Chest and Back Muscles Flashcards
Pectoralis major
large, thick, fan-shaped muscle that covers the superior part of the thorax; prinicpal flexor of the arm
What are the origin points of pectoralis major?
Clavicle, sternum, costal cartilages of ribs 2-6
What is the insertion point of Pectoralis major?
Intertubercular groove of humerus
What is the action of Pectoralis major?
a gonist of arm flexion; also adducts and medially rotates arm
Pectoralis minor
thin, flat triangular muscle deep to the pectoralis major; muscle helps depress and protract (pull anteriorly) the scapula
What is the origin point of Pectoralis minor?
ribs 3,4,5
What is the insertion point of Pectoralis minor?
coracoid process of scapula
What is the action of Pectoralis minor?
proctracts and depresses scapula
Serratus anterior
a large, flat, fan-shaped muscle positioned between the ribs and the scapula.
Where is the point of origin for serratus anterior?
Ribs 1-8
Where is the insertion point of serratus anterior?
anterior aspect of medial (vertebral) border of scapula
What is the action of serratus anterior?
Protracts and rotates scapula superiorly (“boxer’s muscle”)
Trapezius
a large, flat, diamond shaped muscle that extends from the skull and vertebral column to the pectoral girdle, laterally.
Where is the origin point of trapezius?
occipital bone, spines of C7, and all Thoracic vertebrae
Where is the insertion point of trapezius?
the spine, acrominon of scapula, and lateral clavicle
What is the action of trapezius?
elevates, rotates, retracts, and depresses scapula
Latissimus dorsi
broad, triangular muscle located on the inferior part of the back; “swimmer’s muscle”
What is the origin point of latissimus dorsi?
via thoracolumbar fascia, the spinous processes of T7-T12, ribs 8-12, and the iliac crest
Where is the point of insertion of latissimus dorsi?
Intertubercular groove of humerus
What is the action of latissimus dorsi?
a gonist of arm extension; also adducts and medially rotates arm
