Facial Expressions and the Occipitofrontalis Muscle
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Questions and Answers

What is the primary action of the levator anguli oris muscle?

  • Depressing the angle of the mouth
  • Retracting the jaw
  • Protruding the lower lip
  • Elevating the angle of the mouth (correct)

    • Which muscle is primarily responsible for keeping food between the teeth during chewing?

  • Mentalis
  • Buccinator (correct)
  • Risorius
  • Platysma

    • Which cranial nerve innervates the mentalis muscle?

  • Cranial nerve VII (correct)
  • Cranial nerve VIII
  • Cranial nerve V
  • Cranial nerve VI

    • What is the primary function of the platysma muscle?

    <p>Tensing the skin of the neck</p> Signup and view all the answers

    The lateral pterygoid muscle is involved in which of the following actions?

    <p>Protruding the jaw</p> Signup and view all the answers

    Which muscle originates from the zygomatic arch and is responsible for elevating the jaw?

    <p>Masseter</p> Signup and view all the answers

    Which of the following muscles contributes to expressions of doubt or dislike?

    <p>Mentalis</p> Signup and view all the answers

    What is a key function of the buccinator muscle?

    <p>Controlling airflow during speech</p> Signup and view all the answers

    Which muscle’s insertion blends with the fibers of the orbicularis oris?

    <p>Buccinator</p> Signup and view all the answers

    What action does the risorius muscle perform?

    <p>Drawing the corners of the mouth laterally</p> Signup and view all the answers

    Which muscle primarily functions to elevate the upper eyelid?

    <p>Levator palpebrae superioris</p> Signup and view all the answers

    What action is performed by the zygomaticus major muscle?

    <p>Draws the angle of the mouth superiorly and laterally</p> Signup and view all the answers

    Which muscle is involved in the expression of disgust?

    <p>Nasalis</p> Signup and view all the answers

    What is the primary action of the depressor anguli oris muscle?

    <p>Pulls the corners of the mouth downward</p> Signup and view all the answers

    What is the innervation of the occipital belly of the occipitofrontalis muscle?

    <p>Posterior auricular nerve</p> Signup and view all the answers

    Which facial expression is characterized by furrowed brows and tightly pressed lips?

    <p>Anger</p> Signup and view all the answers

    What is the function of the orbicularis oculi muscle?

    <p>Closes the eye</p> Signup and view all the answers

    What is the main action performed by the corrugator supercilia muscle?

    <p>Draws the eyebrows inferiorly</p> Signup and view all the answers

    Which muscle helps in flaring the nostrils?

    <p>Alar nasalis</p> Signup and view all the answers

    What structure connects the frontal and occipital parts of the occipitofrontalis muscle?

    <p>Epicranial aponeurosis</p> Signup and view all the answers

    Study Notes

    Facial Expressions

    • Happiness is associated with a smile, raised cheeks, and crow's feet around the eyes.
    • Sadness is characterized by a frown, downturned lips, and drooping eyelids.
    • Anger is shown by furrowed brows, tightly pressed lips, and flared nostrils.
    • Surprise involves raised eyebrows, wide-open eyes, and a dropped jaw.
    • Fear is similar to surprise but more pronounced, with wide eyes and a tense, often raised, forehead.
    • Disgust is characterized by a wrinkled nose, raised upper lip, and squinted eyes.
    • Arrogance or superiority is displayed with one side of the mouth raised (half-smile or smirk) and often a combination of other expressions.

