Glossary of Head and Neck 08 -- Oral Cavity
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- What forms the anterosuperior border of the oral cavity?
- Maxillary teeth, superior alveolar ridge, hard palate.
- What forms the inferior border of the oral cavity?
- Mandibular teeth, inferior alveolar ridge, and floor of mouth.
- What structure forms the floor of the mouth?
- Mylohyoid muscle.
- What is an alveolar ridge?
- A ridge with alveoli
- What are alveoli?
- Alveolus means "socket"
- So what is the alveolar ridge?
- The area or the mandibular and maxillary jaws that the teeth stick out from
- What is the lateral border of the oral cavity?
- The cheeks
- What forms the posterior border of the oral cavity?
- Formed by a ring of structures
- What is the superior structure in the ring forming the posterior border of the oral carity?
- Soft palate
- What are the lateral structures in the ring forming the posterior border of the oral carity?
- The anterior tonsillar pillars
- What is the inferior structure in the ring forming the posterior border of the oral carity?
- Circumvallate papillae
- What is the centerpiece of the oral cavity?
- The oral tongue
- What is the oral tongue?
- The anterior 2/3 of the tongue
- What is the other part of the tongue called?
- Tongue base
- What divides the tongue into the oral tongue and tongue base?
- Circumvallate papillae
- What forms the surface of all structures within the oral cavity, except the teeth?
- What kind of mucosa?
- Stratified squamous
- What is true of this mucosa?
- Any part of this mucosa can serve as the origin for SCCa
- What is found beneath the mucosa throughout the oral cavity?
- Collections of minor salivary glands
- What is true of these minor salivary glands?
- Tumors may arise from any of these minor salivary glands
- What types of tumors can arise?
- Benign or malignant
- What kind of benign tumor can arise from the minor salivary glands?
- Benign mixed tumor
- What are the areas of the oral cavity?
- There are two spaces and a third major area
- What are the two spaces of the oral cavity?
- 1) Sublingual space
2) Submandibular space
- What is the third major area of the oral cavity?
- The mucosal area
- Why is the mucosal area given special bearing, even though it is not a true space?
- Because it gives rise to its own set of diseases, which often are different from lesions of the SLS and the SMS.
- How are lesions of the oral cavity assigned a space/area?
- If they are in the mucosal area, that is evident clinically.
The position of the lesion relative to the mylohyoid can be used to determine whether a lesion is in the submandibular or sublingual space.
- What is the mylohyoid?
- It forms the floor of the mouth
- What can the mylohyoid be thought of as?
- The "levator ani" or diaphragm of the oral cavity
- What is the mylohyoid actually?
- A muscular hammock
- Where does it attach?
- To the medial surfaces of the mandibular bodies
- That accounts for the anterior and lateral aspects of the mylohyoid attachment. Where is the posterior attachment?
- There is none. It is a free edge.
- What does the mylohyoid to with respect to the spaces of the oral cavity?
- It divides them
- Which space is on top of the mylohyoid (sitting in the hammock)?
- Which do you think?
Probably the one closest to the tongue, since the tongue is on the hammock side of the mylohyoid.
- So which space is on top of the mylohyoid?
- Sublingual space
- Which space is on the convex side of the mylohyoid?
- Submandibular space
- So, if a lesion is seen lateral to the mylohyoid on an axial image, what space is it in?
- Submandibular space
- What is the posterior separation of the sublingual and submandibular spaces?
- There is none.
Where the free edge of the mylohyoid is, there is free passage between the sublingual and submandibular spaces
- What is the floor of the mouth?
- Refers specifically to the mylohyoid
- What is the root of the tongue?
- Refers to:
1) The deep muscles of the oral cavity
2) The posterior sublingual space
- What are the deep muscles of the oral cavity?
- 1) Genioglossus
- What is the lingual tonsil?
- The majority of the tongue base
- What are the surfaces of the mucosal area of the oral cavity?
- What parts of the mucosal area have the highest concentrations of minor salivary glands?
- Inner surface of lip
- When a mucosal lesion is found in the oral cavity, what are the most important quesions the clinician wants answered?
