Podcast
Questions and Answers
What is the primary action of the orbicularis oculi muscle?
What is the primary action of the orbicularis oculi muscle?
From which origin does the temporalis muscle arise?
From which origin does the temporalis muscle arise?
Which muscle is responsible for smiling by raising the corners of the mouth?
Which muscle is responsible for smiling by raising the corners of the mouth?
What action does the sternocleidomastoid muscle perform when both sides contract?
What action does the sternocleidomastoid muscle perform when both sides contract?
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Which muscle acts to depress the mandible while frowning?
Which muscle acts to depress the mandible while frowning?
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What action does the deltoid muscle's anterior part perform?
What action does the deltoid muscle's anterior part perform?
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What is the insertion point of the masseter muscle?
What is the insertion point of the masseter muscle?
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Which muscle medially rotates the humerus at the shoulder?
Which muscle medially rotates the humerus at the shoulder?
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What is the action of the splenius capitis muscle when only one side is contracted?
What is the action of the splenius capitis muscle when only one side is contracted?
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Which muscle primarily assists in chewing by elevating the mandible?
Which muscle primarily assists in chewing by elevating the mandible?
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What is the origin of the deltoid muscle's posterior part?
What is the origin of the deltoid muscle's posterior part?
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Which muscle acts upon the jaw for both mastication and facial expression?
Which muscle acts upon the jaw for both mastication and facial expression?
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Which muscle is NOT involved in raising the eyebrows?
Which muscle is NOT involved in raising the eyebrows?
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What action does the latissimus dorsi muscle perform at the shoulder?
What action does the latissimus dorsi muscle perform at the shoulder?
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What action is primarily performed by the Supraspinatus muscle?
What action is primarily performed by the Supraspinatus muscle?
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Which muscle is responsible for laterally rotating the humerus at the shoulder?
Which muscle is responsible for laterally rotating the humerus at the shoulder?
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Which muscle originates from the occipital bone and C1-C7 and elevates the scapula?
Which muscle originates from the occipital bone and C1-C7 and elevates the scapula?
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What is the primary action of the Biceps brachii muscle?
What is the primary action of the Biceps brachii muscle?
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What is the role of the Serratus anterior in shoulder movement?
What is the role of the Serratus anterior in shoulder movement?
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Which of the following muscles extends the hip and flexes the knee?
Which of the following muscles extends the hip and flexes the knee?
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What action is performed by the Rectus femoris during a kicking motion?
What action is performed by the Rectus femoris during a kicking motion?
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Which muscle acts primarily to perform plantar flexion at the ankle?
Which muscle acts primarily to perform plantar flexion at the ankle?
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What is the primary action of the Extensor carpi radialis brevis?
What is the primary action of the Extensor carpi radialis brevis?
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Which muscle is responsible for the dorsiflexion and inversion at the ankle?
Which muscle is responsible for the dorsiflexion and inversion at the ankle?
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What action is achieved by the external intercostals during inspiration?
What action is achieved by the external intercostals during inspiration?
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Which muscle primarily compresses the abdomen?
Which muscle primarily compresses the abdomen?
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Which of the following actions is NOT associated with the Trapezius muscle?
Which of the following actions is NOT associated with the Trapezius muscle?
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Study Notes
Muscles of Facial Expression
- Orbicularis Oculi: Closes the eye and lowers the eyebrows. Originates from the frontal bone and maxilla and inserts into the eyelid.
- Orbicularis Oris: Closes the lips, purses, and protrudes. Originates from the maxilla and mandible and inserts into the skin and muscle around the mouth.
- Zygomaticus Major: Raises the corners of the mouth, causing a smile. Originates from the zygomatic bone and inserts into the skin and muscle at the corner of the mouth.
- Buccinator: Compresses the cheeks for actions like whistling and sucking. Originates from the mandible and maxilla molar regions and inserts into the orbicularis oris.
- Frontalis: Raises the eyebrows. Originates from the epicranial aponeurosis and inserts into the skin of the eyebrows.
Muscles that act on the Jaw
- Masseter: Elevates the mandible for closing the mouth during chewing. Originates from the zygomatic arch and bone and inserts into the mandible ramus and angle.
- Temporalis: Elevates the mandible. Originates from the temporal, frontal, and parietal bones and inserts into the coronoid process of the mandible.
- Platysma: Pulls the lower lip down for frowning and depresses the mandible for opening the mouth during chewing or surprise. Originates from the pectoralis muscles and inserts into the mandible and skin of the lower face.
Muscles that act on the Neck
- Sternocleidomastoid: Flexes the neck for looking down when both sides contract and cocks the head when one side contracts. Originates from the manubrium and clavicle and inserts into the mastoid process of the temporal bone.
- Splenius Capitis: Extends the neck for looking up when both sides contract and cocks the head when one side contracts. Originates from C7 to T3 and inserts into the nuchal line and mastoid process.
Muscles that act on the Shoulder
- Deltoid (Anterior): Flexes and medially rotates the humerus at the shoulder. Originates from the clavicle and inserts into the deltoid tuberosity of the humerus.
- Deltoid (Middle): Abducts the humerus at the shoulder for upward flap motion. Originates from the acromion and inserts into the deltoid tuberosity of the humerus.
- Deltoid (Posterior): Extends and laterally rotates the humerus at the shoulder. Originates from the scapular spine and inserts into the deltoid tuberosity of the humerus.
- Pectoralis Major: Flexes, adducts, and medially rotates the humerus at the shoulder for actions like overhead fist raise or bench press motion. Originates from the sternum, ribs 7, and medial half of the clavicle and inserts into the intertubercular groove of the humerus.
- Latissimus Dorsi: Extends, adducts, and medially rotates the humerus at the shoulder for gym lat pull-downs. Originates from T7 to L5, ribs 10 to 12, and the iliac crest and inserts into the intertubercular groove of the humerus (travels under the axillary region).
Rotator Cuff Muscles
- Subscapularis: Medially rotates the humerus at the shoulder. Originates from the subscapular fossa of the scapula and inserts into the lesser tubercle of the humerus.
- Rotator Cuff Muscles: These small muscles help keep the head of the humerus snug in the glenoid fossa.
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Description
This quiz covers the key muscles involved in facial expressions and those that act on the jaw. You'll explore the origins, insertions, and functions of various muscles such as Orbicularis Oculi, Zygomaticus Major, and Masseter. Test your knowledge on how these muscles contribute to facial movement and chewing actions.
