Lab 6: Axial Muscles

Origin

the less moveable attachment point of a muscle

Insertion

The more moveable attachment point of a muscle

Agonist

prime mover muscle

Synergist

assists the prime mover (agonist) in performing a movement

Antagonist

opposes the movement of the agonist

Epicranius

Buccinator

Levator labii superioris

depressor labii inferioris

depressor anguli oris

mentalis

orbicularis oris

zygomaticus

orbicularis oculi

temporalis

masseter

medial pterygoid

lateral pterygoid

Platysma

Digastric

Sternocleidomastoid

Scalene

Splenius

Origin, Insertion, and action of Epicranius

• Superior nuchal line

• skin at the eyebrow

• raises eyebrow and wrinkles forehead

Action of Buccinator

compresses cheeks

Action of Levator labii superioris

help raise the upper lip

Action for Depressiors labii inferioris

depress lower lip

Action and antagonist for Depressor anguli oris

• draw corner of the mouth down but to the side laterally

• zygomatic muscle

Action for mentalis

helps wrinkle chin and protrudes chin lower

action for orbicularis oris

helps closes and pucker lips

Origin, Insertion, Action, and antagonist for Zygomaticus

• Zygomatic bone

• corner of the mouth

• helps smile

• depressor anguli oris

Origin, Insertion, Action, and antagonist for temporalis

• temporal fossa

• coronoid process and ramus of the mandible

• helps close jaw and elevate and retract mandible

• lateral pterygoid and digastric

Origin, Insertion, Action, and antagonist for Masseter

• Zygomatic arch

• mandibular ramus and mandibular angle

• involved with chewing

• temporalis

Origin, Insertion, Action, and antagonist for medial pterygoid

• palatine bone and pterygoid processes

• mandibular ramus and mandibular angle

• elevation and bringing the jaw foward

• lateral pterygoid and digastic

Origin, Insertion, Action for Lateral Pterygoid

• greater wing of Sphenoid bone

• condylar process

• moves mandible side to side

Action for orbicularis oculi

closes eye

Origin, Insertion, and Action for Platysma

• fascia of chest

• lower margin of mandible

• tenses the neck and lowers mandible

Origin, Insertion, Action, and antagonist for Digastric

• inner surface of the mandible

• hyoid bone

• helps elevate hyoid bone and depress the mandible

• masseter, temporalis, medial pterygoid, and superior division of lateral pterygoid

Origin, Insertion, Action, and antagonist for Sternocleidomastoid

• manubrium of the sternum

• mastoid process of the temporal bone

• flexes and laterally rotates the head

• longus capitis and rectus capitis anterior and upper fibers of trapezius and levator scapulae

Origin, Insertion, Action, and antagonist for scalene

• transverse processes of the cervical vertebrae

• antrolaterally on the first two ribs

• elevates the first two ribs, and helps flex and rotate the neck

• splenius cervicis and other deep neck muscles

Origin, Action, and antagonist for splenius

• spinous process

• extend the head and neck, laterally flexes and rotates the head and neck to the same side

• sternocleidomastoid