- 1) What is its deep tissue extent
2) What vital neurovascular structures are involved
- The most common lesion in this area is SCCa, so what is the next task of the radiologist in these cases?
- What questions must be answered by the radiologist in order to stage SCCa of the oral cavity?
What is the first question?
- 1) Does the tumor cross the midline lingual septum?
- What is the lingual septum?
- The median vertical fibrous partition of the tongue.
- What does the lingual septum merge into posteriorly?
- The aponeurosis of the tongue.
- What is the second question that must be answered for staging of SCCa?
- 2) Is the root of the tongue involved?
- What is the root of the tongue not?
- Its not the base of the tongue.
- How is the root of the tongue most commonly involved?
- Via the mylohyoid
- What is the third question that must be answered for staging of SCCa?
- 3) Is the mandible involved?
- What is the fourth question that must be answered for staging of SCCa?
- 4) Are 1st order drainage nodes affected?
- What are the first order drainage nodes?
- 1) Submental
- In what case may another node be a first-order drainage?
- If the lesion is in the posterior oral cavity.
- What node is a first order drainage site for the posterior oral cavity mucosal lesion?
- Jugulodigastric node
- What is the jugulodigastric node?
- Highest deep cervical chain node.
- What is an important fact to remember about the lymphatic drainage of SCCa of the oral cavity?
- Often bilateral
- Which is the preferred modality in staging of SCCa? CT or MRI?
- Why is MRI better?
- 1) Less dental amalgam artifact
2) More sensitive to the true extent of tumor
- With whom must you review your images when staging SCCa of the oral cavity?
- The ENT surgeon.
- After filling up one side of the sublingual space, pus can find its way through a small space under the frenulum of the tongue far anterior, where it can pass to the contralateral sublingual space.
- What will failure to do this lead to?
- Failure to do this will lead to serious errors of interpretation.
- What are the lesion classifications of the mucosal area?
- 1) Congenital/Developmental
3) Benign tumor
4) Malignant tumor
- What are the congenital/developmental lesions of the mucosal area of the oral cavity?
- 1) Hemangioma
3) Lingual thyroid tissue
- What is the other name for lymphangioma?
- Cystic hygroma
- How is the diagnosis of hemangioma made?
- Usually clinically
- What is the appearance when hemangioma undergoes an enhanced CT?
- Intense enhancement
- Where is cystic hygroma usually located?
- Submandibular space
- How does it involve the mucosa?
- It can project right to the mucosal surface.
- What is the clinical presentation of lingual thyroid tissue?
- Lobular mass that is seen projecting upward "like a golf ball" at the back of the tongue in the midline when the tongue is stuck out.
- Where does the thyroid normally descend from?
- From the foramen cecum of the tongue base to the lower neck
- What is a lingual thyroid?
- Normal thyroid tissue that did not descend
- What is seen on imaging?
- Midline mass in base of tongue
- From the mucosal surface of the tongue base, anteriorly into the medial sublingual space.
- What is seen on CT?
- The mass appears hyperdense, with or without contrast.
- How is the presence of functioning lingual thyroid tissue assessed?
- I-123 scan
- What does nuclear medicine test also assess?
- Whether there is other (ectopic, orthotopic) thyroid tissue in the neck.
- What happens in most cases where lingual thyroid tissue is removed?
- Permanent hypothyroidism
- What predisposes to infection of the oral cavity mucosa?
- Infection of the submandibular and sublingual spaces. The oral cavity mucosa is involved only by proximity.
- What are benign tumors of the oral mucosal area?
- Benign mixed tumor of the minor salivary glands
- What is the clinical presentation of benign mixed tumor of the minor salivary glands?
- Pedunculated mass
- Where are these most commonly?
- Hanging into the oral cavity from the palatal mucosa
- What are the imaging features of benign mixed tumor?
- Well circumscribed
- What are the malignant tumors of the mucosal area of the oral cavity?
- 1) SCCa
2) Minor salivary gland malignancies
- What are the differences in clinical presentation between SCCa and minor salivary gland malignancies of the oral cavity?
- There are none. They are clinically indistinguishable.
