David S. Klein, M.D.
Non-Cardiac Chest Wall Pain
Common Causes and Treatment
A common cause of numbness and tingling in the arm is actually caused by an injury to a muscle in the anterior chest wall. An article that I published in MD News is copied to the following link: Atypical Chest Pain
Pectoralis Minor Syndrome
The patient complaining with non-cardiac chest pain is a commonly encountered in clinical practice. After thoroughly eliminating the life-threatening cardiac possibilities, the clinician is often left with the patient complaining of symptoms originating or referred to the chest. One of the most commonly encountered musculoskeletal disorders that resemble cardiac pain is Pectoralis Minor Syndrome.
Pectoralis Minor Muscle Syndrome (PMMS) is a common clinical entity that results from spasm of the Pectoralis Minor Muscle at the attachment on the Coronoid Process of the Scapula. (Fig. 1). Chronic spasm can result in inflammation & swelling of the tendinous attachment, and this, in turn, results in irritation of the Brachial Plexus as it passes under the Clavicle. The combination of muscle-related, dull, cramping pain with dysaesthesias, typically to the forearm, thumb, index and middle fingers can be frighteningly similar to symptoms commonly encountered with common angina. Physical examination is often all that is necessary to identify PMMS as the cause of complaints.
The clinical picture of PMMS is as follows:
- Stabbing, intermittent pain
- Knife-like-difficult to identify precise location
- Sometimes worse with certain movements
- Pain with reaching, writing, as well as with many other ordinary, daily activities
- Pain in the anterior chest and arm
- Aching under the breast
- Feels as if it were a heart attack
- Often confused with angina or heart attack
- Often hurts with breathing in, cough, and with tight-fitting garments (bra-strap)
- Inconsistent ‘numbness’ or tingling in the arm, pain up the neck, and behind the shoulder blade
- Muscular spasm on the side of injury
- Referred pain to the shoulder blade and thoracic spine sometimes occurs
- Vasomotor symptoms present in a minority of patients
Essentially, PMMS is a cause of mild Thoracic Outlet Syndrome. The degree of vasomotor instability seems to be dependent upon the degree of inflammation and swelling present. (Fig 3).
Coronoid Process of the Scapulae. Site of attachment of the PMM. Directly posterior & inferior lies the Brachial Plexus. It is easy to see how movement of the Scapula will result in neurological symptoms, and it is easy to see how swelling in this area can result in dysaesthesias to the upper extremity.
Figure 3.
Figure 1. Pectoralis Minor Muscle Attachment on the Coronoid Process of the (right) Scapula.
The Levator Scapulae is often tender, and may demonstrate mild spasm.
Fig. 2. Referred Pain Pattern
Treatment consists of a combination of mild oral muscle relaxants that are best given at bedtime. Anti-inflammatories are of minimal benefit in this situation. Injection of a minimal amount of a steroidal anti-inflammatory combined with a low volume of local anesthetic will relieve the symptoms in a matter of seconds, and the effective duration of action can be weeks to months. It may take 2 or three injections to accomplish control of this problem. Prolonged analgesia can be expected if Sarapin®, a mild C-fiber neurolytic is added to the injectate. Physical therapy is sometimes necessary, and the patient will almost always benefit from self-massage of the PMM. Acupressure techniques seem to be the most effective approach.
The injection technique is not a complicated endeavor, but careful avoidance of the apex of the lung as well as avoidance of the Brachial Plexus is advised. Further, the needle placement is best-accomplished medial and inferior to the fibrous portion of the PMM. If present, breast implants must be retracted and the needle advanced tangentially to the PMM fascia, 3-4 cm proximal to the Coronoid attachment.
David S. Klein, MD, FACA, FACPM, FACMIMS
Director, Pain Center of Orlando
www.suffernomore.com