Muscles Of The Shoulder

Question 1

Origin: External occipital protuberance, medial 1/3 of the superior nuchal line, ligamentum nuchae, and spinous process of C7 through T12
Insertion: Lateral 1/3 of clavicle, acromion, and the spine of the scapula, including the tubercle of the spine of the scapula
Standard actions: Elevates, retracts, upwardly rotates, and depresses the scapula at the Scapulocostal joint
Reverse actions: Extends, contralaterally rotates and laterally flexes the head and neck at the spinal joints

Answer 1

Trapezius Muscle

Question 2

Origin: TVPs of C1-C4
Insertion: Medial border of the scapula, from the superior angle to the root of the spine of the scapula
Standard action: Elevates the scapula at the scapulocostal joint
Reverse action: Extends and laterally rotates the head and neck at spinal joints

Answer 2

Levator Scapulae

Question 3

Origin: SP of T2 - T5
Insertion: Medial border of the scapula, between the root of the spine and the inferior angle of the scapula
Actions: Retracts, elevates and downwardly rotates the scapula at the scapulocostal joints

Answer 3

Rhomboid major

Question 4

O: SP of T7 - L5, posterior Sacrum, and the posterior iliac crest (all via the thoracolumbar fascia) the lower 3-4 ribs and Inferior angle of the scapula
I: Medial lip of the bicipital groove of the humerus
A: Medially rotates the arm at the GH joint
Adducts the arm at the GH joint
Extends the arm at the GH joint

Answer 4

Latissimus Dorsi

Question 5

O: SP of C7 - T1 and the Inferior nuchal ligament
I: The root of the spine of the scapula
A: Retracts the scapula at the scapulocostal joint
Elevates the scapula at the SCC joint
Downwardly rotates the scapula at the SCC joint

Answer 5

Rhomboid Minor

Question 6

O: Inferior angle and the Inferior 1/3 on the dorsal surface of inferior lateral border of the scapula
I: Medial lip of the bicipital groove of the humerus
A: Medially rotates the arm at the GH joint
Adducts the arm at the GH joint
Extends the arm at the GH joint

Answer 6

Teres Major

Question 7

O: Lateral 1/3 of clavicle, acromion and spine of the scapula
I: Deltoid Tuberosity of the humerus
A: Abducts the arm at the GH joint (entire muscle)
Flexes the arm at the GH joint ( anterior deltoid)
Medially rotates the arm at the GH joint ( anterior deltoid)
Horizontally flexes the arm at the GH joint ( anterior deltoid)
Extends the arm at the GH joint ( posterior deltoid)
Horizontally extends the arm at the GH joint ( posterior deltoid)
Laterally rotates the arm at the GH joint ( posterior deltoid)
Downwardly rotates the scapula at the GH and scapulocostal joints ( Reverse Action)

Answer 7

Deltoid

Question 8

O: The superior 2/3 of the dorsal surface of the superior lateral border of the scapula
I: The inferior facet of the greater tubercle of the humerus
A: Laterally rotates the arm at the GH joint

Answer 8

Teres Minor

Question 9

O: Subscapular fossa of the scapula
I: Lesser tubercle of the humerus
A: Medially rotates the arm at the GH joint

Answer 9

Subscapularis

Question 10

O: The medial 2/3 of the infraspinous fossa of the scapula
I: The middle facet of the greater tubercle of the humerus
A: Laterally rotates the arm at the GH joint

Answer 10

Infraspinatus

Question 11

Supraspinatus

Answer 11

O: The medial 2/3 of the supraspinous fossa of the scapula
I: The superior facet of the greater tubercle of the humerus
A: Abducts the arm at the GH joint
Flexes the arm at the GH joint