head Flashcards
1
Q
how many cranial nerves
A
12 pairs, numbered using roman numerals in rostro-caudal direction
2
A
I - olfactory for smell
II - optic for sight
III - occulomotor for movement eyeballs
IV - trochlear for movement eyeballs
V - trigeminal
VI - abducent for movement eyeballs
VII - facial for expression muscs
VIII - vestibulo-cochlear for balance + hearing
IX - glossopharyngeal for 1st part swallowing
X - vagus for thorax + GI
XI - accessory
XII - hypoglossal for movement tongue
3
Q
development mesoderm in trunk
A
mesoderm cavitation results splanchnic + somatic lateral plate mesoderm enclosing coelomic cavity around gut tube
mesoderm gives rise to muscs
4
Q
development mesoderm in head
A
no cavitation, lateral plate mesoderm stays as solid tiss belt around gut tube
* intermediate mesoderm fails develop (disappears) - in trunk it forms kidneys + other structures
5
Q
segments of head
A
- ectoderm = skin
- somites (sk musc) (in S1-7)
- endoderm = gut tube lining
- lateral plate mesoderm (sk musc) (in A1-6)
- segmental arteries -> blood
- neuraxis forms brain
- merves
adult appears not to have
6
Q
distinguishing bet segments
A
marked externally by lateral indentations (pharyngeal clefts)
* 1st segment no have
* equiv to gill slits (sep segments in fish), just no perforate in mammals
7
Q
ectoderm
A
forms outer epithelial covering (skin)
* somatic sensation - press, temp, pain
* innervated by somatic afferents to brain
8
Q
how is ectoderm of segments 1 + 2 special
A
deeply invaginated into them, forming stomodeum (oral opening)
* means segments 1 + 2 no endoderm + oral opening lined ectoderm so has conscious sensory innerv
9
Q
oral plate
A
thin plate tiss where stomodeal ectoderm meets pharyngeal endoderm
* @ boundary bet seg 2 + 3
has perforate so can swallow
10
Q
how does control vary in mouth
A
somatic voluntary control front lined ectoderm
back lined endoderm = involuntary
11
Q
endoderm
A
forms inner epithelial covering w unconscious involuntary control
* sensation via autonomic afferents (AA)
* motor via autonomic efferents (AE) - symp + parasymp
= gut tube
12
Q
parts of endoderm
A
cephalic (1st) part -> pharynx
6 divisions marked by internal gill slits
* fish = perforate -> external gill slits
* mammals = no perforation but still slits on inside = pharyngeal pouches
13
Q
lateral plate mesoderm
A
6 belts sk musc each surrounding pharynx all segs except 1
* each belt = ring donut, sepped by pharyngeal cleft externally + pharyngeal pouch internally
* each belt = pharyngeal arch
* forms special visceral musc of gut tube, e.g. muscs of chewing
* innervated by special visceral efferents (SVE) = conscious voluntary control
nerve fibres = functionally equiv to those from somite (SE)
14
Q
SE vs SVE
A
functionally equivalent conscious voluntary motor control to structures derived from somites vs lateral plate mesoderm
15
Q
somites
A
each seg has pair
* form sk musc of eyeball + tongue
* innerv by somatic efferents (SE) - voluntary conscious control
16
Q
segmental arteries
A
all but 1st seg have pair
* form 6 pairs aortic arches embedded in lat plate mesoderm
* innerv by AA/AE for sensory + constrict/dilate
17
Q
neuraxis
A
differentiates into brain
* each segment of it = meuromere
18
Q
which head structures disappear
= obliterated
A
- somites 4 + 5 (w associated nerves)
- pharyngeal arch 5 (+ associated ectoderm, endoderm, lateral plate mesoderm, nerves + arterial arches)
- arterial arches 1 + 2
- phrayngeal clefts + pouches 5 = 6
- ectoderm of segs 6 + 7
+ therefore no nerves supplying structures that would arise from here
19
Q
which structures of head fail to develop further
A
- endoderm of arch 2 stays as narrow band
- ectoderm of segs 3-5
20
Q
which structures of head migrate
A
somites 6 + 7 move away from original location to floor mouth to give rise muscs tongue
21
Q
development oral + nasal cavity
A
- paired nasal pits invaginate from ectoderm
- nasal cavity breaks through to oral cavity
- palatine process grows w palatine bone + endodermal soft palate (develops from inside)
R + L nasal cavities sepped by nasal septum
22
Q
what happens if lateral palatine folds fail develop
A
cleft palate
* since palate seps oral + nasal cavities this means milk -> nasal cavity -> out nostrils
* can surgically repair but specialist + spenny
23
Q
formation tongue epithelium
A
- front = ectoderm of arch 1
- back = endoderm of arch 3
endoderm of arch 2 fails develop further = tiny band bet others
24
Q
development tongue musc
A
migration of paired somites 6 + 7
* loads = tongue super mobile w intrinsic + extrinsic to move + contract it
25
how do larynx, trachea + lungs form
1. depression in floor of arches 4 + 6 forms laryngo-tracheal groove
2. trachea + lungs develop from this
their epithelial lining = endodermal
26
where are pharyngeal clefts
1 = external ear w boundary @ ear drum
2 - 4 disappear
27
where are pharyngeal pouches
1 = middle ear cavity
2 = palatine tonsil
3 = parathyroid + thymus
4 = parathyroid, thymus + ultimobranchial body
28
which areas do diff seg ectoderms form
1 = skin of top of head
2 = rest of skin of head
3,4,5 = small area skin in external ear
6 + 7 fail to develop
| only 1 + 2 significant
29
what do diff somites form
S1 = all rectus muscs (except lateral rectus) + ventral oblique
S2 = dorsal oblique
S3 = lateral rectus + retractor oculi (pulls eyeball deeper into socket so 3rd eyelid can move across)
S4 + 5 disappear
S6 + 7 = muscs of tongue - intrinsic + extrinsic (-glossus)
| 1,2,3 = extrinsic muscs of eye
30
what does lateral plate mesoderm form
| diff parts
arch 1 = chewing muscs (malleus + incus)
arch 2 = facial muscs (stapes + hyoid)
arch 3 = stylopharyngeus musc/hyoid
arch 4 = pharyngeal muscs + cricothyroid musc + laryngeal cartilages
arch 5 disappears
arch 6 = laryngeal muscs + cartilages
| arch 1 = seg 2, 2 = 3 ... 6 = 7
31
what do aortic arches form
1 + 2 disappear
3 = internal carotid, carotid sinus + body
4: R = subclavian, L = aortic arch, baroreceptor site + aortic bodies
5 disappears
6 = pulm trunk + ductus arteriosus
32
what does each cranial nerve pair have
dorsal + ventral branch
33
diff bet segmental nerves trunk + head
* head = dorsal + ventral root nerves no join (trunk = -> single spinal nerve w all 4 nerve types)
* head = 5th neuronal component - SA, SE, AA, AE **and SVE** (via dorsal root)
34
ventral vs dorsal root nerves
VRN innervate somites = only SE neurons
DRN innerv all structures (pharyngeal arches) = cont SA, AA, AE + SVE neurons
| each segment has DRN + VRN
35
unusual VRNs/DRNs of segments
1 = no pharyngeal arch = borrows DRN from seg 2 = opthalmic division of CN V
2 = DRN splits -> maxillary + mandibular divisions of CN V (for upper/lower 1/2 mouth)
4/5 lost somites = no VRN
6 lost pharyngeal arch = no DRN
6 + 7 somites unite form tongue muscs = VRN unites too (CN XII)
5 + 7 share DRN (X/XI)
| hence trigeminal (V) has 3 branches
36
special sense nerves
CN I = olfactory nerve for smell
CN II = optic nerve for sight
CNVIII = vestibulo-cochlear nerve for balance + hearing
37
segment 1 ventral root nerves
III (occulomotor)
* SE -> somites forming orbital muscs (all rectus bar lateral) + ventral oblique
* AE parasymp -> ciliary musc (constricts pupil)
* SVE -> levator palpebrae superioris (raises upper eyelid)
38
segment 1 dorsal root nerve
opthalmic branch of V (trigeminal)
* SA - ectoderm forming skin top nof head above eye
* no AA< AE or SVE
| no pharyngeal arch so borrowing from segment 2
39
branches of SA opthalmic division V
1. skin forehead + upper eyelid = zygomaticaotemporal + frontal
2. cornea = long ciliary (multiple)
3. medial eyelid/canthus = infratrochlear
4. dorsal turbinates = ethmoidal (invagination ectoderm)
5. base of ox horn (cornual)
| all SA = conscious feel sensation
40
segment 2 ventral root nerve
IV (trochlear)
* SE -> somite forming dorsal oblique orbital musc (moves eyeball)
41
segment 2 dorsal root nerve
V (trigeminal) - lost autonomic fibres
* division of mouth = trigeminal further split maxillary (SA) + madicbular (SA + SVE)
* SA - ectoderm forming most skin of face + rostral 2/3 tongue
* SVE -> pharyngeal arch forms muscs of chewing
| still auto structs, e.g. salivary glands = borrow nerve supply other seg
42
maxillary branch of V branches
ectoderm eyelids -> upper jaw = SA only
* skin lower eyelid = zygomatic
* mucosa nasal cavity = caudal nasal
* mucosa hard palate = major palatine
* mucosa soft palate = minor palatine
* cheek + incisor teeth upper jaw = maxillary alveolar (multiple)
* upper lips, vibrissae (whiskers), muzzle = cutaneous branches
* vestibule of nostril = rostral nasal
43
mandibular division of V branches
ectoderm = SA
* lining cheeks = buccinator
* lower teeth + lower lip = mandibular alveolar + mental (multiple)
* auricular + temporal regions = auricular + temporal branches
* rostral 2/3 tongue = lingual
muscs chewing = SVE
| below mouth
44
muscs of chewing
| from mandibular V, SVE
jaw closers
* masseter m. - prominent in dogs w strong bite
* pterygoid m. (medial + lateral)
* temporalis m.
jaw openers
* rostral belly of digastricus = mylohyoid n.
