Thoracoappendicular Muscles Flashcards
Which muscles are in the thoracoappendicular muscle group?
Pectoralis major and minor, subclavius and serratus anterior
What is the origin of the pectoralis major?
Clavicular head: medial 1/2 of clavicle
Sternocostal head: anterior surface of the sternum, costal cartilages 1-6 and aponeurosis of external Ab domain always oblique muscle
What is the insertion site for pectoralis major?
Lateral edge of intertubercular groove of humerus
What is the action of pectoralis major?
Adduct and medially rotate the humerus, protract and depress the scapula
Clavicular head flexes the humerus
Sternocostal head extends the humerus from the flexed state
What innervates pectoralis major?
Lateral and medial pectoral nerve
Pectoralis minor is usually pierced by what structure?
Medial pectoral nerve
What are the attachment sites for pectoralis minor?
O: medial aspect of ribs 3-5
I: coracoid process of scapula
What is the action of pectoralis minor?
Stabilizes scapula by protraction and depressing it against the thoracic wall
What innervates pectoralis minor?
Medial pectoral nerve
What are the attachment sites for subclavius?
O: upper border of 1st rib and 1st costal cartilage
I: inferior aspect of the clavicle
What is the action of subclavius?
Positions and depresses the clavicle
What is the subclavius muscle innervated by?
Nerve to subclavius
What are the attachment sites for serratus anterior?
O: lateral external surface of ribs 1-8
I: anterior surface of medial border of the scapula
What is the action of serratus anterior?
Protracts scapula, thereby stabilizing it against the thoracic wall and rotates the glenoid cavity superiorly
What innervates serratus anterior?
Long thoracic nerve
