Parotid, Eyes, Mouth, Ears, and Nose Anatomy Flashcards
Outline the bounds of the parotid region
- Superior = Zygomatic arch
- Posterior = External ear and anterior border of SCM
- Medial = ramus of mandible
- Anterior = masseter
- Inferior = angle and inferior border of mandible
List the structures passing through the parotid gland
- Facial nerve and branches (Temporal zygomatic, buccal, mandibular, cervical)
- External carotid artery
- Retromandibular vein
- Auriculotemporal nerve
What encloses the parotid gland
Parotid sheath
How does the parotid duct (Stensen’s duct) enter the oral cavity
Pierces Buccinator to enter cavity opposite 2 maxillary molar tooth
What is the most superficial structure embedded in the parotid gland
Facial nerve
What nerve supplies the skin over the parotid gland
Greater auricular nerve
Describe the secretomotor innervation of the parotid gland
Parasympathetic - Glossopharyngeal to otic ganglion - post-synaptic via auriculotemporal nerve
What type of joint is the TMPJ
Modified hinge-type synovial
Arterial supply of the parotid gland
Branches of the external carotid
Venous drainage of the parotid gland
Retromandibular vein
Lymphatic drainage of the parotid gland
Deep cervical nodes
Describe the differences in saliva output with sympathetic vs parasympathetic stimulation of the parotid
- Parasympathetic = water-rich, serous saliva
- Sympathetic = low-volume, enzyme rich
List the ligaments that attach the mandible to the cranium
- Stylomandibular
- Sphenomandibular
Describe the distribution of the auriculotemporal nerve
- Supplies sensory fibres to auricle and temporal regions
- Sends articular fibres to TMJ
- Conveys postsynaptic parasympathetic fibres to parotid gland
Describe the distribution of the inferior alveolar nerve
- Supplies lower molar and premolar teeth
- Ends as mental nerve
Describe the distribution of the mental nerve
- Supplies skin and mucous membranes of lower lip
- Skin of the chin
What nerve supplies the canines and incisor teeth
Incisor branch of mental/inferior alveolar nerve
Describe the distribution of the lingual nerve
- Sensory to the anterior 2/3rd of the tongue
- Sensory to floor of the mouth and mandibular gums
Describe the course of the lingual nerve
- Arises from posterior trunk of the mandibular nerve (branch of trigeminal)
- Runs past tensor veli palatani and lateral pterygoid where it is joined by chorda tympani
- Runs formward from mylohyoid
- Winds around submandibular duct
- Eventually reaches periosteum of 3rd molar tooth
Where is the otic ganglion situated
Infratemporal fossa - just inferior to foramen ovale
Temporalis (OIIA)
O = floor of temporal fossa I = coronoid process and anterior border of ramus I = CN V3 via deep temporal branches A = elevates mandible
Masseter (OIIA)
O = Inferior border of maxillary process of zygomatic bone I = Angle and lateral surface fo ramus of mandible I = CN V3 via masseteric nerve A = elevates mandible
Lateral Pterygoid (OIIA)
O = two heads 1) infratemporal surface of greater wing of sphenoid, 2) lateral surface of pterygoid plate I = Joint capsule and pterygoid fovea on neck of condyloid process of mandible I = CN V3 via lateral pterygoid nerve A = protracts mandible and depresses chin
Medial Pterygoid (OIIA)
O = two heads 1) medial surface of lateral pterygoid plate, 2) tuberosity of maxilla I = Medial surface of ramus of mandible I = CN V3 via medial pterygoid nerve A = acts synergistically with masseter to elevate jaw, grinds jaw
What muscle forms the floor of the mouth
- Mylohyoid - joins at the midline raphe
- Reinforced by geniohyoid superiorly
What connects the tongue to the mandible
Frenulum
Where are the sublingual papilla situated
Either side of the frenulum
What opens into the sublingual papilla
Submandibular (Wharton’s) duct
Origin of the lingual nerve
Mandibular division of the trigeminal nerve
When is the lingual nerve typically damaged
3rd molar tooth extraction
Which muscles does the hypoglossal nerve innervate
- Supplies superior limb of ansa cervicalis (C1) to innervate infrahyoid muscles
- Supplies all muscle of the tongue except palatoglossus
Describe the sulcus terminalis
- V-shaped groove that separates the buccal and pharyngeal parts of the tongue
- Foramen caecum lies at the apex
Histological structure of the tongue
Covered by thick stratified squamous epithelium bearing papillae on the anterior 2/3rd
Where are the taste buds situated
Within the papillae of the surface epithelium of the tongue
List the extrinsic muscle of the tongue
- Genioglossus
- Styloglossus
- Hyoglossus
- Palatoglossus
Describe the attachments and function of Genioglossus
Attachments: Arises from the mandibular symphsis. Inserts into the body of the hyoid bone and the entire length of the tongue.
