Muscle Types & Names

MusclesMuscles

• Muscles cause movement primarily @ the joints

• Muscles can attach to the body in 3 ways:

-directly to the bone

-by tendons (cords of connective tissue)

-by an aponeurosis (sheet of connective tissue)

Types of MusclesTypes of Muscles

Prime mover – muscle with the major

responsibility for a

certain movement

Antagonist – muscle that opposes or

reverses a prime mover

Types of MusclesTypes of Muscles

Synergist – muscle that aids a prime

mover in a movement and

helps prevent rotation

Fixator – stabilizes the origin of a prime

mover

Naming of Skeletal MusclesNaming of Skeletal Muscles

Direction of muscle fibers

Example: rectus (straight)

Relative size of the muscle

Example: maximus (largest)

Naming of Skeletal MusclesNaming of Skeletal Muscles

Location of the muscle

Example: many muscles are named for bones (e.g., temporalis)

Number of origins

Example: triceps (three heads)

Naming of Skeletal MusclesNaming of Skeletal Muscles

Location of the muscles origin and insertion

Example: sterno (on the sternum)

Shape of the muscle

Example: deltoid (triangular)

Action of the muscle

Example: flexor and extensor (flexes or extends a bone)

Muscles of the Head(Face/Neck)

Muscles of Facial Muscles of Facial ExpressionExpression

• Frontalis:

Origin - cranial aponeurosis

Insertion - skin of eyebrows

Action - raises eyebrows

Muscles of Facial Muscles of Facial ExpressionExpression

• Orbicularis oculi:

Origin - frontal bone & maxilla

Insertion - tissue around eyes

Action - blinks and closes eyes; squinting

*spincter muscle of eyelids*

Muscles of Facial Muscles of Facial ExpressionExpression• Zygomaticus

Origin - zygomatic bone

Insertion - skin & muscle @ corner of lips

Action - raises corner of mouth

(smiling muscle)

*extends diagonally from corner of mouth to cheekbone*

Muscles of Facial Muscles of Facial ExpressionExpression• Orbicularis oris

Origin - mandible & maxilla

Insertion - skin & muscle around mouth

Action - closes mouth, purses and protrudes lips (kissing muscle)

*encircles mouth; sphincter muscle of lips with

fiber that run in many different directions*

Muscles of mastication Muscles of mastication (chewing)(chewing)

• Masseter

Origin - zygomatic arch of temporal bone

Insertion - mandible

Action - closes jaw & elevates mandible

*extends across jawbone*

Muscles of mastication Muscles of mastication (chewing)(chewing)

• Temporalis

Origin - temporal bone

Insertion - mandible

Action - closes jaw & elevates mandible

*fan-shaped muscle over temporal bone*

Muscles of mastication Muscles of mastication (chewing)(chewing)• Buccinator:

Origin - maxilla and mandible near molars

Insertion - orbicularis oris

Action - compresses cheek (as in whistling &

sucking); holds food between teeth

during chewing

*principal muscle of cheek; runs horizontally,

deep to masseter*

Neck MusclesNeck Muscles

• Sternocleidomastoid

Origin - sternum & clavicle

Insertion - mastoid process of temporal bone

Action - flexes neck forward; rotates head

*two-headed muscle located deep to platysma on anterolateral surface of neck*

Neck MusclesNeck Muscles• Platysma

Origin - connective tissue covering superior chest muscles

Insertion - tissue around the mouth

Action - depresses the mandible, pulls corners of mouth inferiorly (frowning muscle)

*thins, sheet-like superficial muscle, plays a role in facial expression*

Head and Neck MusclesHead and Neck Muscles

The End!