Chest wall muscles Flashcards
What is the origin for pectoralis major?
Clavicular part - Clavicle
sternal part - manubrium and body of sternum/costal cartilage ribs 1-6
What is the insertion of pectoralis major?
interturblur groove of hummerus
What aid the function of pec major?
flexes arm
adducts arm
medially rotates arm
What part does the clavicular part of the pec major play in action?
large part of adduction and flexion to 60 degrees
What part does the sterenocostal part of pec major play in the action?
flexes arm when arm is posterior to the midline
ineffective to when flexion greater than 60 degrees
it can depress the shoulder of the hanging arm
how does the sternocostal head of the pec major work on the hummerus from a raised position?
will work with lats to extend hummerus.
will not extend arm dorsal to the midline
Where does tears of th spec major usually occur?
uncommon, tear from hummeral attachment. may be partial or complete.
What signs of tear will show in pec major at hummerus?
loss of axillary fold
What is the innervation of the pec major?
medial pectoral nerve
lateral pectoral nerve
What is the origin of the pec minor?
3-5 ribs
what is the insertion of pec minor?
coracoid process of scapula
What is the action of pec minor?
pull scapula forward against body wall
assist in depressing the shoulder from the lateral side of the scapula (helping rhomboids and levitator scapulae) achieving downward rotation of scapula
What is the innervation of pec minor?
medial pectoral nerve
it anastomos with lateral pec nerve
What are the attachments of the subclavius M.?
From first rib to middle one third of clavicle
What is the purpose of the subclavius M?
helps stabilize shoulder joint
protects underlying structures (axillary A., V and brachial plexus) in case of clavicle fracture
