Anatomy of Hyoid Muscles

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Questions and Answers

What is the primary function of the infrahyoid muscles during swallowing?

Depress the hyoid bone and the larynx (correct)

Raise the hyoid bone and the larynx

Stabilize the mandible

Move the mandible in the opposite direction

Which muscle can depress the mandible when acting in conjunction with infrahyoid and lateral pterygoid muscles?

Sternohyoid

Mylohyoid

Suprahyoid muscles (correct)

Geniohyoid

What is the primary function of the buccinators during swallowing?

Moisten the food with saliva

Assist in mechanical action by moving the mandible (correct)

Break down the carbohydrates

Stop the food from being forced into the vestibule

What is the primary function of the salivary glands during swallowing?

Moisten the food Signup and view all the answers

Which of the following muscles is NOT primarily involved in swallowing?

Sternocleidomastoid Signup and view all the answers

What type of movement does the mandible make when the lateral pterygoid and hyoid muscles contract together?

Depression Signup and view all the answers

What is the primary function of the masseter muscle in regards to the mandible?

Elevation of the mandible Signup and view all the answers

What is the origin of the deep fibres of the masseter muscle?

Zygomatic bone/arch Signup and view all the answers

What is the primary action of the temporalis muscle on the mandible?

Elevation of the mandible Signup and view all the answers

Which of the following structures is NOT an origin of the temporalis muscle?

Ramus of mandible Signup and view all the answers

What is the insertion of the masseter muscle?

Anterior border and angle of the ramus of mandible Signup and view all the answers

What movement of the mandible is facilitated by the superficial fibres of the masseter muscle?

Retrusion of the mandible Signup and view all the answers

What muscle is responsible for opening the oropharyngeal isthmus during bolus formation?

Palatoglossus Signup and view all the answers

Which muscles contract to close the nasopharynx from the oropharynx during swallowing?

Superior constrictor Signup and view all the answers

What is the purpose of the epiglottis during swallowing?

To deflect food and drink into the piriform fossa Signup and view all the answers

Which muscles contract to raise and bring the larynx forward during swallowing?

Geniohyoid and anterior belly of digastric Signup and view all the answers

What is the function of the middle and inferior constrictors during swallowing?

To push the bolus towards the esophagus Signup and view all the answers

What is the duration of the swallowing process from the oropharynx to the stomach?

2 seconds Signup and view all the answers

What type of action is facilitated when the suprahyoid muscles contract bilaterally?

Raising the larynx Signup and view all the answers

What is the primary function of the infrahyoid muscles during swallowing?

Depressing the hyoid bone Signup and view all the answers

Which muscles are responsible for breaking down food mechanically during swallowing?

Molars and premolars Signup and view all the answers

What is the function of ptyalin in saliva during swallowing?

Breaking down carbohydrates Signup and view all the answers

What is the purpose of the lips during swallowing?

Reducing the likelihood of food falling out of the mouth Signup and view all the answers

What is the action of the medial pterygoid muscle when it contracts together with the masseter muscle?

Elevation of the mandible Signup and view all the answers

Which muscle is NOT involved in depressing the mandible during swallowing?

Masseter muscle Signup and view all the answers

What is the action of the lateral pterygoid muscle when it contracts together with its counterpart on the opposite side?

Protrusion of the mandible Signup and view all the answers

What is the shape of the lateral pterygoid muscle?

Triangular Signup and view all the answers

What is the action of the medial pterygoid muscle on the mandible when it contracts unilaterally?

Contralateral excursion Signup and view all the answers

What is the relationship between the medial pterygoid muscle and the masseter muscle?

The medial pterygoid muscle is a mirror of the masseter muscle on the inner surface of the mandible Signup and view all the answers

Which type of fibres are involved in retrusion of the mandible?

Posterior horizontal fibres Signup and view all the answers

What is the primary action of the palatoglossus muscles during bolus formation?

Relaxing to open the oropharyngeal isthmus Signup and view all the answers

What is the name of the joint that allows for the movement of the lower jaw during mastication?

Temporomandibular joint Signup and view all the answers

What is the result of the contraction of the superior constrictor muscles during swallowing?

Closing the nasopharynx from the oropharynx Signup and view all the answers

What is the function of the aryepiglottic and transverse arytenoid muscles during swallowing?

Contracting to reduce the size of the laryngeal inlet Signup and view all the answers

What is the function of the articular disc in the temporomandibular joint?

To divide the joint cavity into two compartments Signup and view all the answers

Which of the following muscles is NOT one of the four major masticatory muscles?

Buccinator Signup and view all the answers

What is the result of the contraction of the levator muscles during swallowing?

Tensing and raising the soft palate Signup and view all the answers

What is the name of the artery that supplies blood to the muscles of mastication?

