Muscles of the Head Flashcards
(148 cards)
1
Q
Describe the platysma muscle.
A
Cutaneous muscle of the head/neck region that passes from the dorsomedial margin of the neck to the angle of the mouth. Muscle fibers are directed cranioventrally.
2
Q
What is the most superficial muscle of the head/neck region beneath the skin?
A
Platysma.
3
Q
What is the origin of the platysma muscle?
A
Dorsal median raphe of the neck.
4
Q
What is the insertion of the platysma muscle?
A
Cheek and commissure of the lips.
5
Q
What is the action of the platysma muscle?
A
Drawing the lips caudally and twitching
6
Q
What is the innervation of the platysma muscle?
A
Caudal auricular branch of the facial nerve.
7
Q
List the 3 structures you can visualize directly beneath the platysma.
A
- Mandibular, parotid, and sublingual salivary glands
- Dorsal and ventral buccal nerve
- Auriculopalpebral nerve (branch of the facial nerve)
8
Q
Where do the mandibular, parotid, and sublingual salivary glands drain into the oral cavity?
A
At around the premolars.
9
Q
What structure drains the parotid salivary gland and where is it found?
A
Parotid duct, lies between the dorsal and ventral buccal nerves.
10
Q
What does the palpebral branch of the auriculopalpebral nerve innervate?
A
The eyelid.
11
Q
What is the landmark for the auriculopalpebral nerve for a nerve block?
A
Tip of the dorsal border of the zygomatic arch.
12
Q
What are the groupings of the muscles of the head?
A
- Muscles of mastication
- Muscles of facial expression
- Other muscles of the head (tongue and eye mm.)
13
Q
Describe the muscles of mastication.
A
Have attachments to the mandible and contractions produce jaw movements associated with chewing.
14
Q
Describe the muscles of facial expression.
A
Move skin and appendages of the face and head; also known as mimetic muscles.
15
Q
Describe the other muscles of the head.
A
Includes tongue muscles and extraocular muscles of the eyes.
16
Q
What are the 4 muscles of mastication?
A
- Digastricus (biventer)
- Masseter
- Temporalis
- Medial and lateral pterygoids
17
Q
What are the general characteristics of the digastricus muscle?
A
- Also called biventer
- Two bellies: rostral and caudal
- Aided by gravity.
18
Q
What is the primary jaw opening muscle?
A
Digastricus.
19
Q
What is the origin of the digastricus?
A
Basioccipital bone
20
Q
What are the 2 insertions of the digastricus?
A
The mandibular angle & the ventral surface of the mandible.
21
Q
What is the action of the digastricus?
A
Aids in mastication by opening the jaw.
22
Q
What is the innervation of the digastricus?
A
Rostral belly: mandibular nerve; caudal belly: facial nerve.
23
Q
What is the location of the masseter muscle in relation to the mandible?
A
lateral to the mandible.
24
Q
What is the origin of the masseter?
A
Zygomatic arch.
25
What are the insertions of the masseter muscle?
Masseteric fossa, angular process, and ventrolateral ramus of the mandible.
26
What is the action of the masseter?
Raise the mandible to close the jaw.
27
What is the innervation of the masseter?
Mandibular nerve.
28
What is the strongest muscle of the head in carnivores?
Temporalis.
29
Describe the location of the temporalis muscle.
Situated on the most dorsolateral aspect of the neurocranium.
30
What is the origin of the temporalis?
Temporal fossa and external sagittal crest.
31
What is the insertion of the temporalis?
Medial and lateral surfaces of the coronoid process of the mandible.
32
What is the action of the temporalis?
Raises the mandible to close the jaw.
33
What is the innervation of the temporalis?
Mandibular nerve.
34
What is masticatory muscle myositis?
Autoimmune disease that causes muscle wasting of the muscles of mastication, primarily the masseter and temporalis muscles.
35
What are the symptoms of masticatory muscle myositis?
Pain, lock jaw, muscle wasting.
36
What are the medial and lateral pterygoid muscles responsible for?
The side to side movement of the mouth typical of herbivore mastication.
37
In what species are the lateral and medial pterygoid muscles most important?
Ruminants; sideways chewing.
38
What is the origin of the pterygoid muscles?