Function: Inferior fibres protrude the tongue, middle fibres depress the tongue, and superior fibres draw the tip back and down
Describe the attachments and function of Styloglossus
Attachments: Originates at the styloid process of the temporal bone and inserts into the side of the tongue
Function: Retracts and elevates the tongue
Describe the attachments and function of Hyoglossus
Attachments: Arises from the hyoid bone and inserts into the side of the tongue
Function: Depresses and retracts the tongue
Describe the attachments and function of palatoglossus
Attachments: Arises from the palatine aponeurosis and inserts broadly across the tongue
Function: Elevates the posterior aspect of the tongue
What innervates palatoglossus
Vagus nerve
Blood supply of the tongue
Lingual branch of the external carotid artery
Outline the lymphatic drainage of the tongue
- Anterior 2/3 shows minimal communication across the midline (unilateral nodal disease)
- Posterior 1/3 have communicating networks (bilateral disease)
- Tip drains to submental nodes to deep cervical nodes
- Mid-portion drains to submandibular nodes to deep cervical nodes (more centrally located tumours will likely have bilateral nodal disease)
Outline the innervation of the tongue
Anterior 2/3: - Sensory = lingual branch of V3 - Taste = chorda tympani of CN 7 Posterior 1/3: - Sensation and taste = CN 9
Describe the result of hypoglossal nerve damage
- Wasting of the tongue on the SAME SIDE of the lesion
- Deviates towards the lesion
Describe the superficial relations of the submandibular gland
- Platysma
- Marginal mandibular branch of facial nerve
- Cervical branch of facial nerve
- Facial vein
Describe the deep relations of the submandibular gland
- Mylohyoid
- Hyoglossus
- Lingual nerve
- Hypoglossal nerve
What nerve crosses the submandibular (Wharton’s) duct
Lingual nerve
Where are the submandibular lymph nodes located
Between the gland and the mandible
What is the most superficial structure faced on approach to the submandibular gland
Facial vein
Where is the incision made to access the submandibular gland
Incision 3cm below the mandible to avoid the mandibular branch of the facial nerve
What nerve innervates the tonsillar fossa
Glossopharyngeal nerve
Where is the sublingual gland located
- Immediately below the mucosa of the floor of the mouth
- Immediately in front of the deep part of the submandibular gland
- Separated from base of tongue medially by lingual nerve and submandibular duct
- Laterally rests on the sublingual groove of the mandible
From where is the ear derived
6 hillocks of His (derived from the first and second branchial arches)
Where is the thyroid derived
Foramen caecum (between 1st and 2nd branchial pouches)
Where are the parafollicular C cells derived
5th branchial pouch
Auricle cartilage type
Elastic
Outline the innervation of the auricle
- Upper lateral surface = auriculotemporal nerve
- Lower lateral and medial surface = great auricular nerve
How long is the EAC
3cm
What produces ear wax
Cerumen wax-producing glands (modified sweat glands)
Outline the sensory supply to the EAC
- Auriculotemporal nerve
- Auricular branch of vagus
- Facial nerve via tympanic plexus
Origin of the eustachian tube, middle-ear cleft, and its extension to the mastoid antrum
First branchial pouch
External ear origin
First branchial cleft
Outline the 3 layers of the tympanic membrane
- Outer ectodermal layer = squamous epithelium
- Inner endodermal layer = respiratory-like epithelium
- Middle mesodermal layer = fibrous layer
How is the tympanic membrane divided
- Pars flaccida (the attic)
- Pars tensa (lower part)
What connects the tympanic membrane to the tympanic annulus of the temporal bone
Fibrous annulus
Outline the external nerve supply of the tympanic membrane
- Auriculotemporal (CN 5)
- Vagus
- Facial
- Glossopharyngeal
Outline the internal nerve supply of the tympanic membrane