- How much more common is SCCa than minor salivary gland malignancy?
- Far more common
- What are the differences in imaging presentation between SCCa and minor salivary gland malignancies of the oral cavity?
- None. Indistinguishable.
- What malignancies of the minor salivary glands occur in the mucosa of the oral cavity?
- Adenoid cystic
- What is the other name for acinic cell?
- What is the location of the sublingual space of the oral cavity?
- Superomedial to the mylohyoid muscle
(i.e. in the hammock)
- What is the fascial lining of the sublingual space?
- How is that?
- Portions of its contents are found within the oral tongue
Its posterior border is not separated from the submandibular space.
- What are the contents of the sublingual space?
- 1) Tongue
2) Anterior aspect of the hyoglossus muscle
5) Sublingual glands and ducts
6) Deep portion of submandibular gland
7) Submandibular gland duct
- What nerves are in the sublingual space?
- 1) CN IX (glossopharyngeal)
2) CN XII (hypoglossal)
3) Lingual nerve
- What is the lingual nerve?
- The sensory branch of cranial nerve V3 = inferior alveolar branch of the mandibular division of the trigeminal nerve. This provides SOMATIC SENSORY.
The chorda tympani branch of the facial nerve, which carries the VISCERAL SENSORY = TASTE to the anterior 2/3 of the tongue
- What are the vessels of the sublingual space?
- Lingual artery and vein
- What is the other name of the submandibular gland duct?
- What do the above named vessels constitute?
- The neurovascular pedicle of the tongue.
- What is the inferior extent of the sublingual space?
- What is the anterior extent of the sublingual space?
- What is the posterior extent of the sublingual space?
- None. The sublingual space ends at the posterior margin of the mylohyoid
- What does this mean?
- Disease from the sublingual space can just flop right into the submandibluar space
- How is a mass said to be primary to the sublingual space?
- Its center is within the oral tongue or soft tissues superomedial to the mylohyoid
- What can be the case when a lesion is seen in the submandibular space, with a small portion of the lesion extending into the sublingual space?
- It may be a sublingual lesion flopping out posterioly into the submandibular space
- What is crucial in imaging the sublingual space with CT?
- The plane of scan must be in plane with the mandibular teeth to limit dental amalgam artifact to as few sections as possible.
- Which is more severely affected by dental amalgam? CT or MRI?
- What are the classes of lesions in the sublingual space?
- 1) Congenital/Developmental
4) Benign tumor
5) Malignant tumor
- What are the common congenital/developmental lesions of the sublingual space?
- 1) Hemangioma
2) Lymphangioma/cystic hygroma
4) Lingual thyroid tissue
- Which of these lesions is most characteristic of the sublingual space?
- Which of those lesions is more common in the sublingual space?
- Where are dermoids of the oral cavity more commonly found?
- Submandibular space
- What is the clinical presentation of epidermoid/dermoid of the sublingual space?
- Slow growing mass under the tongue
- What are the imaging features of epidermoid/dermoid?
- Unilocular mass in the sublingual or submandibular spaces
- What is the density/signal of the contents in an epidermoid?
- Fluid density/signal
- What is the density / signal of the contents in a dermoid?
- Mixed fluid/soft tissue density with or without fat
- What are the two common causes for infection in the sublingual and submandibular spaces?
- 1) Ductal stenosis / calculus
2) Dental manipulation of the lower teeth
- What types of infection are there in the submandibular and sublingual spaces?
- 1) Cellulitis
- When is the term abscess used?
- Only when there are well defined areas of fluid within the broader cellulitc region.
- What is a special type of infection?
- Ludwig's angina
- What is the clinical history?
- Occurs 2-4 days after dental extraction from the lower alveolar ridge
- What is the pathology?
- Severe cellulitis, with abscess involving the sublingual and submandubular spaces
- What is the imaging modality recommended for evaluation of infection involving the sublingual or submandiular spaces?
- When should you call it cellulitis, when should you call it abscess?
- Do not overcall amorphous small fluid areas within cellulitis as abscess.
