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Questions and Answers
Which muscle is considered the most powerful muscle of mastication?
Which muscle is considered the most powerful muscle of mastication?
What is the primary action performed by the muscles of mastication during chewing?
What is the primary action performed by the muscles of mastication during chewing?
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?
What does the term 'trismus' refer to in relation to mastication?
What does the term 'trismus' refer to in relation to mastication?
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Which muscle lays underneath the superficial masseter?
Which muscle lays underneath the superficial masseter?
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How many main movements do the muscles of mastication allow the mandible to perform?
How many main movements do the muscles of mastication allow the mandible to perform?
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What anatomical structure does the masseter muscle attach to for its function?
What anatomical structure does the masseter muscle attach to for its function?
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Which condition may lead to pain during mastication and is often stress-related?
Which condition may lead to pain during mastication and is often stress-related?
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What is the consequence of the masseter muscle's fiber contraction?
What is the consequence of the masseter muscle's fiber contraction?
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Where does the temporalis muscle insert?
Where does the temporalis muscle insert?
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What is the nerve supply for the masseter muscle?
What is the nerve supply for the masseter muscle?
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Which of the following actions is performed by the anterior fibers of the temporalis muscle?
Which of the following actions is performed by the anterior fibers of the temporalis muscle?
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What arteries supply blood to the temporalis muscle?
What arteries supply blood to the temporalis muscle?
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How do the fibers of the masseter muscle run in relation to their insertion?
How do the fibers of the masseter muscle run in relation to their insertion?
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Which muscle has fibers that are described as triangular in shape?
Which muscle has fibers that are described as triangular in shape?
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What action is performed by the posterior fibers of the temporalis muscle?
What action is performed by the posterior fibers of the temporalis muscle?
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What is the primary action of the lateral pterygoid muscle when it contracts bilaterally?
What is the primary action of the lateral pterygoid muscle when it contracts bilaterally?
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Which structure does the lower head of the lateral pterygoid originate from?
Which structure does the lower head of the lateral pterygoid originate from?
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What is the nerve supply for the medial pterygoid muscle?
What is the nerve supply for the medial pterygoid muscle?
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During unilateral contraction of the pterygoid muscles, what type of movement is primarily produced?
During unilateral contraction of the pterygoid muscles, what type of movement is primarily produced?
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What is the insertion point for the medial pterygoid muscle?
What is the insertion point for the medial pterygoid muscle?
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What indicates that the digastric muscle meets the hyoid bone?
What indicates that the digastric muscle meets the hyoid bone?
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Which branches supply blood to the pterygoid muscles?
Which branches supply blood to the pterygoid muscles?
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Which muscles work together with the medial pterygoid muscle to protrude the mandible?
Which muscles work together with the medial pterygoid muscle to protrude the mandible?
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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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Where does the buccinator muscle originate?
Where does the buccinator muscle originate?
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Which artery supplies blood to the posterior belly of the digastric muscle?
Which artery supplies blood to the posterior belly of the digastric muscle?
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What is the primary action of the genioglossus muscle?
What is the primary action of the genioglossus muscle?
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Which of the following nerves innervates the geniohyoid muscle?
Which of the following nerves innervates the geniohyoid muscle?
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In which region does the buccinator muscle help to regulate food during mastication?
In which region does the buccinator muscle help to regulate food during mastication?
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Which artery supplies the genioglossus muscle?
Which artery supplies the genioglossus muscle?
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Study Notes
Muscles of Mastication
- The muscles of mastication are responsible for movement of the mandible 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)
- The muscles of mastication connect to the mandible, aiding in important functions:
- Impact of ID Block through muscle (bruising/post-treatment discomfort)
- Pain during mastication
- Trismus (difficulty opening following radiotherapy)
- Clenching and grinding- potentially stress-related (masseter pain)
Principle Muscles of Mastication
-
Masseter:
- Most powerful of the mastication muscles
- Thick, quadrilateral muscle consisting of two parts: Superficial and Deep
- Superficial Masseter:
- Arises from the anterior two-thirds of the lower border of the zygomatic arch
- Insertions: Passes downwards and backwards to be inserted on the outer surface of the ramus of the mandible
- Deep Masseter:
- Arises from the posterior third of the lower border and the whole of the medial surface of the zygomatic arch
- Insertions: Passes downwards and backwards to be inserted on the ramus above the angle of the mandible
- Action: Fibres contract to close mouth/elevates
- Nerve Supply: Masseteric nerve (anterior division of the mandibular nerve)
- Blood Supply: Facial branch of the superficial temporal artery, Masseteric branch of the maxillary artery
-
Temporalis:
- Fan-shaped muscle situated on either side of the head
- Origin: Fibres arise from the whole of the temporal fossa that is bound at the top by the inferior temporal line
- Insertions: The top and medial surface of the coronoid process, and the anterior border of the ramus of the mandible
-
Action:
- Anterior fibres run vertically and contract to elevate the mandible
- Posterior fibres run obliquely and horizontally contracting to 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 muscle, triangular in shape arising from 2 heads: Upper Head and Lower Head
- Upper Head Origin: The infratemporal surface and crest of the greater wing of sphenoid bone
- Lower Head Origin: The lateral surface of the lateral pterygoid plate of the sphenoid bone
- Insertions: The fibres merge and insert into the pterygoid fovea on the anterior aspect of the neck of the mandible. Some fibres may insert with structures of the TMJ.
-
Action:
- Bilateral contraction: opens and protrudes the mouth
- When the two pterygoid muscles on one side of the head act alternately with those of the other side, grinding or side to side movement is produced.
- 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: Arises by 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
- Insertions: The fibres pass downwards, backwards and laterally to be inserted into the 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 temporal bone
- Insertions: Meet above the hyoid bone at the intermediate tendon. This is held by a fibrous sling anchoring it to the body of the hyoid bone.
- Action: Depression of 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
-
Origin:
-
Buccinator:
- Forms the cheek
- Origin: Pterygomandibular raphae and buccal alveolar bone (in maxillary and mandibular molars regions)
- Insertions: Fibres run horizontally blending with the Orbicularis Oris at the corners of mouth
- Action: Pulls corner of the mouth back and compresses cheek against the buccal surfaces of molars. Muscle 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:
- Narrow muscle situated above the medial part of the mylohyoid line
- Origin: Arises from the inferior genial tubercle
- Insertions: Fibres run downwards and backwards into the 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: Arises from the superior genial tubercle on the inner surface of the mandible
- Insertions: Enters the dorsum of the tongue where it forms a large fan-shaped muscle. Superior fibres pass upwards to the tip of the tongue. Inferior fibres insert on to the body of the hyoid bone.
- Action: Depresses of 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
Test your knowledge on the muscles involved in mastication and their functions. This quiz covers the movements of the mandible and the principal muscles responsible for chewing. Understand the impact of these muscles on dental health and related conditions.
