posterior triangle

Question 1

the anterior and posterior triangles are separated by the ?

Answer 1

sternocleidomastoid

Question 2

boundaries of posterior triangle

Answer 2

anterior: posterior border of SCM
posterior: anterior border of trap
inferior: middle 1/3 of clavicle
apex: where SCM meets the trap on superio nuchal line

Question 3

inferior belly of omohyoid divides posterior triangle into 2 triangles

Answer 3

• occipital: occipital artery and spinal accessory

- subclavian or supraclavicular: contains subclavian vessels and lower end of EJV

Question 4

roof of posterior triangle contains

Answer 4

terminal branches of cervical plexus, external jugular vein, and superficial cervical lymph nodes

Question 5

floor of posterior triangle contains

Answer 5

semispinalis capitis
splenius capitis
levator scapulae
scalene mass: scalene posterior, scaleneus medius

Question 6

what are the muscles of the floor of posterior triangle covered by?

Answer 6

prevertebral layer of deep cervical fascia

Question 7

scalene muscles are hidden under?

Answer 7

SCM

Question 8

nerves of posterior triangle

Answer 8

• spinal accessory
• roots of cervical plexus (C1-C4) and its branches
• roots (C5-T1) and trunks of brachial plexus

Question 9

arteries of posterior triangle

Answer 9

• subclavian (3rd part)
• branches from thyrocervical trunk: suprascapular and transverse cervical arteries
• dorsal scapular (branch of 3rd part)

Question 10

veins of posterior triangle

Answer 10

subclavian

lower end of external jugular vein

Question 11

muscle of posterior triangle

Answer 11

inferior belly of omohyoid

Question 12

contents of posterior triangle

Answer 12

• great auriculuar nerve
• lesser occipital nerve
• spinal acc
• phrenic nerve
• transverse cervical artery
• brachial plexus
• suprascapular artery
• subclavian artery
• subclavian vein
• thyrocervical trunk
• inferior thyroid artery
• ansa cervicalis

Question 13

what nerve goes through the trapezius?

Answer 13

spinal accessory

Question 14

what makes up the ansa cervicalis?

Answer 14

descendense hypoglossi (from C1 motor) and descendens cervicalis (from C2)

Question 15

the lesser occipital nerve and great auricular nerve turn into

Answer 15

transverse cervical

Question 16

supraclavicular nerve comes from?

Answer 16

C3

Question 17

C3, C4, C5 turn into

Answer 17

phrenic nerve above scalene anterior muscle

Question 18

cutaneous branch of cervical plexus

Answer 18

1. great auricular (C2-3): supplies skin over parotid gland and behind the auricle and over angle of jaw
2. lesser occipital nerve (C2): supplies the scalp behind and above the ear
3. transverse cervical nerve (C2-3): crosses SCM to anterior triangle. Supplies skin of the front of neck
4. supraclavicular nerve (C3-4): divides into lateral, intermediate, and medial branches. Supplies the skin of the front of thoracic wall and shoulder

Question 19

motor branch of cervical plexus

Answer 19

1. superior root of ansa cervicalis (C1, descendens hypoglossi)
2. inferior root of ansa cervicalis (C2 & 3, descendens cervicalis)
3. phrenic nerve (mainly C4 with contribution from C3 and C5), descends anterior to scalenes anterior muscle and supplies diaphragm
4. deep motor branches to prevertebral muscles and shoulder muscles

Question 20

spinal accessory nerve

Answer 20

• passes deep to SCM
• supplies SCM before entering junction of upper and middle 1/3 of SCM
• crosses posterior triangle in or below the investing layer of deep fascia and parallel to levator scapula
• disappears under trap at junction bw upper 2/3 and lower 1/3
• supplies SCM and trap

Question 21

parts of accessory nerve

Answer 21

cranial part–jugular

accessory part–magnum (IX, X, XI)

Question 22

isolated spinal sccessory mononeuropathy (SAM)

Answer 22

iatrogenic complication of surgery in posterior triangle

-symptoms: weakness of trap; SCM involved sometimes

Question 23

brachial plexus

Answer 23

• network of nerves supplying upper limb
• composed of ventral rami of lower four (C5-C8) cervical and first thoracic spinal nerves (T1)
• divided by clavicle into supraclavicuar and infraclavicular parts

Question 24

brachial plexus roots to trunks

Answer 24

upper: C5–C6
middle: C7
lower: C8-T1

Question 25

trunks to divisions of brachial plexus

Answer 25

upper: anterior, post middle: anterior, post lower: anterior, post

Question 26

divisions to cords of brachial plexus

Answer 26

posterior to posterior cord post lateral cord to anterior division of upper and middle trunk medial cord--anterior divistion of lower trunk

Question 27

branches of brachial plexus from roots

Answer 27

1. nerve to serratus muscle from C5-C7 2. nerve to rhomboid (dorsal scapular nerve) from C5 3. phrenic nerve from C5

Question 28

branches of brachial plexus from trunks

Answer 28

nerve to subclavius and suprascapular nerves from upper trunk

Question 29

branches of brachial plexus from lateral cord

Answer 29

- musculocutaneous nerve - lateral pectoral nerve - lateral root of median nerve

Question 30

branches from medial cord

Answer 30

``` ulnar nerve medial root of median nerve medial pectoral nerve medial cutaneous nerve of arm medial cutaneous nerve of forearm ```

Question 31

branches from posterior cord

Answer 31

upper and lower subscapular nerves thoracodorsal nerve (to latissmus dorsi) axillary and radial nerves

Question 32

erb-duchenne upper trunk palsy

Answer 32

- paralysis of upper trunk of brachial plexus (C5-C6) | - porter's tip hand

Question 33

dejerine-klumpke lower trunk palsy

Answer 33

paralysis of lower trunk of brachial plexus (C8-T1) | -causes paralysis of intrinsic muscles of the hand causing Claw Hand

Question 34

four types of brachial plexus injuries

Answer 34

1. avulsion: most severe-- nerve torn from spine 2. rupture: nerve torn but not at spinal attachment 3. neuroma: nerve torn and healed but scar tissue pressures on injured nerve and prevents it from conducting signals to muscle 4. neuropraxia or stretch : nerve damaged but not torn**most common

Question 35

the right subclavian artery comes as a ----- while the left comes as a ----

Answer 35

right comes from brachiocephalic artery | left comes from branches

Question 36

origin of subclavian artery

Answer 36

RT: brachiocephalic left: aorta

Question 37

termination of subclavian artery

Answer 37

at outer border of first rib as axillary artery

Question 38

1st part of subclavian branches into?

Answer 38

1. vertebral artery 2. internal thoracic (mammary) artery (breast and thoracic wall) 3. thyrocervical trunk that gives 3 branches: inferior thyroid, transverse cervical, suprascapular

Question 39

2nd part (deep to sc. anterior) of subclavian

Answer 39

costocervical trunk that gives superior intercostal and deep cervical branches

Question 40

from 3rd part of subclavian (lateral to Sc. anterior)

Answer 40

dorsal scapular artery