ch 10- shoulder joint muscles Flashcards
superficial muscle that covers the shoulder joint on the three sides giving the shoulder a round shape; triangular shaped; divided into anterior, middle, and posterior
deltoid
spans the joint on anterior surface at an oblique angle
anterior deltoid
when arm is at shoulder level, the line of pull of the anterior deltoid changes to
horizontal
O- lateral third of clavicle
anterior deltoid
I- deltoid tuberosity
anterior deltoid
A- shoulder abduction, flexion, medial rotation, ad horizontal adduction
anterior deltoid
N- axillary nerve (C5, C6)
anterior deltoid
vertical line of pull lateral to joint axis
middle deltoid
O- acromion process
middle deltoid
I- deltoid tuberosity
middle deltoid
A- shoulder abduction
middle deltoid
N- axillary nerve (C5-6)
middle deltoid
oblique line of pull posterior to joint axis
posterior deltoid
when arm is at shoulder level, the line of pull of posterior deltoid changes to
posterior deltoid
O- spine of scapula
posterior deltoid
I- deltoid tuberosity
posterior deltoid
A- shoulder abduction, extension, hyperextension, lateral rotation, and horizontal abduction
posterior deltoid
N- axillary nerve (C5, C6)
posterior deltoid
large muscle of chest; superficial except for its distal attachment lying under deltoid muscle
pectoralis major
crosses joint on anterior surface in horizontal direction, creating medial pull on humerus
pectoralis major
O- medial third of clavicle, sternum, and costal cartilage of ribs 1-6
pectoralis major
I- lateral lip of bicipital groove of humerus
pectoralis major
A- shoulder adduction, medial rotation, and horizontal adduction
pectoralis major
N- lateral and medial pectoral (C5-T1)
pectoralis major
more vertical line of pull when shoulder is extended and when at shoulder level, it becomes a horizontal line of pull
pectoralis major- clavicular portion
O- medial third of clavicle
pectoralis major- clavicular portion
I- lateral lip of bicipital groove of humerus (inferior to sternal portion)
pectoralis major- clavicular portion
A- shoulder flexion (first 60 degrees)
pectoralis major- clavicular portion
Vertical line of pull when shoulder is in full flexion and loses effectiveness at midrange extension
pectoralis major- sternal portion
O- sternum, costal cartilage of ribs 1-6
pectoralis major- sternal portion
I- lateral lip of bicipital groove of humerus (superior to clavicular portion)
pectoralis major- sternal portion
A- shoulder extension (first 60 degrees- from 180 to 120)
pectoralis major- sternal portion