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What is one of the primary functions of the muscles of mastication?
What is one of the primary functions of the muscles of mastication?
Which muscle of mastication primarily assists with closing the jaw?
Which muscle of mastication primarily assists with closing the jaw?
In which direction does the action of protrusion move the mandible?
In which direction does the action of protrusion move the mandible?
What is a possible consequence of muscle pain during mastication?
What is a possible consequence of muscle pain during mastication?
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Which condition is associated with difficulty in opening the mouth after radiotherapy?
Which condition is associated with difficulty in opening the mouth after radiotherapy?
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How many main ways can the mandible move according to the content provided?
How many main ways can the mandible move according to the content provided?
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What is the function of the masseter muscle?
What is the function of the masseter muscle?
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Which action corresponds to the term 'elevation' of the mandible?
Which action corresponds to the term 'elevation' of the mandible?
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What could be an impact of an inferior alveolar block injection through the muscles?
What could be an impact of an inferior alveolar block injection through the muscles?
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Which of the following movements is NOT associated with the muscles of mastication?
Which of the following movements is NOT associated with the muscles of mastication?
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What is the primary action of the posterior belly of the digastric muscle?
What is the primary action of the posterior belly of the digastric muscle?
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Which nerve supplies the anterior belly of the digastric muscle?
Which nerve supplies the anterior belly of the digastric muscle?
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What is the main action of the buccinator muscle?
What is the main action of the buccinator muscle?
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From which anatomical structure does the geniohyoid muscle originate?
From which anatomical structure does the geniohyoid muscle originate?
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Which artery supplies blood to the anterior belly of the digastric muscle?
Which artery supplies blood to the anterior belly of the digastric muscle?
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What is the insertion point of the genioglossus muscle?
What is the insertion point of the genioglossus muscle?
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Which of the following nerves innervates the genioglossus muscle?
Which of the following nerves innervates the genioglossus muscle?
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What action does the geniohyoid muscle perform?
What action does the geniohyoid muscle perform?
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Which structure serves as an origin point for the buccinator muscle?
Which structure serves as an origin point for the buccinator muscle?
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Which of the following actions does the genioglossus muscle NOT perform?
Which of the following actions does the genioglossus muscle NOT perform?
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What is the main action of the deep masseter?
What is the main action of the deep masseter?
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Where do the fibers of the temporalis muscle insert?
Where do the fibers of the temporalis muscle insert?
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Which blood vessel supplies the lateral pterygoid muscle?
Which blood vessel supplies the lateral pterygoid muscle?
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Which branch of the mandibular nerve supplies the masseter muscle?
Which branch of the mandibular nerve supplies the masseter muscle?
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What is the shape of the temporalis muscle?
What is the shape of the temporalis muscle?
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From which bone does the upper head of the lateral pterygoid muscle originate?
From which bone does the upper head of the lateral pterygoid muscle originate?
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What is the primary function of the posterior fibers of the temporalis muscle?
What is the primary function of the posterior fibers of the temporalis muscle?
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Where does the deep masseter arise from?
Where does the deep masseter arise from?
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Which artery provides blood supply to the temporalis muscle?
Which artery provides blood supply to the temporalis muscle?
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What is the origin of the lower head of the lateral pterygoid muscle?
What is the origin of the lower head of the lateral pterygoid muscle?
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What is the primary action of the lateral pterygoid muscle when both sides contract bilaterally?
What is the primary action of the lateral pterygoid muscle when both sides contract bilaterally?
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Which nerve supplies the medial pterygoid muscle?
Which nerve supplies the medial pterygoid muscle?
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What structures do the fibres of the medial pterygoid muscle insert into?
What structures do the fibres of the medial pterygoid muscle insert into?
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Which artery provides blood supply to the lateral pterygoid and medial pterygoid muscles?
Which artery provides blood supply to the lateral pterygoid and medial pterygoid muscles?
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What is a unique feature of the digastric muscle?
What is a unique feature of the digastric muscle?
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What would most likely occur when one side of the pterygoid muscles contracts alternately?
What would most likely occur when one side of the pterygoid muscles contracts alternately?
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Which muscle primarily elevates the mandible during mastication?
Which muscle primarily elevates the mandible during mastication?
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What is the origin of the large deep head of the medial pterygoid muscle?
What is the origin of the large deep head of the medial pterygoid muscle?
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Which part of the digastric muscle arises from the digastric fossa on the lower border of the mandible?
Which part of the digastric muscle arises from the digastric fossa on the lower border of the mandible?
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Which muscle is NOT considered an accessory muscle of mastication?
Which muscle is NOT considered an accessory muscle of mastication?
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Study Notes
Muscles of Mastication
- Muscles of mastication connect to the mandible and allow for movement during chewing and grinding.
