Fascia is made up of collagen, elastin and a polysaccharide gel complex forming a three-dimensional cobweb covering the body’s tissues (Fig. 8.1). It has three continuous layers: (1) a superficial layer under the skin, (2) a deeper, ‘ensheathing’ layer which covers muscles, bone, nerves, blood vessels, and organs right down to the cellular level, and (3) the deepest layer, which connects with the dura of the central nervous system. The muscle is intimately connected with fascia, hence the term ‘myofascia’. Fascia functions to support our body, absorb shock, enhance cellular respiration and metabolism, and assist with fluid and lymphatic flow.

Fig. 8.1 The fascial ‘cobweb’ is made up of collagen, elastin and a polysaccharide gel.

Malfunction of the fascial system can occur from poor or prolonged postures causing asymmetrical loading, trauma, and repetitive strain. Changes in fascial mobility occur when the fascia is bound down or restricted in areas. Due to its continuous nature it causes a global effect by pulling on the body at points distal to the primary site of dysfunction (see Chs 2, 3). This stimulates nociceptors, causing pain, and reduces the body’s ability to absorb and distribute forces that may be incurred with sudden trauma or repetitive loading. It can also alter an individual’s biomechanics and influence his or her posture and dynamic balance. Injuries to the fascial system do not result in typical nerve root or trigger point referral patterns and standard imaging tests (i.e. X-rays, CT scans, MRI, etc.) will not pick up fascial dysfunction, so typically these malfunctions usually go undiagnosed.

Therapeutic interventions can alter our fascia by: stretching its elastic component, shearing the cross-links that may have developed, changing the viscosity of the ground substance by increasing the production of hyaluronic acid, and increasing its mobility and fluid flow. Techniques which have a direct affect on fascia include myofascial release, visceral manipulation, cranial osteopathy, craniosacral therapy, Bowen therapy, acupuncture and IMS.

Ligaments

Ligaments consist of fibrous collagen tissue that connects one bone to another. Ligaments differ from other connective tissues in that their fibrils are organized in a predominantly parallel fashion. They are vascularized, have C nerve fibres which transmit pain signals, and contain mechanoreceptors. They are built to share load so that no single ligament in a joint takes the entire load at any one time. Since ligaments have elastic properties only under tension, the amount of load a ligament can adapt to depends on the speed of load application. The lengthening of a ligament up to its ‘yield point’ is reversible. Stretching a ligament beyond the yield point will cause tearing and irreversible lengthening.

When ligaments heal, fibrous scar tissue forms. This fills in the tear and creates a longer, weaker and less extensible structure. Ligaments respond to joint mobilization and deep transverse frictions as these help with the alignment of the collagen fibres, break up fibrous tissue deposited in the wrong direction (cross-links), stimulate a release of endogenous opioids for pain relief, and increase inter-fibre lubrication as the proteoglycans bind with water.

Tendons

Tendons are bands of fibrous connective tissue that connect muscle to bone. They are mostly made up of collagen but also have some elastin (~ 2%) which gives them the ability to store and recover energy in movements, similar to a spring (Järvinen et al. 1997). Their primary function is to work with muscles to exert a pulling force causing bone movement.

Tendon length will vary among individuals; there seems to be a genetical predisposition. It does not tend to lengthen or shorten in response to injury or environmental demands, thus body imbalances are believed to be due to changes in other structures such as muscles and fascia (Curwin 1994; Kvist 2002).

Contractile tissue

Muscles are comprised of bundles of fasciculi that, in turn, are made up of bundles of muscle fibres (Fig. 8.2; the latter) themselves are formed from bundles of myofilaments (myofibrils) composed of two main proteins, actin and myosin: the contractile elements of the muscle. Each layer of a bundle is separated by fascial tissue that helps transmit forces from muscle to tendon and bone.

Fig. 8.2 Muscle belly split into its various component parts.

Muscles are always in some degree of contraction known as ‘muscle tone’. The tone of a muscle is determined by impulses coming from the spinal cord which depend on the amount of alpha activity in nerves. This activity is influenced by one’s psychological state, neurochemistry, and feedback from receptors within the muscles. There are two types of muscle receptors:

1. the muscle spindle, which provides feedback regarding the length of the extrafusal fibres, and

2. the Golgi tendon organ, which is located in the tendomuscular junction and gives information about muscle tension.

These muscle receptor mechanisms work in opposite ways to help control muscle tone. Muscle spindles use a positive feedback cycle to continuously monitor muscle length and rate of length change by stimulating the anterior horn cells in the spinal cord which, in turn, provides the stimuli for increasing muscle tone. Conversely, Golgi tendon organs use a negative feedback system to protect the muscle from sudden forces and tearing. They excite an inhibitory interneuron in the spinal cord to suppress the alpha motor neuron and allow the muscle to relax. This is believed to be the mechanism behind trigger point and acupressure release techniques.

When joint receptors are damaged by injury, the damage will alter the body’s position sense – or proprioception – and also affects muscle tone. When the antagonist muscles are unable to relax or are pathologically shortened, the normal range of motion is restricted which will again influence muscle tone. Certain muscles are over-active and tend to shorten, while others are underactive and tend to lengthening or atrophy. These are factors that contribute to the ‘malalignment syndrome’, where the pattern of muscular ‘facilitation’/’inhibition’ and strength is noted to be asymmetrical with an ‘upslip’ and ‘rotational malalignment’ (see Boxes 8.1, 8.2 for an example of muscles which become shortened or lengthened).