* caudal belly from arch 2 = innerv VII (SVE)
others
* tensor tympani m.
* tensor veli palatini m.
45
digastricus musc
2 bellies, rostral 1 originates segment 2, other seg 3
* = innerv 2 diff CNs - fibres from V vs VII
46
innerv nasal cavity
1. dorsal turbinates = invag = ectoderm seg 1 = ethmoidal n. from opthalmic V
2. rest from ectoderm seg 2 = caudal nasal n. + rostral nasal n. from maxillary V
| 1 = upper supply, 2 = lower supply
47
segment 3 ventral root nerve
VI (abducent)
* SE - somite forming lateral rectus (eyeball away from midline) + retractor oculi/bulbi (move eyeball back into head)
48
segment 3 dorsal root nerve
VII (facial)
* SA - ectoderm forming small area skin in external ear cavity
* SVE - phar arch muscs facial expression
* AA - taste from rostral 2/3 tongue + palate (territory of V as lost auto component), running thru middle ear cavity (infection = damage)
* AE -> mandibular/sublingual glands, nasal cavity glands, lacrimal gland
| major branches subcut = easy damage - buckle, lat recumben, anaesthetic
49
branches of facial nerve SA
internal auricular n. = skin of external ear
50
branches of facial nerve AA
* taste rostral 2/3 tongue = chorda tympani
* taste from palate = major petrosal
| taste buds
51
branches facial nerve AE
* mandibular/sublingual salivary glands = chorda tympani
* nasal/lacrimal glands = major petrosal
52
what do autonomic efferents usually cause
glands secrete or sm musc contract
53
branches facial nerve SVE
* caudal auricular nerves -> caudal muscs ears to move
* auriculopalpebral -> auricular n. (rostral muscs ear)/palpebral n. -> muscs eyelid/face (wink, shut eyes)
* dorsal/ventral buccal -> facial muscs (flare nostrils, lips, cheek)
* -> caudal belly of digastricus
* branch -> stylohyoid musc
* branch -> stapedius musc
54
how does facial nerve invade territory of CN V
1. major petrosal nerve -> pterygopalatine ganglion
2. chorda tympani (AA + AE) -> lingual n. in mandibular V
55
how does major petrosal nerve run
-> pterygopalatine ganglion then
* AE -> lacrimal piggybacking on opthalmic V
* AE -> nasal glands piggbacking on caudal nasal n. (maxillary V)
* AA for taste from palate piggyback on palatine n. (maxillary V)
all thru middle ear cavity
| out skull as facial then jumps across to area of trigeminal
56
what do muscs facial expression control
move:
* eyelids
* lips
* cheeks
* nostrils
* ears
57
nostril muscs
dilate in breathing
* super important in race horse as obligate nasal breathers + need incr RR + intake - damage = retire
58
cheek muscs
buccinator - like diaphragm to keep cheek taught
* damage = chew + food no forced into mouth, goes into cheeks + drops out if head down = quidding in horses
59
lip muscs
oval slit w flaps above + below
1. close = orbicularis oris
2. lift upper flap = levator labii superioris
3. depress lower flap = depressor labii inferioris
60
eyelid muscs
oval slit w flaps above + below
1. close = orbicularis oculae
2. lift upper flap = levator palpebrae superioris
3. depress lower flap = depressor palpebrae inferioris
4. medial lifter = levator anguli oculis
5. retractor laterally = retractor anguli oculis
also extra bundles sm musc to lift upper lid/depress lower
| autonomic = protect w/o thinking
61
eyelid muscs innerv
mainly facial but:
* levator palpebrae superioris = occulomotor branches (VRN, SVE)
* sm musc = symp from cranial cervical ganglion
62
ptosis
drooping of upper eyelid
* partial if damage to facial nerve as still have innerv from occulomotor
63
ear muscs
* pull ear forwards + abduct = auricular n.
* pull ear backwards + adduct = caudal auricular + C1/C2 via great auricular n.
* + cervicoauricularis musc pulls ear back + attached laterally to cartilage so rotates ear outwards - some innerv cervical asw so ear stuck like this (esp just one) = sign CN VII damage)
| back + rotated out = sign horse pissed off
64
segment 4 ventral root nerve
none - somite 4 lost
65
segment 4 dorsal root nerve
IX (glossopharyngeal)
* SA - ectoderm forms small area in ear canal
* SVE - phar arch 3 forms stylopharyngeus musc (only pharyngeal dilator, w/o it can't swallow)
* AA - endoderm forms pharynx lining + caudal 1/3 tongue + aortic arch 3 (internal carotid, carotid sinus + bod) (taste)
* AE -> parotid salivary gland + initiate swallowing reflex
66
specific branches glosso-pharyngeal nerve
* SA -> external ear = tympanic n.
* AA taste + sensation caudal tongue = lingual
* AA sensation pharynx = pharyngeal branch
* AA -> chemo/baroreceptors = carotid sinus n.
* AE -> parotid salivary gland contract + secr saliva = minor petrosal n.
67
segment 5 VRN
none - somite 5 lost
68
segment 5 DRN
X (vagus) + XI (accessory) == vagal-accessory complex
* SA - ectoderm forms small area ear canal
* SVE - phar arch 4 forms rest pharyngeal muscs + cricothyroid musc
* AA - **endoderm forms lining common pharynx + larynx**, aortic arch root aorta/R subclavian
* AE - **endoderm GI tract** (constr, dil)
69
SA nerve of vagal-accessory complex
auricular nerve for conscious sensation external ear
70
AA nerves vagal-accessory complex
1. recurrent laryngeal n. for epithelium oes, caudal larynx, trachea
2. cranial laryngeal n. for cranial larynx + taste in surrounding mucosa
3. pulmonary branches for lungs
4. aortic n. for chemo/baroreceptors in aorta
epithelium of GI tract -> transverse colon asw
71
SVE nerves of vagal-accessory complex
1. pharyngeal n. -> muscs of pharynx
2. recurrent laryngeal n. -> muscs of larynx
3. cranial laryngeal n. -> cricothyroideus m.
72
segment 6 VRN
XII (hypoglossal) - migrates to embed under tongue
* SE -> somite forming muscs of tongue
73
segment 6 DRN
none - phar arch 5 lost
74
segment 7 VRN
XII (hypoglossal)
* SE -> somite 7 forming muscs of tongue
75
segment 7 DRN
X/XI (vagal-accessory complex)
* SA none
* SVE - phar arch 6 forms rest laryngeal muscs
* AA - endoderm forms lining larynx caudal to vocal folds inc **resp sys**
* **AE -> endoderm GI tract**
76
# [](http://)
which parts endoderm does AA DRN seg 7 innerv
trachea, lungs, GI tract, aortic arch 6 forming pulm art + ductus arteriosus
77
all segments w innerv + parts present/not
| table
78
skin of head innerv
1 = ectoderm seg 1 = opthalmic V
2,3,4 = ectoderm seg 2
2 = maxillary V, 3 = zygomatic branch max. V, 4 = mandibular V
| SA, 3 = opthalmic V in dog
## Footnote
5 = cervical spinal nerves
79
damage to trigeminal =
* loss sensation - SA
* inability chew - SVE
* dropped lower jaw in dogs (sometimes)
* -> temporalis musc wastage = ridged appearance to crown of head
| where on nerve damage determines extent of effects, e.g. branches trigem
80
what causes musc wastage
atrophy due to there being no nerve supply
81
torn lower lip horse - how + what do?
