The Shoulder Joint Muscles of the Shoulder Joint

The Shoulder Joint

Muscles of the Shoulder Joint Chapter 5

Anterior Shoulder Muscles • Coracobrachialis • Pectoralis Major • Subscapularis

Coracobrachialis • O: Coracoid process • I: Anteromedial surface of midshaft of humerus • Actions: – Flexion – Adduction of the shoulder – Horizontal Adduction

Pectoralis Major • Origin: – Medial two-thirds of clavicle – Sternum • Insertion: intertubercular groove • Actions – Upper fibers (Clavicular) • Internal rotation • Horizontal Adduction • Flexion • Adduction – Lower fibers (Sternal) • Internal Rotation • Horizontal adduction • Extension • Adduction

Subscapularis • O: Subscapular fossa • I: Lesser tubercle and crest of humerus • Actions: – Internal Rotation – Adduction – Extension • Stabilization • Anterior Rotator Cuff Muscle.

Superior Shoulder Muscles • Deltoid • Supraspinatus

Deltoid • Origin – Lateral 1/3 of clavicle (Anterior fibers) – Acromion process (Middle fibers) – Spine of scapula (Posterior fibers) • Insertion – deltoid tuberosity Actions Anterior – Abduction, Flexion, Horizontal adduction, & Internal rotation. Middle – Abduction Posterior – Abduction, Extension, Horizontal abduction, & External rotation

Supraspinatus • O: Supraspinous fossa • I: Greater tubercle • Action: – Abduction • Stabilization • Superior Rotator Cuff Muscle. • Most injuired rotator cuff muscle

Inferior Shoulder Muscles • Latissimus Dorsi • Teres Major

Latissimus Dorsi • O: Spinous process of lower 6 thorasic and all lumbar and sacral vertebrae; iliac crest • I: Intertubercular groove • Actions: – – Adduction Extension Internal Rotation Horizontal Abduction

Teres Major • O: Inferior angle of scapula • I: Intertubercular groove • Actions: – Extension – Adduction – Internal rotation • “Lats little helper”

Posterior Shoulder Muscles • Infraspinatus • Teres Minor

Infraspinatus • O: Infraspinous fossa • I: Greater tubercle • Actions: – External rotation – Horizontal abduction – Extension • Stabilization • Posterior Rotator Cuff Muscle • Second most commonly injured rotator cuff muscle

Teres Minor • O: Upper 2/3 of lateral border of scapula • I: Greater tubercle • Actions: – External rotation – Horizontal abduction – Extension • Stabilization • Posterior Rotator Cuff Muscle

Study guide • List the muscles for • Name the muscles Horizontal Adduction for Horizontal Abduction

Practice • List the muscles that do flexion of the shoulder • List the muscles that do extension of the shoulder

Practice • List the muscles that do adduction of the shoulder List the muscles that do abduction of the shoulder

Practice • List the muscles that do internal rotation of the shoulder • List the muscles that do external rotation of the shoulder

Name the muscle. Coracobrachialis Name the action Adduction of the shoulder

Name the muscle. Pectoralis Major

Name the muscle. Subscapularis Name the action Internal rotation of the shoulder

Name the muscle. Deltoid Name the action Abduction of shoulder

Name the muscle. Infraspinatus Name the action External rotation

Name the muscle. Name the action Teres Major Adduction of scapula

Name the muscle. Teres Minor Name the action if the humerus move directly to the posterior Extension of the shoulder

Name the muscle. Supraspinatus Name the action Abduction of the shoulder

Coracobrachialis Subscapularis Pect. Major Deltoid

Supraspinatus Teres Major Infraspinatus Teres Minor