Thumb Pain and the Brachialis Muscle
By David Kent
Thumb Pain and the Brachialis Muscle
By David Kent
While I was lecturing at the Florida State Massage Therapy Association convention, some therapists asked about the causes of pain on the dorsal side of the base of the thumb (carpometacarpal joint) and the adjacent web space between the thumb and finger. While there are many reasons for pain in this region, this article will discuss the role of referred pain from trigger points in the brachialis muscle and methods for treating it with massage.
Anatomy: The brachialis muscle lies deep to the biceps brachii muscle. It attaches above the elbow, proximally, on the lower half of the anterior surface of the humerus. Just below the elbow, distally, it attaches on the coronoid process of the ulna. (Photo 1)
Function: The brachialis flexes the elbow and works synergistically with the biceps brachii and the brachioradialis muscles. The antagonist to brachialis is the triceps brachii. The movement created by the contraction of the brachialis muscle is determined by which attachment is fixed and which attachment moves. When the humerus is in a fixed position and the brachialis muscle contracts, such as during a bicep curl, the forearm moves toward the humerus. When the forearm or distal attachment of the brachialis muscle is fixed, such as during a pull-up exercise, the brachialis moves the humerus toward the forearm.
Referred Pain: Trigger points in the distal region of the brachialis produce "referred pain [that] is felt in the base of the thumb at rest and often with the use of the thumb. Diffuse soreness of the thumb is characteristic of its referred tenderness."1 (Photo 1)
Nerve Entrapment: The brachialis muscle can entrap the superficial sensory branch of the radial nerve, which is a cutaneous-monitoring nerve. When entrapment occurs, it can produce dysesthesia on the dorsum of the thumb. Dysesthesia is an impairment that produces sensitivity to touch, tingling and numbness. Additionally, the coracobrachialis muscle can entrap the musculocutaneous nerve that innervates the brachialis.
Perpetuating Factors: Trigger points can form and remain in the brachialis due to elbow flexion movements that overstress the muscle and/or require the muscle to remain in a flexed position for an extended period of time. Some examples include holding a child, lifting heavy tools, carrying groceries or boxes, and playing an instrument such as a violin or guitar. "Related trigger points are frequently found in the brachioradialis, supinator or the adductor pollisis."1
Precautions: Integrate muscle testing to identify each muscle, as well as to avoid treating neurovascular structures located on the medial side of the arm. Be cautious of the brachial artery and the median, musculocutaneous and ulnar nerves. These are positioned, on the medial side of the arm, between the anterior compartment containing the biceps, brachialis and coracobrachialis and the posterior compartment containing the triceps.
Pressure: Check in with the client frequently to determine if treatment pressure is appropriate and look for warning signs of too much pressure, such as muscle tightening, teeth clenching or pulling away. Additionally, if the tenderness in the area of treatment and/or the intensity of the referred pain does not ease up within eight to 12 seconds of holding static pressure on the trigger point, leave the area and return later, using less pressure.
Step 1 - Positioning: Place the client in the supine position with the elbow passively flexed between 30 and 45 degrees and the forearm appropriately supported. Stand at the level of the client's abdomen, facing their head. This position shortens the brachialis and biceps, and will allow you to displace the superficial biceps medially and laterally so the deep brachialis can be thoroughly treated.
Step 2 - Ulna Attachment: The attachment of the brachialis on the coronoid process of the ulna is approximately one inch distal to the crease of the elbow (Photo 1) on the pinkie side of the forearm. To treat this attachment, supinate the client's hand, with the palm facing upward. Apply friction integrating with fiber and then cross-fiber movements on the attachment (Photo 2).
Step 3 - Humeral Attachment (Lateral Side): Apply lubrication to treat the large attachment of the brachialis on the humerus from the lateral and medial side; muscle-test the biceps to determine its location. Treat the lateral aspect by using your non-treating hand to move the biceps medially, while the other hand treats the lateral aspect of brachialis on the humerus. Apply treatment at a 45-degree angle against the humerus while gliding distal to proximal, stopping just above the level of the deltoid tuberosity (Photo 3).
Step 4 - Humeral Attachment (Medial Side): Next, treat the medial attachment on the humerus. Use the non-treating hand to move the biceps laterally, while the other hand treats the medial aspect of brachialis on the humerus. Apply treatment at a 45-degree angle against the humerus while gliding distal to proximal, stopping just above the level of the deltoid tuberosity (Photo 4).
Step 5 - Muscle Belly: Face the pads of your thumbs toward each other with one thumb on the medial side and the other on the lateral side of the brachialis muscle, deep to the biceps, at the level of the elbow. Use your fingers to cup the arm while they make contact with the triceps muscle (Photo 5). Glide distal to proximal.
Clients will typically seek your services when pain begins affecting their activities of daily living. Educate every client on the causes of their muscular pain, treatment options you provide and proactive self-care steps that they can use outside of the treatment room. Advise them that pain is a symptom and that it is important to address the cause. Below are some suggested methods of assessment and client education.
We all know the saying, "a picture is worth a thousand words." Postural-analysis photos provide visual documentation of a client's posture, showing which muscles are shortened and which are overlengthened. The better a client understands the relationship of their poor posture, trigger points and pain, the more likely they will be to follow through with a recommended treatment plan. Clients benefit by knowing that one reason trigger points form is due to the stress caused by poor posture.
Trigger-point charts and other types of charts help educate clients about referred pain patterns. Some trigger-point charts show which muscles refer pain to specific regions of the body, like the base of the thumb in this case. This information is also helpful to developing and implementing an effective treatment plan.
Review the advantages of proper ergonomics and instruct your client on the ways they can incorporate ergonomics into daily activities. Teach clients stretching exercises that will help prevent their symptoms from returning.
If you use topical analgesics in your sessions, educate your clients on how to use them to control their discomfort between treatments. Selling topical analgesics will provide you with additional income, as well.
Remember that a client's pain is typically a symptom and its origin is often in an area other than the region of the pain. Your clients appreciate every bit of knowledge you share. Give them the knowledge to make informed decisions about their care.
I wish you the greatest of successes in the treatment room.
- Simons DG, Travell JG. Myofascial Pain and Dysfunction, the Trigger Point Manual. Vol. 1 Upper Body, 2nd ed. Baltimore: Lippincott, Williams and Wilkins, 1999, p 661.