anatomy of biting, chewing and swallowing

Question 1

oral cavity and problem with palatine muscles/nerve DIAGRAM

Answer 1

there are 2 folds- palatopharyngeal fold and palatoglossal fold (anterior fold between palate and tongue), with palatine tonsil in between uvula is present as well- muscles in palate innervated by vagus nerve activated when you open mouth, and uvula should rise straight and in midline- if it deviates, suggests problem with palatine muscles/vagus nerve- deviation occurs AWAY from where injury is eg left side of palate

Question 2

sagittal view of pharynx DIAGRAM

Answer 2

3 regions of pharynx are nasopharynx, oropharynx (can be seen in oral cavity) and laryngopharynx, with oesophagus posterior also hard palate (helps break down food) and soft palate, with uvula there as well epiglottis RETROFLEXES to prevent food going down airway

Question 3

posterior view of pharynx DIAGRAM

Answer 3

3 regions shown- nasopharynx stops at uvula- in oropharynx is tongue and epiglottis in laryngopharynx is inlet and PIRIFORM FOSSA- these are either side of larynx, where food can get stuck

Question 4

regions of pharynx+ innervation of muscles

Answer 4

the 3 regions, along with superior, middle and inferior constrictor muscles to allow sequential contraction for swallowing- sensory goes via glossopharyngeal and vagus nerve, motor via vagus nerve

Question 5

stages of swallowing

Answer 5

tongue lifted and retracted using styloglossus and intrinsic muscle palatoglossus moves bolus into oropharynx, with nasopharynx closed off by levator muscles, which lift soft palate larynx is raised to close airway by epiglottis constrictor muscles undergo peristaltic wave cricopharyngeas muscle (at top of oesophafgus) relaxes to allow bolus into oesophagus

Question 6

salivary glands, innervation and fluid produced DIAGRAM

Answer 6

parotid (innervated by GLOSSOPHARYNGEAL) produces serous fluid, opening into parotid duct- right in front of ear, with green tube pearcing cheek and opening into 2ND MOLAR TOOTH submandibular (innervated by FACIAL) also serous (liquidy) sublingual (innervated by FACIAL) produces mucous (thick fluid)- right under tongue

Question 7

tongue- muscles and innervation

Answer 7

styloglossus, hyoglossus (between hyoid and tongue), genioglossus ( between mandible and tongue) and intrinsic muscles innervated by hypoglossal nerve

Question 8

sagittal view of tongue DIAGRAM- genioglossus and lingual nerve

Answer 8

genioglossus causes tongue to come out- if there is damage to muscles, like uvula tongue deviates, but this time it deviates TOWARDS where injury is lingual nerve also needed for touch sensation and taste perception- has submandibular ganglion

Question 9

innervation of tongue DIAGRAM

Answer 9

can be divided into anterior 2/3rds and posterior 3rd- anterior part innervated by trigeminal (touch) and facial nerve (taste- goes to nucleus solitarus): posterior (both touch and taste) by glossopharyngeal nerve, and a bit by vagus

Question 10

superficial muscles of mastication (breaking down food)- function , location and innervation DIAGRAM

Answer 10

masseter muscles- elevates mandible to close mouth (when you clench teeth, muscles bulge out on each cheeck( temporalis- elevates mandible as well, and RETRACTS buccimator also present- pushes food to middle of mouth, and where parotid duct goes- all muscles of mastication innervated by trigeminal nerve EXCEPT buccimator( facial)

Question 11

deep muscles of mastication DIAGRAM

Answer 11

lateral pterygoid- attached to sphenoid and NECK of mandible: lowers and protracts mandible to open mouth (above medial) medial pterygoid- ANGLE OF mandible to pterygoid splate of sphenoid: elevates, protracts and LATERAL MOVEMENT of mandible (for chewing)

