Lecture 7: The Muscular System - Appendicular Musculature Flashcards
The Appendicular Musculature
FUNCTION
Appendicular muscles are responsible for:
o Stabilizing the pectoral and pelvic girdles
o Moving the upper and lower limbs
o Absorbing shocks and jolts as you walk, run, or jump
o Aiding in strengthening the joint area
Appendicular Muscles account for roughly ____ percent of the skeletal muscles in the body
Appendicular Muscles account for roughly 40 percent of the skeletal muscles in the body
Two major groups of appendicular muscles:
The muscles of the pectoral girdle and upper limbs
The muscles of the pelvic girdle and lower limbs
Muscles of the Pectoral Girdle and Upper Limbs
Divided into 4 groups
o Muscles that position the pectoral girdle
o Muscles that move the arm
o Muscles that move the forearm and hand
o Muscles that move the hand and fingers
Muscles of the Pectoral Girdle and Upper Limbs
Divided into 4 groups
1) Muscles That Position the Pectoral Girdle
These muscles also coordinate with the muscles that move the arm
o Levator Scapulae – elevates scapula
o Rhomboid major – adducts and performs downward rotation of scapula
o Rhomboid minor – same as above
o Serratus anterior – protracts shoulder, upward rotation of scapula
o Subclavius – depresses and protracts shoulder
o Pectoralis minor – depresses and protracts shoulder, downward rotation of scapula, and elevates ribs
o Trapezius – may elevate, retract, depress or rotate scapula depending on other muscles and extend
neck
Muscles of the Pectoral Girdle and Upper Limbs
Divided into 4 groups
2) Muscles That Move the Arm
ANTERIOR VIEW
o Coracobrachialis: adduction at the shoulder
o Deltoid: abducts the arm
o Pectoralis major: adducts and medially rotates the arm
o Biceps brachii: flexes the lower arm
POSTERIOR VIEW
Rotator Cuff – muscles that stabilize the glenohumeral (shoulder) joint
o Supraspinatus: abduction at the shoulder
o Infraspinatus: lateral rotation at the shoulder
o Teres minor: adduction and lateral rotation at the shoulder
o Subscapularis: medial rotation at the shoulder
(subscapularis medially rotates the humerus (as when winding up for a pitch), the supraspinatus abducts
the humerus (as when throwing the pitch) and the infraspinatus and teres minor laterally rotate the humerus
(as when completing the pitch and slowing down the pitching arm)
Other muscles that move the arm
o Teres major: extension and medial rotation at the shoulder
o Triceps brachii: extension of the lower arm
o Latissimus dorsi: adduction and medial rotation at the shoulder
