Question | Answer |
Serratus anterior origin | Lateral parts of the 1th-8th ribs |
Serratus anterior insertion | Anterior surface of medial border of scapula |
Serratus anterior innervation | long thoracic nerve |
Serratus anterior action | 1. protracts scapula
2. holds scapula against the thoracic wall
3. superior rotation of the scapula |
Deltoid origin | lateral third of clavicle, acromion process, and spine of scapula |
Deltoid insertion | deltoid tuberosity |
Deltoid innervation | axillary nerve |
Deltoid Action | 1. All three simultaneously: abduct the humerus after 15 degrees to the horizontal and stabilize the shoulder
2. Anterior: flexion and medial rotation of the humerus
3. Posterior: extension and lateral rotates the humerus |
Teres Major origin | inferior angle of scapula (posterior surface) |
Teres major insertion | medial lip of intertubercular sulcus |
Teres major innervation | lower subscapular nerve |
Teres major action | adducts and medially rotates the humerus |
Name the rotator cuff muscles | "SITS" Supraspinatus, Infrapinatous, Teres minor, Subscapularis |
Supraspinatus origin | Supraspinous fossa |
Supraspinatus insertion | superior aspect of greater tubercle |
Supraspinatus innervation | suprascapular nerve |
Supraspinatus action | 1. Abduct the arm for the first 15 degrees
2. Tonic contraction stabilizes the glenohumeral joint |
Infraspinatus origin | Infraspinous fossa |
Infraspinatus insertion | middle aspect of the greater tubercle |
infraspinatus innervation | suprascapular nerve |
infraspinatous action | 1. tonic contraction stabilizes the glenohumeral joint
2. laterally rotates arm |
teres minor origin | middle part of lateral border of scapula |
teres minor insertion | inferior aspect of greater tubercle |
teres minor innervation | axillary nerve |
teres minor action | 1. tonic contraction stabilizes the glenohumeral joint
2. laterally rotates the arm |
subscapularis origin | subscapular fossa |
subscapularis insertion | lesser tubercle |
subscapularis innervation | upper and lower subscapular nerves |
subscapularis action | 1. tonic contaction stabilizes glenohumeral joint
2. medially rotates arm |