Muscles of the Pectoral Region

Question 1

3 muscles

Answer 1

Pectoralis major, pectoralis minor and serratus anterior

Question 2

Pectoralis major

Answer 2

Large, fan shaped, most superficial 
Makes up anterior wall of axilla 
Two heads - clavicular and sternocostal 
Origin - clavicle and sternum and ribs 
Attachment - intertubecular sulcus of humerus

Question 3

Actions of pectoralis major

Answer 3

Two heads together - adduct and medially rotate humerus and shoulder
Clavicular head - flexion

Question 4

Innervation of pectoralis major

Answer 4

Medial and lateral pectoral nerves

Question 5

Pectoralis minor

Answer 5

Lies posterior to pec major
Forms part of anterior wall of axilla with pec major
Origin - ribs 3-5
Attachment - coracoid process of scapula

Question 6

Actions of pectoralis minor

Answer 6

Contraction - depresses the shoulder

Question 7

Innervation of pectoralis minor

Answer 7

Medial pectoral nerve

Question 8

Serratus anterior

Answer 8

Lateral in the chest 
Forms medial wall of axilla
Several strips 
Origin - ribs 2-8 
Attachment - costal surface of medial border of scapula

Question 9

Actions of serratus anterior

Answer 9

Rotate scapula - allows arm to be raised above 90 degrees

Holds scapula against ribcage

Question 10

Innervation of serratus anterior

Answer 10

Long thoracic nerve