself, he set about reorganizing medical theory. In 1892, he established the first school of osteopathy in Kirksville, Missouri. As a rural institution, osteopathy spread slowly and experienced much prejudice. In the United States, there are currently 26 medical schools of osteopathy and approximately 66 000 osteopathic practitioners with full medical practice rights. Brought to England at the turn of the century by J. Martin Littlejohn, osteopathy spread to the rest of Europe, and the Empire (now Commonwealth).

The origins of some of Still’s treatments apparently predate his professional separation from his allopathic colleagues. When he was a young man suffering from chronic headaches, Still treated himself with a rope-swing. He lowered the rope to a few inches above the ground and slung a blanket across it. Lying on the ground, he positioned himself with the contraption supporting his neck at the base of the skull, and subsequently fell asleep. He awakened refreshed and pain-free. This method may represent inhibition as well as a positional intervention (Still 1908). Some descriptions of both inhibition and stimulation methods were included in Still’s early writings (Still 1902).

Some of Still’s early students likewise described inhibitory techniques as well as their rationale. Eduard Goetz, one of Still’s earliest students, described and illustrated inhibition for various conditions, both somatic and visceral, in his book A Manual of Osteopathy (Goetz 1905). Selected photographs in this small handbook clearly demonstrate and detail inhibitory treatment of several regions. Two such areas are the orbital and suboccipital regions of the head. In one such approach, pressure is applied individually to each of these areas for a few minutes.

Dain L. Tasker delivers a more extensive description in Principles of Osteopathy (Tasker 1916). Tasker describes a rationale as to the effectiveness of inhibition and that it is a natural phenomenon. Activities such as defecation and urination could not come under conscious and unconscious control without the ability of the individual to perform inhibition. In discussing the ability of externally applied inhibitory pressure, applied by a practitioner of manual medicine, to lessen hyperactivity, Tasker states that it is not the palpation itself but the initiation or alteration of the reflex arc that occurs. Observation reveals that placing a pressure should be a form of stimulation because it is impacting on the soft tissue. The effect of inhibitory pressure is to produce neural resetting of tone, modification of the dysfunction, and a beneficial modulation of distant or deeper reflexively linked structures. In citing Hilton’s law ‘that the skin, muscles and synovial membrane of a joint, or the skin, muscles of the abdomen and contents covered by peritoneum, are innervated from the same segment of the cord’, Tasker states that the ‘over-stimulation’ caused by inhibition brings about a diminution or elimination of the overreactivity.

Osteopathic point and/or pressure techniques

Strain/counterstrain (see also p. 196)

Several passive direct and indirect systems of osteopathic treatment of somatic dysfunction exist. Standard points and diagnoses are used as fulcrums, or monitoring locations, in practically all. Monitoring by constant palpation at the points allows both practitioner and patient to experience feedback as to the success of the treatment when performing Jones’ strain/counterstrain treatment (Glover & Yates 1997, Jones 1981, Jones et al 1995).

The practitioner determines a tender point, such as those that have been identified and mapped by Laurence Jones and his followers. The pressure on the point is designed to create a mild degree of discomfort, which the patient reports on as the tissues are positioned to remove the discomfort. The positioning of the region or the whole patient into a direction of ease is the actual therapeutic intervention. Although the diagnostic points are named for spinal segments, bony landmarks, ligaments or muscles, it appears that the treatment positions bring about shortening, and therefore relaxation of the muscles and ligaments.

In theory, during the period spent in a position of ease, muscle spindle resetting occurs. The muscle spindle apparatus is a sensory organ embedded into the larger muscle. Small, almost primitive, fibres exist in parallel within the larger extrafusal muscle. Two distinct shapes of the muscular fibres, as well as two of the sensory ends of the nerve fibres, exist. The nuclear bag muscle spindle fibre has all the nuclei collected in the centre. Nuclear chain fibres have the nuclei set almost in line. The primary type of sensory fibres to the nuclear bag appear almost like a coiled spring, and are termed annulospiral. The descriptive name ‘flower spray’ is applied to the endings of the fibres that primarily service the nuclear bag fibres. The muscle spindle fibres, unlike the other large extrafusal muscle fibres, do not have a great deal of contractile ability.

The sensory nerves to these intrafusal spindle fibres are stimulated by stretch of any kind. The annulospiral is more responsive to rate of stretch, and the other to constant stretch. This assists in the regulation of muscle tonicity as stretch brings about reflexive muscular contraction. Ordinarily, this is short in duration and recovery is quick. Sometimes, the reflex persists longer than is appropriate. The signals from the spindle continue as if the tissue were being stretched too rapidly, or overstretched, even though the length may be normal.

