This document describes the six intrinsic muscles of the shoulder - the deltoid, teres major, supraspinatus, infraspinatus, subscapularis, and teres minor. For each muscle it lists the origin, insertion, action, and innervation. The deltoid abducts the arm at the shoulder, while the other muscles act to adduct, medially or laterally rotate the arm.

1. Muscles of
Chest
Muscles of Sh
oulder (INTRI
NSIC)

2. •Deltoid
•Teres Major
•Supraspinatus
•Infraspinatus
•Subscapularis
•Teres minor

3. •Deltoid
• Scapula and clavicle
• Deltoid tuberosity of humerus
• Anterior fibers flex posterior fiber
extend and midle fiber abduct the
arm at shoulder
• Axillary nerve

4. •Teres major
• Inferior angle on posterior surface
of scapula
• Medial lip of Intertubercular sulc
us
• Adducts and medialy rotate the ar
m
• Lower Subscapularis nerve

6. •Supraspinatus
•Suprasinous fossa of scapula
•Greater tubercle of humerus
•Adducts the arm 0-15°
•Suprscapular nerve

7. •Infraspinatus
•Infraspinous fossa of scapula
•Greater tubercle of humerus
•Letraly rotate the arm
•Suprascapular nerve

8. •Subscapularis
• Subscapular fossa on costal surfa
ce of scapula
• Lesser tubercle of humerus
• Medialy rotate the arm
• Upper and lower subscapular ner
ve

9. •Teres minor
•Letral border on posterior sur
face of scapula
•Greater tubercle of humerus
•Letraly rotate the arm
•Axillary nerve