[Muscles] Shoulder and posterior scapular regions

Question 1

Trapezius

Answer 1

O: superior nuchal line, external occipital protuberance, ligamentum nuchae spinous processes vertebrae C7-T12
Ins: spine of scapula, acromion, lateral third of clavicle
Inn: spinal accessory nerve (CN XI) 
Bs: transverse cervical artery
Action: Upper - elevates scapula
middle - retracts scapula
lower - depresses scapula 
rotates scapula for full arm ABD

Question 2

Deltoid

Answer 2

O: spine of scapula, lateral margin of acromion, lateral third of clavicle
Ins: deltoid tuberosity of humerus
Inn: axillary nerve
Bs: posterior circumflex humeral artery
Action: abduction of the arm (initiated by the supraspinatus)
Anterior: assists with flexion of arm
Posterior: assists with extension of arm

Question 3

Levator scapulae

Answer 3

O: Transverse processes vertebrae of C1-C4
Ins: Medial border of scapula, superior angle of the root to the spine of the scapula
Inn: Dorsal scapular nerve
Bs: dorsal scapular artery
action: elevate superior angel of the scapula, downward rotation of scapula

Question 4

Rhomboids

Answer 4

O: Minor - spinous processes of C7-T1
Major - spinous process of T2-T5 
Ins: medial border of scapula
Inn: Dorsal scapular nerve
Bs: Dorsal scapular artery 
Action: retracts scapula, elevates scapula, fixes scapula to thoracic wall

Question 5

Supraspinatus

Answer 5

O: supraspinous fossa of the scapula 
Ins: Superior facet of the greater tubercle of the humerus 
Inn: Suprascapular nerve 
Bs: Suprascapular artery 
Action: Initiates ABD of arm at GHJ 
Lateral rotator of arm at GHJ

Question 6

Infraspinatus

Answer 6

O: infraspinous fossa of the scapula
Ins: middle facet of the greater tubercle of the humerus 
Inn: Suprascapular nerve
Bs: Suprascapular artery
Action: lateral rotator of arm at GHJ

Question 7

Teres minor

Answer 7

O: lateral border of the scapula
Ins: Inferior facet of the greater tubercle of the humerus 
Inn: Axillary nerve
Bs: circumflex scapular artery
Action: lateral rotator of arm at GHJ

Question 8

Teres Major

Answer 8

O: posterior surface of inferior border of the scapula
Ins: medial lip inter tubercular groove of the humerus
inn: lower sub scapular nerve
Bs: circumflex scapular artery
Action: medial rotator of the arm at GHJ