Tympanic branch of the glossopharyngeal nerve (Jacobsen’s nerve)
Which muscle protects the ear when loud noise is present
Tensor tympani - inserts into the malleus (tenses the tympanic membrane)
Describe the roof of the middle ear
Thin layer of bone called the tegmen tympani separates the MEC from the dura of the middle cranial fossa
Describe the promontory of the MEC
Bulge into the MEC formed by the basal turn of the cochlea - it is covered by the tympanic plexus (from the glossopharyngeal nerve)
What type of joint is between the ossicles
Synovial joint
Describe the course of Chorda tympani
- Arises from the descending portion of the facial nerve (in the mastoid)
- Passes posteriorly between the layers of tympanic membrane
- Exits the MEC through the petrotympanic fissue
- Joins the lingual nerve and supplies taste to anterior 2/3 of tongue
Describe the tympanic plexus
- Formed from CN 9 and CN 7
- Forms Jacobsen’s nerve (CN 9) which forms the lesser petrosal nerve as it leaves the MEC
- Joins the auriculotemporal nerve and is parasympathetic to the parotid gland
Origin of the inner ear (labyrinth)
Otic placode of ectoderm at 3 weeks gestation
List the semicircular canals of the inner ear
- Anterior
- Posterior
- Lateral
Blood supply to the inner ear
Labyrinthine artery (branch of the basilar artery)
Outline the blood supply to the nose
- Lateral nasal artery (branch of facial artery)
- Nasal dorsal artery (terminal branch of ophthalmic artery)
- External nasal artery (from anterior ethmoidal artery)
How is the nasal cavity divided
- Vestibule
- Respiratory region
- Olfactory region
What innervates the septum and lateral walls of the nose
- Nasopalatine nerve (branch of the maxillary nerve)
- Nasociliary nerve (branch of ophthalmic nerve)
What innervates the external skin of the nose
Trigeminal nerve
Where do the paranasal sinuses drain
Middle meatus of the nasal cavity
List the paranasal sinuses
- Maxillary
- Frontal
- Ethmoid
- Sphenoid
What divides the tongue into anterior 2/3rd and posterior 1/3rd
Sulcum terminalis
What forms the anterior tonsillar pillar
Palatoglossus muscle
What forms the posterior tonsillar pillar
Palatopharyngeus muscle
Define the bounds of the oral cavity
Vermillion border of the lips to the anterior tonsillar pillar
What are circumvillate papillae
Taste receptors
Name the space between the base of the tongue and the epiglottis
Vallecula
Origin of the posterior 1/3rd of the tongue
3rd branchial arch
Function of genioglossus
Protrudes the tongue
Function of styloglossus
Retracts the tongue
Function of hyoglossus
Rolls the tongue
Function of palatolgossus
Closes the oropharyngeal isthmus when swallowing
Blood supply and venous drainage of the tongue
- Lingual artery
- Directly to internal jugular vein
Blood supply of the hard palate
Greater palatine artery
Lymphatic drainage of the hard palate
Retropharyngeal nodes
Innervation of hard palate
Branches of maxillary nerve:
- Nasopalatine nerve (via incisive foramen)
- Greater palatine nerve (vial greater palatine foramen)
List the 4 main muscles of the soft palate
- Tensor veli palatani (forms posterior edge)
- Levator veli palatani (superior surface)
- Palatoglossus (anterior edge)
- Palatopharyngeus (posterior pillar)
List the divisions of the ophthalmic branch of the trigeminal
- Lacrimal
- Supraorbital
- Supratrochlear
- Infratrochlear
- External nasal
List the divisions of the maxillary branch of the trigeminal
- Zygomaticotemporal
- Zygomaticofacial
- Infraorbital
List the divisions of the mandibular branch of the trigeminal
- Auriculotemporal
- Buccal
- Mental
Secretomotor fibres of the lacrimal apparatus
Parasympathetic fibres of the pterygopalatine ganglion:
- Pre-ganglionic = greater petrosal nerve, branch of facial nerve
- Post-ganglionic = zygomaticotemporal nerve
Arterial supply of the lacrimal glands
Lacrimal branch of ophthalmic artery