cut on nail holding hay net when pulling to eat
mental foramen palpable on outer mandible w mental nerve supplying SA -> lower lip
* inject anaesthetic around it (not in) to desensitise area + stitch up
82
vagal-accessory complex components which innerv
vagus (X) = SA, AA, AE -> head + AA, AE -> thorax/abdom
cranial accessory (XI) = SVE -> head
spinal accessory = SE -> neck + forelimb
| treated as single bc makes up complex w all 4 nerve types
83
facial nerve paralysis
buccal nerves + auriculopalpebral nerves subcut = prone damage ->
* loss tone in muscs lips + nostrils, can't constrict = drool
* quidding + bulging of food in cheek as can't contract buccinator
* slight ptosis
* weak palpebral/corneal reflex (shutting of eyelids) bc orbicularis oculi paralysed
* ear stuck rotated out + back as C1/C2 supply intact
84
components of skull
1. face = bone extension enclosing nasal cavity + roof of mouth
2. cranium = bone box protecting brain
3. mandible = lower law bone
85
bones of skull
PAIRED
* temporal - houses inner ear
* frontal
* parietal
* exoccipital = occipital bones
* nasal
* incisive - incisors out of
* maxilla - side nasal cavity + mouth roof
* zygomatic
* palatine
* lacrimal - front of eye where tear ducts run
* pterygoid
* mandible
* dorsal turbinates
* ventral turbinates
* ethmoturbinates
UNPAIRED
* supraoccipital
* basioccipital
* basisphenoid
* presphenoid
* ethmoid
* vomer
86
label
dog skull
87
which bones make up zygomatic arch
1. zygomatic
2. temporal
3. + small part (zygomatic process) of maxilla
| only zygomatic + temporal in horse
88
which bones make up external nares
nasal + incisive
89
which bones make up hard palate
incisive, maxilla + palatine
90
what does hyoid apparatus articulate w
rotrally: temporal bones just caudal to external auditory meatus
ventrally: w thyroid cartilage of larynx
91
which bones are smaller in brachycephalic
bones of face: incisive, nasal, maxilla, palatine, lacrimal, vomer
92
sagittal crest
only on larger dogs, made from frontal + parietal bones
93
label
horse skull
94
what makes up hard palate
* palatine processes of incisive bones
* palatine processes of maxillae
* horizontal plates of palatine bones
95
label
ventrodorsal view
hard palate circled, covere by soft tiss irl
96
development hard palate
primary palate = lip + incisive bone
secondary palate = hard + soft palate
1. prim grows in from rostral end
2. secondary grows in from sides
3. all fuse
97
cleft lip
palatoschisis type where primary palate fails to close
-> abnormal comms bet oral + nasal cavity - congenital oronasal fistula
| = milk suckled -> lungs
98
cleft palate
palatoschisis type where secondary palate fails to close
-> abnormal comms bet oral + nasal cavity - congenital oronasal fistula
| = milk suckled -> lungs
99
occipital bone
4 parts that fuse
100
caudal view structures skull
101
syringomyelia
congenital condition w undersized occipital bone (hypoplasia)
-> cerebellum pressed against foramen magnum
== interrupted flow cerebrospinal fluid
-> pockets CSF build up in brain, causing neurological conditions
head tilt, phantom scratch back of head
| notably cavaliers, just bc inbreeding over time, doesn't appear til late
102
structures dorsal aspect skull
palpate foramen, important for nerve block
103
ox skull differences
massive frontal bone
lacrimal more kinda rectangular
104
mandible features
genu = sharp turn at front
mental foramen = nerve for sensation front teeth, lower lip + chin (inferior alveolar)
inferior alveolar foramen = inferior alveolar nerve, sensory to teeth
105
how is herbivore mandible different
more vertical coronoid process
massive slab of bone w/o angular process
106
label
palpable landmarks:
* nasoincisive notch
* zygomatic arch
* facial crest
| cattle = facial tuberosity instead of facial crest
107
young vs mature animal skull
young = temporary dentition + identifiable skull suture lines
mature = permanent dentition, fused skull suture lines
* temporozygomatic suture remains unfused = radiographically visible
108
tympanic bulla
part of temporal bone, filled w air + conts middle ear
* laterally bounded by tympanic mem (eardrum) covering external auditory meatus (ear hole)
* dark bc air filled = radiographically visible
109
hyoid apparatus
series small bones + cartilages forming suspensory mech for tongue + larynx
| radiographically visible palpable, but not if conscious bc painful
110
how does hyoid sit in skull dog
111
how is hyoid different horse
* stylohyoid fused w epihyoid in adult
* extra sticky outy lingual process of basihyoid
| mostly sits under mandible
112
foramina dog/cat
1. infraorbital -> infraorbital nerve of max. trigeminal
2. inferior/mandibular alveolar foramen -> mandibular alveolar of mandib. trigem
3. mental foramen -> mental nerve of mandib. trigem
| palpable
113
foramina in herbivores
1. infraorbital
2. inferior alveolar
3. mental
4. supraorbital -> supraorbital branch of frontal n. of orbital trigem
114
other foramina
1. ethmoidal foramina for ethmoid branches of opthalmic V
2. optic canal for CNII
3. orbital fissure for CNIII, CNIV, opthalmic V, CNVI
4. rostral alar foramina for maxillary CNV
5. caudal alar foramina for maxillary CNV
6. oval foramen for mandib CNV
7. jugular foramen/tympano-occipital fissure for CN IX, X, XI
8. stylomastoid foramen for CNVII
9. hypoglossal foramen for CNXII
115
dog head shapes
116
problems due brachycephalic dog skull
* stenotic nares w too much cartilage + soft tiss for tinu nasal bones = hard breathe thru nose (often have to go thru mouth)
* long soft palate (not reduced w skeletal support), occludes larynx = hard breathe
* usual no. teeth in smaller space at unusual orientations = hard eat, incr dental disease. mandib less reduced that max. = malocclusion
* exopthalmic eyes - bulging bc shallow sockets = prone damage, lid can't close properly = ulceration, more prone proptosis (eye way forward
* wrinkly skin bc proportionally more soft tiss => skin infections, inward turning eyelids bc too big (entropian)
117
cat head shapes
brachycephalic cats have similar problems but live more sedentary = less of an issue
118
horse head shapes
119
nasal cavity structure + functions
1. large SA for water + heat exchange to warm + humidify air -> lungs (body temp)
2. hairs at entrance to trap large particles + surface covered mucous trap small = filter particles from air so no -> lungs
3. loads sensory receptor cells to detect odour mols on air - food safe?, mating
120
anatomy nasal cavity
divided 2 fossae (spaces) by nasal septum (cartil sheet rostral, ethmoid bone caudal 1/3)
* in space = scroll-shaped turbinate bones (== nasal conchae) + meatii (spaces) bet them
121
purpose turbinate bones
incr A nasal cavity = more surface to humidify, warm, filter air
122
structure turbinate bones
thin scrolls originating from nasal + maxillary walls
1. ethmoturbinates (up to 30 each side) = small, towards back nasal cavity, attached nasal septum, lateral nasal wall + cribriform plate of ethmoid bone
2. dorsal turbinate = single scroll attached nasal wall/bone (= from it)
3. ventral turbinate = double scroll attached maxilla (= from it)
| general plan as in sheep
123
cribriform plate
dividing wall bet nose + brain
* has holes for stuff brain -> nose - several branches CNI bc majority receptors on ethmoturbinates
124
where do meatii go
dorsal -> olfactory mucosa
middle -> sinus sys
ventral -> principal airway
common = middle communication part
125
how are dog turbinates different
multiple leaflets arising from ventral w v little ventral space
126
sagittal section dog turbinate bones
127
how are horse turbinates different
ventral turbinate bottom scroll lost = larger ventral space, easy put stuff up
128
paranasal sinuses are
air-filled extensions (diverticula) of nasal cavity
* spaces bet inner + outer tables of bone = w/in bone
* retain connection nasal cavity via narrow opwnings = prone blockage by inflamm or congestion
* continuous w nasal cavity = lined nasal epithel
* share innerv w nasal cavity - branches of opthalmic + max. of trigeminal
129
functions of paranasal sinuses
enlarge skull to allow more SA musc attachments, larger oral cavity for larger teeth (take in more food) **w/o adding weight**
* mean outside head diff shape to inside
| not acc sure
130
main sinuses
1. frontal w/in frontal bone
2. maxillary w/in maxilla
3. sphenopalatine w/in sphenoid + palate
4. lacrimal w/in lacrimal bone
5. ethmoidal w/in ethmoid
131
frontal sinus
up to 5 sep compartments
* ox/sheep, 1 compart = cornual process, entending into horn (air -> nasal cav -> sinus -> horn)
* all domestic *except horse* comms directly w nasal cavity thru openings at caudal end nasal cavity bet ethmoturbinates
132
frontal sinus on radiograph
133
horns vs antlers
horns = permanent
antlers shed annually
| horns in male + female, often larger in male
134
ox frontal sinus
horn arises from cornual process of frontal bone + base invaded by frontal sinus (less in small ruminants)
* extensive sinus, often invaginating parietal + occipital asw
* -> 1 major caudal frontal sinus + 4 minor rostral, each w sep opening -> caudal nasal cavity
135
innerv horn
1. cornual n. of zygomaticotemporal of opthalmic of trigem - block for dehorn
2. cornual branch of infratrochlear of opthalmic trigem - also need block
3. frontal n. of opthalmic trigem
4. cutaneous from C1/C2
| all cattle have 1, most 2, far less have 3
136
euthanasia by shooting
aim for medulla oblongata bc resp + CV centre = humane bc gone fast
== avoid midline on species w strong bony midline septum
* also consider brain not at top head bc frontal sinus
137
how is frontal sinus horse diff
* extends into lacrimal + nasal bones
* drains into caudal max. sinus not nasal cav
* extends rostrally into 'closed' caudal part dorsal turb == conchofrontal sinus
138
spaces w/in turbs
as move caudally scrolls of dorsal/ventral turns curl round on selves to encapsulate more space
* space w/in each curl divided to rostral + caudal part by thin septum
caudodorsal space comms w frontal sinus (-> conchofrontal sinus)
caudoventral space comms w rostromaxillary sinus
139
maxillary sinus basic structure
comms w nasal cavity via middle meatus
140
maxillary sinus dogs/cats
== maxillary recess bc comms v freely w nasal cavity
141
passage air in horse nose
caudal + rostral ends max sinus sepped by bony plate = no comm
nasal cavity -> frontal sinus -> caudal max. -> nasal cavity
nasal cavity -> rostral max. -> nasal cavity
142
further sections max. sin.