Allow today's powerful antibiotics to work, and perform closely spaced follow-up imaging in order to see if there is progression or if surgical management will be in fact needed.
- What does a large abscess of the sublingual space appear like?
- An upside-down horseshoe
- What types of ranulae are there?
- Simple ranula
- What is a simple ranula of the sublingual space?
- Postinflammatory retention cyst of the sublingual gland or minor salivary glands
- Where is a sublinbual simple ranula located?
- In the sublingual space
- What is it lined with?
- What is the appearance of simple ranula on CT or MRI?
- Unilocular cystic mass in the sublingual space
- What is the DDx for this appearance?
- This appearance of simple ranula does not distinguish it from
--unilocular cystic hygroma
- What is a diving ranula?
- Occurs when the simple ranula enlarges, and ruptures backwards out into the submandibular space.
- What is the diving ranula lined with?
- Nothing. It is a pseudocyst.
- Where is a sublingual diving ranula located?
- Submandibular space
- Then how can it be recognized as being from the sublingual space?
- Look for the characteristic "tail sign", with the submandibular mass having a thin tail projecting back superoanteriorly into the sublingual space. This indicates that its origin is in the sublingual space.
- What is important to know about this appearance of diving ranula?
- It is highly suggestive (specific) for the diagnosis
- What is the pseudotumor of the sublingual space?
- Hypoglossal nerve injury
- What is the CT appearance?
- The injured side undergoes atrophy and fatty infiltration of the tongue and tongue root muscles.
Therefore, the normal contralateral side appears to be involved with tumor.
- What is the appearance of early hypoglossal nerve injury on MRI?
- Early motor atrophy of the tongue appears like infiltrating tumor on the IPSILATERAL side as the atrophy begins to develop.
I think there is initially swelling of the denervated side prior to onset of atrophy.
- What are benign tumors of the sublingual space?
- Benign mixed tumor of the sublingual gland
- What are malignant tumors of the sublingual space?
- 1) SCCa
2) Sublingual gland or minor salivary gland malignancy
- What is the most common malignant tumor of the sublingual space?
- How does SCCa get into the sublingual space?
- All it has to do is invade through the basement membrane of the tongue or undersurface of tongue mucosa, and its already there.
- What are the most common places that the mucosal lesion is located?
- Oral tongue
Base of tongue
- How does oral tongue SCCa invade the sublingual space?
- Superior to inferior
- How does base of tongue SCCa invade the sublingual space?
- Posterior to anterior
- How common are sublingual gland malignancies and minor salivary gland malignancies of the sublingual space?
- Extremely rare
- What is the location of the submandibular space?
- Inferolateral to the mylohyoid (on the concave surface of the hammock)
Superior to the hyoid
- What are the fascial margins of the sublingual space?
- The superficial layer of deep cervical fascia splits to encircle the submandibular space
- Where does the top layer run?
- The inferior surface of the mylohyoid
- Where does the bottom layer run?
- The inner surface of the platysma
- Is the submandibular space fully enclosed?
- Where is it open?
- It is open at its posterior aspect
- We already know that disease from the sublingual space can enter the submandibular space, but what common space do the posterior aspects of the submandibular and sublingual spaces both open into?
- The inferior portion of the parapharyngeal space
- What are the contents of the submandibular space?
- 1) Anterior belly of digastric
2) Submandibular gland (superficial portion)
3) Lymph nodes (submandibular and submental)
4) Facial artery and vein
5) Inferior loop of hypoglossal nerve (CN XII)
- What are the most important contents of the submandibular space?
- Submandibular gland (the bulk of it, anyway)
Nodal groups (both)
- Why are these structures the most important in this space?
- Primary disease of the submandibular space arises from the gland or the nodes in most cases.
- What is the overall shape of the submandibular space?
- Horseshoe shaped, carved out by the mylohyoid above
- How is a mass diagnosed as primary to the submandibular space?
- Its center is in the submandibular space, inferolateral to the mylohyoid
- When do lesions of the submandibular space crawl up into the sublingual space?
- Very rarely
- What are the categories of lesions of the submandibular space?
- What are the common congenital lesions of the submandibular space?
