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.

CharacteristicSkeletal muscleSmooth muscleCardiac muscle LocationAttached to skeletonWalls of intestines, blood vessels, etc. Walls of heart Type of controlVoluntaryInvoluntary StriationsPresentAbsentPresent Speed of contractionMost rapidSlowestIntermediate Ability to remain contracted LeastGreatestIntermediate

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

Zygomaticus minor

Frontalis Zygomaticus minor Zygomaticus major

Frontalis Zygomaticus minor Zygomaticus major Risorius

Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis

Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis Orbicularis oculi

Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis Orbicularis oculi Levator labii superioris

Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis Orbicularis oculi Levator labii superioris Orbicularis oris

Frontalis Zygomaticus minor Zygomaticus major Risorius Mentalis Orbicularis oculi Levator labii superioris Orbicularis oris Depressor labii inferioris

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 Platysma Trapezius

Muscles of head/neck Temporalis Occipitalis Sternocleidomastoid Platysma Trapezius Masseter

Muscles of head/neck Temporalis Occipitalis Sternocleidomastoid Platysma Trapezius 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