ventral parts split medial + lateral spaces by bony plate supporting infraoorbital canal
* medial boundary = ventral turbinate
* frontal sinus fuses w closed part dorsal turb bone
143
ways sinus infection
1. resp tract infection nose -> sinuses
2. tooth root infection breaks down thin bone layer -> sinus infec
144
why is max. sin. prone infection
1. resp tract infection nose -> sinuses (breathe in infec)
2. tooth root infection breaks down thin bone layer -> sinus infec (near cheek teeth)
3. warm, moist, w ventilation not too intense = ideal for infec
4. lots pus build up b4 starts naturally drain bc just lil exit right at top
145
trephine pts horse
frontal + max. sin. can be opened via these in case of infection to drain
* max. sin can also be used to access unerupted parts cheek teeth to aid extraction
146
label
147
dorsal + ventral conchal (= turbinate) bullae
sep compartment w/in concha formed from curling of turbs
* no comm w sinus
* rostral to sinuses
* can become infected
148
general structure tooth
* bulk tooth = dentine
* pulp chamber inside (cont bvs, nerves, lymphatics)
* enamel above gumline
* cementum lining outside below gumline
* sits in bony socket (alveolar process) - innerv inferior alveolar n.
* bet socket + cementum = peridontal ligament made collagen = can move sligtly = less chips
149
enamel
hard outer part tooth projecting above gums
* ectodermal origin
* formed by ameloblasts
* acellular + can't regen (chip = stay chipped)
150
dentine
bulk of tooth, formed odontoblasts
* mesodermal origin
* structure like bone but odontoblasts no stay in matrix, recede from new formed + remain as layer on surface of pulp cavity = prod 2° dentine (darker) = pulp cavity decr in size thru life
| 2nd hardest tooth mat
151
3° dentine
may occur at sites injury, also darker than 1°
152
cementum
formed from calcified CT (= softer) -> outer lining of tooth in socket (brachydont), whole covering (hypsodont)
* mesodermal origin
* continuously proded (slowly) = thicker in older
153
pulp cavity
central part cont bvs, nerves, lymphatics
* present in each tooth root
* open at apical foramen (top in upper arcade, bottom in lower)
* smaller in older as filled 2° dentine
154
peridontium
= gingiva (gum) + peridontal ligament + cementum + alveolar bone
--> anchor tooth in skull + suspensory apparatus to absorb stress from biting (support)
155
gingiva
oral mucosa covering alveolar processes + neck of teeth
* keratinised stratified eipthel
free = coronal to cemento-enamel junction
attached = tightly attached to periosteum of alveolus
156
periodontal ligament
| PDL
collagen fibres bet cementum + alveolus
* fibres in sling formation = shock absorbers + allow small teeth movements in mastication
157
alveolar bone
layer next to PDL v dense = lamina dura
| radiographically visible as thin white line
158
teeth innerv
upper teeth = maxillary/superior alveolar n. from max. from trigem
lower teeth = mandibular/inferior alveolar from mandibular from trigem
159
mammalian teeth categories
deciduous + permanent = diphyodont (= milk + adult)
diff types specialised teeth = heterodont
160
standard mammal teeth types + nos.
incisors 3/3
canines 1/1
premolars 4/4
molars (permanent only) 3/3
total = 44
| only 1 side mouth upper/lower
161
hypsodont
long crowned w unerupted crown lying beneath gum in all but v aged
* root usually shorter than crown
* crown has cementum as outer layer (worn away at occlusal surface)
| all herbivores have at least some
162
brachydont
low crowned = all of crown erupted by adulthood
* root of tooth longer than crown
* crown fully covered enamel as outer layer
| those of dog, cat, human no reserve crown
163
aradicular/elodont
teeth grow throughout life + never develop true roots = open rooted
* always hypsodont
164
radicular/anelodont
teeth have true anatomical root + don't continuously grow throughout life (finite amount wear)
* hypsodont or brachydont
165
clinical vs anatomical crown
clinical = exposed part of tooth, regardless of structure
anatomical = enamel covered part of teeth, regardless of location (could be below gum)
166
labial tooth surface
surface next to lips
167
buccal tooth surface
surface next to cheek
168
lingual tooth surface
surface next to tongue
169
mesial tooth surface
surface touching tooth in front
170
distal tooth surface
surface touching tooth behind
171
occlusal tooth surface
masticatory surface == table, in contact w food
172
carnivore dentition
radicular brachydont
* incisors for grooming + nibbling
* canines to pierce flesh - hold/kill prey
* premolars/molars to cut like scissors == **carnassials**
* molars cut/crush (even bones to extract marrow)
173
canine adult + deciduous teeth nos
I 3/3 C 1/1 P 4/4 M 2/3 ==> 42
I 3/3 C 1/1 P 3/3 M 0/0 ==> 28
| adult then deciduous
174
cats dental formulae
I 3/3 C 1/1 P 3/2 M 1/1 ==> 30
I 3/3 C 1/1 P 3/2 M 0/0 ==> 26
| adult then deciduous
175
ferret dental formulae (= small carnivore)
I 3/3 C 1/1 P 3/3 M 1/2 ==> 34
I 3/3 C 1/1 P 3/3 M 0/0 ==> 28
more teeth + more heterodont than cat but less than dog
all adult erupted by 9 months
| adult then deciduous
176
pig dental formulae
I 3/3 C 1/1 P 4/4 M 3/3 ==> 44
I 3/3 C 1/1 P 3/3 M 0/0 ==> 28
born w U + L I3 + C (= 8) - sharp + point forward
no gain full adult dentition til at least 18mo = deciduous at slaughter
| adult then deciduous
177
when do teeth erupt approximately dogs + cats
all dog/cat deciduous @ 6 weeks
all dog permanent @ 7 months
all cat permanent @ 6 months
178
anatomy of dentition w/in head
carnassials = sectorials = cut food as move past each other
* at most powerful (widest) part jaw (1/3 along from back)
179
how does cat dentition differ from dog
* much more sectorial bc more carnivorous so less processing of food in oral cavity
* not much differentiation bet cheek teeth (P +M)
180
features that show mouth is healthy
1. normal occlusion w space bet UP + LP so no clash
2. pH 7.5 (dogs + cats)
3. saliva maintains pH + conts enzs, lysozymes, immunoglobulins to moderate bac colonisation + mechanically wash teeth (+ antiviral + antifungal - preventative)
181
congenital malocclusions
= teeth don't meet as should
1. prognathism bc lower jaw too long (brachycephalics)
2. brachygnathism bc lower jaw too short (doliocephalics)
| can still eat + drink - no fatal
182
tooth fractures
due trauma, e.g. stones etc
can't do much - if in pain, remove tooth, otherwise leave it
183
periodontal disease
disease of gingiva, periodontal lig, cementum + alveolar bone
stage 1: gingivitis = inflammation of gingiva
stage 2: early periodontis = inflammation gingiva + PDL
stage 3: further brakdown of support tiss -> tooth mobility -> tooth loss
advanced in upper arcade, esp of canines can lead oronasal fistulas
| v common
184
fistula
abnormal opening bet 2 organs
185
plaque
= biofilm on teeth formed by bac colonising dental pellicle
-> inorganic substances from saliva deposited into bacterial plaque, forms calculus (= tartar)
-> surface calculus readily colonised by plaque ....
