Muscles of Shoulder & Arm Flashcards
What muscles attach the pectoral girdle to the trunk from the thoracic wall?
pec major, pec minor, subclavius, serratus anterior
What muscles attach the pectoral girdle to the trunk from the vertebral column?
trapezius, lat dorsi, rhomboid major, rhomboid minor, levator scapulae
What is the origin and insertion of pec major?
clavicular and sternocostal head with an insertion on proximal humerus
What is the action of pec major?
adduction and medial rotation of the upper limb and an accessory muscle of respiration if the humerus is fixed
What is the origin and insertion of pec minor?
costal cartiage or ribs 3,4,5 and inserts on the coracoid process
What is the action of pec minor?
stabilises scapula and depresses the shoulder an an accessory muscle of inspiration
What is the origin and insertion of subclavius?
origin on the anteromedial part of first rib and insertion on the lateral inferior surface of the clavicle
What is action of subclavius?
stabilises clavicle and depresses shoulder
What is the origin and insertion of serratus anterior?
saw tooth attachment on ribs 1-8 and inserts on the medial border of the scapula
What is the action of serratus anterior?
reaching forward - allows scapula to travel around chest wall - boxers muscle
What is the nerve supply of serratus anterior?
long thoracic nerve
What do you see in a patient with a damaged long thoracic nerve?
winged scapula
What muscles attach the humerus to the scapula?
deltoid, subscapularis, supraspinatus, infraspinatus, teres minor, teres major
What is the origin and insertion of deltoid?
origin the spine of the scapula, the acromion process and the clavicle and inserts on the deltoid tubercle on the humerus
What is the action of deltoid?
powerful abducter - but can’t initiate abduction - also flexion and extension
What are the muscles of the rotator cuff?
supraspinatus, infraspinatus, subscapularis and teres minor
What is the feature of all muscles of the rotator cuff?
they blend with the capsule of the shoulder joint
Where do supraspinatus, infraspinatus and teres minor all insert?
on the greater tubercle of the humerus
What is the action of supraspinatus?
initiates abduction
What is the action of infraspinatus and teres minor?
lateral rotation
What is the insertion of subscapularis?
lesser tubercle of the humerus
What is the action of subscapularis?
medial rotator
From what muscle is teres major derived?
subscapularis
What is the origin of teres major?
inferior angle of the scapula
What is the action of teres major?
abducts and medially rotates
What are the muscles of the anterior compartment of the arm?
biceps brachii, coracobrachialis, brachialis
What is the origin of the long head of biceps?
supraglenoid tubercle
What is the origin of the short head of biceps?
coracoid process
What is the insertion of biceps tendon?
radial tuberosity
What is the action of biceps brachii?
flexion at the elbow and supination when elbow is flexed
What is the origin of brachialis?
distal half of shaft of the humerus
What is the insertion of brachialis?
coranoid process of the ulna
What is the action of brachialis?
flexion at the elbow
What is the origin of coracobrachialis?
coracoid process
What is the insertion of coracobrachialis?
shaft of the mid humerus
What is the action of coracobrachialis?
flexion and adduction at the shoulder
What is the origin of the long head of triceps?
infraglenoid tubercle
What is the origin of the lateral head of triceps?
linear origin on the proximal part of the posterior aspect of humerus
What is the origin of the medial (deep) head of triceps?
clothes the posterior aspect of the shaft of humerus
What is the insertion of triceps?
olecranon of the ulna
What is the action of triceps?
extension at the elbow
