Posterior Cervical Triangle

Question 1

What are the borders of the posterior cervical triangle?

Answer 1

• Sternocleidomastoid muscle
• Trapezius muscle
• Clavicle

Question 2

Posterior triangle is divided by…

Answer 2

inferior belly of omohyoid

Question 3

The inferior belly of omohyoid divides the posterior cervical triangle into what two smaller triangles?

Answer 3

• Occipital triangle
• Subclavian triangle

Question 4

What six muscles can be found in the posterior triangle?

Answer 4

• Splenius capitis
• Levator scapulae
• Anterior scalene (inferomedial angle of triangle or behind SCM)
• Middle scalene
• Posterior scalene
• Omohyoid (inferior belly)

Question 5

Innervation of splenius capitis

Answer 5

Posterior rami of middle cervical spinal nerves

Question 6

Actions of splenius capitis

Answer 6

Laterally flexes and rotates head and neck to same side; acting bilaterally, extends head and neck

Question 7

Innervation of levator scapulae

Answer 7

Dorsal scapular nerve C5 and cervical spinal nerves C3 and C4

Question 8

Actions of levator scapulae

Answer 8

Downward rotation of scapula and tilts its glenoid cavity inferiorly by rotating scapula

Question 9

Innervation of anterior scalene

Answer 9

Cervical spinal nerves C4-C6

Question 10

Actions of anterior scalene

Answer 10

Flex head

Question 11

Innervation of middle scalene

Answer 11

Anterior rami of cervical spinal nerves

Question 12

Actions of middle scalene

Answer 12

Flexes neck laterally; elevates 1st rib during forced inspiration

Question 13

Innervation of posterior scalene

Answer 13

Anterior rami of cervical spinal nerve C7 and C8

Question 14

Actions of posterior scalene

Answer 14

Flexes neck laterally; elevates 2nd rib during forced inspiration

Question 15

Which arteries of the posterior triangle are branches of thyrocervical trunk?

Answer 15

• Transverse cervical artery
• Suprascapular artery

Question 16

The transverse cervical artery is superficial to…

Answer 16

• anterior scalene
• phrenic nerve
• trunks of brachial plexus

Question 17

The transverse cervical artery runs ___ toward ___ and bifurcates into ___

Answer 17

…runs posteriorly toward trapezius and bifurcates into superficial and deep branches

Question 18

The suprascapular artery is ___ to the clavicle

Answer 18

posterior

Question 19

The suprascapular artery is inferolateral across…

Answer 19

• anterior scalene
• phrenic nerve
• 3rd part of subclavian artery
• cords of brachial plexus

Question 20

What are the arteries of the posterior triangle?

Answer 20

• Branches of thyrocervical trunk (transverse cervical and suprascapular arteries)
• Third part of subclavian artery
• Occipital artery

Question 21

Where is the third part of the subclavian artery in relation to ribs and brachial plexus?

Answer 21

• Lies on first rib
• Anterior to inferior (lower) trunk of brachial plexus

Question 22

What are the veins of the posterior triangle?

Answer 22

• External jugular vein
• Subclavian vein

Question 23

The external jugular vein is deep to ___ and superficial to ___

Answer 23

deep to platysma and superficial to SCM

Question 24

Describe drainage by the external jugular vein

Answer 24

Drains most of scalp and lateral face into subclavian vein

Question 25

The subclavian vein is anterior to...

Answer 25

anterior scalene

Question 26

The subclavian vein joins ___ to form the ___ posterior to the medial end of the clavicle

Answer 26

joins **internal jugular vein** to form the **brachiocephalic vein** posterior to the medial end of the clavicle

Question 27

What are the three main motor innervation sources of the posterior triangle?

Answer 27

* Spinal accessory (CN XI) * Trunks of brachial plexus * Deep motor branches of cervical plexus

Question 28

Which trunks of the brachial plexus innervate the posterior triangle?

Answer 28

* Superior (upper) trunk: C5-C6 * Middle trunk: C7 * Inferior (lower) trunk: C8-T1

Question 29

Where in the brachial plexus will the suprascapular nerve (C4-C6) branch from?

Answer 29

Superior (upper) trunk

Question 30

What are the deep motor branches of the cervical plexus innervating the posterior triangle?

Answer 30

* Dorsal scapular nerve (C4-C5) * Long thoracic nerve (C5-C7) * Nerve to subclavius (usually C4-C6) * Phrenic nerve (C3-C5)

Question 31

What structures are innervated by the dorsal scapular nerve?

Answer 31

Rhomboids; occasionally levator scapulae

Question 32

What structures are innervated by the long thoracic nerve?

Answer 32

Serratus anterior

Question 33

What structures are innervated by the suprascapular nerve?

Answer 33

Supraspinatous and infraspinatus muscles; glenohumeral joint

Question 34

What structures are innervated by the subclavian nerve?

Answer 34

Subclavius and sternoclavicular joint

Question 35

Sensory nerves of the posterior triangle are derived from...

Answer 35

cervical plexus

Question 36

Which sensory nerves are in the nerve point of the neck (Erb's point)?

Answer 36

* Lesser occipital nerve (C2) * Great auricular nerve (C2-C3) * Transverse cervical nerve (C2-C3) * Supraclavicular nerves (C3-C4) (medial, intermediate, lateral)