Trigger points within muscles of the head, neck, and shoulders can cause headache by themselves, and this type of condition is often called myofascial pain. In addition, trigger points can be present in patients with Migraine, tension-type, post-traumatic, and other headache disorders, and can be worsening or perpetuating factors for the underlying headache condition.
A trigger point injection is a procedure where a medication, usually a local anesthetic, is injected into the painful muscle to provide relief. The pain relief should be experienced not only in the affected muscle, but in the area of referred pain as well. Patients that have specific trigger points that can be elicited with palpation (a firm touch) may experience the most relief from injections. They may be very helpful for immediate relief for severe pain in patients with an individual headache or Migraine attack, or can help treat an overall worsening of head pain in patients with chronic headache disorders who are having an exacerbation.
In the trigger point procedure, a health care provider inserts a small needle into the patient’s specific area of pain (trigger point) in a muscle. The injection usually contains only a local anesthetic, but occasionally may contain a steroid medication. This procedure can be performed in a doctor’s office and does not require sedation. The patient is positioned sitting or lying down. Your doctor will first palpate and identify the painful areas within a muscle. After identifying such trigger points, your doctor will inject those areas. Depending on how many trigger points are identified, more than one injection may be required.
Read the full article here: http://www.achenet.org/resources/the_basics_of_trigger_point_injections_for_headache_and_migraine/