Mouth, ear, and neck anatomy Flashcards
What are the bones and cartilages of the neck?
Cervical vertebrae - flexion and extension of cervical spine
Hyoid bone - helps to keep pharynx open and provides attachment point for muscles
Larynx - protects the airway
Describe the sternocleidomastoid muscle?
Attached to the sternum, clavicle and mastoid
It can act unilaterally or bilaterally
Innervated by the accessory nerve
What are the boundaries of the anterior triangle?
Anteriorly: midline of neck
Posteriorly: sternocleiodomastoid
Superiorly: lower border of mandible
What does the anterior triangle contain?
Trachea
Larynx
Thyroid / parathyroid glands
Suprahyoid muscles
Infrahyoid muscles
Common carotid artery
Branches of external carotid artery
Internal jugular vein
Branches of facial, glossopharyngeal, vagus, accessory and hypoglossal
Ansa cervicales (fibres from c1-c3)
What are the boundaries of the posterior triangle?
Anteriorly: Posterior border of sternocleidomastoid
Posteriorly: Anterior border of trapezius
Inferiorly: clavicle
What does the posterior triangle contain?
Muscles that move head
Part of subclavian artery and vein
External jugular vein
Accessory nerve
Root of brachial plexus
Cervical plexus
Phrenic nerve
What are the 4 paired muscles of the suprahyoid muscles?
Mylohoid
Geniohyoid
Stylohyoid
Digastric
What is the function of the suprahyoid muscles?
Lie superior to the hyoid bone. When they contract, they raise the hyoid bone and larynx during speech and swallowing.
What is the function of the infrahyoid muscles?
Lie inferior to the hyoid bone. They draw the hyoid bone and larynx inferiorly during speech and swallowing.
Sternohyoid and omohyoid lie superficially
Sternothyroid and thyrohyoid lie deep
What are the 2 lobes of the thyroid joined by?
The isthmus
What is the function of the thyroid?
Produces hormones which play an important role in the regulation of metabolic processes.
What is the thyroid supplied by?
Left and right superior thyroid arteries
Left and right inferior thyroid arteries
What veins drain the thyroid gland?
Superior, middle and inferior thyroid veins
Describe the parathyroid glands…
There are 4 parathyroid glands, located posterior to the thyroid gland.
They produce the parathyroid hormone which plays a role in calcium regulation.
Supplied by the inferior thyroid arteries.
Where can the pulse of the internal carotid artery be palpated?
Immediately lateral to the larynx
Describe the internal carotid artery…
It does not give rise to other branches and enters the cranium and supplies the brain
Describe the external carotid artery…
Gives rise to several branches that supply the head and neck.
What is the carotid sinus located?
At the point of bifurcation of the common carotid artery.
What is the function of the carotid sinus?
Contain baroreceptors which monitor arterial blood pressure. This visceral sensory information is relayed back to the CNS via the glossopharyngeal nerve resulting in reflex responses regulating blood pressure.
What is the function of the external jugular vein?
Drains the blood from scalp and face.
What is the function of the internal jugular vein?
Drains blood from the brain and part of the face
What does the facial nerve supply in the neck?
Platysma
What does the glossopharyngeal nerve supply in the neck?
Pharynx
Carotid sinus
What does the vagus nerve supply in the neck?
Muscles of pharynx
Larynx
What does the accessory nerve supply in the neck?
Sternocleidomastoid
Trapezius muscle
What is the carotid sheath?
The vagus nerve runs between the internal jugular vein, the internal carotid artery and the common carotid artery. The 3 structures run together to form the carotid sheath.
What is the pharynx?
A muscular tube that lies in the neck.
What are the outer muscles of the walls of the pharynx?
Outer layer: circular muscle composed of 3 constrictor muscles; superior, middle and inferior constrictors that overlap.
They contract superior to inferior so swallowed food moves down the pharynx.
What are the inner muscles of the walls of the pharynx?
Longitudinal muscle.
What is the epiglottis and its function?
One of the cartilages of the larynx
It closes off the laryngeal inlet and prevents food/liquids from entering the larynx.
What are the 3 parts of the internal pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What are tonsils?
Collections of lymphoid tissue in the upper parts if the pharynx
What are the 4 tonsils and where are they located?
- Pharyngeal - roof of nasopharynx
- Tubal - nasopharynx near openings of auditory tube
- Palatine - next to pharyngeal wall in oropharynx
- Lingual tonsil - posterior aspect of tongue
How is the pharynx innervated?
By sensory fibres from the glossopharyngeal nerve and motor fibres from the vagus nerve.
How many cartilages is the larynx made up of?
9 cartilage
3 unpaired
3 paired
What are the 3 unpaired cartilages of the larynx?
Epiglottis; Thyroid cartilage; Cricoid cartilage
What are the 3 paired cartilages of the larynx?
