The supraspinatus muscle makes up part of the rotator cuff. It is responsible for assisting in shoulder abduction as well lateral rotation and stabilizing the shoulder joint. This muscle is often overloaded in labourers and tradesman who have to do a lot of overhead work. Athletes who do a lot of throwing movements will also frequently have Tigger point in this muscle. These trigger points will cause pain to be felt into the shoulder and down the arm, as well as stiffness and weakness.
The Trapezius muscle is a large diamond shaped muscle located in the back and neck. It is responsible for for a number of shoulder and neck movements and helps maintain proper posture. This muscle is probably the most common muscle that I work on in the clinic. It is frequently strained and develops trigger points easily. The trigger points in the upper portion of this muscle are the most common to be found in the body. Trigger points will refer pain into the upper back, neck, shoulder, and even into the head and temple causing headaches. Chronic trigger points in this muscle are also a frequent cause of a stiff neck.
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 Teres minor muscle is on of the rotator cuff muscles. It originates on the lateral border of the scapula, and inserts on the inferior facet of the greater tubercle of the humerus. This muscle assists with external rotation of the humerus as well as shoulder stability. This muscle is often damaged with a shoulder injury. Trigger points will refer into the posterior deltoid 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.