Head and Neck Muscles

2 categories of head muscles

1. Facial muscles

2. Chewing muscles

facial muscles

insert into the soft tissues such as other muscles/ skin

(allow us to express emotion)

chewing muscles

begin the breakdown of food in the body

all head and neck muscles are paired except for the ___________ , ______________ oris, __________, + ____________

1. platysma

2. Orbicularis

3. frontalis

4. occipitalis

frontalis

covers the frontal bone, runs from cranial aponeurosis + inserts into the skin of eyebrows

i.e. allows you to raise your eyebrows

occipitalis

covers the posterior aspect of the skull and pulls the scalp posteriorly

orbicularis oculi

fibers run circularly around the eye

i.e. can squint, blink/ wink

orbicularis oris

circular muscle of the lips

i.e. closes mouth + protrudes lips

Buccinator

runs horizontally across the cheek, inserts into orbicularis oris

i.e. flattens the cheek to whistle, compresses cheek when eating

Zygomaticus

extends from the corners of the mouth to the cheekbone

i.e. smiling

masseter

runs from zygomatic process of temporal bone to the mandible,

i.e. closes lower jaw by elevating the mandible

temporalis

fan-shaped muscle overlying the temporal bone, inserts into the mandible + acts as a synergist of the masseter

i.e. closes jaw

neck muscles

platysma, sternocleidomastoid, trapezius

Platysma

single sheet-like muscle, covers the front of neck, origin at the connective tissue covering chest muscles + inserts into area around the mouth

i.e. pulls mouth downward

Sternocleidomastoid

paired muscles found on the right and left side of the neck, one head from the sternum, one from the clavicle, both heads fuse before inserting into the mastoid process,

i.e. when both contract--> flex the neck, head can bow forward

- when one contracts--> face rotates to the opposite shoulder

Trapezius

most superficial of the neck muscles, form a diamond, runs from the occipital bone to the vertebral column to the end of thoracic vertebrae, they flare + insert on the scapular spine and clavicle

i.e. extends head, + elevates, depresses, adducts, + stabilizes the scapula