Box 8.1 Muscles that commonly become overactive and shorten

Upper lumbar extensors

Pectoralis major and minor

Upper trapezius

Sternocleidomastoid

Box 8.2 Muscles that are commonly ‘underactive’ and lengthen

Vastus medialis

Transversus abdominis

Oblique abdominals

Middle and lower trapezius

Serratus anterior

Gluteus medius and minimus

Longus capitus

Tibialis posterior

With muscle imbalances or the ‘malalignment syndrome’ there is a higher tendency for injury as there is less flexibility, strength and endurance in certain structures. Treatment techniques that affect muscle tone in particular include joint mobilization, muscle energy techniques, myofascial release, and counter-strain technique (discussed below).

Neural tissue

The nervous system is a continuous network of specialized cells that communicates information from the body to the brain and vice versa (Fig. 8.3). These messages or electrical signals, including perception and movement, are responsible for interaction with the environment. The nervous system is composed of neurons and glial cells which together generate electrical impulses that travel between our central nervous system (CNS) and peripheral nervous system (PNS). Generally, our CNS processes information in our spinal cord and brain and then sends signals back to our PNS where sensory, motor, and autonomic nerves leave the spinal cord to innervate our muscles, articular structures, organs, and glands. The neurons communicate with each other via electrochemical signals or neurotransmitters to transmit impulses from one neuron to the next.

Fig. 8.3 The nervous system is continuous from the CNS to the peripheral nerves.

The nervous system is continuous from the CNS to the peripheral nerves. Stress placed on one part of the system can be transmitted to other parts during movement (Breig 1978). In normal conditions, pain does not occur with movement or normal compression. However, the neural tissue can produce adverse symptoms with even minor stimuli if irritation due to a mechanical (compression or tension) and/or chemical (inflammation or ischemia) cause is present. Dahlin & Mclean (1986) showed that:

1. lack of oxygen secondary to compression will cause increased intraneural pressure that can take several weeks to reverse

2. separation of nerve fibres occurs with sustained pressure

Common sites of injury include soft tissue, osseous tunnels (i.e. a spinal nerve exiting through an intervertebral foramen), nerve branches, and tension points (C6, T6, L4, posterior knee, and anterior elbow) where nervous tissues are relatively fixed.

Neural tissue has some elastic properties and can tolerate up to 20% elongation. If compression and traction occur together, only 15% elongation is required to stimulate the nociceptors and produce pain (Sunderland 1978). In addition, neural tension can cause venous stasis and stop intraneural blood flow at approximately 15% elongation (Ogata & Naito 1986; Rydevik et al. 1981). If the nerve’s distal axon shows evidence of degeneration or is injured, it will be more susceptible to mechanical and chemical irritants. Both compression and elongation contribute to the body’s physiological response by causing inflammation (Dahlin & Mclean, 1986) and/or ischemia (Rydevik et al. 1981).

Treatment of the nervous system is geared to restoring proper neural mobility, reducing chemical irritation, and minimizing any mechanical pressure or tension. David Butler (2000) advocated that mobilization of the nervous system can have a mechanical effect on the vascular system by dispersing intraneural oedema. Altering the mechanical restraints on the axoplasm and improving circulation will increase the energy available for axonal transport. Mobilization may also help the axons to regenerate by allowing better contact guidance (Lundborg 1988), and causing micro-trauma that may stimulate neurite promoting factors (Heumann et al. 1987). When there is rapid improvement of the nerve, it may be due to increased blood supply or changes in availability of CSF as nerves and nerve roots get at least half their metabolic requirements from these fluids.

Articular structures

The main components of the articular structures (the body’s joints) are bones, cartilage, synovial fluid, and joint receptors. While these components are predominantly responsible for allowing movement, they have a direct influence on posture and muscle length-tension relationships which can lead to malalignment and development of the ‘malalignment syndrome’.

Type 3 receptors are found in ligaments near bony attachments but not in the longitudinal ligaments of the spine (Fig. 3.68). These receptors are stimulated by extremes of dynamic movement when the ligaments are stressed. They are dynamic receptors that are inactive at rest, have a high threshold and are slow to adapt. Clinically, these receptors can be stimulated by providing a strong, prolonged distraction on a joint to help reduce tone in the surrounding muscles.

Type 4 receptors are a plexus of free nerve endings found in fibrous capsules, articular fat pads, ligaments, the periosteum, and the walls of blood vessels. They are pain receptors and are stimulated by mechanical and chemical factors. While they have a high threshold, they are a protective mechanism and are, thus, non-adapting and inactive at rest. Stimulation of Type 4 receptors will produce a gamma withdrawal reflex in an attempt to remove the joint from possible or further injury.

Visceral tissue

Visceral tissue is specialized tissue unique to each organ/viscera in the body, all of which are encapsulated in a fascial covering. With the support of fascia and specialized ligaments, viscera and organs are suspended in the body, decreasing gravitational strain on these important structures (Fig. 4.43). Posture, alignment of the bones and muscle balance all play a role in ensuring the proper force through the fascia required to maintain the position of the organs and viscera. When the ‘malalignment syndrome’ is present, fascial pull through the body can affect organ position and cause stress to affect its function. A detailed explanation of viscera and organ tissue is beyond the scope of this book. It is suggested the reader refer to more specialized anatomy and physiology texts.