posterior triangle of the neck

Question 1

what are the borders of the posterior triangle of the neck?

Answer 1

anterior border: posterior border of SCM
posterior border: anterior border of trapezius
base: clavicle

Question 2

what are the contents of the posterior triangle of the neck?

Answer 2

external jugular vein
roots of the brachial plexus
accessory nerve
cranial and supraclavicular lymph nodes

Question 3

what is the course of the lesser occipital nerve?

Answer 3

it passes from beneath the SCM to ascend the neck towards the suboccipital region

Question 4

what do supraclavicualr nerves supply?

Answer 4

the skin on the lateral side of the neck and clavicle

Question 5

explain the course of the great auricular nerve

Answer 5

it passes from beneath the SCM to cross the anterior surface of SCM accompanied by the external jugular vein

Question 6

which veins form the external jugular vein?

Answer 6

the external jugular vein is formed by the union of the posterior auricuarl vein w/ the posterior division of the retromandibular vein

Question 7

explain the course of the external jugular vein

Answer 7

it crosses the anterior surface of SCM to pass into the posterior triangle and cross the anterior surface of the posterior belly of omohyoid to reach the subclavian vein deep in the root of the neck

Question 8

what nerve supplies trapezius and SCM w/ motor innervation?

Answer 8

the spinal accessory nerve

Question 9

which muscle is found in both triangles of the neck?

Answer 9

omohyoid

the posterior belly of omohyoid crosses the posterior triangle

Question 10

which 3 small vessels cross the posterior triangle immediately posterior to omohyoid?

Answer 10

transverse cervical artery
supra scapular artery
suprascapular vein

Question 11

what nerve roots are seen in the posterior triangle of the neck?

Answer 11

the roots of the brachial plexus and the phrenic nerve

Question 12

what are the nerve roots of the phrenic nerve?

Answer 12

C3,C4,C5

Question 13

explain the course of the phrenic nerve

Answer 13

it descends into the neck and crosses the anterior scalene muscle in the root of the neck before passing into the thorax

Question 14

explain the course of the roots of the brachial plexus

Answer 14

the roots of the brachial plexus arise from C5-T1 and cross through the posterior triangle of the neck to pass under the clavicle and into the axilla

Question 15

what are the muscles of the posterior triangle of the neck?

Answer 15

sternocleidomastoid
trapezius
omohyoid
scalane muscles
levator scapulae
splenuius capitis

Question 16

which triangle does SCM lie in?

Answer 16

it forms the borders between the triangles of the neck so technically doesn’t lie in either triangle

Question 17

explain the distribution of SCM

Answer 17

it is a v large muscle that attaches to the mastoid process of the temporal bone and crosses the neck to attach to both the clavicle and the sternum

Question 18

what is the innervation of SCM?

Answer 18

motor innervation: spinal accessory nerve (CN11)

proprioception: cervical plexus (C2,3)

Question 19

what does lateral flexion of SCM do?

Answer 19

brings the head closer to the shoulder

Question 20

what does extension of SCM do?

Answer 20

pulls the head backwards

Question 21

what does flexion of SCM do?

Answer 21

pulls the chin towards the body wall

Question 22

does trapezius lie in the posterior triangle?

Answer 22

no, it forms the posterior boundary of the posterior triangle so does not lie w/in the triangle itself

Question 23

what forms the muscular floor of the posterior triangle?

Answer 23

omohyoid, scalene muscles, levator scapulae and splenius capitis

Question 24

what is the function of omohyoid?

Answer 24

depresses the hyoid bone

Question 25

what is the innervation of omohyoid?

Answer 25

it is innervated by ansa cervicalis

Question 26

what are the two functions of splenius capitis?

Answer 26

elevate the scapula
laterally flex the neck if the shoulder is in a fixed position

Question 27

what is the innervation of levator scapulae?

Answer 27

innervated directly by C3,C4 and C5 via the dorsal scapular nerve

Question 28

which nerve crosses the anterior scalene?

Answer 28

the phrenic nerve

Question 29

where in relation to the scalenes do the roots of the brachial plexus lie?

Answer 29

between anterior and middle scalenes

Question 30

what are the functions of the scalene muscles?

Answer 30

flex the neck (bilateral)
tilt the head to the same side (unilateral)
elevate the upper ribs

Question 31

what is the innervation of the posterior scalene?

Answer 31

anterior rami of C5-C7

Question 32

what is the innervation of the anterior scalene?

Answer 32

anterior rami of C4-C7

Question 33

what is the innervation of the middle scalene?

Answer 33

anterior rami of C3-C7