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LIF101 Anatomy. Lecture 8: Head and Neck Muscles, Eyes and Nose. Muscles of the Head and Face. Lie in scalp and face, just beneath skin Thinner, flatter than body muscles Insert into skin (instead of bone) Facilitate facial expressions. Muscles of the Head and Face.
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LIF101Anatomy Lecture 8: Head and Neck Muscles, Eyes and Nose
Muscles of the Head and Face • Lie in scalp and face, just beneath skin • Thinner, flatter than body muscles • Insert into skin (instead of bone) • Facilitate facial expressions
Muscles of the Head and Face • Epicraneous consists of 2 parts: • frontal portion: inserts in the fascia of facial muscles and in the skin above the eyes and nose. Draws the scalp back • occipital portion: insertion points on nuchal lines and on mastoid process • Connected by epicranial aponeurosis
Connected by Epicranial Aponeurosis • Connects frontal and occipital muscles A wide thin tendon that covers the top of the cranium. In humans, the epicraneous muscle only serves for facial expressions
Muscles of the Head and Face • Temporalis • origin: temporal line • insertion: coranoid process of mandible, which is just anterior to TMJ • Function: raises lower jaw/elevates and retracts mandible (holds it in place) • Can be felt over temporal bone when clenching teeth
Temporal-mandibular joint • TMJ syndrome: • Pain or dysfunction of the temporal-mandibular joint is commonly referred to as "TMJ", • Problems involving the TMJs and the muscles, tendons, ligaments, blood vessels, and other tissues associated with them.
Muscles of the Head and Face • Orbicularis Oris • circular muscle around mouth • for closing lips, puckering, kissing • Orbicularis Oculi • circular muscles around eyes • for blinking, squinting
Muscles of the Head and Face • Levator Palpebra • raises upper eyelid
Muscles of the Head and Face • Zygomaticus major and minor • raises corners of mouth outward and upward (smile) • minor is smaller and more anterior than major
Zygomaticus minor origin: zygomatic bone insertion: corners of mouth
Muscles of the Head and Face • Triangularis • origin: mandible • insertion: corners of mouth • Draws corners of mouth downward/frowning • Quadratus labii inferioris • origin: mandible • insertion: below lower lip • Draws lower lip outward and downward
Muscles of the Head and Face • Triangularis • pulls down corners of mouth • Quadratus labii inferioris • draws lower lip down and out (pout)
Muscles of the Head and Face • Masseter • origin: anterior zygomatic arch • insertion: angle of mandible • Function: raises lower jaw • Can be felt and seen over sides of mandible when chewing
Muscles of the Head and Face • Masseter • for chewing • can be seen during chewing (sometimes striations can be seen as well.)
Muscles of the Neck • Platysma • Thin muscle that covers anterior neck and upper chest • Draws lower lip downward and outward; raises skin of neck from underlying parts • signals strain
The platysma is the muscle in your upper torso starting from your face, neck, and upper chest. Controls facial expressions, by helping move the lower lip down and sideways. • Exercising the platysma muscle has been a proven way to get rid of double chin, which occurs when unneeded fat gets stored in that area.
Muscles of the Neck • Sternocleidomastoid • dual origin: medial clavicle and manubrium of sternum • insertion: mastoid process of temporal bone • Functions: • Together: they lift face and tip head back • Separately: turns head to opposite sides
Muscles of the Neck • Sternocleidomastoid • tilt head backward (both together) • rotates head to opposite side (separately)
Muscles of the Neck • Sternohyoid • origin: sternum • insertion: hyoid bone • often can be seen between the “V” of sternocleidomastoid • Function: draws hyoid bone backward and upward
Hyoid Bone • The hyoid is anchored by muscles from the anterior, posterior, and inferior directions and aids in tongue movement and swallowing. • Doesn’t articulate with any other bones
Parotid Gland • Anterior and inferior to ear • partially covers masseter muscle • gives roundness to face • Largest salivary gland
Thyroid Cartilage • A.K.A. “Adam’s Apple” • Anterior neck surface landmark • Surrounds upper trachea • Encloses larynx • Larger and more angular in male
The Eye • Lies in orbit, slightly superior and lateral to center • Spherical, except at cornea
Parts of the Eye • Sclera • Iris • Pupil • Cornea • Lids (upper and lower)
Cornea • Clear covering over the iris and pupil. Non vascular and easily transplantable. No nerves = no feeling
Parts of the Eye • Inner canthus • Outer canthus • Caruncle • Infrapalpebral furrow • Eyelashes • Eyebrow
Parts of the Nose(underlying structures in parentheses) • Bridge (nasal bone) • Lateral surfaces (lateral cartilage) • Apex (alar cartilage) • Ala (alar fat) • Septum (septal cartilage) • Alar furrows • Nostrils (holes)
Assignments • Peck, pp. 96 – 101, 162 - 165, 168 – 169 • QUIZ NEXT WEEK: Head, neck, and face muscles, eye and nose anatomy