Floor of the Mouth and Tongue Flashcards
Name the boundaries of the oral cavity:
Anterior - alveolar bone of dental arches of mandible and maxilla
Posterior - oropharyngeal ishthmus (space between oral cavity and oropharynx behind
Roof - hard and soft palate
Floor - tongue, muscles of FOM
Lateral borders - buccinator
What type of epithelium lines the red areas?
What brings together the left and right mylohyoid muscles?
- the midline raphe stitches the right and left mylohyoid together
Explain the relationship between submandibular duct and lingual nerve:
- a crossing over of these structures, the duct passes over the top of the lingual nerve
What is the nerve supply to anterior belly of digastric?
What are the attachment points of the mylohyoid?
Where is sublingual gland found?
Name the supply and function of geniohyoid:
What are the attachment points of geniohyoid?
- CN V3, nerve to mylohyoid
- mylohyoid attaches to hyoid bone and mylohyoid line on mandible
- sublingual gland is deep to mylohyoid
- geniohyoid supplied by C1 of hypoglossal nerve - movement of tongue and hyoid during swallowing
- geniohyoid attaches from inferior mental spines/genial tubercles, extending back to hyoid
Explain the parasympathetic secretomotor nerve supply to submandibular and sublingual glands:
- from facial nerve CN VII –> branch of CN VII, chorda tympani
Chorda tympani carries presynaptic parasympathetic fibres to submandibular ganglion, synapse occurs, where post synaptic nerve fibres are carried to sublingual and submandibular glands
- chorda tympani also conveys special sensory fibres from the anterior 2/3rds of tongue back towards CNS
List the functions of the tongue:
- formation of a food bolus
- pushing food bolus to posterior part of oral cavity ready to be swallowed
- keeping mouth clean
- speech
- tasting and sensing food
What divides the tongue into anterior and posterior parts?
What is present on the middle of this division?
What supplies posterior 1/3rd of tongue?
Any features to be aware of in posterior 1/3rd?
What supplies anterior tongue?
- terminal sulcus
- foramen caecum: formed by descent of thyroid gland down through tongue during embryological development
- general sensation and taste both supplied by CN IX
- lingual tonsil under mucosa
- general sensation by CN V3 (lingual nerve)
- taste sensation by CN VII (via lingual nerve to chorda tympani)
Name the papillae on the tongue and their supply:
- Circumvallate: CN IX (exception as in anterior 2/3rds)
- Foliate: CN VII
- Fungiform: CN VII
- Filiform: touch, movement, CN V3
Describe the path of the hypoglossal nerve:
- passes between internal carotid artery and internal jugular vein, lying on surface of carotid sheath, passes deep to posterior belly of digastric, into submandibular region –> lateral to hyoglossus muscle, deep to mylohyoid in order to reach the tongue muscles
What groups of muscles are the tongue composed of?
- intrinsic: originate and insert within tongue
- extrinsic: originate outwith tongue and insert onto it
Tongue is a mass of skeletal muscle covered by mucosa
What is the purpose of intrinsic muscles of the tongue and their types?
- act to alter the shape of the tongue
Longitudinal: make tongue short and thick
Transverse and vertical: make tongue long and narrow
Name the extrinsic muscles of the tongue and their attachment points:
Which nerve supplies the tongue muscles? Are there any exceptions?
- palatoglossus: arises on soft palate and inserts onto side of tongue
- styloglossus: arises on styloid process
- genioglossus: main tongue muscle, arises from genial tubercles, controls sticking tongue out
- hyoglossus: arises from hyoid bone
All tongue muscles supplied by CN XII except palatoglossus (CN X) as it is a muscle of the palate
How can you clinically test the hypoglossal nerve?
- ask patient to stick tongue straight out
- if both CN XII are normal, the tongue tip should stick out and remain in the midline
- if one CN XII is damaged, the tongue tip will point towards side of injured nerve e.g. if right nerve is damaged, tongue will point to right side
List the functions of the oral cavity:
Preparation of a food bolus for swallowing:
- mastication
- saliva
- the tongue
Defence against ingestion of toxins/infection:
- tonsils
- special sense of taste
Speech:
- oral and nasal sounds (soft palate)
- articulation (tongue/lips)
