Trapezius muscle is a broad triangular muscle at neck and upper back, one of the largest superficial muscles at the back. It attaches to the base of the skull and extends down to the neck, the upper back until mid-back; laterally it inserts to the shoulder blades. There are three functional regions to the muscle: the Upper, middle, and lower trapezius, and each region has its own function: upper region moves the shoulder blades and support the arms; the middle region retracts the shoulder blades, and the lower region rotates and depresses the shoulder blades.
Pain caused from this muscle may be on the top of the shoulder, neck, mid back and/or upper shoulder pain; pain at the back of the shoulder blade which could go down the inside of the arm to the ring and little fingers.
Latissimus dorsi is the largest flat muscle at the back. This muscle is involved in adducting the arms, extending the shoulders, and rotating shoulder joints medially. It also plays a role in extension and lateral flexion of the lumbar spine. The latissimus dorsi originated from the lumbodorsal fascia of the lower back, arising from the inferior thoracic and lumbar vertebrae, sacrum, iliac crest, and the four most inferior ribs, it runs laterally up through the back, inferior part of shoulder blades and insert on the humerus at the upper front of the upper arm. Tight latissimus dorsi and the trigger points on the muscles could be one of the causes of chronic mid back pain, shoulder pain, forearm pain, pain between shoulder blades, shoulder blades and pain in front of shoulder. The characteristic of pain is at lower shoulder blade and mid back and also the pain can go down the backside of the arm or the inner side of the arm and reach the hand and 4th and 5th fingers. Pain can be present at the front of the shoulder and to the side of the body just above the hip.
Rotator cuff comprises four muscles which are supraspinatus muscle, the infraspinatus muscle, teres minor muscle, and the subscapularis muscle. They all originate from the scapula and insert into humerus. They connect scapula to the head to humerus, stabilize shoulder joint and contribute to shoulder joint movement including abduction, internal rotation, and external rotation of the shoulder.
Rotator cuff disorder is one of the problems that cause shoulder pain. The main symptoms are pain around the shoulder and reduced shoulder joint movement. Acupuncture can help reduce the pain.
Teres major muscle
Teres major muscle is the muscle that connects shoulder blades to the upper arms. It starts from lower angle of the shoulder blade and ends at the upper arm in the front of the shoulder. The teres major muscle adducts the arm, extends the shoulder and rotates it inwardly. It also helps stabilize the humeral head. The pain caused in the teres major trigger is the back of your shoulder and also this pain can radiate to the front and side of the shoulder and down the backside of the arm. The trigger points for this muscle can be found at the lower angle of shoulder blades. Acupuncture can help release the pain.
Muscles connect the humerus (upper arm) to the scapula (shoulder blade)
There are muscles that connect the upper arm to the shoulder blades and help the movement of the shoulder. Do you know how many of them? There are seven muscles that connect the upper arm to the shoulder blades. They are coracobrachialis muscle, four rotator cuff muscles including infraspinatus, subscapularis, supraspinatus and teres minor muscles, teres major muscle and deltoid muscle. Overuse or injury to these muscles can cause shoulder and arm pain. Acupuncture can help release the pain.
The deltoid muscle is the big muscle on the shoulder which forms the rounded contour of the shoulder. It has three parts; the front or anterior, middle and back or posterior. The anterior fibers are involved in flexing the shoulder and internally rotating the arm. The posterior fibers are involved in extending the shoulder and externally rotating the arm. The lateral fibers are involved in shoulder abduction. Deltoid muscle strain is less common than rotator cuff muscles strain.
Pectoralis major and minor muscles and shoulder pain
The perctoralis major muscle is a muscle located at the chest. Underneath the pectoralis major is the pectoralis minor muscle- a small triangular muscle.
The pectoralis muscle originated from inner half of the clavicular bone, sternum as well as the cartilage of the sixth or seventh rib and the aponeurosis of the abdominal muscle. The muscle run laterally and insert into the upper humerus. It adducts the arm and rotates the shoulder inwardly, pull down the shoulder joint and elevated the arm in front of you. The muscle trigger points contribute to the shoulder pain and upper and inner side of the forearm.
Pectoralis minor originates from the third, fourth and fifth ribs and it runs upward and laterally and inserts to the surface of the coracoids process of the scapula. It pulls the shoulder blade downward, forward and inward towards the ribs, stabilizes the shoulder, prevents the shoulder blade from being pushed backwards. The trigger point of themuscle contributes to the pain in front of the shoulder, that could radiate to your chest and all the way down the inner arm.
Biceps and the shoulder, arm and elbow pain
In the upper arm, there is a muscle called biceps brachii or biceps. This muscle is two headed lies on the upper arm between the shoulder and the elbow. The two heads start from the scapular of the shoulder and join together to one muscle on the upper arm (humarus) and attach to the bones radius and ulnar in the front of the elbow. The biceps turn the arm outward, turn the palm upward, flex the elbow and flex the shoulder (bring the shoulder forward and upwards). The biceps can contribute to the pain on the front of the arm, the elbow and the shoulder. Also it contributes to the medial rotation of the shoulder.
The triceps brachii muscle or three headed muscle of the arm is the large muscle on the back of the upper limb. The three heads include long head, medial head and lateral head. The long head originates from the top of the scapula (the infraglenoid tubercle of the scapula). The medial head originates from the upper part of the limb (the groove of the radial nerve, the dorsal surface of the humerus, the medial intermuscular septum and the lateral intermuscular septum). The lateral head originates from the back of the upper limb (the dorsal surface of the humerus, lateral and proximal to the groove of the radial nerve, the greater tubercle down to the region of the lateral intermuscular septum. The three heads join together, form a tendon and attach to the elbow (the olecranon process of the ulna). The triceps extend the elbow and shoulder joint to straighten the elbow and move the arm backwards and also pull the arm towards the body. If the triceps contain trigger points, you can experience pain on the shoulder, arm, elbow or the pain can radiate to the forearm.