The supraspinatous muscle is one of the four muscles of the rotator cuff, and the most common cause of shoulder tendonitis.
The Infraspinatous Muscle
The infraspinatus muscle is a thick triangular muscle and the main function of this muscle is to externally rotate the arm and stabilize the shoulder joint.
A condition characterized by stiffness and pain in the shoulder joint.
Typically develops slowly in three stages: painful stage, frozen stage, and thawing stage. Each of these stages can last a number of months. For some people, pain gets worse during the night, while sometimes disrupting normal sleep patterns.
Painful stage: In this stage, pain occurs with any movement of the shoulder. The shoulder’s range of motion starts to become limited.
Frozen stage: Pain may begin to diminish during this stage. Although, the shoulder becomes stiffer, and range of motion decreases noticeably.
Thawing stage: In this stage, range of motion in shoulders begins to improve.
Frozen shoulder is more likely to occur in people who have recently experienced prolonged immobilization of their shoulder, such as after surgery or an arm fracture. Diabetics are also at risk with this condition due to an autoimmune basis.
The Biceps Muscle Group
A two headed muscle located on the upper arm. Both muscles arise on the scapula and join to for a single muscle belly which is attached to the upper forearm.
Pain and soreness
People who weight train or body build may work or stain the bicep muscle too hard, while using poor form.
The Acromial-Clavicular Joint
The acromioclavicular joint is located at the top of the shoulder where the acromion process and the clavicle meet to form a joint.
AC joint separation or arthritis usually induces significant pain.
In most cases of AC joints injuries occur in bicycle wrecks, contact sports, and car accidents and most commonly occur in active or athletic young adults.