Interaction between Trigger Points and Joint Hypomobility: A Clinical Perspective.

The relationship between muscle trigger points (TrPs) and joint hypomobility is frequently recognized by clinicians. Among different manual therapies aimed at inactivating muscle TrPs, ischemic compression and spinal manipulation have shown moderately strong evidence for immediate pain relief. Reduction of joint mobility appears related to local muscles innervated from the segment, which suggests that muscle and joint impairments may be indivisible and related disorders in pain patients. Two clinical studies have investigated the relationship between the presence of muscle TrPs and joint hypomobility in patients with neck pain. Both studies reported that all patients exhibited segmental hypo-mobility at C3-C4 zygapophyseal joint and TrPs in the upper trapezius, sternocleidomastoid, or levator scapulae muscles. There are several theories that have discussed the relationship between TrP and joint hypomobility. First, increased tension of the taut muscular bands associated with a TrP and facilitation of motor activity can maintain displacement stress on the joint. Alternatively, it may be that the abnormal sensory input from the joint hypomobility may reflexively activate TrPs. It is also conceivable that TrPs provide a nociceptive barrage to the dorsal horn neurons and facilitate joint hypomobility. There is scientific evidence showing change in muscle sensitivity in muscle TrP after spinal manipulation, which suggests that clinicians should include treatment of joint hypomobility in the management of TrPs. Nevertheless, the order in which these muscle and joint impairments should be treated is not known and requires further investigation.