- 1) Second branchial cleft cyst
2) Cystic hygroma/lymphangioma
- What is a less common congenital lesion of the submandibular space?
- Suprahyoid thyroglossal duct cyst
- By when does the second branchial cleft normally involute?
- 9th week of gestation
- What happens when involution is incomplete?
- The remnant tissue can grow into a branchial cleft anomaly
- What percentage of all branchial cleft anomalies arise from the second branchial apparatus?
- Where is the second branchial cleft cyst palpated/seen?
- Angle of mandible
- When do branchial cleft anomalies present?
- Bimodal distribution
- When is the initial peak?
- What is sometimes seen in these patients
- A sinus tract
- What is the deal with the sinus tract?
- It has a superior and inferior portion.
- What is the relationship of the tract to the branchial cleft cyst?
- The cyst is actually a saccular dilatation along the tract.
- Where is the superior end of the tract?
- The superior end of the tract is located at the faucial tonsil.
- Where is the saccular dilatation of the cyst?
- At the mandibular angle.
- What is the cyst located next to?
- Just lateral to the CN XI and XII.
- Where does the inferior end of the tract go?
- All the way down to the anterior neck just above the clavicle.
- When does the second peak in second branchial cleft cysts occur?
- Young adults
- Why does the lesion present?
- Trauma or viral infection
- What is a typical history the radiologist is presented with (maybe not so much now, since things get imaged earlier)
- Unsuccessful abscess drainage
- Imaging features of second branchial cleft cyst?
- Unilocular cystic mass
In the posterior aspect of the submandibular space, at the angle of the mandible
- What is the displacement pattern of the second branchial cleft cyst? Firstly, what structures does it displace?
- Submandibular gland
- How does the second branchial cleft cyst displace the submandibular gland?
- How does the second branchial cleft cyst displace the sternocleidomastoid?
- How does the second branchial cleft cyst displace the carotid space?
- What is a finding that is characteristic for second branchial cleft cyst?
- A beak on the cyst
- Where does the beak point?
- Where medially?
- Between the internal and external carotid arteries
- What is this beak?
- It is the superior portion of the duct as it passes between the internal and external carotid arteries, arching toward the faucial tonsil
- What is the most common imaging appearance of second branchial cleft cyst?
- Cystic mass, without evidence of sinus tract or fistula.
- When describing a second branchial cleft cyst, how do you do it?
- Completely. Describe the full deep tissue extent of the lesion, tracts, fistulas, and all.
- Why is this so important?
- Because the entire cyst lining must be removed in order to prevent recurrence.
- What is done if there is cutaneous evidence of a sinus tract, but no cystic mass?
- What is the clinical presentation of a cystic hygroma?
- Fluid filled cystic mass. Difficult to assess by palpation.
- What is a cystic hygroma?
- Congenital malformation of lymphatic channels.
- What percentage of cystic hygromas are present at birth?
- By what age are 90% clinically apparent?
- Age 3
- Where is this lesion most commonly located in the infant?
- Posterior cervical space
- Where is this lesion most commonly located in the adult?
- 1) Submandibular space
2) Sublingual space
3) Parotid space
- What separates the two sides of the submandibular space?
- There is no separation. So disease freely transmits from one side of the submandibular space to the other.
- What is the appearance in teh submandibular space?
- Multilocular fluid containing mass.
- What may the lesion do?
- Cross anteriorly into the contralateral side of the SMS
- What is the nature of cystic hygroma?
- Tenacious, difficult to remove lesion
- What does it often do to adjacent neurovascular structures?
- Wraps around them
- In the case of the SMS or SLS cystic hydroma, relationship to what structures should be commented on?
- Neurovascular pedicle of the tongue
- When both the SMS and SLS are involved with cystic hygroma, what is in the differential diagnosis?
- Diving ranula
- Cystic mass involving the SLS and SMS simultaneously suggests a limited differential diagnosis. What is it?
- Diving ranula
- What supports diving ranula?
- What supports cystic hygroma?
- What supports abscess?
- Appropriate clinical history
- What are the inflammatory/infectious diseases of the submandibular space?
