Questions and Answers
Which of these are among the 4 main groups of muscles?
What are the muscles of the head and neck responsible for?
Facial expression, eye movement, mastication, and controlling the neck.
Where does the origin of the muscles of facial expression occur?
Surface of the skull.
What does the Obicularis Oris muscle do?
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What is the action of the Buccinator muscle?
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What does the Mentalis muscle do?
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What is the action of the Depressor Anguli Oris muscle?
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Where does the Zygomaticus Major muscle originate?
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What is the function of the Obicularis Oculi muscle?
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What is the role of the Superior Rectus muscle?
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What is the function of the Erector Spinae muscles?
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What are Internal Intercostals involved in?
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What does the Diaphragm do during contraction?
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What muscle group controls external genitalia?
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What separates the two sides of the Rectus Abdominis?
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What do the Muscles of the Pelvic Floor support?
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Study Notes
Main Groups of Muscles
- Muscles categorized into four main groups: head and neck, vertebral column, oblique and rectus muscles, and pelvic floor muscles.
Muscles of the Head and Neck
- Responsible for facial expressions and mastication.
- Includes extra-ocular muscles, tongue muscles, pharyngeal muscles, and anterior neck muscles.
Muscles of Facial Expression
- Originates from the surface of the skull and inserts into the dermis via collagen fibers.
- Innervated by the facial nerve.
Specific Facial Muscles
- Obicularis Oris: Purses lips when contracted; mouth opens when relaxed.
- Buccinator: Compresses cheeks; useful in making a "fish face."
- Mentalis: Elevates/protrudes lower lip; located around the mental foramen.
- Depressor Anguli Oris: Depresses corners of the mouth, creating a frown.
- Zygomaticus Major: Elevates mouth corners for smiling; larger zygomatic muscle.
- Zygomaticus Minor: Assists in elevating the upper lip.
- Obicularis Oculi: Circular muscle around the eyes; closes the eyes.
- Corrugator Supercilii: Winkles brow; moves eyebrows downward medially.
- Procerus: Located at the nose's upper region; works with corrugator to move brows.
- Nasalis: Crosses the nose bridge; changes nostril position.
- Temporoparietalis: Covers temporal/parietal bones; tenses scalp and can slightly move ears.
- Occipitofrontalis: Consists of frontal (raises eyebrows) and occipital (retracts scalp) bellies.
- Platysma: Tenses neck skin, depresses mandible, and assists in mouth opening.
Extra-Ocular Muscles
- Primarily responsible for eye position; innervated by cranial nerves 3, 4, and 6.
- Four rectus and two oblique muscles control eye movements.
Movements of Extra-Ocular Muscles
- Superior Rectus: Moves eye upward.
- Inferior Rectus: Moves eye downward.
- Lateral Rectus: Moves eye laterally.
- Medial Rectus: Moves eye medially.
- Inferior Oblique: Rolls eye upward.
- Superior Oblique: Rolls eye downward.
Muscles of Mastication
- Inserts on the mandible; innervated by cranial nerve 5 (trigeminal).
- Responsible for moving the mandible during chewing.
Specific Mastication Muscles
- Masseter: Strongest muscle; elevates mandible, assists in protraction/retraction.
- Temporalis: Elevates and retracts mandible; aids in side-to-side movement.
- Medial Pterygoid: Elevates and assists in side-to-side movement.
- Lateral Pterygoid: Depresses, protracts mandible; enables side-to-side movement.
Muscles Related to Swallowing and Phonation
- Muscles of the Tongue: Initiate swallowing; innervated by cranial nerve 12.
- Pharyngeal Constrictors: Propel food to the esophagus.
- Laryngeal Elevators: Elevate larynx; protect airways during swallowing.
- Palatial Muscles: Elevate soft palate; ensure correct swallowing pathway.
Anterior Neck Muscles
- Comprised of superficial hyoid and infrahyoid muscles; support larynx and mandible movements.
Specific Neck Muscles
- Sternocleidomastoid: Allows neck flexion and lateral flexion; rotates head.
- Digastric Muscle: Depresses mandible; works with platysma and lateral pterygoid.
Muscles of the Vertebral Column
- Organized into three layers: superficial (movement), intermediate (extension), and deep (stabilization).
- Erector Spinae: Extends and maintains posture; consists of spinalis, longissimus, and iliocostalis.
Additional Spinal Muscles
- Deep Intrinsic: Stabilize vertebrae and allow slight movements; important for nerve health.
- Quadratus Lumborum: Aids in rib depression and lateral flexion of the spine.
Intercostal Muscles
- External Intercostals: Elevate ribs; involved in inhalation.
- Internal Intercostals: Depress ribs; involved in exhalation.
Abdominal Muscles
- External Abdominal Oblique: Compresses abdomen; allows for trunk flexion or rotation.
- Internal Abdominal Oblique: Compress abdomen; rotates vertebral column.
- Transversus Abdominis: Provides abdominal compression; consists of layered fibers.
- Diaphragm: Primary muscle for breathing; expands thoracic cavity.
Rectus Abdominis
- Fosters rib depression and trunk flexion; responsible for abdominal compression.
- Tendinous Inscriptions: Create sections for six-pack appearance.
- Linea Alba: Connective tissue separating the abdominal muscles.
Pelvic Floor Muscles
- Ascend from sacrum/coccyx to ischium/pubis; support pelvic organs and control urethra/anus functions.
Triangles of the Pelvic Floor
- Urogenital Triangle: Controls external genitalia.
- Anal Triangle: Composed of muscle sheets supporting pelvic organs.
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Description
Test your knowledge on the four main groups of muscles, including those of the head and neck, and their specific functions. This quiz covers muscle types, such as facial expression and the pelvic floor. Challenge yourself to understand muscle anatomy better!