prevent periodontal disease = plaque control = mechanical - chew coarse food + brush teeth
186
dental pellicle
prot film on teeth surface formed by saliva + food
187
tooth decay
== caries
* caused by bac
* less common in carnivores than humans
188
tooth abcesses
due periodontal disease or tooth disease/fractures
-> facial/mandibular swellings (clinical signs)
189
normal dentition pigs
* more generalised (not specialised so much)
* lower incisors point forwards to root in soil
* canines = tusks = open rooted in male (grow throughout life) U + L rub against to keep edge sharp
* canines = tusks = open root 2 yrs in female then stop growing
* P + M similar but teeth larger towards caudal mouth - v tubercular occlusal surface to crush food in oral cavity
190
horse dentition
radicular (finite growth, true roots) + hypsodont (long-crowned)
* cellulose made available to microbes by crushing vegetation = wear to teeth so erupt through life (hence hypso) w bone growing to fill socket/max sin expands (for UP4 + UM1-3)
* cementum covers whole crown but soft so wears = ridging for chew due diff hardness enamel, dentine
191
ruminant tooth type
brachydont (all crown out by adulthood) incisors/canines
radicular (finite) + hypsodont (long crown) premolars + molars
192
horse dental formula
I 3/3 C 0-1/0-1 P 3-4/3-4 M 3/3 == 36-44
I 3/3 C 0/0 P 3/3 M 0/0 == 24
| adult (small ones variable) then deciduous
193
when do horse teeth erupt by
most deciduous by 6 weeks, I3 6-9 months
most permanent by 4.5 years, canines by 6 years
194
arrangement teeth horse
canines all 4 often present male but absent/vestigial female
PM1 = wolf tooth, more common upper but can be both = deciduous PM not shed
incisors to chop grass, PM/M to grind
upper row cheek teeth curved out slightly toward cheek, lower row = straighter
* both rows curve up at caudal end cavity = curve of Spee
195
horse incisor structure
196
how horse incisors used age horses
horse ages, teeth wear down what was pulp cavity but now filled 2° dentine (dark) = exposed = dental star
* further wear = 3° dentine visible in middle
Once worn to bottom infundibulum, reach enamel spot = bright white
197
other methods used age horses
1. incomplete occlusion => incisor hook @ 5-7yrs, maybe recur 11-13yrs
2. Galvayne's groove in horses >10yrs, 1/2 way down @ 15, full down at 20
3. profile angle bet U + L incisors increasingly acute as ages
| NEITHER RELIABLE
198
horse cheek teeth
* = PM + M - all v similar (except wolf tooth)
* 6 upper (plus wolf tooth maybe)
* 6 lower (LPM1 rare)
* ~2-3mm wear per year
* each erupts w 1 pulp cavity, then sep -> 5-8 w varying intercomms (bvs, nerves) bet them
199
diastemata
gap bet cheek teeth in large herbivore due pathology or grown apart or fracture
* leads build up food -> periodontal disease
200
cheek teeth occlusion horse
upper wider + squarer, lower narrower + more rectangular
-> upper arcade wider + mouth closed 1/3 upper in contact 1/2 occ of lower
occlusal surface angled down towards cheek (= linguo-buccal direction) - steeper caudally than rostrally
201
structure cheek teeth horse
upper arcade = 2 infundibula surrounded dentine
lower = enamel infoldings not tru infundibula, open on lingual surface
202
how does overall wear appear horse cheek teeth
12 transverse ridges w upper + lower arcade interdigiting
203
tooth extraction large herbivores
1. per os (thru oral opening) - I, C, PM, wolf
2. Buccotomy = through soft tiss of cheek then remove bone overlaying lateral side - PM
3. repulsion - thru skull/mandible w metal punch on root to drive tooth out - caudal PM, M - can cause more problems bc fractures
204
superficial structures to be aware of
literally just under skin + thin layer cutaneous musc
205
cattle/sheep dental formula
I 0/3 C 0/1 P 3/3 M 3/3 == 32
I 0/3 C 0/1 P 3/3 M 0/0 == 20
canine = corner incisor (same shape as incisor) to grip + pull grass
dental pad instead of upper I/C to chew against
| adult then deciduous
206
why are large herbivore deciduous premolars larger than permanent
unsupported by molars + do all of grinding work in young animal
207
when do cattle + sheep teeth come in
all deciduous cattle in 3wks, sheep in 4
all permanent cattle in 3.5yrs, sheep most by 2.5yrs, Cs by 4yrs
208
which nerves convey sensory info from frontal sinus
opthalmic + maxillary divisions of trigem
209
how do you landmark maxillary sinus
1. draw line bet medial canthus of eye + nasoincisive notch for top boundary
2. line bet infraorbital foramen + rostral limit facial crest for rostral limit
| to enter it surgically
210
what passes through holes in cribriform plate
olfactory nerve branches for sensory from nasal cavity (mostly ethmoturbinates)
| olfactory nerve (+ vestibulocochlear) never exits inside of skull
211
which tooth roots are associated w maxillary sinus
upper molars 1-3
UPM4 w rostral - less in old, not all individuals anyway
212
prehension =
siezing + conveying food into oral cavity using:
* lips
* cheek
* tongue
* teeth
213
horse prehension
sensitive, mobile lips = main prehensile structures
* drawing grazing drawn back + incisors sever grass at base
* use vibrissae to locate food
214
cattle prehension
long, roughened (lots papillae) tongue = main prehensile organ
1. curves round grass + draws it into mouth then held bet incisors + dental pad
2. sideways head movement rips grass
bigger, less rubbery, less sensitive lips w limited movement
* insensitivy = swallow foreign objects - stones, wire -> reticulum/wall = puncture = fatal
215
sheep prehension
use tongue then head rip like cattle but cleft upper lip = crop grass more closely + tend no swallow foreign objects
216
pig prehension
root w snouts + use pointed lower lip to transfer food -> mouth
217
dog/cat prehension
v long, mobile tongue + teeth main means
* also use tongue lap up liquid - other domestics all use suction
| lips relatively unimportant
218
muscs of food prehension
lip/labium (all innerv facial)
* orbicularis oris
* levator labii superioris
* depressor labii inferioris
* levator nasolabialis
* caninus
* zygomaticus
cheeks/buccae:
* buccinator
219
orbicularis oris
ring musc around mouth to close it + for sucking
innerv: facial (dorsal + ventral buccal branches)
220
levator labii superioris
lift upper lip
innerv: facial
| covers infraorbital foramen
221
levator nasolabialis
lift upper lip + nostril
innerv: facial
222
depressor labii inferioris
depress lower lip
innerv: facial
not in carnivores - done by part buccinator
| tendon covers mental foramen
223
caninus
retract upper lip + nostril
innerv: facial
224
zygomaticus
retract caudal commissure (corner) of lip, runs across zygomatic arch
innerv: facial (auriculopalpebral branch)
| exposes carnassial teeth
225
buccinator
grp muscs acting as one form diaphragm across cheek so food pushed back into oral cavity
* act in opposition or conjuction w tongue
innerv: facial (dorsal buccal branch)
226
sensory supply lips + cheek
lips: trigem nerve - upper = max., lower = mandib. branch
cheeks (internal mucosa + external skin): buccinator n. of mandib. of trigem
227
tongue functions
* manipulation foodstuff w/in + outside mouth
* tasting
* lapping water
* grooming
* vocalisation/articulation of sound
228
species variation tongue
1. free end wider + rounder (spatulate) horses + dogs vs pointed ox, sheep, pig
2. ruminants have torus linguae = mound on caudal part to squash food on roof mouth
3. soft surface in horse, pig, dog vs rough in cats, ruminants
4. dogs have median sulcus = line running down middle
5. dogs have lyssa = white cartilagenous rod in ventral tip to shape tongue, e.g. bowl to lap water
229
extrinsic muscs of tongue
3 pairs:
1. genioglossus
2. styloglossus
3. hyoglossus
all innerv hypoglossal XII
230
genioglossus
from genu - tongue
puts tongue out
innerv: hypoglossal
231
styloglossus
from styloid process hyoid -> tongue
retracts tongue
innerv: hypoglossal
232
hyoglossus
from basihyoid -> tongue
depresses + retracts tongue
inner: hypoglossal
233
geniohyoids
pair muscs lying below tongue
genu -> hyoid
contracts = hyoid forward = tongue forward
innerv: hypoglossal
234
sternohyoids
pair muscs sternum -> basihyoid
contract = hyoid caudal = tongue caudal
run up neck so innerv: cervical
235
intrinsic muscs tongue
propria linguae = musc bundles running longitudinal, transverse + vertical
-> tongue change shape + rigidity
innerv: hypoglossal
236
tongue innerv
motor: SE in hypoglossal
sensory:
rostral 2/3 = lingual n. of mandib trigem (SA bc ectoderm of arch 1)
caudal 1/3 glossopharyngeal + vagus (AA for endoderm arch 3)
taste (special sense):
rostral 2/3 = chorda tympani of facial (AA)
caudal 1/3 = glossopharyngeal + vagus (AA)
| chord tymp runs w lingual
237
label
238
tongue mucosa
tongue lining = stratified squamous keratinised
* thinner on ventral than dorsal
* dorsal surface + margins covered mucosal projections = papillae cont taste buds or just for rough surface
* vallate papillae (5 or 7) mark division bet rostral 2/3 + caudal 1/3
239
mastication
tearing, grinding + chewing food inc:
* teeth
* temporomandibular + symphysial joints
* masticatory muscs
240
temporomandibular joint (TMJ)
condyle sits in concave surface
* one each side, sat bet temporal bones
* can't move independently of each other
241
TMJ joint capsule
1. laterally thickened form mandibular ligament
2. divided into upper (meniscotemporal) + lower (meniscomandibular) compartment by fibrocartilagenous disc
| holds joint together
242
movement at TMJ
* hinge movement bet mandible + articular disc
* lateral movement (translations) bet disc + temporal bone
243
how is TMJ diff in herbivores