Pterygopalatine fossa.
39
What is the insertion of the pterygoid muscles?
Medial aspect of the coronoid process of the mandible and the angular process of the mandible.
40
What is the action of the pterygoid muscles?
Lateral chewing primarily; medial pterygoid helps close the jaw as well.
41
What is the innervation of the pterygoid muscles?
Mandibular nerve.
42
The muscles of facial expression can be divided into what groups?
- Muscles of the cheek
- Muscles of the lips
- Muscles of the forehead
- Muscles of the eyelid
43
What are the muscles of the cheek?
- Platysma
- Buccinator
44
What is the primary muscle of the cheek?
Buccinator.
45
Describe the location of the buccinator.
Non-cutaneous substance of the cheek that lies deep to the platysma.
46
What is the origin and insertion of the buccinator?
Alveolar margins of the maxilla and mandible.
47
What is the action of the buccinator?
Compress the cheek against the teeth, tensing and compressing the oral vestibule.
48
What is the innervation of the buccinator?
Dorsal and ventral buccal nerves, which are a branch of the facial nerve.
49
What are the muscles of the lips?
- Levatornasolabialis
- Orbicularis oris
- Zygomaticus
- Mentalis
- Maxilonasolabialis
50
Describe the location of the levatornasolabialis.
Covers the lateral surface of the nasal bone and maxilla.
51
What is the origin of the levatornasolabialis?
Medial canthus of the eye where the nasal bone and maxilla meet.
52
What is the insertion of the levatornasolabialis?
Superior margin of the lips and external nares.
53
What is the action of the levatornasolabialis?
Nasal dilation and elevates the lips.
54
What is the innervation of the levatornasolabialis?
Auriculopalpebral nerve, which is a branch of the facial nerve.
55
What are the characteristics of the orbicularis oris muscle?
- Fibers run longitudinally around the opening of the mouth
- Deep to the platysma and levatornasolabialis
- Superficial to the buccinator.
56
What muscle is referred to as the kissing muscle?
Orbicularis oris.
57
What muscle has its fibers embedded/firmly attached to the orbicularis oris muscle?
Buccinator.
58
What is the origin and insertion of the orbicularis oris?
Margin of the upper and lower lip.
59
What is the action of the orbicularis oris?
Aid in closing of the mouth; sucking function.
60
What is the innervation of the orbicularis oris?
Dorsal and ventral buccal branches of the facial nerve.
61
Describe the zygomaticus muscle.
Smiling cartilage.
62
What is the origin of the zygomaticus?
Scutiform cartilage of the ear at the rostral angle.
63
What is the insertion of the zygomaticus?
Dorsal angle of the mouth.
64
What is the action of the zygomaticus?
Draws the mouth caudally and pulls the ear cranioventrally.
65
What is the innervation of the zygomaticus?
Auriculopalpebral nerve which is a branch of the facial nerve.
66
Describe the mentalis muscle.
Subdivision of the ventral part of the buccinators.
67
What is the origin/insertion of the mentalis muscle?
Rostral aspect of the mandible.
68
What is the action of the mentalis?
Stiffens the apical region of the lower lip; elevates and protrudes the lower lip to aid in sniffing.
69
What is the innervation of the mentalis muscle?
Ventral buccal nerve which is a branch of the facial nerve.
70
Describe the maxilonasolabialis muscle.
- Part of the dorsal portion of the orbicularis oris
- Has a dorsal portion called the levator labii superioris and a ventral portion called the caninus.
71
What is the action of the maxilonasolabialis?
Levator labii superioris: raises the upper lip and dilates the nostrils; caninus: raises the upper lip; snarling function.
72
What is the innervation of the maxilonasolabialis?
Buccal branches of the facial nerve.
73
Describe the frontalis muscle.
- Muscle of the forehead
- Thin sheet of muscle overlying the temporalis.
74
What is the origin of the frontalis?
Rostral part of the scutiform cartilage.
75
What is the insertion of the frontalis?
Nasofrontal fascia of the forehead.
76
What is the action of the frontalis?
Raises the eyebrow and pulls the ears rostrally.
77
What is the innervation of the frontalis?
Auriculopalpebral nerve which is a branch of the facial nerve.
