Muscles of the shoulder region (dave's notes)

Question 1

List the muscles of the shoulder region

Answer 1

Supraspinatus
Infraspinatus
Teres minor
Deltoid
Subscapularis
Teres major

Question 2

What is the origin and insertion of supraspinatus?

Answer 2

Origin: The medial 3/4 of supraspinous fossa of the scapula, upper surface of spine (bipenate)
Insertion: The superior facet of the greater tuberosity of the humerus and capsule of the shoulder joint

Question 3

What is the origin and insertion of infraspinatus?

Answer 3

Origin: The medial 3/4 of infraspinatus fossa and fibrous intermuscular septa
Insertion: The middle facet of the greater tuberosity of the humerus and the capsule of the shoulder joint

Question 4

What is the origin and insertion of Teres minor?

Answer 4

Origin: Middle third lateral border of scapula above teres major
Insertion: Inferior facet of the greater tuberosity of the humerus and capsule of the shoulder joint

Question 5

What is the origin and insertion of deltoid?

Answer 5

Origin: Lateral 3rd of clavicle, acromion, spine of scapula to deltoid tubercle
Insertion: Middle of the lateral surface of humerus

Question 6

What is the origin and insertion of subscapularis?

Answer 6

Origin: Th medial two thirds of the subscapular fossa
Insertion: Lesser tuberosity of the humerus, upper medial lip of the bicipital groove, capsule of the shoulder joint

Question 7

What is the origin and insertion of teres major?

Answer 7

Origin: Oval area (lower 3rd) of lateral side of inferior angle of scapula below teres minor
Insertion: Medial lip of the bicipital groove of the humerus

Question 8

What is the action and nerve supply of supraspinaturs?

Answer 8

Abducts the arm and stabilises the shoulder joint
Suprascapular nerve (C5,6 from upper trunk)

Question 9

What is the nerve supply and action of infraspinatus?

Answer 9

Laterally rotates the arm and stabilises the shoulder joint.

Suprascapular nerve C5,6 from upper trunk

Question 10

What is the nerve supply and action of teres minor?

Answer 10

Laterally rotates the arm and stabilises the shoulder joint 
Axillary nerve (C5,6) from the posterior cord

Question 11

What is the nerve supply and action of deltoid?

Answer 11

Abducts arm, anterior fibres flex, medial rotate, posterior extend, and lateral rotate
Axillary nerve C5,6 from posterior cord

Question 12

What is the nerve supply and action of subscapularis?

Answer 12

Medially rotates arm and stabilises the shoulder joint

Upper and lower subscapular nerves C5,6 from the posterior cord

Question 13

What is the nerve supply and action of teres major?

Answer 13

Medially rotates and adducts the arm, stabilises the shoulder joint.
Lower scapular nerve (C5,6,7 from the posterior cord)

Question 14

What is teres major functionally part of?

Answer 14

Subscapularis

Question 15

What lies above the tendon of supraspinatus?

Answer 15

The subacromial bursa

Question 16

What muscles form the rotator cuff?

Answer 16

Supraspinatus
Infraspinatus
Teres minor

Question 17

What makes up the scapular anastomosis?

Answer 17

The transverse cervical artery from the subclavian has a deep descending branch. The dorsal scapular which runs down the vertebral border. The suprascapular artery passes down through the supraspinous fossa, travels around the spine of the scapula and supplies infraspinous, giving off the circumflex scapular branch.