Head 2 (muscles) Flashcards

1
Q
A

1) Zygomaticus
2) Levator nasolabialis
3) Orbicularis oris
4) Cutaneous facei
5) Cutaneous colli
6) Platysma

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2
Q

Buccinator insertions and action

A

Attaches to the mandible & maxilla @ the alveolar margins of the teeth.

It draws cheeks inward against teeth as in suckling and whistling.
Supports cheek and helps keep food in the oral cavity (even though not technically muscle of mastication), but if injured then food will pool in the cheeks/oral vestibule

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3
Q

Levator nasolabialis action

A

Dilate nostril and elevate upper lip

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4
Q

Orbicularis oris fiber orientation and action

A

fibers run longitudinally
around the mouth opening.

It draws the lips together into “O” shape (“muscle of kissing”)

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5
Q

Name the two components of the platysma

A

Cutaneous facei
Cutaneous colli

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6
Q

Name where the levator labii superioris originates and where it inserts

A

originate @ Infraorbital foramen → upper lip & nostril

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7
Q
A

1) Zygomaticus
2) Levator nasolabialis
3) Levator labii superioris
4) caninus
5) orbicularis oris
6) Buccinator

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8
Q
A

1) Buccinator
2) Caninus
3) Levator labii superioris
4) levator nasolabialis
5) zygomaticus

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9
Q

Caninus muscle action in dog and horse

A

Dog = snarling (show canines)

Horse: Flaring/dilation of nostrils

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10
Q
A

1) Levator nasolabialis
2) Caninus
3) Levator labii superioris
4) Orbicular oris
5) Buccinator
6) Zygomaticus
7) Depressor labii inferioris

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11
Q

Clin sig of levator nasolabialis

A

Muscle flaps used to close maxillary sinus defects

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12
Q
A

1) levator nasolabialis
2) levaotor labii superioris
3) orbicularis oris
4) buccinator

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13
Q
A

1) Levator nasolabialis
2) levator labii superioris
3) caninus
4) depressor labii superioris
5) orbicularis oris
6) buccinator

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14
Q

Clin sig of levator labii superioris (maxillaris) m

A

Covers the IOF. (push it dorsally to palpate the for. & block the infraorbital n).

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15
Q

Levator labii superoris species difference in pig and horse

A

In equine: the 2 tendons join → aponeurosis → upper lip. Important in eating (horses) Lips are the 1ry organs for food prehension in horse (the tongue in case of ox)

It is important in rooting activity (pigs) as it moves the rostrum or snout (the muscle
is attached to the os rostri)

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16
Q

Which muscles close the mouth

A

Masseter, temporalis, pterygoid (medial and lateral)

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17
Q

Which muscle(s) opens the mouth

A

Digastricus (rostral and caudal belly)
occipitomandibularis in horses only

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18
Q

Describe innervation for muscles of facial expression

A

all by CN 7 (facial)

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19
Q

Describe innervation for muscles of mastication

A

Mandibular br of trigeminal nerve (5)

Note: caudal belly of digastricus supplied by facial (7)

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20
Q
A

1) Temporalis
2) Masseter
3) Digastricus
4) Pterygoids

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21
Q

Describe the location of the masseter m

A

Palpable subcutaneously, ventral to zygomatic arch, cranial to parotid sg and caudal to facial v.

From zygomatic arch to lateral ramus of mandible

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22
Q

Name this muscle

A

Masseter m

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23
Q

Clin sig of masseter muscle

A

Due to thick fascia –> can be a cause of compartment syndrome

Atrophy can be a sign of CN5 disease

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24
Q

Which is the largest masticastory muscle in carnivores

A

Temporalis m

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25
Q

Name the location and origin/insertion of the temporalis m

A
  • It fills the temporal fossa and gives the area
    the rounded appearance.

Origin (1): from bones of temporal fossa Insertion (2) : the coronoid process of
mandible

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26
Q

Clin sig of temporalis m

A

Can be used to fill in defect left by removing an eyeball (cosmetic sx) by transpositioning a muscle flap to cover the orbit

Can be done because the cr and ca parts have their own blood and nerve supply

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27
Q

Name this muscle

A

Temporalis m

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28
Q

Clin sig of digastricus m

A

If Paralyzed → jaw being locked in a closed-mouth position.

