We now search for trigger points in the specific, previously identified muscles. The examination is performed in neutral position-muscles that are not involved should be neither approximated nor stretched. The finger tip (Fig. 15.1a-c) is used to palpate the tissue, perpendicular to the longitudinal axis in superficial muscles (shallow palpation). When you encounter a band-like area with obviously elevated tension, you have found the hypertonic muscle spindle with the anticipated trigger point. Within the spindle, you now look for the tenderest spot—the trigger point is identified. Through pressure on this point, you can clearly induce localized and, with sustained pressure, referred pain. The localized pain can arise so strongly, sharply, and spontaneously that patients react with a "jump" sign: they twitch, loudly voice pain, or pull the muscle away from the therapist's reach.
Fig. 15.1 a-f a-c Cross-section that shows the two-dimensional palpation of a tensed muscle fiber bundle (black ring) and its trigger point. Two-dimensional palpation is used with muscles that are only accessible from one side, such as the infraspinatus, a At the beginning of palpation, the skin is pushed away, b The finger tip glides over the muscle fiber; a tensed fiber bundle can be recognized from its rope-like texture, c The skin is lastly pushed to the other side. The same movement is called fast palpation when it is performed more quickly, d-f Cross-section illustrating pinching grip palpation of a tensed muscle fiber bundle (black ring) at the trigger point. Pinching grip palpation is suited for muscles that can be gripped with the fingers. This applies, for example, to the sternocleidomastoid (SCM) muscles, the pectoralis major, and the la-tissimus dorsi. d Muscle fibers in the pinching grip between thumb and fingers, e The tightness of the tensed fiber bundle is clearly detectable when it is rolled around between the fingers. By changing the angle of the finger end joints, a rocking movement is created that allows for better perception of details, f The palpable edge of the tensed fiber bundle clearly stands out when it escapes between the finger tips. Often, a local twitch reaction occurs simultaneously
In deeper-lying muscles, identifying the hypertonic muscle spindle can be complicated or made impossible by the over-laying structures. Here, we apply direct pressure palpation in the deep tissue to find trigger points.
In the case of muscles that can be grasped between two fingers (such as the trapezius), the pinching grip can be useful (Fig. 15.1d-f): a section of the muscle belly is rolled back and forth between thumb and index finger to search for the hypertonic muscle spindle. Within the spindle, the same grip is used to find the trigger point.
When palpating a muscle spindle in the vicinity of a trigger point or when directly palpating a trigger point (Fig. 15.2a), we can often observe a temporary contraction of the muscle fibers within the muscle spindle. The therapist perceives such a muscle reaction clearly as a visible or palpable twitch (Fig. 15.2b). This type of locally limited muscle contraction is par ticularly pronounced when palpating across the longitudinal axis of the spindle. Here, the therapist lets the spindle snap back like a guitar string after having stretched it crosswise—as if plucking the guitar string. This localized twitch reaction is a characteristic of trigger points.
To determine the location of a trigger point with ultimate certainty, palpation is repeated: an active trigger point presents with reproducible results.
Pain that originates in the muscles has to be distinguished from neurological, rheumatic, tumorous, psychogenic, inflammatory, and vascular pain.
Muscle-induced pain comes and goes typically with the activation of the affected muscle by moving or assuming straining positions.
Fig. 15.2a, b Illustration of a tensed fiber bundle, myofascial trigger points, and a local twitch reaction in a cross-section through the muscle, a Palpation of a tensed fiber bundle (straight lines) surrounded by slack, relaxed muscle fibers (wavy lines). The density of dots reflects the degree of pressure sensitivity in the tensed fiber bundle. The trigger point is the most pressure-sensitive place in the fiber bundle, b By rolling the fiber bundle quickly below the finger tip at the location of the trigger point (fast palpation), a local twitch reaction is often caused, which manifests most clearly as the main movement between the trigger point and the attachment of the muscle fibers.
Tensed (palpable) muscle fiber bundle
Tensed (palpable) muscle fiber bundle
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