muscles of the pectoral region

pectoralis minor: action

1) draws the scapula into an anterior tilt of the scapula. 2)Raises the thorax (ribs) when the scapula is fixed, assisting with forced inhalation

pectoralis minor: insertion

coracoid process

2) pectoralis minor:

under the pectoralis major -the major vessels serving the arm (the brachial plexus, axillary artery and vein) cross underneath the pec minor

4) serratus anterior

-lies along the posterior and lateral rib cage -extend from the ribs underneath the scapula and attach to its medial border -most of it is deep to the scapula, latissimus dorsi, or pectoralis minor, but the portion of the serratus below the axilla is superficial -antagonist to the rhomboids

pectoralis major: sternocostal portion-nerve supply

-medial pectoral nerve (C8-T1) (goes into pec minor) -lateral pectoral nerve

pectoralis major: sternocostal portion-action

extension of the shoulder (glenohumeral joint)

serratus anterior: origin

finger-like slips from the external surfaces of the upper eight ribs

pectoralis major: action

1) aDDuct the shoulder (glenohumeral joint) 2) medially rotate the shoulder 3) *humerus fixed*- assist to elevate the thorax during forced inhalation

pectoralis minor: origin

anterior surface of ribs 3-5

pectoralis major: sternocostal portion-origin

anterior surface of the sternum and costal cartilages of the upper 6 ribs

pectoralis major: clavicular portion-insertion

crest of the greater tubercle of the humerus

pectoralis major: sternocostal portion- insertion

crest of the greater tubercle of the humerus

1) pectoralis major

divided into clavicular portion and sternocostal portion

pectoralis minor: nerve

medial pectoral nerve (C8-T1) and communicating fibers from lateral pectoral nerve

subclavius: nerve supply

subclavian nerve from the brachial plexus (C5,6)

subscalpularis: blood supply

subscalpular artery -is the largest branch of the axillary artery -gives off the thoracodorsal and circumflex scapular arteries

3) subscapularis

-located on the anterior surface of the scalpula -part of the rotator cuff muscles -sandwhiched between the subscapular fossa and serratus anterior muscle

5) subclavius

-located underneath the clavicle

subclavius: insertion

groove on the lower surface of the clavicle

serratus anterior: nerve supply

long thoracic nerve (C5-7)

subscapularis: origin

subscalpular fossa of the scapula

subscalpularis: action

1) medially rotate the shoulder (glenohumeral joint) 2) ADDuction of the glenohumeral joint 3) stabilize the head of the humerus in glenoid cavity (only rotator cuff muscle that does medial rotation)

muscles of the pectoral region

1) pectoralis major 2) pectoralis minor 3) subscalpularis 4) serratus anterior 5) subclavius

pectoralis major: clavicular portion- nerve supply

lateral pectoral nerve (C5-7) (runs with thoracoacromioal artery) -part of the brachial plexus

subscalpularis: insertion

lesser tubercle of the humerus

serratus anterior: actions

-aBduct the scapula (scapulothoracic joint) -upwardly rotate the scapula -depress the scapula -holds the scapula against the thoracic wall -if the scapula is fixed, it may elevate the thorax in forced inhulation

subclavius: actions

-draws the clavicle inferiorly and anteriorly -elevates first rib (to assist in inhalation) -restrains excessive elevation and protraction of the clavicle to stabilize the sternoclavicular joint

subclavius: origin

-first rib and its cartilage

pectoralis major: clavicular portion-action

-flex the shoulder (glenohumeral joint) -horizontally ADDuct the shoulder (glenohumeral joint)

serratus anterior: insertion

costal surface of the medial (vertebral) border of the scapula

pectoralis major: clavicular portion- origin

medial half of the clavicle

pectoralis minor: blood supply

thoracoacromioal artery

subscalpularis: nerve

upper and lower subscapular nerve (C5-6)