Maxillary artery Signup and view all the answers

What is the action of the tongue during bolus formation?

Gathering the food into a bolus and pushing it towards the oral pharynx by raising against the hard palate Signup and view all the answers

What is the result of the contraction of the middle and inferior constrictors during swallowing?

Pushing the bolus towards the esophagus Signup and view all the answers

What is the name of the plexus of veins that drains the muscles of mastication?

Pterygoid venous plexus Signup and view all the answers

What is the name of the fossa that allows for the passage of the temporalis and pterygoid muscles?

Infratemporal fossa Signup and view all the answers

What is the nerve responsible for the innervation of the musculature and mucosa of the oral cavity?

Mandibular nerve Signup and view all the answers

What is the type of movement that occurs in the upper compartment of the temporomandibular joint?

Gliding movement Signup and view all the answers

What is the name of the artery that is subdivided into mandibular, pterygoid, and pterygopalatine parts?

Maxillary artery Signup and view all the answers

What is the name of the vein that drains into the internal jugular vein?

Facial vein Signup and view all the answers

What happens to the hyoid bone and larynx after the bolus passes through?

They return to their usual position Signup and view all the answers

What is the role of the intrinsic and extrinsic muscles of the larynx during swallowing?

They prevent food or drink from entering the glottis Signup and view all the answers

What happens to the upper oesophageal sphincter during the upper oesophageal phase?

It constricts Signup and view all the answers

What type of movement is swallowing initially, before it becomes involuntary?

Voluntary Signup and view all the answers

During the pharyngeal phase, what happens to the larynx?

It is elevated Signup and view all the answers

What happens to the soft palate during the buccal phase?

It is raised Signup and view all the answers

What is the primary action of the levator muscles during swallowing?

Tensing the soft palate Signup and view all the answers

What is the function of the palatoglossus muscles during bolus formation?

Relaxing to open the oropharyngeal isthmus Signup and view all the answers

What is the result of the contraction of the superior constrictor muscles during swallowing?

Closure of the nasopharynx Signup and view all the answers

What is the role of the epiglottis during swallowing?

Deflecting food and drink into the piriform fossa Signup and view all the answers

What is the function of the aryepiglottic and transverse arytenoid muscles during swallowing?

Reducing the size of the laryngeal inlet Signup and view all the answers

What is the duration of the swallowing process from the oropharynx to the stomach?

2 seconds Signup and view all the answers

What is the shape of the masseter muscle?

Quadrilateral Signup and view all the answers

What is the origin of the deep fibres of the temporalis muscle?

Temporal bone Signup and view all the answers

What is the action of the superficial fibres of the masseter muscle?

Retrusion of the mandible Signup and view all the answers

What is the insertion of the temporalis muscle?

Coronoid process of the mandible Signup and view all the answers

What is the action of the masseter muscle in regards to the mandible?

Elevation and retrusion Signup and view all the answers

What is the action of the temporalis muscle on the mandible?

Elevation Signup and view all the answers

What is the primary function of the suprahyoid muscles during swallowing when acting in conjunction with the infrahyoid muscles?

Depress the mandible Signup and view all the answers

Which muscle is involved in breaking down food mechanically during swallowing?

Buccinator Signup and view all the answers

What occurs to the hyoid bone and larynx during swallowing?

They are depressed Signup and view all the answers

What is the primary function of ptyalin in saliva during swallowing?

Break down carbohydrates Signup and view all the answers

What is the role of the lips during swallowing?

To reduce the likelihood of the food falling out of the mouth Signup and view all the answers

What type of movement does the mandible make when the contralateral excursion occurs?

It moves in the opposite direction to the side of the muscle contraction Signup and view all the answers

What is the primary function of the articular disc in the temporomandibular joint?

To distribute the forces of biting and grinding Signup and view all the answers

Which of the following muscles is NOT responsible for elevating the mandible?

Lateral pterygoid Signup and view all the answers

What is the primary function of the infratemporal fossa?

To allow for the passage of the temporalis and pterygoid muscles Signup and view all the answers

What is the primary function of the maxillary artery?

To supply blood to the muscles of mastication Signup and view all the answers

What is the primary function of the pterygoid venous plexus?

To drain the muscles of mastication Signup and view all the answers

What is the primary function of the mandibular nerve?

To innervate the musculature of the oral cavity Signup and view all the answers

What type of movement occurs in the lower compartment of the temporomandibular joint?

Hinge Signup and view all the answers

What is the primary function of the temporalis muscle?

To elevate the mandible Signup and view all the answers

What is the primary function of the medial pterygoid muscle?

To elevate the mandible Signup and view all the answers

What is the primary function of the lateral pterygoid muscle?

To depress the mandible Signup and view all the answers

What is the primary function of the larynx during swallowing?

