Posterior Shoulder Muscles Flashcards
Supraspinatus (RC)
Origin
-Supraspinous fossa of scapula
Supraspinatus (RC)
Insertion
-Supraspinous fossa of scapula
Supraspinatus (RC)
Innervation
-Suprascapular nerve (C4, C5, C6)
Supraspinatus (RC)
Action
- Initiates abduction of humerus
- Stabilizes humeral head in glenoid fossa.
Infraspinatus (RC)
Origin
-Infraspinous fossa of scapula
Infraspinatus (RC)
Insertion
-Middle facet of greater tubercle of humerus
Infraspinatus (RC)
Innervation
-Suprascapular nerve (C5, C6)
Infraspinatus (RC)
Action
- Laterally rotates humerus.
- Stabilizes humeral head in glenoid fossa.
Teres Minor (RC) Origin
-Middle part of lateral border of the scapula
Teres Minor (RC) Insertion
-Inferior facet of greater tubercle of humerus
Teres Minor (RC) Innervation
-Axillary nerve (C5, C6)
Teres Minor (RC) Action
- Laterally rotates humerus.
- Stabilizes humeral head in glenoid fossa.
Subscapularis (RC)
Origin
-Subscapular fossa (most of anterior surface of scapula)
Subscapularis (RC)
Insertion
-Lesser tubercle of humerus
Subscapularis (RC)
Innervation
-Upper and lower subscapular nerves (C5, C6, C7)
Subscapularis (RC)
Action
- Adducts and medially rotates humerus
- Stabilizes humeral head in glenoid fossa.
Teres Major
Origin
-Posterior surface of inferior angle of scapula
Teres Major
Insertion
-Medial lip of intertubercular groove of humerus
Teres Major
Innervation
-Lower subscapular nerve (C5, C6)
Teres Major
Action
-Adducts and medially rotates humerus.
Deltoid
Origin
- Lateral third of clavicle
- acromion
- spine of scapula
Deltoid
Insertion
-Deltoid tuberosity of humerus
Deltoid
Innervation
-Axillary nerve (C5, C6)
Deltoid
Action
- Anterior: flexes and medially rotates humerus.
- Middle: abducts humerus.
- Posterior: extends and laterally rotates humerus.
Triceps Brachii Long Head
Origin
-infraglenoid tubercle of scapula
Triceps Brachii
Insertion
-Proximal end of olecranon of ulna and fascia of forearm
Triceps Brachii
Innervation
-Radial nerve (C6, C7, C8)
Triceps Brachii
Action
- Extends forearm
- Long head extends humerus & resists dislocation of glenohumeral joint.
Triceps Brachii Lateral Head
Origin
-posterior surface of humerus, superior to radial groove
Triceps Brachii Medial Head
Origin
-posterior surface of humerus, inferior to radial groove
Anconeus
Origin
-Lateral epicondyle of humerus
Anconeus
Insertion
-Lateral surface of olecranon and superior part of posterior surface of ulna
Anconeus
Innervation
-Radial nerve (C7, C8, T1)
Anconeus
Action
–Extends forearm, stabilize elbow joint, abducts ulna during pronation.
