2. Functions & Boundary :
– Prehension , Selection, Mastication & In salivation of food.
– Extends from lips to entrance of pharynx.
– Boundary : Rostrally - Lips
Laterally - Cheeks
Dorsally - Hard palate
Ventrally - Tongue
Caudally - Oral cavity communicates with oropharynx with Isthmus faucium,
(formed by root of tongue ventrally and dorsally soft palate, laterally by palatogossal
arch & usually closed).
3. Oral cavity :
– Divided by teeth into vestibule and oral cavity proper and both are connected
by diastema.
– Connects to nasal cavity by two narrow Incisive ducts which open on incisive
papilla present caudally to upper incisors.
– Four glands secretions : Labial Most in horses >ox> pig> dog
Buccal
Lingual
Salivary
4. Oral cavity & Lips :
– Rima oris (oral cleft) – bounded by edges of upper and lower lips and unite at
angle of mouth.
– Lips of horses, sheep, goat, carnivores – Quite mobile.
– Lips of ox & pig – less motion.
– Lips used for sucking & prehension of food.
5. Oral cavity :
– In the pig and ox there is an area of modified skin (cornified stratified
epithelium with serous glands ) known as rostral & nasolabial plate.
Nasolabial glands opening.
– The upper lip of carnivores and small ruminants is divided by distinct
median cleft known as philtrum ( vertical indentation or groove
present between base of nose and border of upper lip.)
– In carnivores and pig –lower lip is smaller than upper lip.
– In horse and ox – lower lip presents the chin or Mentum
(Protuberance of muscular and adipose tissue).
Upper lip
Diastema
Incisive papilla
with incisive
ducts
Soft palate
Hard palate
6. Cheeks or Buccae :
– Extend from the angle of mouth to the pterygomandibular fold.
– Caudal portion – Masseter muscles.
– In ruminants buccal mucosa formed cone shaped cornified papilla directed caudally.
– Buccal glands – present between buccal mucosa and musculature.
Two types - Dorsal and ventral
Ox – middle buccal glands
Dog - DBG present medial to zygomatic arch – Zygomatic gland
( Globular Seromucous gland ). Major and minor Ducts open at last
cheek tooth in buccal vestibule.
Cheek with buccal musculature and dorsal buccal glands (pig)
7. Gums or
Gingivae
– In ruminants gums are modified to form dental pad or browsing pad.
– ( Pulvinus dentalis ).
Formed when oral mucosa
intimately united to
periosteum of alveolar
processes of jaws.
8. Hard palate or
Palatum durum
– In horses PD continuous laterally with the gums and caudally with mucous membrane of
soft palate.
– Divide into two halves by palatine raphae. (Palatine uvula to incisive papilla).
– On either side of raphae rugae palatinae are present in transverse manner.
– They are cornified and slightly concave caudally.
– In dog indistinct median crest is present. Slightly elevated
– In horse & pig palatine ridges are extended upto soft palate but in other species 2/3 rd
of the length – ruminants.
– Between dental pad and ist palatine ridge triangular incisive papilla –Ruminants.
Species No. of palatine ridges
Dog 6-10
Pig 20-23
Ox 15-20
Horse 16-18
• Formed by osseous palate
and its mucosa which covered
the oral surface form roof of
oral cavity.
•Made of palatine bone
•Palatine process of premaxilla and
maxilla.
9. Incisive papilla is the central prominence just behind the upper incisors or behind dental
pad ( ruminant ).
IP have two minute opening of incisive ducts except in horses.
palatine ridges
Hard palate
Incisive papillae with incisive duct
Palatine raphae
Ox
10. Soft palate or
Velum palatinum
or
Palatum molle
– Uvula – Median present on the caudal free border of soft palate
(Pig).
– In horse – Exceptionally long except during deglutition its free
border wedged against epiglottis base leads to lying of epiglottis to
dorsal surface soft palate.
– Palatoglossal arches – Two mucosal pillars that connects the soft
palate to root of tongue and form the lateral boundaries of isthmus
faucium.
– Palatopharyngeal arches – helps the anchoring of soft palate to
pharangeal wall & present at lateral wall of pharynx.
Musculomucosal shelf forms the
caudal continuation of hard palate.
Divides the rostral portion of
pharangeal cavity into NP & OP.
Caudal border of soft palate lies on
base of epiglottis.
11. Tongue
or
Lingua
Caudally support by hyoid bone.
Organ of prehensile
Tactile organ with mechanical &
chemical selection of food.
Innervated by 5 cranial nerves , only
hypoglossal (M) ,Trigeminal, facial,
Vagus, Glossopharangeal
Horse
Dorsum linguae
Apex
Corpus linguae or body
Radix linguae or root
Horse toungue have slender bar of cartilage in the median
plane known as Cartilago dorsi linguae
Foliate papillae (pig & horse)
12. Ox
Torus linguae
(Elliptical prominence)
Fossa linguae
(Funnel shape)
Median groove
(Sulcus medianus)
Fungiform – rostral 2/3 rd of
dorsum of tongue
Foliate papillae – edges of
tongue.
Dog
13. Dog
Lyssa exposed
Frenulum linguae
Lyssa – A median filliform
musculature or median spindle
shape spicule present on the ventral
surface of apex of dog.
and
Begins a few millimeters caudal to
the tip and is embedded between
the genioglossus muscles.
The lysssa is a tube of connective
tissue that is filled
Adipose tissue
Middle segment- striated muscle
fibers and small amounts of
cartilage.
