Posterior triangle muscles

Question 1

Platysma is found in the? (origin and insertion)

Answer 1

superficial fascia

Question 2

sternocleidomastoid (SCM) origin

Answer 2

manubrium and medial clavicle

Question 3

SCM insertion

Answer 3

mastoid process and superior nuchal line

Question 4

SCM innervation

Answer 4

CN XI aka Spinal accessory nerve

Question 5

SCM action

Answer 5

• acting unilaterally = laterally flexes and rotates

* acting bilaterally= posterior fibers act to extend the neck; anterior fibers act to flex the neck

Question 6

SCM anterior and posterior fibers attach?

Answer 6

• *posterior fibers attach at superior nuchal line and clavicle AND ACT to extend the neck
• *anterior fibers attach at mastoid process and manubrium AND ACT to flex the neck

Question 7

SCM stands for?

Answer 7

sternocleidomastoid muscle

Question 8

trapezius origin

Answer 8

external occipital protuberance, nuchal ligament, spinous processes down to T12

Question 9

trapezius insertion

Answer 9

lateral 1/3rd of clavicle, acromion, spine of scapula

Question 10

trapezius innervation

Answer 10

CN XI aka Spinal accessory nerve

Question 11

trapezius action

Answer 11

elevate, depress, and retract scapula; rotate scapula superiorly

Question 12

Semispinalis capitis and Splenius capitis origin

Answer 12

upper thoracic and lower cerivical vertebrae

Question 13

Semispinalis capitis and Splenius capitis insertion

Answer 13

occipital bone, between nuchal lines to mastoid process

Question 14

Semispinalis capitis and Splenius capitis innervation

Answer 14

posterior rami of cervical nerves (Dorsal rami because deep neck)

Question 15

Semispinalis capitis and Splenius capitis action

Answer 15

Unilateral = lateral flexion and rotation
bilateral= extension of head

Question 16

What two muscles are innervated by CN XI aka Spinal accessory nerve?

Answer 16

trapezius and sternocleidomastoid (SCM)

Question 17

Levator scapulae origin

Answer 17

C1-C4 vertebrae

Question 18

Levator scapulae insertion

Answer 18

medial border of scapula

Question 19

Levator scapulae innervation

Answer 19

C3-C5 nerves

Question 20

Levator scapulae action

Answer 20

Elevate scapula

Question 21

Posterior, Middle and Anterior Scalene origin?

Answer 21

C2-C7 vertebrae

Question 22

Posterior, Middle and Anterior Scalene insertion?

Answer 22

1st and 2nd ribs

Question 23

Posterior, Middle and Anterior Scalene innervation?

Answer 23

C3-C6 nerves

Question 24

Posterior, Middle and Anterior Scalene action?

Answer 24

Elevate ribs (inspiration)
*scalene muscles are accessory muscles to the diaphragm because they help to elevate the ribs, which increase the volume in the thoracic cavity

Question 25

Inferior belly of omohyoid origin

Answer 25

superior scapula

Question 26

Inferior belly of omohyoid insertion

Answer 26

hyoid bone via intermediate tendon

Question 27

Inferior belly of omohyoid innervation

Answer 27

ansa cervicalis (part of cervical plexus)

Question 28

Inferior belly of omohyoid action

Answer 28

depresses larynx (phonation and swallowing)

Question 29

What triangle is the superior and inferior belly of omohyoid found?

Answer 29

inferior= posterior
superior= anterior

Question 30

Platysma innervation?

Answer 30

facial nerve

Question 31

Platysma action?

Answer 31

tenses skin of neck