- The mandible can move in 5 main ways:
- Forwards (protrusion)
- Backwards (retraction)
- Up/close (elevation)
- Down/open (depression)
- Side-to-side (rotation)
- Muscle action is important to understand for dentistry:
- Impact of injections through muscle (bruising/post-treatment discomfort)
- Pain during mastication
- Trismus (e.g., difficulty opening following radiotherapy)
- Clenching and grinding - potentially stress-related (masseter pain)
Masseter
- A thick, quadrilateral muscle with two parts:
- Superficial
- Deep
Superficial
- Origin: Anterior two-thirds of the lower border of the zygomatic arch
- Insertion: Outer surface of the ramus of the mandible
Deep
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Origin: Posterior third of the lower border and the whole of the medial surface of the zygomatic arch
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Insertion: Ramus above the angle of the mandible (superior to the superficial part)
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Action: Contraction closes the mouth/elevates the mandible
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Nerve Supply: Masseteric nerve (anterior division of the mandibular nerve)
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Blood Supply: Facial branch of the superficial temporal artery, Masseteric branch of the maxillary artery
Temporalis
- Fan-shaped muscle on either side of the head
- Origin: Whole of the temporal fossa, bounded at the top by the inferior temporal line
- Insertion: Coronoid process, anterior border of the ramus of the mandible
- Action: Anterior fibres elevate the mandible, Posterior fibres elevate the mandible and retract the head of the condyle back into the glenoid fossa
- Nerve Supply: Anterior and posterior deep temporal nerves (anterior division of the mandibular nerve)
- Blood Supply: Middle temporal branch of the superficial temporal artery, Deep temporal branches of the maxillary artery
Lateral Pterygoid
- Short, thick, triangular muscle with two heads:
- Upper Head
- Lower Head
Upper Head
- Origin: Infratemporal surface and crest of the greater wing of sphenoid bone
Lower Head
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Origin: Lateral surface of the lateral pterygoid plate of the sphenoid bone
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Insertion: Pterygoid fovea on the anterior aspect of the neck of the mandible (some fibres may insert with structures of the TMJ)
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Action: Bilateral contraction opens and protrudes the mouth, alternating action of the muscle on each side of the head produces grinding/ side-to-side movement
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Nerve Supply: Lateral pterygoid nerve (anterior branch of the mandibular nerve)
-
Blood Supply: Pterygoid branches of the maxillary artery
Medial Pterygoid
- Thick, quadrilateral muscle
- Origin: Two heads:
- Large Deep Head: Medial surface of the lateral pterygoid plate of the sphenoid bone
- Small Superficial Head: Tuberosity of the maxilla, and pyramidal process of the palatine bone
- Insertion: Medial surface of the ramus and angle of the mandible (below and behind the inferior dental foramen)
- Action: Elevates the mandible and, in conjunction with the lateral pterygoid muscle, protrudes the mandible
- Nerve Supply: Medial pterygoid branch of the mandibular nerve
- Blood Supply: Pterygoid branches of maxillary artery
Accessory Muscles of Mastication
Digastric
- Origin:
- Anterior Belly: Digastric fossa on lower border of the mandible
- Posterior Belly: Digastric notch on the mastoid process of the temporal bone
- Insertion: Intermediate tendon above the hyoid bone, held by a fibrous sling anchoring it to the body of the hyoid bone.
- Action: Depresses the mandible, elevates the hyoid bone during chewing and swallowing
- Nerve Supply:
- Anterior Belly: Mylohyoid nerve
- Posterior Belly: Digastric branch of the facial nerve VII
- Blood Supply:
- Anterior Belly: Submental branch of facial artery
- Posterior Belly: Posterior auricular/occipital artery
Buccinator
- Forms the cheek
- Origin: Pterygomandibular raphae and buccal alveolar bone (in maxillary and mandibular molars regions)
- Insertion: Blends with the Orbicularis Oris at the corners of the mouth
- Action: Pulls the corner of the mouth back and compresses the cheek against the buccal surfaces of molars, regulates the vestibular region with the tongue keeping food between teeth during mastication
- Nerve Supply: Facial Nerve, buccal branch
- Blood Supply: Facial & maxillary arteries
Geniohyoid
- Located above the medial part of the mylohyoid line
- Origin: Inferior genial tubercle
- Insertion: Body of the Hyoid bone
- Action: Aids in deglutition and opening the mouth by depressing the mandible
- Nerve Supply: Hypoglossal Nerve
- Blood Supply: Sublingual branch of the lingual artery
Genioglossus
- Origin: Superior genial tubercle on the inner surface of the mandible
- Insertion: Dorsum of the tongue, fan shaped, superior fibres to the tip of the tongue, inferior fibres to the body of the hyoid bone
- Action: Depresses the tongue, inferior fibres retract the tongue, superior fibres protrude the tongue
- Nerve Supply: Hypoglossal nerve
- Blood Supply: Sublingual branch of the lingual artery, Submental branch of the facial artery
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Description
Explore the muscles involved in mastication, focusing on their actions and implications for dental practices. Understand the movements of the mandible and how they relate to common dental issues. This quiz covers key muscles, including the masseter, their origins, and insertions.