Question 12

temporomandibular joint- movement and clinical importance DIAGRAM

Answer 12

between temporal bone and HEAD of mandible- it’s a capsular joint, with mandibular fossa between, and articular tubule (bone at front) SLIGHT opening of jaw causes hinge action, WIDE opening causes hinge and GLIDING action- if overdone can cause dislocation of jaw

Question 13

branches of external carotid with pneumonic

Answer 13

superior thyroid ascending pharyngeal lingual (tongue) facial artery occipital artery posterior auricular artery (behind ear) maxillary artery superficial temporal (on forehead) SOME ANATOMISTS LIKE FREAKING OUT POOR MEDICAL STUDENTS

Question 14

pathway of different branches of external carotid DIAGRAM

Answer 14

facial artery has a torturous (winding) pathway- goes round mandible and towards eye arising from maxillary is middle meningeal (supplies dura)

Question 15

branches of facial nerve, where it emerges from and relation between parotid and facial+ pneumonic

Answer 15

facial nerve emerges from STYLOMASTOID FORAMEN (between mastoid and styloid process) 5 branches of facial nerve anterior to parotid gland- temporal, zygomatic, buccal, mandibular and cervical (innervates platysma) IMPORTANT- parotid NOT innervated by facial, the branches purely come out at same level

TO ZANZIBAR BY MOTOR CAR

Question 16

branches of mandibular nerve+ relationship of facial and trigeminal to lingual DIAGRAM

Answer 16

branch of trigeminal- it forms inferior alveolar and lingual nerve inferior alveolar innervated with lower jaw pain- terminal branch this nerve called mental nerve goes to jaw lingual nerve goes to anterior part of tongue and salivary glands- this nerve gets fibres from FACIAL nerve as well from called CHORDA TYMPANI: therefore lingual nerve has trigeminal (for taste in tongue) and facial (goes to submandibular ganglion, then submandibular and sublingual salivary glands) nerve fibres in it

Question 17

dermatomes of head and neck DIAGRAM

Answer 17

V1 at forehead, V2 at cheek, V3 at chin orange part cervical dermatomes

Question 18

pharygeal muscles

Answer 18

motor innervation by vagus EXCEPT stylopharyngeas (by glossopharyngeal)

circular muscles are superior, middle and inferior constrictor, longitudinals are palatopharyngeus (needed for coughing reflex) and stylopharyngeus

Question 19

tonsils and clinical significance

Answer 19

there are palatine tonsils (can be seen) and lingual tonsils (posterior part of tongue)- can become infected

Question 20

function of oral cavity FOLDS

Answer 20

depress soft palate against tongue, AND seals nasopharynx from oropharynx, preventing food going upwards

Question 21

motor function of tongue + extrinsic muscles with pneumonic

Answer 21

by extrinsic and and intrinsic muscles, which are innervated by hypoglossal nerve, APART from palatoglossus (vagus)

extrinsic muscles are palatoglossus, styloglossus, hyoglossus and genioglossus (PEOPLE SAY HELLO AND GOODBYE)

Question 22

temporomandibular joint- importance and what the different movements are

Answer 22

needed for mastication as the 4 mastication muscles cause movement at this joint

hinge movement moves mandible up and down, glide protracts and retracts it

Question 23

trigeminal nerve branches, what V3 divides into and what they supply DIAGRAM

Answer 23

V1 and 2 are sensory, V3 is motor and sensory- V3 splits anterior into LONG BUCCAL nerve, and posteriorly into alveolar and lingual nerve

SENSORY- V1 supplies forehead, upper eyelids, and eye, V2 supplies upper jaw, cheecks, V3 supplies lower jaw and anterior 2/3rds of tongue#

MOTOR- V3 supplies 4 masticator muscles

Question 24

bells palsy

Answer 24

damage to facial nerve causes facial drooping on one side, where patient can’t open mouth or raise eybrows on one side

Question 25

where does chorda tympani exit from

Answer 25

different to main facial nerve, it is PETROTYMPANIC FISSURE