To prevent food or drink from entering the glottis Signup and view all the answers

What happens to the soft palate during the buccal phase of swallowing?

It ascends to block the entry to the nasal cavity Signup and view all the answers

What is the primary function of the upper oesophageal phase during swallowing?

To constrict the oesophagus to propel the bolus downwards Signup and view all the answers

What is the role of peristalsis during the oesophageal phase of swallowing?

To propel the bolus downwards through the oesophagus Signup and view all the answers

What happens to the hyoid bone and larynx after the bolus passes through?

They descend to their usual position Signup and view all the answers

What is the initial type of movement during swallowing?

Voluntary Signup and view all the answers

What is the function of the articular disc in the temporomandibular joint?

Divides the TMJ cavity and allows for 6 types of movements Signup and view all the answers

What is the name of the fossa that allows for the passage of the temporalis and pterygoid muscles?

Infratemporal fossa Signup and view all the answers

What is the name of the nerve responsible for the innervation of the musculature and mucosa of the oral cavity?

Mandibular nerve Signup and view all the answers

What type of movement occurs in the upper compartment of the temporomandibular joint?

Gliding Signup and view all the answers

What is the name of the plexus of veins that drains the muscles of mastication?

Pterygoid plexus Signup and view all the answers

What is the name of the artery that supplies blood to the muscles of mastication?

Maxillary artery Signup and view all the answers

Which muscle plays a crucial role in protrusion of the mandible?

Lateral pterygoid Signup and view all the answers

What is the primary action of the suprahyoid muscles during swallowing?

Raising the pharynx Signup and view all the answers

What is the role of the maxillary artery in relation to the muscles of mastication?

Provides blood to the muscles Signup and view all the answers

During which stage of swallowing does the bolus pass through the pharynx?

Pharyngeal stage Signup and view all the answers

What is the primary action of the temporalis muscle on the mandible?

Elevation and retrusion Signup and view all the answers

What is the primary function of the buccinator muscle in relation to the mandible?

Stabilization of the cheek Signup and view all the answers

What is the primary function of the infratemporal fossa?

To allow for the passage of the maxillary artery and pterygoid plexus of veins Signup and view all the answers

Which type of movement occurs in the lower compartment of the temporomandibular joint?

Hinge Signup and view all the answers

What is the primary function of the pterygoid plexus of veins?

To drain the muscles of mastication Signup and view all the answers

Which nerve is responsible for the innervation of the muscles of mastication?

Mandibular nerve Signup and view all the answers

What is the primary function of the articular disc in the temporomandibular joint?

To divide the temporomandibular joint cavity Signup and view all the answers

What is the primary artery that supplies blood to the muscles of mastication?

Maxillary artery Signup and view all the answers

What is the primary function of the Maxillary artery?

To provide blood to the muscles of mastication and buccinator muscle Signup and view all the answers

What is the action of the Lateral pterygoid muscle on the mandible when it contracts unilaterally?

Depression, protrusion and contralateral excursion Signup and view all the answers

What is the primary action of the Suprahyoid muscles during swallowing?

Raising the pharynx Signup and view all the answers

What is the sequence of the three main stages of swallowing?

Buccal, pharyngeal, oesophageal Signup and view all the answers

What is the action of the Medial pterygoid muscle on the mandible when it contracts together with the Masseter muscle?

Elevation, retrusion, and ipsilateral excursion Signup and view all the answers

What is the result of the contraction of the Inferior constrictor muscles during swallowing?

Moving the bolus through the oesophagus Signup and view all the answers

Study Notes

Anatomy of the Head and Neck

Mastication, TMJ, and Swallowing
- Lecture outcomes:
  - Describe the functional anatomy of the TMJ
  - List the muscles of mastication, attachments, actions, blood, and innervation
  - Describe the infratemporal fossa and its contents

Mastication

Process of mastication involves movement of the lower jaw
Movement possible due to the synovial joint between the mandible and temporal bone
Movement at the TMJ allows:
- Incisors to function in biting
- Molars to grind food
- Tongue to place/keep food between molars

Temporomandibular Joint (TMJ)

Articular disc divides the joint cavity into two
Allows for six types of movement:
- Lateral deviation
- Protrusion
- Retrusion
- Elevation
- Depression
Movement types:
- Gliding (deviation) in the upper compartment
- Hinge (rotation) in the lower compartment
- Combination of gliding and hinge movements enables six basic movements of the mandible

Infratemporal Fossa

Space posterior to the maxilla and deep to the zygomatic arch and ramus of the mandible
Allows passage of:
- Temporalis and pterygoid muscles
- Maxillary artery and pterygoid venous plexus

Neurovasculature of Muscles of Mastication

Blood supply from the maxillary artery, a terminal branch of the external carotid
Equivalent drainage is the pterygoid venous plexus
Innervation via the anterior trunk of the mandibular nerve
Also responsible for innervation of the musculature and mucosa of the oral cavity and cheeks