* disc thicker
* joint capsule larger
* no retroglenoid process that in dogs prevents backwards movement jaw = temporal surface large + flat
-> accomodate greater range movements
244
symphysial joint
joins 2 halves mandible at rostral end
* allows small changes angulation lower teeth = aids prehension
* most unfused carnivores + cattle, most fused horses (= more vs less changes)
| dislocated in RTAs + wired back into position
245
muscs of mastication
from mesoderm phar arch 1 + innerv mandib trigem (SVE):
* temporalis
* masseter
* pterygoids
digastricus from arch 1 (rostral, trigem) + arch 2 (caudal, facial) - SVE, banana shape
246
temporalis
temporal fossa on lateral cranium -> coronoid process mandible
== jaw upward = jaw closer
innerv: mandibular branch trigem
| largest + strongest in carnis, side zygomatic arch to allow for bulk
247
masseter
zygomatic arch -> large area insert on caudal mandible
* lies lateral to mandible, ventral to zygomatic arch
* 3 layers w fibres running diff directions w slight diff functions in herbis
moves jaw up = jaw closer AND moves laterally in herbis
innerv: mandib trigem
| largest of head in herbis, smaller carnis bc less lateral movement
248
pterygoids
large medial + small lateral
pterygoid fossa on pterygoid palatine + sphenoid bones -> medial aspect mandible
== mandible up, medial + forward = jaw closer
inner: mandib trigem
herbis: functioning pair w contralateral masseter (other side) to move jaw to functioning side
249
digastricus
paracondylar processes of exoccipital bones -> ventral border mandible
== jaw opener
innerv: rostral mandib V, caudal VII
| occipitomandibularis in horses = division of digas + does same function
250
compare muscs mastication carnis + herbis
carnis = large area origin for temporalis (A), small area insertion for masseter + digastricus (B)
herbis = opposite
| temporalis musc herbis feels thin
251
small salivary glands
labial, buccal, lingual, pharyngeal, oesophageal
* all around oral cavity, constant low-level mucous secr acting locally keep area oral cavity moist, clean, healthy
252
large salivary glands
1. parotid - serous all species (mixed mainly serous carnis)
2. mandibular - mixed (mainly mucous carnis)
3. sublingual - mixed
4. zygomatic (carnis)/buccal (herbis) - mixed
| one of each on L + R
253
nerve supply salivary glands
SYMP from cranial cervical ganglion = decr prod = dry mouth
PARASYMP from salivatory nuclei in brainstem, then via facial or glosspharyngeal, then trigem
-> normal production + incr when in presence food
| all symp to head from cranial cervical ganglion
254
parotid salivary gland
lobulated, next to ear, duct runs over masseter to open in mouth near UPM4 (upper carnassial) bc lots action here (esp in carnis) so want lots saliva
255
mandibular salivary gland
duct runs w sublingual duct (deeper) + opens on small papillae (*sublingual crauncles*) at rostral end frenulum on floor mouth
256
frenulum
connects tongue to floor mouth
257
sublingual salivary gland
duct of monostomatic part runs -> sublingual caruncles
polystomatic parts (lots smaller bubbles of glands) secr directly into oral cavity
258
zygomatic salivary gland
ducts (1 major, up to 4 minor) open near last UM
| only carnis (analogous buccal in other species)
259
arrangement salivary glands dog/cat
260
arrangement salivary glands horse
v large parotid w duct running ventral to masseter not across
dorsal + ventral buccal glands, ventral lies near sublingual
261
arrangement salivary glands pig
dorsal + ventral buccal glands, ventral lies near sublingual
262
arrangement salivary glands ruminant
v large mandibular
263
upper resp tract components
* nasal cavity + paranasal sinuses
* mouth
* pharynx
* larynx
* trachea + bronchi
264
functions upper resp tract
1. modify inspired air
2. defend bod against harmful substances
3. olfaction + gustation
4. vocalisation
265
how is air modified upper resp tract
1. -> body temp bc large A w good blood supply
2. humidify, picking up water from evap from mucous covering airway
3. remove particulate matter
266
how does upper resp tract defend against harmful substances
* filtration
* coughing + sneezing
* reflex closure glottis @ entrance to larynx on mech stim
* continuous movement cilia
* mucous conts lysozyme which may destroy some bac
* lymphoid tiss: palatine tonsils in mouth for food + pharyngeal in nasal cavity for air - trap pathogens + phagocytose --> retropharyngeal node
267
how does olfaction work
air drawn -> caudal part nasal cavity to pass over ethmoturbs
* mucosa conts lots olfactory cells (-> AA)
* axons AAs thru cribriform plate -> olfactory bulb brain
268
gustation
== taste
269
sniffing
deliberately bringing air in contact w ethmoturbs
270
palatine fissure
opening in incisive bone (paired), either side midline
* almost completely covered soft tiss w small raised incisive papilla at midline
* = entrance to both L + R incisive ducts
| in hard palate
271
incisive duct
== nasopalatine duct
small tubes linking oral + nasal cavities
* in all domestic species except equids
272
vomeronasal organ
small, paired, detect pheromones
* arises caudally from incisive duct, lying on floor nasal cavity, embedded in hard palate
* innerv: olfactory CNI + max trigem
273
how is vomeronasal organ diff in horses
ducts to it (nasopalatine) only comm w nasal cavity, not oral
274
flehmen behaviour
air cont pheromones drawn over vomeronasal organ = scent detection
275
vocalisation
caused by vibration of vocal chords lying w/in larynx
* v important for communication + behaviour
276
obligate nasal breathers
v long soft palate so epiglottis sits above soft palate (except when swallowing)
| horses, domestic cats, lagomorphs, rodents
277
mods to upper resp tract horses in exercise
1. dilation external nares comma -> circle shape
2. vasoconstriction nasal mucosa - v vascular to = common + ventral meatii dilate
3. dilation glottis (airway w/in larynx)
278
horse nostril structure
alar fold = open bit, made up alar cartilages to control shape
279
how does nostril dilate
alar cartilage pulled medially w laminar part pulled dorsally by dilator naris labialis
* caninus + levator nasolabialis + dilator naris apicalis + lateralis nasi all dilate nostril
| all innerv facial
280
vasoconstriction nostril mucosa
false nostril = soft tiss structure - constricts = more space for air
281
how does larynx widen horse exercise
arytenoid cartilages of larynx abduct = more air thru
282
pharynx is
chamber continuation of oral + nasal cavities
* functions during nasal breathing, mouth breathing, swallowing, vomiting
* size + shape changeable bc walls made soft tiss
283
hard palate
bony shelf made of incisive, maxilla + palatine bones, dividing nasal + oral cavity
284
soft palate
caudal continuation hard palate
* made soft tiss w muscs, salivary glands, covered mucosa - resp on dorsal surface, oral mucosa on ventral
285
larynx is
gateway to trachea
* made 4 cartilages - epiglottis, arytenoids, thyroid, cricoid
286
pharynx parts
1. nasopharynx - above soft palate
2. oropharynx - space below soft palate
3. laryngopharynx - space above larynx
287
nose breathing
epiglottis in downward position so trachea open + air down
* epiglottis tip above soft palate = can see underside epiglottis as look in oral cavity, can't see airway = tube in mouth, lift epiglottis + insert
288
mouth breathing
panting animals
* soft palate elevated - horses can't do
289
swallowing diagram
tongue to back = epiglottis up = food up to oes dorsal to trachea
290
pharynx arches
folds mucosa in lateral wall running ventrally = wall thickenings
1. glossopalatine bet oropharynx + oral cavity
2. pharyngopalatine bet nasopharynx + laryngopharynx
291
radiography pharynx
soft palate pushed up + epiglottis pushed down by ET tube
292
tonsils tongue
lymphoid tiss performing protectice role against pathogens
293
auditory tubes
comm bet pharynx + middle ear
* entrance = ostia = a slit then tubes go up
294
pharynx muscs do
alter size + shape chamber
* 3 pairs constrict
* 2 pairs shorten
* 1 pair dilates
all innerv: glossopharyngeal et vagus complex
295
pharynx constrictors
sequentially constrict to push bolus caudally in swallowing
1. rostral: hyopharyngeus from thyrohyoid + ceratohyoid -> pharynx wall
2. middle: thyropharyngeus from thyroid cartilage -> pharynx wall
3. caudal: cricopharyngeus from cricoid cartilage -> pharynx wall
296
pharynx shorteners
during swallowing to bring oes opening closer to caudal part tongue = close off laryngeal airway
1. palatopharyngeus from soft palate -> dorsal wall pharynx (also constrict to form palatophar arch for cuff round larynx in nose breathing)
2. ptergopharyngeus from pterygoid process -> dorsal wall pharynx
297
pharynx dilator
widens pharynx in swallowing to accomodate food bolus
1. stylopharyngeus from stylohyoid bone -> lateral wall pharynx
contract, bone no move, soft tiss will = pharynx dilates
298
soft palate muscs
1. tensor veli palatini tenses soft palate - e.g. pull tight when lifting it, mandib trigem SVE
2. levator veli palatini elevates - glossophar + vagus complex
3. palatinus shortens soft palate - glossophar + vagus complex
299
nerve supply mucosa soft palate + pharynx
* sensation + taste = glossophar + vagus complex (AA)
* glands = parasymp motor fibres from facial, glossophar + vagus/symp from cranial cervical ganglion
300
articulation hyoid bone
dorsally = petrous temporal bone just caudal to tympanic bulla
ventrally = articulates w larynx (thyrohyoid bones to thyroid cartilage of larynx)
301
muscs hyoid apparatus
1. sternohyoideus = move hyoid caudal (cervical n.)
