Ligaments and tendons are key components to the structure of a human shoulder. Both function as connective tissue; ligaments adhere bones to each other, while tendons attach muscle to bone. Both ligaments and tendons play roles in the mechanics and movement of the shoulder. Lending flexibility to the joint, they allow for a wide range of motion. The tendons, along with muscle, form the outermost layer of the shoulder's structure (beneath the skin), while the ligaments lie one layer deeper.
Joining two bones together, ligaments are an important structural component of the shoulder. The ligaments of the shoulder lie within the joint capsule and are categorized by location as anterior (located in front), posterior (located behind), and inferior (found at the bottom).
The ligaments in the shoulder fall into three different categories, one being the Acromioclavicular ligaments. Within this group lies the Superior and Inferior Acromioclavicular and Coracoclavicular ligaments. The Coracoclavicular ligaments are made up of two distinctively separate ligaments: the Conoid and Trapezoid ligaments. These, as well as the Superior and Inferior Acromioclavicular ligaments, simultaneously work in conjunction with the Acromioclavicular Joint in order to stabilize the clavicle. The Coracoacromial ligament is found in the same general location and also aids in the general stability of the shoulder.
The second group of ligaments in the shoulder is the Sternoclavicular ligaments, surrounding the Sternoclavicular Joint. This includes the Capsular, Sternoclavicular, and Inter- and Costo- Clavicular ligaments. The Capsular ligaments surround the joint capsule of the shoulder, fastening the bones of the joint capsule into place. It is located around the Rotator Cuff. The Sternoclavicular ligaments, both anterior and posterior, are connected to the clavicle. The Inter- and Costo- Clavicular ligaments also attach to the clavicle.
The Glenohumeral ligaments make up the third and final group. The Glenohumeral ligaments are located in proximity of the Glenohumeral Joint, and are used as stabilizers. The Capsular, Coracohumeral, and Transverse Humeral ligaments also fall into this category.
Tendons are essential to the structure of the shoulder, ensuring the attachment of muscle to bone. There are five main tendons located in the shoulder joint.
The first is the Biceps Brachii tendon, informally known as the Biceps Long Head tendon. This tendon attaches the Biceps Brachii muscle to the scapula, or shoulder blade. The Biceps Brachii tendon is found directly below the Rotator Cuff. The muscle itself is located in the upper arm and is responsible for mobility of the elbow.
The remaining shoulder tendons lie in connection with the Rotator Cuff Muscles. These include the Infraspinatous, Subscapularis, Supraspinatous, and Teres Minor tendons. These tendons are all located within the Rotator Cuff and connect to their specific muscles. (The Infraspinatous tendon works with the Infraspinatous muscle; the Subscapularis tendon connects to the Subscapularis muscle, etc.)