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29
Q

Species difference of digastricus m

A
  • in carnivores it has no 2 visible bellies

Horses have a “third” part called occipitomandibularis m

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30
Q

What muscle is this

A

Digastricus m
1) rostral belly
2) Fibrous intersection
3) Caudal belly
4) Digastricus

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31
Q
A

1) Rostal belly of digastricus
2) intermediate tendon
3) caudal belly of digastricus
4) occipitomandibularis (unique to horses)

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32
Q

Pterygoid origin and insertions

A

Origin: pterygopalatine fossa

Insertion:
* The medial → angular process of the mandible
* The lateral → pterygoid fovea

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33
Q

Pterygoid action

A

Assists masseter in closing mouth and horizontal/lateral chewing

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34
Q
A
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35
Q

Name this muscle

A

Pterygoid muscle
1) lateral pterygoid
2) medial petrygoid
3) medial pterygoid
4) lateral petygoid

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36
Q

Describe tongue innervation

A

Hypoglossal (CN 12) innervates all muscles (intrinsic and extrinsic)

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37
Q

Describe the intrinsic tongue muscles

A

Longitudinal, vertical & transverse muscle bundles intermixed with fat

This fat is very resistant to mobilization in starvation

when contract stiffens the tongue

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38
Q

Name the extrinsic tongue muscles

A

Hyoglossus
Genioglossus
Styloglossus

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39
Q

Where does the hyoglossus attach and what is its action

A

Basihyoid bone → tongue
- Draws tongue caudally

40
Q

Where does the genioglossus attach and what is its action

A

Chin to tongue
- Draws tongue rostrally and ventrally

41
Q

Where does the styloglossus attach and what is its action

A
  • Stylohyoid bone to tongue
  • Draws tongue caudodorsally
42
Q
A

1) Hyoglossus
2) genioglossus
3) Styloglossus

43
Q

List the muscles of the soft palate

A

Tensor veli palatini
Levator veli palatini
palatinus (intrinsic m of the soft palate)

44
Q
A

1) tensor veli palatini
2) levator veli palatini
3) palatinus

45
Q

Tensor veli palatini action and innervation

A

Depress
Mandibular n.(V3)

46
Q

Levator veli palatini action and innervation

A

Elevate
IX,X

47
Q

Palatinus action and innervation

A

Shorten
IX,X

48
Q

List the hyoid muscles

A

(…hyoideus)
Sterno
Genio
Mylo
Stylo
Thyro
Omo (horse)

49
Q
A

1) geniohyoidus
2) Mylohyoideus

50
Q

What innervates the mylohyoid m

A

Mylohyoid nerve of CNV3

51
Q

What innervates the geniohyoideus

A

CN 12

52
Q

Describe the sternohyoideus physical characteristic

A

Strap like (on ventral aspect of trachea) - Longest hyoid M. (from manubrium to basihyoid -

53
Q

Sternohyoideus action and innervation

A

Draws the tongue caudally -
Cervical spinal nerves & XII

54
Q

Thryohyoideus origin and insertion

A

From lamina of thyroid cartilage to thyrohyoid bone

55
Q

Thyrohyoideus action and innervation

A

retracts hyoid apparatus & tongue -
Nerve XII

56
Q
A

1) Sternohyoideus
2) Thyrohyoideus

57
Q

Describe the boundaries of the oropharynx

A

from palatoglossal arches- to base of the epiglottis.
* The root of the tongue is the ventral boundary.

58
Q

Describe the nasopharyngeal opening

A

auditory “Eustachian” tube
- Connects nasopharynx to middle ear
- In the horse, it is guarded by salpingeopharyngeal
fold and leads to the guttural pouch (GP) - Tubal tonsil surround the opening.

59
Q

What marks the junction of laryngopharynx and esophagus

A

Pharyngoesophageal limen

60
Q
A

Pharyngoesophageal limen

61
Q

List the rostral pharyngeal constrictor muscles

A

Pterygopharyngeus
palatopharyngeus

62
Q

List the middle pharyngeal constrictor muscles

A

hyopharyngeus

63
Q

List the caudal pharyngeal constructor muscles

A

Thyropharyngeus
Cricopharyngeus

64
Q

List the dilator pharyngeal muscle

A

Stylopharyngeus

65
Q
A

1) Pterygopharygeus
2) Stylopharyngeus
3) Cricopharyngeus
4) Median raphe

66
Q

Where do all pharyngeal muscles insert?

