Back Muscles

Question 1

trapezius

Answer 1

• function:
  
  • assists in rotating the scapula during ABduction of humerus above horizontal
  • elevation of the scapula
• innervation
  
  • accessory nerve (motor)
  • cervical spinal nerves C3 and C4

Question 2

latissimus dorsi

Answer 2

• function:
  
  • extends, ADDucts and medially rotates humerus
• innvervation:
  
  • thoracodorsal nerve (C6-C8)

Question 3

levator scapulae

Answer 3

• function:
  
  • elevates scapula
• innervation:
  
  • C3 to C4
  • dorsal scapular nerve

Question 4

rhomboid major

Answer 4

• function:
  
  • retracts (adducts) and elevates scapula
• innervation:
  
  • dorsal scapular nerve (C4-C5)

Question 5

rhomboid minor

Answer 5

• function:
  
  • retracts (ADDucts) and elevates scapula
• innervation:
  
  • dorsal scapular nerve (C4-C5)

Question 6

serratus posterior superio

Answer 6

• function:
  
  • elevates ribs II to V
• innervation:
  
  • anterior rami of upper thoracic nerves T2 to T5

Question 7

serratus posterior inferior

Answer 7

• function:
  
  • depresses ribs IX to XII and may prevent lower ribs from elevating when diaphragm contracts
• innervation:
  
  • anterior rami of lower thoracic nerves T9 to T12

Question 8

anterior wall of axilla

Answer 8

• Pectoralis major and minor muscles
  
  • function: flexion, adduction and medial rotation of the arm
  • innervation: medial and lateral pectoral nerves
• subclavius muscle
• clavipectoral fascia

Question 9

lateral wall of axila

Answer 9

• intertubercular sulcus

Question 10

posterior wall of axilla

Answer 10

• subscapularis
  
  • function: medial rotation of the arm
  • innervation: subscapular nerves (upper and lower)
• teres major
  
  • function: medial rotation, adduction, extension of arm
  • innervation: lower subscapular nerve
• latissimus dorsi
  
  • function: medial rotation, adduction, extension of arm
  • innervation: thoracodorsal nerve

Question 11

medial wall of axilla

Answer 11

• serratus anterior
  
  • function: rotates scapula upward to allow lifting arm above 90 degrees; protracts the scapula to keep the medial border against the thoracic wall
  • innervation: long thoracic nerve

Question 12

subclavius

Answer 12

• function:
  
  • anchors clavicle
• innervation:
  
  • nerve to subclavius C5, C6

Question 13

teres major

Answer 13

• function:
  
  • arm medial rotation + extension
• innervation:
  
  • lower subscapular C5-C7

Question 14

name the rotator cuff muscles

Answer 14

• SITS
  
  • supraspinatus
  • infraspinatus
  • teres minor
  • subscapularis

Question 15

supraspinatus

Answer 15

• function:
  
  • suprascapular C5, C6
• innervation:
  
  • ABducts arm 0-15º

Question 16

infraspinatus

Answer 16

• function:
  
  • arm lateral rotation
• innervation:
  
  • suprascapular C5, C6

Question 17

teres minor

Answer 17

• function:
  
  • arm lateral rotation
• innervation:
  
  • axillary C5, C6

Question 18

subscapularis

Answer 18

• function:
  
  • arm medial rotation
• innervation:
  
  • upper + lower subscapular C5-C7