| Question | Answer |
| What is the most important abductor of the shoulder? | Deltoid. |
| Which muscle resembles the Gluteals structurally? | Deltoid. |
| Which muscle, if discovered today, would be considered three independent muscles instead of one? | Deltoid. |
| Which muscle of the shoulder can be an antagonist to itself? | Deltoid. |
| What are the origins of the Deltoid muscle? | lateral third (1/3) of the clavicle
acromion process
scapular spine |
| What is the insertion of the Deltoid muscle? | Deltoid tuberosity. |
| What are the actions of the Deltoid muscle? | flexes the shoulder (anterior fibers)
medially rotates the shoulder (anterior fibers)
abducts the shoulder (middle fibers)
extends the shoulder (posterior fibers)
laterally rotates the shoulder (posterior fibers) |
| What is the nerve of the Deltoid muscle? | Axillary. |
| What is the origins of the Pectoralis Major? | medial half (1/2) of the clavicle
edge of the sternal body
ribs 1 through 7 (costal cartilages) |
| What is the insertion of Pectoralis Major? | intertubercle groove of the humerus (lateral lip) |
| What is the actions of the Pectoralis Major? | adduct the shoulder
medially rotates the shoulder
flexes the shoulder
extends the shoulder |
| What is the nerve for Pectoralis Major? | Medial pectoral nerve. |
| Which muscle forms the upper anterior chest wall and anterior axillary fold? | Pectoralis Major. |
| Tightness in which muscle can cause constriction of the chest and angina pectoralis - like pain or postural distortion such as rounded shoulders? | Pectoralis Major. |
| What is the origin of Coracobrachialis? | Coranoid process of the scapula. |
| What is the insertion of Coracobrachialis? | Medial humeral shaft (middle region). |
| What are the actions of Coracobrachialis? | flexes the shoulder
adducts the shoulder |
| What is the nerve for Coracobrachialis? | Musculocutaneous nerve. |
