5/23 extrinsic back muscles

Question 1

Trapezius

Answer 1

Origin

• medial 3rd of sup nuchal line
• EOP
• nuchal ligament
• SP C7-T12

insertion

• lateral 3rd clavicle
• acromion
• spine of scapula

innervation

• accessory nerve
• c3,c4

Action

• elevates, depress, retracts scapula
• rotate glanoid cavity supriorly

Question 2

Latissimus dorsi

Answer 2

MA

• SP inf 6 thoracic vertebrae
• thoracolumbar fascia
• iliac crest
• inf 3 or 4 ribs

LA
-floor of intertubercular sulcus of humerus

I
-thoracodorsal c6 c7

A

• extends, adducts, and medially rotates shoulder joint
• raises body toward arms during climbing

Question 3

levator scapulae

Answer 3

M
-post tubercles of TP of C1-C4

L
-medial border of scapula sup to root of spine

I

• dorsal scapular C5
• C3C4

A
-elevates scapula and tilts its glenoid cavity by rotating scapula

Question 4

rhomboids

Answer 4

M
(minor)
-nuchal ligament 
-SP C7-T1
(major)
-SP T2-T5

L
(minor)
-tri at medial end of spine
(major)
-medial border of scapular from spine to inf angle 

I
-dorsal scapular nerve C5

A

• retract scapula and rotate it to depress glanoid cavity
• fix scapula to thoracic wall