Pectoral & Scapula Region. Anterior Axio-appendicular muscles p698 Moore
Name the pectoralis major heads
clavicular sternocostal
Sub-clavius innervation
Nerves to subclavius C5 (main), C6
Sub-clavius action
anchors & depresses clavicle
Pectoralis minor origin
3rd - 5th ribs near their costal cartilages
Pectoralis Major Action
Adducts & medially rotates humerus Draws scapula anteriorly & inferiorly Acting alone, clavicular head flexes humerus & sternocostal head extend it from the flexed position
What anterior axio-appendicular muscles move the pectoral girdle?
pectoralis major pectoralis minor subclavius serrator anterior
What landmarks is the pectoralis minor useful for identifying?
structures in the axilla e.g. axillary artery.
How do you test the pectoralis major sternocostal head?
Abduct arm 90 degrees then adducted against resistance. If acts normally muscle can be seen & palpated
How do you test the pectoralis major clavicular head?
Abduct arm 90 degrees; individual moves arm anteriorly against resistance. If acts normally muscle can be seen & palpated
Pectoralis Major Origin
Clavicular head:Anterior surface of medial half of clavicle Sternocostal head: anterior surface of sternum, superior six costal cartilages, aponeurosis of external oblique muscles
Sub-clavius insertion
Inferior surface of middle third clavicle
Sub-clavius origin
Junction of 1st rib & it's costal cartilage
Pectoralis Major Innervation
Lateral & medial pectoral nerves Clavicular head: C5, C6 (main) Sternocostal head: C7, C8 (main) T1
Pectoralis Major Insertion
Lateral lip of inter tubercular sulcus of humerus
Serratus anterior innervation
Long thoracic nerve C5, C6 (main), C7 (main)
Pectoralis minor innervation
Medial pectoral nerve C8, T1
Serratus anterior action
Protracts scapula & holds it against thoracic wall Rotates scapula
Pectoralis minor action
Stabilises scapula by drawing it inferiorly & anteriorly against thoracic wall
Serratus anterior insertion
anterior surface of medial border of scapula
Serratus anterior origin
external surface of lateral parts of 1st-8th ribs
How do you test the serratus anterior?
hand of outstretch limb is pushed against a wall. if acting normally several digitations of the muscle can be seen & palpated.
Why is the subclavius muscle useful during tug-of-war?
helps resist tendency for clavicle to dislocate at the sternoclaviuclar joint
Pectoralis minor insertion
medial border & superior surface of coracoid process of scapula
Name a movement pectoralis minor is used for
stabilise scapular when stretching the upper limb forward to touch an object just out of reach
What shape is the pectoralis minor?
Trianglular