Shoulder muscles Flashcards
Trapezius
Origin
insertion
function
O-
* medial 1/3rd of superior nuchal line of occipital bone
* spinous processes and supraspinous ligaments of C7 and T1-12
I
* superior edge of crest of spine of scapula.
* medial border of acromion
* posterior border of lateral 1/3rd of clavicle
F-
scapular - elevation, rotation during abduction of humerus above horizontal
middle fibers retract, lower fibers depress scap
Levator scapulae
Origin
insertion
function
O
- transverse process of C1,2
- posterior tubercles of transverse processes of C3,4
I- posterior surface of medial border of scapula from superior angle to root of spine of scapula
F
- elevates scapula
- aids in retraction & sidefelxion of neck
Rhomboid minor
Origin
insertion
function
O
- spinous processes of C7,T1
- lower part of ligamentum nuchae
I
- posterior surface of medial border of scapula at the root of spine of scapula
F- elevate and retract scapula
Rhomboid major
Origin
insertion
function
O- spinous process of T2-5 and intervening supraspinous ligaments
I-posterior surface of medial border of scapula from root of spine of scapula to the inferior angle
F- elevate and retract scapula
Pectoralis major
Origin
insertion
function
O
- clavicular head - anterior surface of medial half of clavicle
- sternocostal head- anterior surface of sternum
- first 7 costal cartilage
- sternal end of 6th rib
- aponeurosis of external oblique
I- lateral lip of intertubercular sulcus of humerus
F-
flexion, adduction & medial rotation of glenohumeral joint
Clavicular head- flexion of extended arm
sternocostal head- extension of flexed arm
Latissimus dorsi
Origin
insertion
function
O
- spinous process of lower 6 thoracic vertebrae & relatted interspinous ligaments via the thoracolumbar fascia
- to the spinous process of lumbar vertebrae, illiac crest, lower 3/4 ribs
I- twists to insert into floor of the intertubercular sulcus of humerus below the shoulder joint
F- Adduction, medial rotation & extension of arm
Deltoid
Origin
insertion
function
O
Anterior fibers- anterior border of lateral 1/3rd of clavicle
Middle fibers- lateral margin of acromion process
posterior fibers - inferior edge of crest of spine of scapula
I- deltoid tuberosityy of humerus
F- abbductor of the arm
- anterior fibers assist in arm flexion
- posterior fibers assist in extendion arm
Supraspinatus
Origin
insertion
function
O- medial 2/3rds of supraspinous fossa of scapula
I- superior facet on the greater tubercle of humerus
F- initiates abduction of arm to 15° at the glenohumeral joint
Infraspinatus
Origin
insertion
function
O- medial 2/3rds of infraspinous fossa of scapula
I- middle facet on posterior surface of greater tubercle of humerus
F- lateral rotation of arm at glenohumeral
Teres minor
Origin
insertion
function
O- upper 2/3rds of a strip of bone on posterior surface of scapula immediately adjacent to lateral border of scapula
I- inferior facet on the greater tubercle of humerus
F- lateral rotation of arm at glenohumeral joint
Subscapularis
Origin
insertion
function
O- medial 2/3rds of subscapular fossa
I- lesser tubercle of humerus
F- Medial rotation of shoulder at glenohumeral
Teres Major
Origin
insertion
function
O- Oval area on lower third of posterior surface of inferior angle of scapula
I- medial lip of intertubercular sulcus on anterior surface of humerus
F- mmedial rotation & extension of shoulder
Biceps brachii
Origin
insertion
function
O-
long head - supraglenoid tubercle of scapula
short head- tip of coracoid process
I- radial tuberosity
F- powerful flexor of forearm at elbow joint, supinates forearm
Brachialis
Origin
insertion
function
O- anterior aspect of humerus and adjacent muscular septae
I- tuberosity of ulna
F- flexor of forearm at elbow joint
Coracobrachialis
Origin
insertion
function
O- Tip of coracoid process
I- medial aspect of humerus at mid-shaft
F- flexor of arm at glenohumeral joint
