Clavicle, Scapula, & Thorax

1. Clavicle, Scapula, & Thorax Jenna Erickson, Becca Goldstein, Sam McKeon, Alissa Migliore, & Stephanie Vicari

2. Types of Joints in Clavicle • Glenohumeral joint- also known as the shoulder joint, is a synovialball and socket joint and involves articulation between the glenoid fossa of the scapula (shoulder blade) and the head of the humerus (upper arm bone). It helps you move your shoulder forward and backward. It also enables your arm to rotate in a circular manner or move outward. The glenohumeral joint is composed of the socket on your shoulder blade (glenoid) and the "ball" at the top of your arm bone (the humerus). Uniquely, the ball of the upper arm bone is twice the size of the shoulder blade socket. • A false joint is formed where the shoulder blade glides against the thorax (the rib cage). This joint, called the scapulothoracic joint, is important because it requires that the muscles surrounding the shoulder blade work together to keep the socket lined up during shoulder movements.

3. Types of Joints in Clavicle (contd) • Sternoclavicular joint (SCJ)- is the connection of the sternum (breastbone) to the clavicle (collarbone). A freely moveable synovial joint links the upper extremity to the torso, with the sternoclavicular joint (SCJ) participating in all movements of the upper extremity. The SCJ is a saddle-type joint that provides free movement of the clavicle in nearly all planes. The ability to thrust the arm and shoulder forward requires sound function of the SCJ. • Acromioclavicular joint (ACJ)- is the gliding joint that is located between your shoulder blade (acromion) and your collar bone (clavicle). It is part of the mechanism that allows the shoulder to rise and fall (shrug), and to raise the arm above the head. It functions as a pivoting joint, although technically it is a gliding synovial joint

4. Articulation • 1.Acromioclavicular Joint • 1.Planar type joint between lateral portion of the clavicle and the acromion of the scapula. • 2.Sternoclavicular Joint • 1.Sellar joint between the medial end of the clavicle and the manubrium of the sternum. • 3. Glenohumeral ( Shoulder ) Joint • 1.Ball and socket articulation between head of humerus and glenoid cavity. • 2.Favors mobility over stability • 4.Scapulothoracic "Joint” • 1.Scapula suspended on rib cage by muscles • 1.highly mobile • 2.capula movements increases range of motion at the shoulder joint

5. Scapula • The scapula is suspended on the thoracic wall by muscle forming a "functional joint" called the scapulothoracic joint. These muscles act to stabilize and/ or to actively move the scapula. Active movements of the scapula help increase the range of motion of the shoulder joint. • Scapulothoracic Articulation • 1. Stability • 1.Dependent upon activity of extrinsic muscles • 2.Winged scapula • 2. Alignment • 1.Upwardly rotated and elevated position of scapula at rest • 1.action of trapezius muscle

6. Movements of the Scapula • 1.Elevation - moving the superior border of the scapula and the acromion in an upward direction. • 2.Depression - moving the superior border of the scapula and the acromion in an downward direction. • 3.Upward Rotation - Moving the scapula so that the glenoid cavity faces upward. • 1.Increased the ranges of motion during abduction and/or flexion of the shoulder. • 4.Downward Rotation - moving the scapula so that the glenoid cavity faces inferiorly. • 1.Increases range of motion during extension and / or adduction of the shoulder. • 5.Protraction ( Abduction) - moving the scapula away from the midline • 6.Retraction (Adduction) - moving the scapula toward the midline