Frenulum linguae – Median fold connects
the ventral surface of tongue to floor of
oral cavity.
14. Lingua papillae
Filliform (Mechanical) – gromming
and eating
Conical (Mechanical) , lenticular.
Fungiform (Gustatory)
Vallate (Gustatory) , circumvallate
Foliate (Gustatory) – absent in
ruminants except ox ( rudimentary).
Filliform papillae - dorsum of tongue
Conical (
Lenticular
Fungiform papillae
(Dorsum)
Taste buds
Vallate papillae (8-17
on each side)
(Rostral to root of tongue)
1 pair – horse & pig
2-3 pairs - dog on each side
Ox
Foliate papillae (pig & horse & dog less)
Rostral to palatoglossal arch on lateral edges.
7-8 mm in pig
20mm – in horses
Orobasal organ – slit like opening – caudal to
central incisors. – Two epithelial canal
horse
Orobasal organ – median ridge
Caudal to central incisors two
epithelial canals end in minute
depression
15. Lingual Tonsils:
– These are the diffuse lymphocytic accumulations (may be solitary or
aggregations) present over the root of tongue.
– Lingual septum divides the tongue into two symmetrical halves.
– Lingual muscles :
Extrinsic - Genioglossus , Hyoglossus , Styloglossus
Intrinsic - Superficial (T & L) , Deep
17. Salivary glands :
– Three major large salivary glands :
Parotid
Sublingual
Mandibular
Saliva - Mucous & serous secretions of salivary gland produced in large amount (40-50 ) litres in ox and
horse.
It helps in mastication, lubrication, swallowing and digestion ( ptyalin in pig –hydrolysis of starch)
Salivary glands of herbivores are more developed than carnivores.
18. Parotid gland
– In horse PG attached with Guttural pouch, diagastricus , and sternomandibularis muscle.
– Papilla parotidea – Small elevation on lateral wall of buccal vestibule where PG opened.
– PG ( Species ) Shape Size Position PD Opening
Dog & cat Roughly Small Apex ventrally Op. of 2nd UCT (C)
Triangular base towards Op. of 3rd UCT (D)
auricular cartilage
Pig Triangular large MA mandibular angle Cranially towards masseter Op. of 3 & 4th UCT
CA extends caudally to full
length of neck
Ox Club shape Large Thick end towards ear Op. of 5th UCT
Narrow end ventrally towards
angle of mandible.
Horse Quadrilateral Largest Fills RMF completely Op. of 3rd UCT
Dorsal end – base of ear
Ventral end – B/w EJV and LFV
Present in retromandibular fossa (RMF).
Caudal to ventral rami of mandible and
ventral to wing of atlas.
Dorsally - close to ear
Ventrally – going in b/w intremandibular
spaces.
Laterally – parotid fascia &
parotidoauricularis
Medially – Ext. jugular & carotid artery
along with hyoid bone & its muscles.
19. Mandibular and Sublingual gland :
Mandibular
– Present b/w basihyoid and wing of atlas &
partly cover by PG.
– Dog - Oval and larger than PG. Duct open
indistinct in sublingual caruncle.
– Pig - Oval and smaller than PG.
– Ruminats – large and extent from wing of atlas
to IMS.
– Horse – Long & narrow , much smaller and
extend to basihyoid.
Opens at sublingual floor of oral cavity at
sublingual caruncle level.
Sublingual
– Two in number.
– Lie under the mucosa of sublingual recess.
– And lateral surface of tongue.
– Monostoamatic : absent in horse
one excretory duct ( MSLD)
opens in sublingual caruncle
– Polystomatic : Multiple lobules
Minor sublingual duct
opens into sublingual recess
– Both glands together from the palatoglossal arch to the
symphysis of mandible.
22. Pharynx
– Funnel shape musculo-membranous passage connects oral cavity to esophagus and
nasal cavity to larynx.
– Boundaries :
– Roof - base of cranium ( Vomer & sphenoid bone, LCM longus capitis & RCV rectus
capitis ventralis).
– In horse pharynx is pushed away from these muscles and bones due to presence of
guttural pouches.
– Laterally – related with stylohyoid and pterygoid muscles. ( to guttural pouch in horse ).
– Floor – extend from root of tongue over to level of cricoid cartilage of larynx.
23. Pharynx
– Rostral portion of pharynx divide into two parts by soft palate :
Nasopharynx (pars nasalis pharyngis)
Oropharynx (pars oralis pharyngis)
Caudal portion of pharynx known as laryngopharynx (pars laryngea pharyngis)
– The free border of the soft palate and the paired palatopharyngeal arches
surround the intrapharyngeal opening (ostium intrapharyngeum which is
located above the entrance (aditus) to the larynx.
24. Pharyngeal openings :
- The paired choana (rosrodorsally) - connect the nasopharynx with the nasal
cavity.
– The paired pharyngeal openings of the auditory tubes (dorsolaterally) connect
the nasopharynx with the auditory tubes and to the middle ears.
– The slitlike (isthmus faucium) lead from the oral cavity into the oropharynx and
bounded laterally by the palatoglossal arches, dorsally by the soft palate, and
ventrally by the root of the tongue.
– The (aditus laryngis) caudoventrally- surrounded by the rostral laryngeal
cartilages, which project upward from the floor of the laryngo pharynx . During
swallowing the aditus is closed by the epiglottis.
– The entrance into the esophagus at the caudal end of the laryngopharynx.