Arytenoids; Cuneiforms; Corniculate cartilage.
They are smaller than the unpaired cartilages of the larynx
How is the laryngeal prominence (Adam apple) formed?
The thyroid cartilage is composed of 2 flat cartilages that meet in the anterior midline.
What do the superior and inferior horns of the larynx articulate with?
Superior horns attach to hyoid bone.
Inferior horns attach to the cricoid cartilage.
What can injury to the nerves that supply the intrinsic laryngeal muscles do?
Affect speech as the intrinsic muscles move the laryngeal cartilages which move the vocal cords
What are the 2 pairs of mucous membrane folds that project into the cavity of the larynx?
Vestibular folds superiorly and vocal cords inferiorly
What is the function of the vocal cords?
They protect the vocal ligaments and together form the true vocal cords
What is the space between the true vocal cords called?
Rims glottidis
Adduction and abduction of the true vocal cords:
Adduction - closes the rima glottidis
Abduction - opens the rima glottidis
Describe the 2 groups of muscles that act upon the larynx:
Extrinsic - suprahyoid and infrahyoid muscles
Intrinsic - Left and right cricothyroid, posterior cricoarytenoids, transverse arytenoid.
What is the function of the intrinsic muscles acting on the larynx?
Intrinsic - move the laryngeal cartilages which move the vocal cords.
What are the 2 important nerves of the larynx?
Superior laryngeal nerve - innervates the cricothyroid muscle
Recurrent laryngeal nerve - innervates all intrinsic muscles except cricothyroid
How are the left and right nasal cavities separated?
A thin midline septum formed of cartilage and bone
How are the nasal cavities separated from the oral cavity?
The hard palate (floor of nasal cavity)
How are the nasal cavities separated from the brain?
Bone of the roof of the nasal cavity
What forms the posterior septum?
Perpendicular plate of ethmoid bone forms the superior part of the posterior septum.
Vomer forms the inferior part of the posterior septum.
How is the nasal cavity separated from the cranium and brain?
The cribriform plate
Blood supply and innervation of the nasal cavity?
Blood supply: maxillary artery - a terminal branch of the external carotid artery
Innervation: Branches of trigeminal nerve
What are the 4 paranasal sinuses and where do they drain and what is their nerve innervation?
Frontal - drain into middle meatus - Opthalmic division
Ethmoid - drain into superior and middle meatus - Ophthalmic and maxillary nerve
Sphenoid - drains into spheno-ethmoidal recess - ophthalmic
Maxillary - drains into the middle meatus -
What is the function of the nasolacrimal duct?
Drains tears. The duct opens into the inferior meatus.
What connects the middle ear to the nasopharynx?
Auditory tube (Eustachian tube)
What is the function of the auditory tube (Eustachian tube)?
Allows air to pass into the middle ear so the pressure on either side of the tymphatic membrane is equal. this allows for optimal conduction of sound waves.
Why is the hard palate functionally important?
Prevents food/ fluid entering the nasal cavity
Push tongue up against hard palate during swallowing which forces food towards oropharynx
Push tongue against hard palate to articulate certain sounds.
How are the muscles of the soft palate innervated?
Vagus nerve
What are the boundaries of the oral cavity?
Superior: hard and soft palate
Inferior: soft tissues and muscles
Lateral: cheeks
What are the structures of the oral cavity?
Tongue, teeth, gums and openings of salivary ducts
How many teeth do adults have?
- 16 in maxilla and 16 in mandible
4 incisors, 2 canines, 4 premolars, 6 molars
Teeth are composed of:
Inner pulp containing blood vessels and nerves
Dentin surrounding pulp
Outer hard coat of enamel
What detects taste on the tongue?
Papillae
What is the vallecula?
The space between the posterior tongue and the anterior aspect of the epiglottis.
How are the muscles of the tongue innervated?
Hypoglossal nerve
What are the functions of intrinsic and extrinsic muscles of the tongue?
Intrinsic : change shape of tongue.
Extrinsic : move the tongue
What cranial nerves provide sensory innervation to the tongue?
Taste in anterior 2/3 tongue is innervated by facial nerve
General sensation in anterior 2/3 tongue innervated by trigeminal nerve
Taste and general sensation in the posterior third innervated by glossopharyngeal nerve.
Innervation of the oral cavity:
Supplied by lingual, maxillary, and facial arteries (branches of the external carotid arteries).
What are the 3 pairs of salivary glands that secrete saliva into the oral cavity and how is secretion stimulated?
Parotid - secretion is stimulated by parasympathetic fibres in the glossopharyngeal nerve.
Submandiubular - secretion stimulated by the parasympathetic fibres in the facial nerve
Sublingual - secretion stimulated by the parasympathetic fibres in facial nerve
