4 Muscles (Anterior Thoracoappendicular)

Question 1

What are the 4 muscles of the anterior thoracoappendicular muscles?

Answer 1

Pectoralis major
Pectoralis minor
Serratus anterior
Subclavius

Question 2

Practice an oral presentation of the pectoralis major muscle.

Answer 2

Location: part of the anterior thoracoappendicular muscle group, the most superficial muscle of the anterior chest wall.

Structure: multipennate muscle, two heads (clavicular and sternocostal heads) converging on a common tendinous insertion

Function:
internally rotates humerus

adducts humerus

draws scapula anteriorly and inferiorly

Clavicular head: flexes humerus

SC head: extends humerus from flexed position

PA:
Clavicular head: anterior medial half of clavicle
SC head: anterior surface of sternum, superior 6 costal cartilages, and aponeurosis of external oblique muscle

DA: bicipital groove of humerus

NS: lateral and medial pectoral nerves (C5-T1)

Question 3

Practice an oral presentation of the pectoralis minor muscle.

Answer 3

Location:
part of the anterior axioappendicular muscle compartment. Located deep to the pectoralis minor muscle. forms part of the anterior axilla wall

Function:
draws scapula inferiorly and anteriorly

stabilizes scapula

respiration (elevates ribs when pectoral girdle is fixed)

PA:
ribs 3-5 near the costal cartilages

DA: coracoid process of scapula

NS: medial pectoral nerve (C8, T1)

Question 4

Practice an oral presentation of the serratus anterior.

Answer 4

Location:
part of the anterior thoracoappendicular muscle compartment. located on the supero-lateral surface of the chest wall.

Function:
stabilizes the scapula and draws the scapula against the thoracic rib cage

protracts scapula

rotates scapula (glenoid fossa superiorly)

accessory muscle of respiration

PA: ribs 1-8 laterally

DA: medial border of the anterior surface of the scapula

NS: long thoracic nerve (C5, C6, C7)

Question 5

Practice an oral presentation of the subclavius muscle.

Answer 5

Location: part of the anterior thoracoappendicular muscle compartment. Located inferiorly to the clavicle.

Function:
stabilizes and depresses clavicle

PA: junction of the 1st rib and costal cartilage

DA: subclavian groove on the inferior surface of the medial third of the clavicle

NS: nerve to the subclavius (C5, C6)