- 1) Reactive adenopathy
- Imaging appearance or reactive nodes:
- Reactive nodes are homogeneous internally.
- What is the meaning if internal nodal architecture becomes inhomogeneous?
- What are the sources of cellulitis within the SMS?
- 1) Suppurative adenopathy
2) Submandibular gland infection
3) Infected tooth/socket/mandible
- What are the typical causes of submandibular gland infection?
- Ductal stone
- What is another cause of submandibular gland inflammation, due to ductal obstruction?
- What is the clinical presentation of submandibular gland inflammation?
- Unilateral painful submandibular space swelling, often associated with eating or psychological gustatory stimulation
- What is this clinical syndrome called?
- Salivary colic
- What percentage of sialoliths occur in the parotid, submandibular, and sublingual ductal systems?
- Parotid -- 15%
SUBMANDIBULAR -- 85%
Sublingual -- 0%
- How is stone location described?
- Either distal or proximal
- What is distal?
- Towards ductal opening in mouth
- What is proximal?
- Towards hilum of submandibular gland
- Why is description of stone location as proximal or distal important?
- For distal stone, surgery to remove the stone is performed.
For proximal stone, removal of the proximal duct and GLAND may be necessary, especially if stone is in the hilum.
- What is the percentage of sialoliths visible on CT?
- In the setting of a dilated submandibular duct, if no stone is seen, what is done next?
- Search for FLOOR OF MOUTH TUMORS
- How is the search done?
- Both clinically and with imaging
- What if no tumor is found?
- Then the duct is assumed stenotic. BUT NOT UNTIL TUMOR IS EXCLUDED AS THE CAUSE OF DUCTAL OBSTRUCTION.
- More basic anatomy:
Where is the submandibular gland in relation to the mylohyoid?
- The majority of it (superficial portion) is on the concave surface of the mylohyoid, wedged between the mylohyoid and the mandibular ramus.
However, the most superior portion of it is indented by the free edge of the mylohyoid, and wraps on top of it, like a loft.
- Where does the submandibular gland come off?
- It comes off of this posterorsuperior "deep" portion of the submandibular gland which is where the hilum of the submandibular gland is located.
- What is the submandibular duct course?
- Starts off on this medial side of the mylohyoid, and stays there, as it wraps towards the frenulum at the anterior undersurface of the tongue.
- How long is the submandiblular duct in relation to the submandibular gland?
- 1.5 times longer
- What are benign tumors of the submandibular space?
- 1) Lipoma
3) Submandibular gland benign mixed tumor
- What is appearance of submandibular gland benign mixed tumor?
- Well circumscribed mass in an enlarged submandibular gland
- What must benign mixed tumor of the submandibular gland be differentiated from?
- Parotid tail mass pedunculating into the submandibular space
- How is this possible?
- ?Remember that the inferomedial aspect of the parotid space is directly contiguous with the submandibular space?
Parotid tail masses do commonly present as angle of mandible masses.
- How do you make this differentiation?
- Look first for a normal or compressed submandibular gland before assuming the mass is submandibular gland.
- Why is this determination so important?
- Excision of a parotid tail mass from a submandibular approach will result in FACIAL NERVE INJURY
- What is the most common malignancy of the SMS?
- Malignant adenopathy from SCCa
- Which nodes?
- Submental and submandbular
- Where do they receive drainage from?
- Facial skin
Oral cavity mucosa
- What is considered malignant node by imaging?
- > 1 cm
ANY node with central inhomogeneity
In a patient with known SCCa.
- What about multiple large homogenous nodes in the submental and submandibular groups?
- How common is malignancy of the submandibular gland?
- What does this mean for benign mixed tumor of the submandibular gland?
- Even more rare.
- What are classes of pathology of mandible?
- 1) Fracture
3) Bony cyst
4) Benign tumor
5) Malignant tumor
- What is simple mandibular fracture?
- Linear fracture that does not communicate with the oral cavity
- What is compound fracture of the mandible?
- Fracture through the alveolar ridge involving roots of erupted teeth
- What is complicated mandibular fx?
- Fx involves inferior alveolar artery or nerve
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