Eileen - oral cancer, larynx anatomy Flashcards
What are the two main signs of precancerous and benign neoplastic disease?
Leukoplakia
Erythroplakia
Define leukoplakia.
A white patch or plaque that can’t be scraped off and can’t be characterised clinically or pathologically as any other disease
How many leukoplakial lesions are pre-malignant?
5-25%
Where a leukoplakial lesion most often found within the mouth?
Vermilion border of the lower lip
Buccaneers mucosa
Hard and soft palates
Not that often seen on the floor of the mouth
Describe erythroplakia
Red velvety patches of epithelial atrophy and pronounced dysplasia
Where is erythroplakia most commonly seen within the oral cavity?
On the buccal mucosa or the palate
What are the possible head and neck cancers?
Squamous cell carcinomas - 95%
Adenocarcinomas
Melanomas
Various carcinomas
How do SCCs arise pathologically?
Derived from epithelial lining - it’s an aggressive epithelial malignancy
May arise from existing dysplasia (erythroplakia or leukoplakia)
What is the long-term survival rate for squamous cell carcinoma - and why?
50%- it’s so low because oral cancer are often quite advanced by the time they are diagnosed - also, multiple primary tumours often develop
What are the risk factors for oral cancers?
Smoking Alcohol HPV - at least half of oral cancers (particularly if they involve the tonsils, base of tongue or the orophyarynx, involves oncogenic variants of HPV) Genetics Actinic radiation Nutritional deficiency
Why will HPV-associated HNSCC surpass that of cervical cancer in the next decade?
Anatomical sites of origin (tonsils, base of tongue, orophyarynx) aren’t readily accessible not to cytology cal screening - unlike the cervix
Describe the macroscopic structure of the HNSCC.
Raised modular lesions
Central ulceration with hard raised edges
Describe the microscopic structure of the HNSCC.
The tumour is well-differentiated and keratinising
Where are the sites that a HNSCC often forms?
Lips - recognised early and amenable to surgery Tongue - lateral border of anterior two thirds
Cheek or floor of mouth - asymptomatic, resulting in extensive local invasion and making surgical removal difficult
Describe the five stages of histological progression.
Normal Hyperplasia/hyperkeratosis Mild/moderate dysplasia Severe dysplasia/carcinoma in situ Squamous cell carcinoma
Why do people not often report lesions in their mouths?
Incomplete understanding that small, asymptotic lesions can have massive malignant potential
Dentists aren’t properly performing a basic oral cancer examination to achieve the early detection
How could more people with these lesions be identified at an earlier stage?
Health education programmes
Tools to improve screening methods
Dentists perform visual and tactile examination Identification of high risk individuals and implementation of efficient chemoprevention and molecular targeting strategies
What influences the time until diagnosis?
Socioeconomic status
Patient reluctance to go to a doctor
Professional delay in diagnosis and treatment
Where are the superficial lymph nodes and what do they drain?
They form a ring around the head
Drain the face and the scalp
Where are the occipital nodes and what do they drain?
Near the attachment of the trapezius to the skull
Associated with the occipital artery
Drain the posterior scalp and neck
Where are the post auricle nodes and what do they drain?
Posterior to the ear and near the attachment of the sternocleidomastoid muscle
Associated with the postauricular artery
Lymphatic drainage is from the postero-lateral part of the scalp
Where are the preauricular nodes and what do they drain?
Anterior to the ear
Associated with superficial temporal and transverse facial arteries
Drains the anterior auricle, anterolateral scalp and upper half of face, eyelids and checks
Where are the submandibular nodes and what do they drain?
Inferior to the border of the mandible
Associated with the facial artery
Drains the structures along the path of the facial artery, as well as gums, teeth and tongue
Where are the sub entail nodes and what do they drain?
Inferior and posterior to the chin
Drains the central part of the lower lip, chin, floor of mouth, tip of tongue and lower incisor teeth
Where do the occipital and postauricular lymph nodes drain to?
Superficial cervical lymph nodes
Where do the preauricular, submental and submandibular nodes drain to?
The deep cervical lymph nodes
Where are the superficial cervical lymph nodes, where do they drain to?
They run along the external jugular vein on the superficial surface of the sternocleidomastoid muscle
They drain to the deep cervical nodes
Where are the deep cervical lymph nodes, and where do they drain?
They form a chain along the internal jugular vein
Drain to jugular trunks - these empty into the right lymphatic duct on the right and the thoracic duct on the left
The tendon of which muscle divides the deep cervical lymph nodes in upper and lower groups?
Intermediate tendon of the omohyoid muscle
What is the most superior node of the deep cervical nodes?
Jugulodiagastric - receives drainage from the tonsils and the tonsilliar region
Which node receives drainage from the tongue?
Jugulo-omohyoid
Describe the full lymphatic drainage of the tongue.
Submental node drains the tip
Submandibular nodes drain the body of the tongue
These both drain into the deep cervical nodes (specifically the jugulo-omohyoid)
This then drain to the jugular trunk and into either the right lymphatic duct (right) or the thoracic duct (left)
What are the intrinsic muscles of the tongue?
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
Where are the inferior and superior longitudinal muscles of the tongue, and what do they do?
They run from the root to the apex of the tongue
Move the tip up and down
Where does the transverse muscle travel and what does it do?
It travels across the tongue, inferior to the superior longitudinal muscle
This muscle narrows and lengthens the tongue
Where is the vertical muscle in the tongue, and what does it do?
