Rotator Cuff Muscles | Origins, Insertions, Innervations, and Actions

The video tutorial provides an in-depth look at the rotator cuff muscles, distinguishing them from the shoulder girdle muscles. It covers the anatomy of the scapula and humerus, focusing on the four rotator cuff muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. Each muscle's origin, insertion, blood supply, innervation, and function are discussed, with emphasis on their roles in shoulder movement and stability. The video also explains why teres major is not considered a rotator cuff muscle.

Which of the following muscles is not part of the rotator cuff?

• Infraspinatus

• Supraspinatus

• Subscapularis

• Teres Major

What is the primary function of the rotator cuff muscles?

• Extend the wrist

• Move the scapula

• Stabilize the shoulder joint

• Flex the elbow

Which part of the scapula articulates with the humerus to form the shoulder joint?

• Inferior angle

• Spine of the scapula

• Glenoid fossa

• Acromion process

Where does the supraspinatus muscle insert?

• Lesser tubercle

• Greater tubercle

• Medial border of the scapula

• Coracoid process

What is the unique function of the supraspinatus muscle?

• Assists in shoulder adduction

• Facilitates shoulder flexion

• Initiates shoulder abduction

• Enables shoulder extension

Which artery supplies blood to the infraspinatus muscle?

• Brachial artery

• Axillary artery

• Circumflex scapular artery

• Subscapular artery

What is the primary action of the infraspinatus muscle?

• Adduction of the shoulder

• Abduction of the shoulder

• External rotation of the shoulder

• Internal rotation of the shoulder

Which nerve innervates the teres minor muscle?

• Suprascapular nerve

• Median nerve

• Axillary nerve

• Radial nerve

Where does the subscapularis muscle insert?

• Acromion process

• Greater tubercle

• Medial border of the scapula

• Lesser tubercle

Why is the teres major not considered a rotator cuff muscle?

• It does not stabilize the shoulder joint

• It does not insert on the greater or lesser tubercle

• It does not facilitate shoulder rotation

• It does not originate on the scapula