Muscles of the face, head, and neck

Functions of muscles

• 1. Movement• 2. Heat production• 3. Maintain posture/body position

Types of muscle• There are approx. 640 muscles in the body (~320 pairs).

These muscles are grouped into 3 categories. • Skeletal muscle (striated): Muscle that is under voluntary

control. Most are attached to the skeleton by tendons at one or both ends, but some are attached to skin, cartilage, or organs.

• Smooth muscle(non-striated): muscle that is involuntary. Most of this muscular tissue is found in internal organs. It is under the control of the autonomic nervous system so it doesn’t involve voluntary control.

• Cardiac muscle(striated): Special muscle only found in the heart. Although it’s striated like skeletal, it’s involuntary. This muscle generates its own electrical impulses and requires a constant supply of oxygen.

Characteristic Skeletal muscle Smooth muscle Cardiac muscle

Location Attached to skeleton Walls of intestines, blood vessels, etc.

Walls of heart

Type of control Voluntary Involuntary Involuntary

Striations Present Absent Present

Speed of contraction Most rapid Slowest Intermediate

Ability to remain contracted

Least Greatest Intermediate

Energy Production

• The energy required for muscle contraction is derived from the metabolism of glucose (sugar). Muscle fibers need to continually resynthesize ATP (energy) because they can only store small amounts. The oxidation of glucose produces carbon dioxide and water, which in turn produces lactic acid.

• Only 1/3 of the energy muscles receive is used for work, the remainder is released in the form of heat to maintain body temperature. Our muscles can create heat through voluntary activity (walking) or involuntary activity (shivering)

Helpful hints for naming muscles

• Size: • Vastus • Maximus • Longus • Minimus • Brevis • Shape: • Deltoid • Latissimus • Teres • Trapezius • Rhombus

• Location: • Pectoralis • Gluteus • Brachii • Supra- • Infra- • Sub- • Lateralis • Medialis• Intermedius• Direction of muscle fibers:• Rectus • Oblique

• Action: • Adductor • abductor • flexor• Extensor • Levator • Number of attachments:• Triceps • Biceps • Quadriceps

More terms!!!

• Prime mover: Muscle whose contraction is the major source of a particular movement

• Antagonist: muscle that opposes the action of a prime mover or initiates an opposite movement.

• Tendon: Band that connects muscle to bone• Origin: Typically, a muscle’s proximal attachment

and most stationary point• Insertion: Typically, a muscle’s distal attachment

that moves with the bone during contraction.

Helpful hints for naming muscles

• Size: vastus (huge)• maximus (large)• longus (long)• minimus (small)• brevis (short)• Shape: Deltoid (triangle)• latissimus (wide)• teres (round)• trapezius (trapezoid)• rhombus (rhomboid).

• Location: Pectoralis (chest)• gluteus (buttock)• brachii (arm)• supra-(above) • infra-(below) • sub-(under, beneath) • lateralis (lateral)• Direction of muscle fibers:• Rectus (Straight)• Oblique (Angular)

• Action: adductor (towards midline)• abductor (away from midline)• flexor (flexes)• extensor (extends)• levator (to lift or elevate)• Number of attachments:• Triceps (3 attachments)• Biceps (2 attachments)• Quadriceps (4 attachments)

Frontalis

Frontalis

Zygomaticusminor

Frontalis

Zygomaticusminor

Zygomaticus major

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Mentalis

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Mentalis

Orbicularis oculi

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Mentalis

Orbicularis oculi

Levator labii superioris

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Mentalis

Orbicularis oculi

Levator labii superioris

Orbicularis oris

Frontalis

Zygomaticusminor

Zygomaticus major

Risorius

Mentalis

Orbicularis oculi

Levator labii superioris

Orbicularis oris

Depressor labiiinferioris

Muscles of head/neck

Temporalis

Muscles of head/neck

Temporalis

Occipitalis

Muscles of head/neck

Temporalis

Occipitalis

Sternocleidomastoid

Muscles of head/neck

Temporalis

Occipitalis

Sternocleidomastoid

Trapezius

Muscles of head/neck

Temporalis

Occipitalis

Sternocleidomastoid

PlatysmaTrapezius

Muscles of head/neck

Temporalis

Occipitalis

Sternocleidomastoid

PlatysmaTrapezius

Masseter

Muscles of head/neck

Temporalis

Occipitalis

Sternocleidomastoid

PlatysmaTrapezius

Masseter

Buccinator

Actions of facial muscles• Orbicularis Oculi-Closes eye as in blinking• Frontalis & Occipitalis-Together are known as the epicranius and

are responsible for raising the eyebrows, wrinkling the skin of the forehead

• Zygomaticus major: Elevates and retracts corner of the mouth• Zygomaticus minor: Elevates and retracts upper lip• Levator labii superioris: Elevates and puckers upper lip• Risorius: Moves corners of mouth laterally • Orbicularis oris: Closes lips (kissing muscle)• Depressor labii inferioris: Depresses lower lip (frown)• Mentalis: Moves lower lip forward• Masseter: Closes jaw • Buccinator: Compresses cheeks against teeth (sucking), allows

cheeks to expand during blowing (trumpeter muscle).

Actions of head/neck muscles

• Temporalis: closes jaw• Platysma: Depresses mandible, draws corner

of mouth downward, tenses skin of neck• Sternocleidomastoid: Flexes and rotates neck• Trapezius: Extends and rotates neck