Increased neural activity is evidenced by increased sensitivity of a ‘tender point’. Applied pressure elicits a report of tenderness. The positioning process during application of strain/counterstrain technique shortens the whole muscle, allowing the spindle reflex mechanism to be reset. The position that relieves the tenderness in the palpated point is typically held for 90 seconds and is then slowly returned to neutral. When successful, the previously hypertonic muscles relax and the sensitivity disappears.

Facilitated positional release

Facilitated positional release (FPR) (Schiowitz 1997) is similar in many respects to strain/counterstrain. It differs in its use of an activating force, usually compression or torsion, after initially positioning the region in neutral (ease). By comparison, strain/counterstrain is a form of positional release, whereas FPR utilizes an additional facilitating force. As with most manipulative techniques, the efficacy is directly proportional to the accuracy of diagnosis. The diagnosis includes relative motion freedom in the sagittal plane (flexion/extension), coronal plane (lateral flexion/abduction/adduction) and horizontal plane (rotation). Any increase in tissue tension in the surrounding tissue is also noted by means of palpation.

Initially, at least with spinal dysfunctions, the region is brought into a neutral position relative to the sagittal (anterior–posterior) plane. The lordosis of the cervical spine and the kyphosis of the thoracic spine are flattened. The practitioner then further brings the somatic dysfunction into the directions of relative ease. A facilitating force, usually compression and/or torsion, follows this. Release of the dysfunction and localized tension is noted almost immediately, as shown by the practitioner’s monitoring finger.

Both strain/counterstrain and FPR theoretically utilize the same neurophysiological mechanism. However, because of an inverse myotactic reflex caused by the facilitating force, a release occurs within seconds instead of in 1.5 minutes. The muscle spindle has a specialized motor nerve known as the gamma motor neuron. Even though the nuclear chain and bag fibres are weakly contractile, increased gamma activity causes the ends to contract and the central regions become stretched. Regardless of whether the whole muscle is stretched or not, the spindle will react as if it were. The reaction results in overall protective contraction. The gamma gain, as it is known, tends to persist longer than is necessary and is modified by many factors including stress, pain, anxiety, endocrine alterations, medications and food substances. FPR, with its initial manoeuvres to flatten curves and adding a facilitating force, addresses the gamma activity component as well as the spindle stretch response. Diagnosis for FPR is less reliant on the localization of a tender point, but when such a point is found it is used solely for the purpose of monitoring.

Still technique

The recently described Still technique (van Buskirk 1996) shares many similar applications with these two previously described techniques. Richard van Buskirk attributes the writings of Charles Hazzard (Hazzard 1905), as well as those of Still himself, as the sources for the method. The descriptions revolve around the palpatory diagnosis of dysfunctions followed by motion into the directions of freedom/ease, and finally by movement past the neutral point into the barrier directions. A low-velocity, relatively low-amplitude articulatory movement towards the barriers follows positional treatment and the utilization of forces into the directions of ease (freedoms).

Functional technique

Functional technique (Johnston 1997) utilizes the diagnostic tender points to define the somatic dysfunction that exists at that level relative to the two adjoining vertebrae, the one above and the one below. Detection is typically made by percussion testing to scan and screen the regions. Once an anomaly is determined, the practitioner tests the dysfunction more specifically. The practitioner guides the region into a compound position of freedom (‘ease’, comfort) along various axes. Fine tuning to achieve release of the dysfunction includes side-bending and lateral translation, flexion/extension together with anterior or posterior translation, as well as rotation combined with compression or distraction. Breathing is then held in either exhalation or inhalation, dependent upon which phase is associated with greatest sense of tissue freedom.

Additional osteopathic methods using palpated points

Monitoring points as sites where some form of pressure is exerted to relieve dysfunction is used in other osteopathic techniques. The intent goes beyond monitoring.

Elaine Wallace developed Torque unwinding (Dowling 2005) and has taught this on a limited basis. She advises that the body can be imagined as a collection of adjacent or overlapping cubes. Injuries place forces into a whole ‘cube’. Even though the vector force may be straight initially, after entry into the complex body it rarely remains so fixed. The pathway, because of bodily composition, motion or twists, becomes arced or more twisted. The tissues, especially the fascia, maintain memory for these injurious forces. The practitioner’s fingers direct rhythmic, balancing, pressures centrally from two opposing cube faces. Placed on the contralateral sides of the head, trunk or extremity, the therapeutic forces negate the residual traumatic ones. A light percussive test on one side that is monitored on the other yields a sense of resonance that confirms the correct selection of the connected points.

