The Teres major muscle is located at the back of the armpit. It originates on the posterior aspect of the inferior angle of the scapula, and inserts and inserts on the medial lip of the intertubercular sulcus of the humerus. It’s main function is to assist adduction, internal rotation, and extension of the arm. This muscle only becomes active when there is resistance added to these movements. Trigger point pain from this muscle will cause pain to be felt deep into the posterior shoulder and down the back of the arm.
The Subclavius muscle is a small muscle on the underside of the clavicle. It originates on the first rib and it’s cartilage, and inserts on the inferior clavicle. It’s main function is to assist in protraction of the shoulder. This muscle is often shortened and tight from poor rounded shoulder posture. When trigger points form in this muscle they can refer pain into the anterior shoulder and down the radial part of the arm. Pain can also be referred into the thumb and first two fingers.
The sternalis muscle is a little known muscle located at the sternum. This muscle seems to be vestigial in that it doesn’t have a known function. In originates on the superior portion of the sternum and the upper part of the pectoralis muscle. It’s insertion is the cartilage of ribs 3-7, or sometimes the sheath of the rectus abdominis, or the lower part of pectoralis major. Even though this muscle doesn’t seem to have a purpose anymore it can still harbour trigger points. These points will cause pain to be felt intensely deep in the sternum, with spillover pain radiating down the inside of the arm.
The supraspinatus muscle is one of the muscles that makes up your rotator cuff. It attaches from the scapula to the humerus. It functions mainly to laterally rotate the arm as well as stabilize the shoulder joint. It also assists in abduction of the arm. This muscle can often harbour stubborn trigger points. These points refer pain into the shoulder, down the arm, into the elbow, and even into the forearm if irritated enough. These points can be effectively treated with trigger point massage therapy.
The triceps muscle is the main extensor of the elbow. It is the muscle in the back part of the arm and travels from the shoulder to the elbow. Trigger points in this muscle will cause pain when trying to straighten the elbow. Tricep trigger points refer pain into both the inside and outside of the elbow and are thus a common cause of both tennis and golfers elbow.