    Scalp Muscle: Occipitofrontalis

    • The Occipitofrontalis is a long and wide muscle responsible for facial expressions in the scalp.
    • It spans from the eyebrows to the superior nuchal lines of the occipital bone.
    • It forms the epicranial group with the temporoparietalis muscle.
    • The Occipitofrontalis has two bellies: the occipital belly and the frontal belly, each containing a pair of quadrangular muscle heads.
    • These bellies are connected by the epicranial aponeurosis (galea aponeurotica), a connective tissue layer forming the scalp's third and middle layers.
    • Functions:
      • Elevates the eyebrows and wrinkles the forehead skin with its frontal part.
      • Retracts the scalp with its occipital part.
    • Origin:
      • Frontal belly (frontalis): skin of eyebrow and muscles of the forehead.
      • Occipital belly (occipitalis): lateral ⅔ rd of the superior nuchal line.
    • Insertion: Epicranial aponeurosis.
    • Action:
      • Frontal belly: elevates eyebrows, wrinkles skin of the forehead.
      • Occipital belly: retracts the scalp.
    • Innervation:
      • Frontal belly: temporal branches of the facial nerve (CN VII).
      • Occipital belly: posterior auricular nerve (branch of the facial nerve CN VII).
    • Blood Supply: superficial temporal, ophthalmic, posterior auricular, and occipital arteries.

    Orbit & Eyebrow Muscles

    • Orbicularis Oculi:
      • Has three portions: orbital, palpebral, and lacrimal.
      • Origin: medial wall of the orbit.
      • Insertion: circular path around the orbit.
      • Action:
        • Closes the eye.
        • Assists in tear transport and drainage.
        • Controls spontaneous and reflex blinking (palpebral portion).
        • Forced closure: orbital and palpebral portions.
      • Innervation: CN VII (facial nerve).
    • Corrugator Supercilia:
      • Origin: medial end of the superciliary arch of the frontal bone.
      • Insertion: skin deep to the medial eyebrow.
      • Action:
        • Draws the eyebrow inferiorly.
        • Wrinkles the skin of the forehead vertically (frowning).
      • Innervation: CN VII (facial nerve).
      • Botox injected too far in this area can cause eyelid drooping.
    • Levator Palpebrae Superioris:
      • Origin: roof of the orbit at the lesser wing of the sphenoid bone.
      • Insertion: skin of the upper eyelid.
      • Action: elevates the upper eyelid.
      • Innervation: CN III (oculomotor nerve).

    Nose Muscles

    • Nasalis:
      • Transverse Nasalis Muscle:
        • Located on the bridge of the nose.
        • Connects from one side of the nasal cartilage to the other, blending with the procerus superiorly.
        • Origin: maxilla, near the nasal bone and cartilage.
        • Insertion: skin over the bridge of the nose, particularly at the midline.
        • Innervation: cranial nerve VII.
        • Function: Compresses the nostrils.
      • Alar Nasalis Muscle:
        • Arises from the maxilla and extends up to the wing of the nostril (alar cartilage).
        • Origin: maxilla, just above the canine fossa.
        • Insertion: alar cartilage of the nostril and the skin of the nostril.
        • Innervation: cranial nerve VII.
        • Function: flaring the nostrils.
    • Procerus:
      • Origin: fascia over the nasal bone.
      • Insertion: skin between the eyebrows.
      • Action:
        • Draws down the medial eyebrows.
        • Wrinkles the skin of the nose.
        • Gives the look of frowning and helps shield eyes from bright light.
      • Innervation: CN VII (Facial nerve).
    • Depressor Septi Nasi:
      • Origin: maxilla, above the incisor teeth.
      • Insertion: nasal septum and the lower part of the cartilage of the nose.
      • Function: pulls the nasal septum downward to widen the nostrils.
      • Innervation: cranial nerve VII.

