Podcast
Questions and Answers
How many cranial bones are present in the human skull?
How many cranial bones are present in the human skull?
Which of the following bones is NOT classified as a facial bone?
Which of the following bones is NOT classified as a facial bone?
What is the primary action of the Orbicularis Oculi muscle?
What is the primary action of the Orbicularis Oculi muscle?
What structure passes through the foramen magnum of the occipital bone?
What structure passes through the foramen magnum of the occipital bone?
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Which muscle is responsible for compressing the cheeks during blowing activities?
Which muscle is responsible for compressing the cheeks during blowing activities?
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Which bone articulates with the mandible to form the temporomandibular joint?
Which bone articulates with the mandible to form the temporomandibular joint?
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What is the function of the occipital condyles?
What is the function of the occipital condyles?
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Which muscle has no bony attachments and is primarily responsible for closing the lips?
Which muscle has no bony attachments and is primarily responsible for closing the lips?
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The Occipitofrontalis muscle is unique due to having how many muscle bellies?
The Occipitofrontalis muscle is unique due to having how many muscle bellies?
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Which of the following describes the shape of the mandible?
Which of the following describes the shape of the mandible?
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The hyoid bone is unique because it has which of the following characteristics?
The hyoid bone is unique because it has which of the following characteristics?
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Which movements are associated with the mandible?
Which movements are associated with the mandible?
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How many bones make up the facial skeleton?
How many bones make up the facial skeleton?
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What is the resting position of the mandible?
What is the resting position of the mandible?
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Which ligament of the TMJ primarily limits anterior movement?
Which ligament of the TMJ primarily limits anterior movement?
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What is the function of the lateral pterygoid muscle?
What is the function of the lateral pterygoid muscle?
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How many fingers should normally fit between the upper and lower teeth during TMJ motion?
How many fingers should normally fit between the upper and lower teeth during TMJ motion?
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Which of the following muscles is NOT a prime mover of mastication?
Which of the following muscles is NOT a prime mover of mastication?
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Which muscle primarily innervates the muscles of mastication?
Which muscle primarily innervates the muscles of mastication?
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Which muscle accounts for lateral deviation in the contralateral direction?
Which muscle accounts for lateral deviation in the contralateral direction?
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What is the primary action of the temporalis muscle?
What is the primary action of the temporalis muscle?
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Study Notes
Skull
- Composed of 22 bones - 8 cranial and 14 facial bones
- Houses and protects the brain
- Cranial bones are joined by fibrous sutures
- Facial bones provide structure and support for the face
Cranial Bones
- Frontal bone: Forms the forehead
- Occipital bone: Forms the back of the skull
- Sphenoid bone: Forms part of the base of the skull
- Ethmoid bone: Forms part of the roof of the nasal cavity
- Temporal bones (2): Form the sides of the skull
- Parietal bones (2): Form the top of the skull
Facial Bones
- Maxilla (2): Forms the upper jaw
- Zygomatic (2): Forms the cheekbones
- Lacrimal (2): Forms part of the eye socket
- Nasal (2): Forms the bridge of the nose
- Inferior nasal conchae (2): Form part of the nasal cavity
- Palatine (2): Form part of the roof of the mouth
- Vomer (1): Forms part of the nasal septum
- Mandible (1): Forms the lower jaw
Occipital Bone
- Located at the posterior and base of the skull
- Foramen magnum: Large opening where the spinal cord passes through
- Occipital condyles: Articulate with the first vertebra (atlas)
Mandible
- The largest and strongest facial bone
- Horseshoe-shaped
- Articulates with the temporal bone on each side to form the temporomandibular joint (TMJ)
Temporomandibular Joint (TMJ)
- Located anterior to the ear
- Comprised of the articular fossa of the temporal bone and the condyle of the mandible
- Contains a joint capsule, articular disc, and four ligaments
- Responsible for a variety of movements including elevation, depression, protraction, retraction, and lateral deviation
TMJ Ligaments
- Lateral ligament: Limits downward, posterior, and lateral movement of the mandible
- Sphenomandibular ligament: Restricts anterior movement of the mandible
- Stylomandibular ligament: Restricts anterior movement of the mandible
- Stylohyoid ligament: Holds the hyoid bone in place
Muscles of Mastication
- Four prime movers that control movement of the TMJ:
- Temporalis
- Masseter
- Medial Pterygoid
- Lateral Pterygoid
- All are innervated by the trigeminal nerve (CN V)
- Action is bilateral - occurs at both joints simultaneously
Temporalis
- Origin: Temporal fossa
- Insertion: Coronoid process of the mandible
- Action: Elevates and retracts the mandible; unilaterally: ipsilateral lateral deviation
Masseter
- Origin: Zygomatic arch
- Insertion: Angle of the ramus and coronoid process of the mandible
- Action: Elevates the mandible; (ipsilateral lateral deviation)
Medial Pterygoid
- Origin: Sphenoid bone
- Insertion: Ramus and angle of the mandible
- Action: Elevates and protracts the mandible; (contralateral lateral deviation)
Lateral Pterygoid
- Origin: Sphenoid bone
- Insertion: Mandibular condyle
- Action: Depresses and protracts the mandible; (contralateral lateral deviation)
Muscles of Facial Expression
- 4 groups: mouth, eyes, nose, scalp
- 30 muscles create a vast array of facial expressions
- Mimic muscles: Embedded in superficial fascia and skin, express emotion
- Innervated by the facial nerve (CN VII)
Muscles of the Eyes
- Orbicularis oculi: Closes the eye
- Corrugator supercilii: Draws the eyebrow towards the midline (frowning)
- Occipitofrontalis: Wrinkles the forehead and raises the eyebrow
Muscles of the Mouth
- Buccinator: Compresses the cheeks for blowing air
- Orbicularis oris: Closes the lips
- Platysma: Depresses the lower lip and mandible
Hyoid Bone
- Horseshoe-shaped bone
- Located superior to the thyroid cartilage at the level of C3
- Does not directly articulate with any other bone
- Suspended by muscles from the styloid processes of the temporal bones
- Provides attachment for tongue muscles and muscles that help depress the mandible
TMJ Location
- The TMJ is located anterior to the ear
- The TMJ is an articulation between the articular fossa of the temporal bone of the cranium and the condyle of the mandible
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Description
This quiz covers the anatomy of the skull, including its composition of cranial and facial bones. Learn about the specific bones that make up the skull and their functions in protecting the brain and providing structure to the face.
