Trigger Point Injection

Trigger points are small tender nodes of degenerated muscle tissue that may be dormant producing no symptoms until unpredictable motion or pressure, such as extended jaw opening, causes severe pain and muscle spasm. Trigger points develop after prolonged spasm or muscle tension, and they can be the sequelae of chronic or acute trauma. Endocrine imbalance may produce generalized muscle pain and trigger points.

The most recent works on trigger points have been done by Dr. Hans Kraus and Dr. Janet Travell. However, historically, trigger points were reported in literature as far back as 1843.

Pain Patterns of Trigger Points

The distribution of trigger points often is typical, however, trigger points may be found in any skeletal muscle. The following are typical trigger point and radiation areas:

  1. Head : Temporal, masseter and occipital muscles.

  2. Neck : Sternocleidomastoid (often causing dizziness), scalene and posterior neck muscles.

  3. Upper Back : Upper trapezius radiating to the neck, head or shoulder; levator scapulae radiating to the head and shoulder.

  4. Upper Extremities: Pectoral muscles with pain radiating toward the arm (can simulate cardiac pain if the trigger point is on the left); deltoid muscles with pain radiating to the arm (often associates with upper back and neck pain).

Trigger points are extremely common. Because they can be successfully treated, it is imperative to recognize their existence even though their pathophysiologic basis needs further exploration, research and clinical data.


Treatment of trigger points has been done with deep point massage, dry needling, injection of saline solution or the injection of “Caine” anesthetics. To be treated by injection, the patient should be in a comfortable position with the muscle fully relaxed. This may require the application of moist heat to the muscle or muscles to be injected prior to cleansing the areas. After identifying the trigger point, it is marked with an indelible point. The trigger point is then injected with the anesthetic.