2. thyrohyoideus = move hyoid caudal (cervical n.)
3. mylohyoideus = move hyoid rostral (trigem)
4. geniohyoideus = move hyoid rostral (hypoglossal)
| some other small ones asw
302
radiography hyoid apparatus
303
larynx is
cartilagenous muscular tube suspended from skull by hyoid apparatus
* some cartilages mobile so shape can be altered
primary role = protect lower resp tract from foreign bods
* secondary = phonation (voice production)
304
airway of larynx components
1. vestibule = rostral, funnel shaped part
2. glottis = narrow vertical slit
3. infragottic cavity = wide from glottis -> trachea
305
vestibule
entrance from common pharynx = laryngeal aditus (circularish)
* ventral floor of opening = epiglottis, roof of arytenoid cartilages + lateral aspects aryepiglottic fold
306
aryepiglottic fold
joins epiglottis to arytenoids
307
glottis
technically wall of slit + actual airway = rima glottidus
walls ventrally formed by paired vocal folds + dorsally arytenoid cartilages
| can just say whole thing = glottis
308
larynx cartilages
1. epiglottis (unpaired) - forms spout-like entrance to larynx
2. arytenoid (paired) - can widen/narrow glottis
3. thyroid (unpaired) - v big, articulates w cricoid
4. cricoid (unpaired) - signet ring shape (narrow bottom, wide top)
| other ones not important + vary size/shape/if there bet species
309
label
310
mucosal folds of larynx
1. vestibular fold marks caudal end of vestibule
2. vocal fold = vocal chord = responsible for vocalisation by vibration
3. aryepiglottic fold from epiglottic to arytenoid
311
laryngeal muscs general
* 7 pairs close glottis reflexively v fast if eating to protect airway
* 1 pair opens glottis
* others vary tension on vocal chords
* all innerv = recurrent laryngeal but cricothyroid (closes) = cranial laryngeal - both branches of vago-accessory complex (SVE)
312
cricoarytenoideus dorsalis
abducts arytenoids + opens glottis (only one)
innerv: recurrent laryngeal
313
cricoarytenoideus lateralis
one that closes glottis
innerv: recurrent laryngeal
314
label
315
larynx nerve supply
vagus accessory complex (X/XI)
1. cranial laryngeal nerve
2. recurrent laryngeal nerve
316
cranial laryngeal nerve
branch of vagus as runs cranium -> pelvic inlet
1. AAs from larynx rostral to vocal cords
2. AEs parasymp to mucosal glands
3. SVEs -> cricothyroideus musc
317
recurrent laryngeal nerve
1. AAs from larynx mucosa caudal to vocal folds
2. AE parasymp -> mucosal glands
3. SVE -> all larynx muscs but cricothyroideus
R + L branches given off vagus in thorax, curve round a structure then go back up to innerv larynx
* L round ligamentum arteriosum
* R curves round R subclavian artery
318
swallowing reflex
1. afferents glossopharyngeal + vagus (cr/rec laryngeal) initiate. cranial laryngeal coveys stim from rostral larynx for reflex closure glottis
2. vagus-accessory complex (via pharyngeus nerve of vagus) = efferents -> pharyngeal muscs except stylopharyngeus (glossopharyngeal)
3. then bolus pharynx -> stom
319
laryngeal saccule
deep blind ending pocket of mucosa in lateral wall larynx (one each side)
* opening bet vestibular + vocal fold = laryngeal ventricle, saccule w/in that space
320
BOAS dogs
1. stenotic nares
2. abnormal shape/position nasal turbinates
3. extra long soft palate
4. hypoplastic (narrow) trachea
5. tracheal collapse
6. everted laryngeal saccules = stick out into glottis bc breathing so hard (bc long soft palate etc) been pulled out, then obstruct airway = even harder breather
321
dorsal displacement soft palate
should lie ventral to epiglottis, on top = inhaled into larynx => coughing, gurgling, affects performance
| in horses
322
possible surgeries for DDSP
1. tie forward = sutures bet basihyoid + thyroid cartilage so larynx more rostral + dorsal
2. induction of palatal fibrosis = thermal/laser cautery, stiffening soft palate
3. staphylectomy = partial soft palate resection by trimming caudal part w scissors
| 1 currently best option (60% horses back to race performance)
323
recurrent laryngeal neuropathy
unilateral paralysis (usually L) arytenoid cartilage as cricoarytenoideus dorsal musc fails contract + abduct
* only abduct in exercise, wouldn't notice in normal life
324
surgical options for recurrent laryngeal paralysis
1. hobday = remove ventricle + vocal cord that side to widen airway - improves noise but not improve airflow = owner thinks it's good but no
2. tie back = suture bet cricoid cartilage + muscular process left arytenoid to mimic action musc so permanently abducted
325
laryngeal reflexes
mucosa v sensitive to mech stim from small particles => coughing, reflex closure glottis
* severe stim = prolonged closure due spasm laryngeal muscs
* so local anaesthetic for cats + rabbits to intubate bc their mucosa v v sensitive
326
adnexa of eye
structures associated w movement, protection + support of eye
327
label
nictation mem = 3rd eyelid
328
palpebral fissure
space bet eyelids when open, not there when eyes closed
329
eyelid structure
1. external skin
2. musculofibrous layer - phar arch muscs, somite musc, sm musc, CT, glands
3. palpebral conjunctiva (conts across front of cornea as bulbar conjunctiva) = mucous mem lining inside
330
tarsal plate
stiff plate CT supporting free edge each lid w tarsal glands in it
331
tarsal gland
small openings in upper (~40) + lower (~30) lids
* secr thin film waxy substance form waterproof barrier stop tears spilling out onto face
332
eyelid muscs
palpebral branch of auriculopalpebral of facial (SVE):
* orbicularis oculi closes eyelid = tears across front = eye clean + moist (fail = corneal ulcers)
* superciliaris lifts upper eyelid + eyebrow
* retractor anguli occuli draws lateral canthus caudal (= narrow palpebral fissure)
occulomotor (SE):
* levator palpebrae superioris lifts upper eyelid
cranial cervical ganglion at top neck symp nerves (AE) -> sm musc U + L lids
| diff innervs = facial nerve paralysis only => partial eyelid drooping
333
sensory supply region around eye
all trigem
* frontal + zygomaticotemporal of opthalmic to upper lid
* zygomatic of maxillary to lower lid
dog: zygomaticotemporal = branch of maxillary
334
entropion
inward rolling of eyelid margin (L or U)
--> conjunctivitis + corneal ulcers as fur brushed front eye
correct w surgery
335
ectropian
eversion of eyelid margin (usually L)
-> exposed conjunctiva -> epiphora (excessive tear prod, not drained = down face) + conjuctivitis
sorrect w surgery
| esp in breeds w 'droopy' eyes
336
conjunctival flap
to treat deep corneal ulcers
conjunctiva from inner surface eyelid partially detached + swung round (keep blood supply) + sewn on cornea
= blood supply -> cornea = can repair itself
after several weeks connection cut + flap conjunctiva dies + drops off
337
lacrimal apparatus
lacrimal gland, small associated glands, 3rd eyelid gland, lacrimal duct
tears sit corner eye = lacrimal lake, heald back by waxy from tarsal - too much = overflow -> face
338
lacrimal gland
flat, lobulated, secr serous + mucous
* moisten eye + supply cornea w some nutrients
* innerv: AE from facial via pterygopalatine ganglion onto opthalmic division of trigem
* symp run along bvs from cranial cervical ganglion
339
nasolacrimal duct
series tubes to drain lacrimal lake -> lacrimal sac -> lacrimal duct -> nasal cavity -> ultimately just inside external nares where fluid drips
* initially thru maxilla wall then on internal surface covered mucosa rostral 1/3 nas cav