Osteopathic literature is filled with many other variations of myofascial or fascial release techniques (Chila 1997, Ward 1997) that utilize point contacts as references, contact points and/or diagnostic reflections. Steven Typaldos (1994) has written about trigger band technique – a method intended to change the pathological cross-linkages of fascial bands. Using an instrument or fingers, the practitioner exerts significant pressure along certain connective pathways. This occurs along involved tissue in a basically linear fashion from an area of relative dysfunction towards the more involved region. Leon Chaitow (Chaitow 1980, 1996) describes the development of neuromuscular technique by two of his relatives, Stanley Lief and Boris Chaitow. Consisting mostly of point localization, reflected dysfunctions are treated by pressure followed by deep stroking and/or rolling of the tissue.

Standardized patterns of Chapman’s point treatment (Owens 1937) reflect a neurological/endocrine/lymphatic internal alteration to the surface. The palpatory finding has been described as a lenticular (bean-shaped) subcutaneous structure. Although they may not be tender or sensitive to pressure, clinical correlation should raise suspicion either to locate Chapman’s points or possibly to search for a latent visceral correlate. Apparently developed independently, some of the specific points are similar to those of acupuncture. Circular pressures are applied rhythmically by the pad of the manipulator’s finger(s) to the nodular findings that are related to visceral conditions.

Non-osteopathic point and/or pressure systems

There are some similarities between typical inhibition technique and some other manual medicine systems of treatment. These include the Cyriax method (Cyriax 1959), trigger point therapy (Chaitow 1990, Travell & Simons 1983), acupressure (Kenyon 1988, Cerney 1974), reflexology, rolfing and shiatsu (Schultz 1976, Weil 1995). Some of the common elements include the practitioner providing the treatment by pressing the patient’s soft tissue with the intent of bringing about a persistent alteration. Another similarity is the reliance upon a system of diagnosis and/or treatment points.

James Cyriax was most noted as a medical orthopaedist who practised joint mobilization and massage. He discussed the use of a ‘pinching’ technique on several locations (Cyriax 1959). The end goal was relaxation and stretching of tissue, as well as a relative hyperaemia. Triggerpoint therapy, developed by Janet Travell, recognizes the relationship between a remote referral point and a damaged myofascial nexus. Manual pressure can be used, but more commonly dry needling, vapocoolant spray, or a combination of anaesthetic and/or steroid agents are injected into the trigger point. By these means the practitioner locates and interrupts the aberrant patterns. Regardless of the method, theoretically restricted soft tissue is released by means of deep pressure applied to the selected points. Another manual version of the triggerpoint concept, Bonnie Prudden myotherapy, consists of primary points, as well as satellite points. Both are treated for short intervals several times a day over several sessions (Burton Goldberg Group 1994, Prudden 1980). After the treatment, stretching is also incorporated.

Like the better-known acupuncture, acupressure utilizes similar surface points that represent reflections of visceral changes. Traditional Oriental concept meridians align the specific point locations. Generally, one or two points are treated at any given time and the technique generally involves the application of pressure as well as circular motions.

Injured in a horse-riding accident as a young girl and treated by an osteopathic practitioner, Ida Rolf developed the eponymous system, Rolfing (Burton Goldberg Group 1994). She proposed utilizing deeply applied pressure on regions of the body as the tool to re-establish symmetry and more normal function. The actual force of deeply applied pressure used in this modality exceeds that which is commonly applied in inhibition. Some initial discomfort to the patient usually results. There is a great deal of emphasis placed on approximating ideal symmetry and alignment. Modifications to this basic theme were made by followers of Rolf, and integrated into other modalities involving movement patterns (Hellerwork, Aston-patterning).

One of the oldest forms of manual therapy, shiatsu, usually involves relatively heavier pressures applied for short intervals. Increases in ‘the circulation of vital energy’ (Schultz 1976) are reflected by a reduction of the tissue tension. The amount of force, especially in the hands of a traditional practitioner, is intense and brief (10 lb for 10 seconds), as opposed to the lower, steady and unrelenting force used in inhibition. Specific conditions dictate the sequencing of points based on energy flows throughout the body. Some points are adjacent, and others are quite distant to the primary location.

Reflexology correlates treatment points with certain visceral organs that are hypothesized as reflecting onto resonant areas located on the hands, feet and ears. In theory, the name has more to do with the functional contribution to the integrity or energy component of the organ than to the actual physical structure.