Masseter Muscle

Quadrilateral in shape
Originates from the zygomatic bone/arch and inserts on the anterior border and angle of the ramus of the mandible
Superficial fibers run obliquely, while deep fibers run vertically
Actions:
- Elevation: uses both masseter muscles, enabling teeth to be clenched
- Retrusion: uses superficial fibers, retruding a protruded mandible
- Ipsilateral excursion: a single masseter can move the mandible to the same side

Temporalis Muscle

Fan-shaped muscle
Originates from the side of the skull and inserts at the coronoid process of the mandible
Arises from two heads: temporal bone and temporal fascia
Actions:
- Resting tonus: maintains normal mandibular rest position when upright
- Elevation: enables the teeth to be clenched

Hyoid Muscles

Supra- and infrahyoid muscles primarily involved in swallowing
Contract bilaterally
Actions:
- Infrahyoid muscles: depress the hyoid bone and larynx during swallowing
- Suprahyoid muscles: raise the hyoid bone and larynx when the mandible is stabilized, but can also depress the mandible when acting with infrahyoid and lateral pterygoid muscles
Muscles involved:
- Geniohyoid
- Stylohyoid
- Thyrohyoid
- Sternothyroid
- Sternohyoid
- Omohyoid
- Digastric
- Mylohyoid

Bolus Formation and Swallowing

Incisors and canines take in small portions of solid food
Food is moistened by saliva containing ptyalin, which breaks down carbohydrates
Mechanical action by molars and premolars, assisted by the tongue, breaks down food
Cheeks prevent food from entering the vestibule
Lips reduce the likelihood of food falling out of the mouth
Tongue gathers food into a bolus and pushes it towards the oral pharynx
Palatoglossus muscles relax to open the oropharyngeal isthmus
Swallowing involves:
- Pharyngeal phase: bolus comes into contact with the pharyngeal wall, and muscles propel it towards the esophagus
- Oesophageal phase: bolus passes through the upper and lower oesophagus, driven by peristalsis### Mastication and TMJ
The TMJ cavity is divided by the articular disc and allows for 6 types of movements: lateral deviation, protusion, retrusion, elevation, and depression.
Gliding movement occurs in the upper compartment between the moving disc and stationary fossa.
Hinge movement occurs in the lower compartment between the moving condyle and stationary disc.
The infratemporal fossa is a space found posterior to the maxilla and deep to the zygomatic arch and ramus of mandible, allowing the passage of muscles of mastication (temporalis and pterygoid), the maxillary artery, and the pterygoid plexus of veins.

Muscles of Mastication

Masseter muscle: originates from the zygomatic arch/bone, inserts into the anterior border of the angle and ramus of mandible, and performs elevation, retrusion, and ipsilateral excursion.
Temporalis muscle: originates from the side of the skull (mostly temporal bone), inserts into the coronoid process of mandible, and performs elevation, retrusion, and ipsilateral excursion, as well as tonus.
Medial pterygoid muscle: originates from the medial surface of the lateral pterygoid plate, inserts into the ramus and angle of the mandible, and performs elevation, protrusion, and contralateral excursion.
Lateral pterygoid muscle: originates from the lateral pterygoid plate and sphenoid bones, inserts into the condyle of the mandible, and performs depression, protrusion, and contralateral excursion.

Blood Supply and Innervation

The maxillary artery provides blood to the muscles of mastication and the buccinator (cheek) muscle.
The pterygoid plexus of veins drains into the maxillary vein and anastomoses with the facial vein.
The mandibular nerve supplies muscles of mastication, as well as the muscles and mucosa of the floor and the buccinator muscle.

Swallowing

Swallowing involves moving the pharynx (and larynx) upwards, opening its lumen, and moving the hyoid bone.
Raising the pharynx is achieved by contracting the suprahyoid muscles while stabilizing the mandible.
Depressing the pharynx is achieved by contracting the infrahyoid and lateral pterygoid muscles.
The timeline of swallowing consists of 3 main stages: buccal, pharyngeal, and oesophageal.
Bolus formation: the tongue gathers the food into a bolus and pushes it towards the oral pharynx by raising against the hard palate.
The palatoglossus muscles relax to open the oropharyngeal isthmus.
As the bolus reaches the oropharynx, the soft palate is tensed and raised by the levator muscles.
The superior constrictor contracts to close the nasopharynx from the oropharynx, and the suprahyoid muscles contract to raise and bring the larynx forward.

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Description

This quiz covers the anatomy of hyoid muscles, including their functions in swallowing and movement of the mandible and hyoid bone. Learn about the suprahyoid and infrahyoid muscles and their roles in depression and elevation.