Posterior Triangle of the Neck

Question 1

What is the anterior border of the posterior triangle?

Answer 1

Posterior border of the SCM

Question 2

What is the posterior border of the posterior triangle?

Answer 2

Anterior border of trapezius

Question 3

What is the base of the posterior triangle?

Answer 3

Clavicle

Question 4

What are the contents of the posterior triangle?

Answer 4

• External jugular vein
• Roots of brachial plexus
• Accessory nerve
• Cervical and supra-clavicular lymph nodes

Question 5

What nerves are present in the posterior triangle?

Answer 5

• Lesser occipital (C2)
• Great auricular (C2,3)
• Lateral supraclavicular (C3,4)
• Medial supraclavicular (C3,4)

Question 6

What cutaneous nerves are present in the posterior triangle?

Answer 6

• Greater occipital
• Lesser occipital
• Post. rami of C3-5

Question 7

What veins are present in the posterior triangle of the neck?

Answer 7

External jugular anterior to SCM

Question 8

What deep structures are present in the posterior triangle?

Answer 8

• Transverse cervical artery
• Internal jugular vein
• Suprascapular

Question 9

What does the phrenic nerve pass over?

Answer 9

Crosses obliquely over anterior surface of anterior scalene

Question 10

What do the roots of the brachial plexus pass through?

Answer 10

Between middle and anterior scalene

Question 11

What is the innervation of the SCM?

Answer 11

• Motor innervation = spinal accessory nerve (CN XI)
• Proprioception = cervical plexus C2,3

Question 12

What movements are permitted by the SCM?

Answer 12

• Lateral flexion with rotation
• Extension at atlanto-occipital joints
• Flexion of cervical vertebrae (person is supine)

Question 13

What is this muscle? picture

Answer 13

Trapezius
A = Ascending part
B = Transverse part
C = Descending part

Question 14

What is the action of the ascending part of the trapezius?

Answer 14

Depress the scapula

Question 15

What is the action of the transverse part of the trapezius?

Answer 15

Retracts the scapula

Question 16

What is the action of the descending part of the trapezius?

Answer 16

• Elevate scapula
• Rotate glenoid cavity

Question 17

What innervates the trapezius?

Answer 17

• Spinal accessory nerve (CN XI)
• Cervical plexus C3,4 (proprioception)

Question 18

What muscles form the floor of the posterior triangle?

Answer 18

• Omohyoid
• Splenius capitis

Question 19

What is this muscle? picture

Answer 19

Omohyoid

Question 20

What is the function of the omohyoid?

Answer 20

Depress the hyoid bone

Question 21

What innervates the omohyoid?

Answer 21

Ansa cervicalis

Question 22

What is this muscle? picture

Answer 22

Splenius capitis

Question 23

What is the function of the splenius capitis?

Answer 23

Extend and rotate the neck

Question 24

What innervates the splenius capitis?

Answer 24

Dorsal rami middle cervical

Question 25

What is this muscle?

Answer 25

Levator scapulae

Question 26

What is the origin of the levator scapulae?

Answer 26

- Transverse processes of atlas and axis - 3rd and 4th C vertebrae

Question 27

What is the insertion of the levator scapulae?

Answer 27

- Medial scapular border between superior angle between medial end of scapular spine

Question 28

What is the function of the levator scapulae?

Answer 28

- Control scapular position - Elevate shoulder with trapezius - Shoulder fixed - Lateral flexion of neck to the same side

Question 29

What innervates the levator scapulae?

Answer 29

Direct C3,4,5 via dorsal scapular nerve

Question 30

What are these muscles? picture

Answer 30

picture

Question 31

What innervates the scalenes?

Answer 31

Anterior scalene = ant. rami C4-7 Middle scalene = ant. rami C3-7 Posterior scalene = ant. rami C5-7

Question 32

What is the function of the scalenes?

Answer 32

- Flex neck (bilateral) - Tilt head to same side (unilateral) - Elevate upper ribs