It travels superior to inferior (inferior to the superior longitudinal muscle)
Flattens and depresses the tongue
What do the intrinsic muscles of the tongue contribute to?
Precise tongue movements required for speech, eating and swallowing
Describe the genioglossus muscle.
A thick-fan shaped muscle
Occurs on each side of the midline septum that separates right and left sides of the tongue
Arises from the mental symphysis and inserts into the dorsal of the tongue
What is the function and innervation of the genioglossus?
It’s depresses the central part of the tongue
Sticks the tongue out
Draws the tip back and down Innervated by the hypoglossal nerve
Describe the hyoglossus muscle.
A thin quadrangular muscle lateral to the genioglossus muscle
Originates on the hyoid bone and inserts into the side of the tongue
What is the function and innervation of the hyoglossus?
It depresses the tongue Innervated by the hypoglossal nerve
Describe the styloglosses muscle.
Originates from the anterior surface of the styloid process of the temporal bone and inserts into the side of the tongue
What is the function and innervation of the styloglossus muscle?
It draws the tongue back and pulls the back of the tongue superiorly Innervated by hypoglossal nerve
Describe the palatoglossus muscle.
Originates on the palatine aponeuroses and inserts broadly across the tongue
What is the function and innervation of the palatoglossus muscle?
Depresses the soft palate
Elevates the back of the tongue
Moves palatoglossal arches of mucosa towards the midline Innervated by vagus nerve
Name the pieces of single cartilages.
Thyroid
Cricoid
Epiglottis
Name the paired pieces of cartilage.
Arytenoid
Cuneiform
Corniculate
What is the function of the arytenoid cartilage?
Influences changes in the position and tension of the vocal folds
What is the part of the cavity above the vocal folds called?
Vestibule of the larynx
Why does the thyroid cartilage have a triangular shape?
It made up of two fused plates of hyaline cartilage - join anteriorly to form the laryngeal prominence
Why is the thyroid cartilage larger in males?
Influence of male sex hormones during puberty
What do the superior and inferior horns of the thyroid cartilage articulate with?
Superior horn - hyoid boneInferior horn - cricoid cartilage
What is the name of the structure that connects the thyroid to the hyoid bone?
The thyrohyoid ligament
Describe the epiglottis.
A large, leaf shaped piece of elastic cartilage covered with epithelium, that marks the entrance to the larynx
Describe the action of the larynx, pharynx and epiglottis during swallowing.
The pharynx and larynx rise - pharynx elevation widens it to receive food and drink- larynx elevation causes the epiglottis to move down and form a lid over the glottis
What is the glottis?
A pair of folds of mucous membrane, vocal folds in the larynx and the space in between them (rima glottidis)
Describe the cricoid cartilage
A ring of hyaline cartilage that forms the inferior wall of the trachea
How is the cricoid cartilage attached to the trachea and the thyroid cartilage?
1st ring of the trachea - cricotracheal ligament
Thyroid cartilage - cricothryoid ligament
What is the landmark for an emergency tracheostomy?
The cricoid cartilage
Describe the arytenoid cartilages.
Triangular pieces of hyaline cartilage located at the superior, posterior border of the cricoid cartilage
Forms synovial joints with the cricoid cartilage - wide range of mobility
Describe the corniculate cartilages.
Horn-shaped pieces of elastic cartilage
Located at the apex of each arytenoid cartilage
Describe the cuneiform cartilages.
Club-shaped elastic cartilages found anterior to the corniculate cartilages
They have no direct attachment and are found within the army-epiglottic folds
How does the cuneform cartilages function?
They strengthen the vocal folds and parts of the epiglottis
What are the four parts of the arytenoid cartilage?
Apex - articulates with corniculate cartilages
Base - articulates with cricoid cartilage
Muscular process - provides attachment for posterior and lateral cricoarytenoid muscles
Vocal process - attachment for vocal ligament
What is the epithelial lining of the larynx superior to the vocal folds?
Non-keratinised stratifies squamous
What is the epithelial lining of the larynx inferior to the vocal folds?
Pseudostratified ciliate columnar epithelium - ciliated goblet cells- goblet cells- basal cells
What are the folds produced by the mucous membrane of the larynx?
Superior pair - ventricular folds (false vocal cords)Inferior pair - vocal folds (true vocal folds)
When is the space between the ventricular folds known as?
Rima vestibule
What is the function of the ventricular folds, if they don’t affect voice production?
Hold breath against pressure in the thoracic cavity- e.g. When straining to lift heavy objects
What structures are found deep to the mucous membrane in the vocal folds?
Bands of elastic ligaments stretched between the rigid cartilage of the larynx
How do the vocal cords move?
They are attached to intrinsic laryngeal muscles (which are also attached to the rigid cartilage of the larynx) - when theses muscles contract they move the cartilage, which pulls the elastic ligaments tight and stretches the vocal cords into the airway- this narrows the rima glottidis
How is the pitch and volume of speech achieve?
Pitch - related to the tension of the vocal cords
Volume - greater the pressure of air passing through the cords, the louder the sound produced by their vibrations
How is early stage (histological progression I and II) SCC treated?
Surgery or radiation - same 5yr survival rate - decision is made on basis of tumour site and size, histological findings, patients wishes and MDT advice
How is advanced stage (III and IV) SCC treated?
When most patients present
Therapy is more complex and prognosis is worse
Combination of surgery and radiation therapy gives best survival- has worst complications and morbidities
