These are the focal tender points of the fatigued or injured muscles and tendons that can be injected to relieve pain.
Trigger points are ‘tension points’ in the painful muscle. In chronic cases, they are taut and even calcified. Experienced practitioner often describes a sensation of ‘crepitance’ when penetrating a trigger point with a needle due to tissue calcification.
Cortisone is sometimes added to local anesthetic as an anti-inflammatory but injection of cortisone into muscles can at times cause localized muscle atrophy.
Local anesthetic and the action of the tiny needle ‘trauma’ help to bring increased circulation to the dormant muscle. Local anesthetic, which blocks pain impulses also further helps by breaking the pain cycle.