Muscles Anatomy Quiz

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.