340
finding nasolacrimal duct horse
basically straight line from medial canthus eye -> nasoincisive notch
follow infraorbital canal on radiograph + nasolacrimal duct = black tube following rostrally from end (bc layers on top of each other in 3D horse)
341
what happens w nasolacrimal duct rabbits
poor diet/husbandry = not wearing teeth = press from occlusion = grow back into sockets = occlude duct = blocked = backflow tears -> lacrimal lake = watery eyes
342
nictitating mem
| (3rd eyelid)
T shaped cartilage supporting fold conjunctiva that passively sweeps across cornea when eyeball retracted
* at rest situated at medial canthus of eye, retracts back by contraction sm musc w/in (innerv: symp that run thru middle ear)
* has lacrimal gland (gland of 3rd eyelid) associated
343
prolapsed 3rd eyelid
== cherry eye, need surgically remove
344
periorbital fascia
cone shaped fibrous tunic surrounding eye + extraocular muscs made 3 layers:
1. periorbita = most superficial
2. 2nd = superficial muscular fascia (envelops levator palpebrae superioris + lacrimal gland)
3. deep muscular fascia, reflecting round extraocular muscs + optic nerve
345
extraocular muscs
* 4 rectus (dorsal, medial, ventral, lateral), inserting rostral to equator = pull that direction
* 2 oblique - dorsal + ventral, insert rostral to equator
* 1 retractor - retractor bulbi, inserts caudal to equator
all but ventral oblique originate from region of optic canal + orbital fissure
ventral oblique arises from ventromedial wall of orbit
all join at bottom ice cream cone w eyeball as ice cream
| all work in conjunction not isolation + movement eyeball complex
346
retractor bulbi musc
pull eyeball back in socket - blink, eye back, mic mem across
divided 4 fasciculi (continuous ring in herbis)
innerv: mix occulomotor + abducent nerves
347
rectus muscs
dorsal = dorsal tilting of pupil
ventral = ventral tilting of pupil
lateral = abduction of pupil (move out away midline of bod)
medial = adduction of pupil (to bod midline)
lateral innerv = abducent CNVI
others innerv: occulomotor CNIII
348
oblique muscs
dorsal = dorsal part eyeball moved medially + ventrally (bc pulls back of eye up so front down)
innerv: trochlear CNIV (all it does)
ventral = ventral part moved medially + dorsally
innerv: occulomotor CNIII
349
cartilages of external ear
space running inside -> tympanic mem = external auditory/acoustic meatus (ear canal)
* curved = tricky see tympanic mem
350
muscs of external ear
3 grps:
1. pre auricular move ear forward
2. ventral auricular move ear ventrally
3. post auricular move ear caudally + medially
e.g. scutuloauricularis superficial accessorius, medius, dorsalis; parotidoauricularis (over parotid + important veins)
351
parotidoauricularis
depresses ear
innerv: palpebral branch of facial
352
motor nerve supply external ear
rostral ear muscs = rostral auricular nerve
caudal ear muscs = caudal auricular nerve
also great auricular nerve for C2 to caudal ear muscs
353
sensory nerve supply external ear
1. auriculotemporal branches of mandib trigem do small rostral part external ear + deep ear canal
2. cervical spinal do rest of 'outside of ear
3. internal auricular branch of facial supplies inside of ear canal
| ear flap = pinna = top flop of ear
354
root facial nerve
root near base ear + ear surgery common so be careful no cut thru
* spreads everywhere
* lies deep to parotid salivary gland
355
middle ear
cavity that lies w/in temporal bone
* ventral floor = tympanic bulla
* laterally lies tympanic mem (eardrum)
* medially + dorsally lies petrous (dense) temporal bone housing inner ear
facial nerve runs on dorsal part of cavity, inc chorda tympani
356
tympanic mem
seps inner + outer ear
357
auditory tube
bet middle ear cavity + wall nasopharynx
* stabilise air press either side tympanic mem - press outside incr = swallowed air forced in so press in mid cav incr (or air forced out nose) = balance
* bc entrance (ostia) opened w yawning/swallowing
358
guttural pouch general
only found perrisodactyla (odd-toed ungulates, e.g. horses)
== air-filled ventral diverticulum of auditory tube w capacity 300-500ml air
* ventral part divided medial 2/3 + lateral 1/3 by stylohyoid bone
| one on each side
359
what does guttural pouch do
not known, probs another air-filled space so head structures can be where they need to w/o being heavy bone, maybe also:
* reg internal carotid artery press
* cool blood flow to head
360
location guttural pouch
dorsal = skull + C1
ventral = pharynx + retropharyngeal lymph nodes
medial = median septum bet L + R (v thin soft tiss sheet)
lateral = pterygoid muscs, parotid + mandibular salivary glands
opens cranially into nasopharynx, entrance = ostia
361
structures associated w walls guttural pouch
lateral:
* external carotid artery
* maxillary artery
* facial nerve
* mandibular trigeminal nerve
medial:
* internal carotid artery
* cranial cervical ganglion + symp nerves
* glossopharyngeal nerve
* vagus nerve
* accessory nerve
* hypoglossal nerve
* longus capitus musc
362
drainage of guttural pouch
lined mucosa = always proding mucous so moist = needs open regularly + drain
ostia dorsal to most of pouch when head horizontal = only drain when head down
need be swallowing so ostia open
363
surgical approach guttural pouch
Viborg's triangle:
1. caudal border = tendon on insertion of sternocephalicus
2. 2 ventral border = linguofacial vein
3. cranial border = caudal mandible
| obvs don't cut into veins etc
364
diseases of guttural pouch
1. tympany = air distension if ostia no closing properly = not all air out, more in = soft tiss expands like balloon (down neck)
2. empyema = bac infec
3. mycosis = fungal infec => erosion of artery, cann affect nerves in wall
diagnosis by endoscopy + radiography
365
signs of guttural pouch disease + causes
1. epistaxis (nonsebleed) - internal/external carotid artery affected
2. nasal discharge (could be due nasal or sinus disease)
3. nerve dysfunction
4. swelling/dyspnoea (struggling to breathe) due pharyngeal wall/roof collapse
unilateral but thin septum = easily destroyed + spread
366
nerve dysfunction caused guttural pouch disease
1. dysphagia (difficulty swallowing) - pharyngeal branch of vagus/glossopharyngeal
2. laryngeal paralysis - vagus nerve
3. ptosis (drooping eyelid) + miosis (constricted pupil) = horners syndrome - symp nerves
4. facial asymmetry - facial n. + symp nerves
367
guttural pouch empyema
often spreads from retropharyngeal node
=> fluid (pus) in (horizontal line radiograph bc gravity)
* can get chondroids = inspissated purulant mat (solid balls pus) as pus coagulates over time
368
platysma
origin: fascia covering clavicle
insert: commissural portion of lips
function: retract caudal lip commissure (eating, panting, behavioural)
innerv: dorsal + ventral buccal of facial in head region, cervical spinal in neck region
damage = caudal commissure droops, drop food/water
369
head veins
jugular
-> maxillary -> caudal auricular/superficial temporal
-> linguofacial -> lingual/facial -> deep facial/ventral labial
370
what does lingual vein drain
tongue
371
what does ventral labial vein drain
lower lip
372
main facial nerve branches
ventral buccal = SVE -> muscs of lower lip
373
buccinator branch
of mandib trigem
sensory to mucosal surface inside cheek + skin surface
374
what type of nerve is infraorbital
sensory SA -> upper muzzle