A

pharyngeal raohe

67
Q

List where the pharyngeal muscles originiate

A

Pterygopharyngeus (from pterygoid bone)
Palatopharyngeus (from aponeurosis of soft
palate)
Hyopharyngeus (from hyoid bone)
Thyropharyngeus (from thyroid cartilage)
Cricopharyngeus ( from cricoid cartilage)
stylopharyngeus (styloid bone)

68
Q

What orientation are the fibers in the rostral pharyngeal muscles

A

longitudinal

69
Q

What orientation are the fibers in the caudal pharyngeal muscles

A

circular

70
Q

What innervates the pharyngeal muscles

A

CN 9 (stylopharyngeus) and 10

71
Q
A

1) Tensor veli palatini
2) Levator veli palatini
3) Pterygopharyngeus
4) Palatopharyngeus

72
Q
A

1) Pterygopharyngeus
2) Stylopharyngeus caudalis
3) Hyopharyngeus
4) Thyropharyngeus
5) Cricopharyngeus

73
Q

cricopharyngeus clinical significance

A

Should remain contracted to prevent reflux of food unless swallowing

Not contracting can lead to esophageal reflux

Tonic contraction or dysfunction of this muscle can lead
to dysphagia. This is called Cricopharyngeal Achalasia

74
Q

List the lymph nodes of the head

A

parotid ln
mandibular ln
lateral retropharyngeal ln
medial retropharyngeal ln

75
Q

Describe location of parotid ln

A

Rostral to or embedded in the parotid SG.

76
Q

Describe location of mandibular ln

A

Rostral to mandibular SG., near the linguofacial V.

In the horse, in the intermandibular space

77
Q

Describe the location of the lateral retropharyngeal ln and species differences

A

constant in cats (inconstant in dogs)

  • caudal to & covered by parotid SG. & caudal to tubus auris
78
Q

Clin sig of medial retropharyngeal ln

A

collecting center of the head in the cat, dog and horse

all other head lnn drain here

In ruminants it is the lateral one that is the main ln

79
Q

describe the location of the medial retropharyngeal ln and what important structures are nearby

A

medial to mandibular SG. -
ventromedial to wing of atlas (ventral to longus colli m.)
- related to:
- The terminal part of common carotid a.
- The dorsolateral aspect of the pharynx

80
Q
A

1) parotid ln
2) mandibular ln
3) lateral retropharyngeal ln
4) medial retropharyngeal ln

81
Q

What does the parotid ln drain

A
  • Superficial structures of dorsal head (dorsal to palate) and ear
82
Q

What does the mandibular ln drain

A

Drain superficial and deep structures of ventral
head.

83
Q

What does the retropharyngeal ln (medial and lateral) drain

A

Deep structures of the head (tongue, larynx, pharynx)
and other lnn of head

84
Q

Clin sig of mandibular and retropharyngeal ln in horses

A

Mandibular: V shape in intermandibular space
Palapable in strangles

retropharyngeal: on medial and caudal aspect of guttural pouches
In diseases such as ‘strangles’, these nodes enlarge & cause dyspnea
and/or dysphagia

85
Q

Clin sig of medial retropharyngeal ln in ruminants

A

Enlarged medial retropharyngeal lnn. can compress nasopharynx and cause airway obstruction

86
Q

Where are lingual tonsils found

A

Glossoepiglotic fold

87
Q

Where are tonsils of the soft palate foudn

A

ventral surfa ce of soft palate

88
Q

clin sig of tonsils of the soft palate

A

is clinically significant in the pig (the soft palate is collected at slaughter to monitor for Classic Swine Fever, “Hog Cholera”).

89
Q

Where is the palatine tonsil found

A

on floor of oropharynx lateral to the median glossoepiglottic fold
& extends to base of epiglottis.

90
Q

Species differences with location of palatine tonsil

A

Lie within tonsillar sinus covered by semilunar fold,
lie within tonsillar fossa in ruminants
Indistinct in horse, but clear in young foals.

Note: NOT the palatine sinus (this is the sinus in ruminant skulls)

91
Q

How many parathyroid glands in the thyroid

A

Each lobe of the thyroid gland is associated
with one external (superior) and one internal
(inferior) parathyroid gland in dogs.

two per thyroid lobe (four total)

92
Q

Thyroid species differences

A

Pig has one mass not a right and left lobe

93
Q

What connects the thyroid lobes

A

isthmus on ventral side (either glandular or fibrous)

94
Q

Where is the thyroid located

A

Lies dorsolateral on the trachea just caudal
to the larynx

95
Q

Thyroid and parathyroid clin sig

A

The thyroid lobes are loosely connected to the trachea by fascia - in case of thyroid tumor, the gland may gravitate towards the lower neck.

The parathyroids are important organs. If the thyroid lobes were to be removed, the external parathyroids may be retained in-situ, because they have distinct separate blood supply. In case blood supply is compromised, the parathyroid gland can be sliced into small bits & injected subcutaneously, & the gland will function normally.