    Mouth Muscles

    • Orbicularis Oris:
      • Origin: surrounds the mouth.
      • Insertion: skin at the corner of the mouth.
      • Action:
        • Closes the mouth.
        • Protrudes the lips (like kissing).
        • Compresses lips against teeth.
        • Shapes lips during speech.
      • Innervation: CN VII (Facial nerve).
    • Zygomaticus Major:
      • Origin: zygomatic bone.
      • Insertion: skin at the angle of the mouth and orbicularis oris.
      • Action: draws the angle of the mouth superiorly and laterally (smiling).
      • Innervation: CN VII (Facial nerve).
    • Zygomaticus Minor:
      • Origin: zygomatic bone.
      • Insertion: upper lip.
      • Action: elevation of the upper lip.
      • Innervation: CN VII (Facial nerve).
    • Levator Labii Superioris:
      • Origin: superior to the infraorbital foramen of the maxilla.
      • Insertion: orbicularis oris (upper lip).
      • Action: elevation of the upper lip.
      • Innervation: CN VII (Facial nerve).
    • Depressor Labii Inferioris:
      • Origin: mandible.
      • Insertion: skin of the lower lip.
      • Action: depression of the lower lip.
      • Innervation: CN VII (Facial nerve).
    • Depressor Anguli Oris:
      • Origin: mandible.
      • Insertion: angle of the mouth.
      • Action: pulls the corners of the mouth downward (frowning/sadness).
      • Innervation: facial nerve (CN VII).
    • Levator Anguli Oris:
      • Origin: maxilla, just inferior to the infraorbital foramen.
      • Insertion: skin of the upper lip and orbicularis oris (angle of the mouth).
      • Action: elevation of the angle of the mouth.
      • Innervation: CN VII (Facial nerve).
    • Buccinator:
      • Located in the fleshy part of the cheek.
      • Origin: outer surfaces of the maxilla and mandible near the molars and the pterygomandibular raphe.
      • Insertion: orbicularis oris.
      • Action:
        • Pressing the cheeks against the teeth during chewing.
        • Aiding in airflow control during speech.
        • Smiling and blowing.
      • Innervation: facial nerve (CN VII).
    • Risorius:
      • Origin: fascia covering the masseter muscle.
      • Insertion: skin at the corner of the mouth, blending with fibers of other facial muscles.
      • Action: draws the corners of the mouth laterally (smiling/grinning).
      • Innervation: facial nerve (CN VII).
    • Mentalis:
      • Origin: mandible.
      • Insertion: skin of the chin.
      • Action:
        • Elevates and protrudes the lower lip.
        • Pulls the skin of the chin up (pouting).
        • Wrinkles the skin of the chin.
        • Contributes to facial expressions of doubt, pouting, or dislike.
      • Innervation: CN VII (Facial nerve).

    Platysma (Neck Muscle)

    • Origin: fascia over the pectoralis major and deltoid muscles in the chest and shoulder.
    • Insertion: lower mandible and skin of the lower face, as well as the muscles around the mouth.
    • Function:
      • Tensing the skin of the neck.
      • Depresses the mandible.
      • Helps in skin movements over the neck during expressions.
    • Innervation: cervical branch of cranial nerve VII.

    Muscles of Mastication

    • Masseter:
      • Origin: zygomatic arch.
      • Insertion: ramus of the mandible.
      • Action: elevates and closes the jaw (biting and chewing).
      • Innervation: mandibular division of the trigeminal nerve (CN V).
    • Temporalis:
      • Origin: temporal fossa of the skull.
      • Insertion: coronoid process of the mandible.
      • Action: elevates and retracts the jaw.
      • Innervation: mandibular division of the trigeminal nerve (CN V).
    • Medial Pterygoid:
      • Origin: medial surface of the lateral pterygoid plate of the sphenoid bone.
      • Insertion: medial surface of the angle of the mandible.
      • Action: elevates the jaw and assists in grinding movements.
      • Innervation: mandibular division of the trigeminal nerve (CN V).
    • Lateral Pterygoid:
      • Origin: greater wing and lateral surface of the lateral portion of the pterygoid process of the sphenoid bone.
      • Insertion: condyle of the mandible and articular disc of the temporomandibular joint (TMJ).
      • Action: protrudes the jaw and assists in side-to-side movements.
      • Innervation: mandibular division of the trigeminal nerve (CN V).

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    Muscles of Facial Expression PDF

    Description

    This quiz explores the various facial expressions and the anatomical muscle responsible for them, the Occipitofrontalis. Learn how emotions such as happiness, sadness, and anger are expressed through specific muscle movements. Understand the significance of facial expressions in communication and anatomy.

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