UPPER-BODY Muscles of the Chest and Back

OBJECTIVE  Students will be able to list and identify and explain the major functions of the front and back of the human torso.  Students will be able to demonstrate different exercises as they relate to a particular muscle

LETS LEARN

PECTORALS

WHAT IS THE FUNCTION OF THE PECTORAL MUSCLE?  The pectoralis major has four actions which are primarily responsible for movement of the shoulder joint. The first action is flexion of the humerus, as in throwing a ball side-arm, and in lifting a child. Secondly, it adducts the humerus, as when flapping the arms. Thirdly, it rotates the humerus medially, as occurs when arm-wrestling. The pectoralis major is also responsible for keeping the arm attached to the trunk of the body.

WHAT IS THE FUNCTION OF THE PECTORAL MUSCLE? CONT’  It has two different parts which are responsible for different actions. The clavicular part is close to the deltoid muscle and contributes to flexion, horizontal adduction, and inward rotation of the humerus. When at an approximately 110 degree angle, it contributes to adduction of the humerus. The sternocostal part is antagonistic to the clavicular part contributing to downward and forward movement of the arm and inward rotation when accompanied by adduction. The sternal fibers can also contribute to extension, but not beyond anatomical position.deltoid muscle

PECTORALIS MINOR

 The pectoralis minor is a thin, flat muscle found immediately under the pectoralis major. This is the smaller of the two pectoral muscles, or muscles of the chest.  Primary actions include the stabilization, depression, abduction or protraction, upward tilt, and downward rotation of the scapula.  There are two parallel pectoralis minor muscles, one on each side of the sternum. Both pectoralis muscles work with the serratus anterior muscles to create a full range of movement for the scapula.

TRAPEZIOUS, DELTOIDS, LATISSIMUS DORSI

DIAGRAMS AND FUNCTIONS 

CLOSURE  Students will label the muscles learned on handouts.