78
What are the muscles of the eyelid?
- Orbicularis oculi
- Retractor anguli oculi lateralis
- Levator anguli oculi medialis
79
Describe the orbicularis oculi muscle.
Circular arrangement of muscle fibers that surrounds the palpebral fissure.
80
What is the origin/insertion of the orbicularis oculi?
Superior and inferior palpebra.
81
What is the action of the orbicularis oculi?
Forceful closure of the eye.
82
What is the innervation of the orbicularis oculi?
Auriculopalpebral nerve which is a branch of the facial nerve.
83
What is the origin of the retractor anguli oculi lateralis?
Temporal fissure.
84
What is the insertion of the retractor anguli oculi lateralis?
Lateral palpebral angle/lateral canthus.
85
What is the action of the retractor anguli oculi lateralis?
Retract the angle of the lateral palpebra.
86
What is the innervation of the retractor anguli oculi lateralis?
Auriculopalpebral nerve which is a branch of the facial nerve.
87
What is the main difference between the retractor anguli oculi lateralis and the levator anguli oculi medialis?
Retractor anguli oculi lateralis: passes from the lateral palpebral angle; levator anguli oculi medialis: passes from the medial palpebral angle.
88
What is the origin of the levator anguli oculi medialis?
Nasofrontal fascia.
89
What is the insertion of the levator anguli oculi medialis?
Medial part of the eyelid.
90
What is the action of the levator anguli oculi medialis?
Elevate the medial part of the eyelid.
91
What is the innervation of the levator anguli oculi medialis?
Zygomatic nerve which is a branch of the facial nerve.
92
The other muscles of the head are divided into what groups?
- Extraocular muscles
- Muscles of the tongue
93
What are the different extraocular muscles?
Dorsal, lateral, medial, and ventral rectus that attach to the eyeball at the sclera; ventral and dorsal obliques; retractor bulbi.
94
What are the 3 main parts of the tongue?
Apex, body, and roots.
95
How is the body of the tongue joined to the oral floor?
A mucosal fold called the frenulum.
96
Describe the dorsal aspect of the tongue.
Marked by longitudinally by a median groove from which a septum extends into the tongue.
97
What is contained within the ventral part of the tongue in carnivores?
A rod-shaped fibrous body, the lyssa, which lies in the median plane, beneath the ventral mucosa.
98
In which species is the lyssa of the tongue absent?
Absent in cats, present in dogs.
99
The tongue is composed primarily of what?
Skeletal muscle.
100
Describe the location of the tongue.
Occupies the greater part of the oral cavity proper and extends into the oropharynx.
101
What are the functions of the tongue?
- Lapping water
- Prehension of food
- Manipulating food within the mouth
- Swallowing
- Panting to manage heat
102
The tongue has receptors for what?
Taste, temperature, and pain.
103
Describe the basic musculature of the tongue.
3 intrinsic and 3 extrinsic muscles of the tongue that are interwoven.
104
What nerve provides motor innervation to all of the tongue muscles?
Hypoglossal nerve.
105
What nerve provides sensory innervation to the tongue?
Glossopharyngeal.
106
What nerve provides taste association to the tongue?
Facial.
107
What nerve provides touch, pain, and temperature sensation to the tongue?
Mandibular branch of the trigeminal nerve.
108
What is the primary role of the intrinsic muscles of the tongue?
Changing the shape of the tongue.
109
What are the 3 intrinsic muscles of the tongue?
- Longitudinal muscle
- Transverse muscle
- Vertical muscle
110
Describe the attachments of the intrinsic muscles of the tongue.
- No bony attachments
- Confined within the tongue
- O and I are within the tongue
111
What are the extrinsic muscles of the tongue?
- Hyoglossus
- Genioglossus
- Styloglossus
112
What is the origin of the hyoglossus?
Basihyoid and thyrohyoid.
113
What is the insertion of the hyoglossus?
Base of the tongue.
114
What is the action of the hyoglossus?
Draws the tongue caudally and depresses the tongue.
115
What is the innervation of the hyoglossus?
Hypoglossal nerve.
116
What is the origin of the genioglossus?
Medial rostral portion of the mandible.
117
What is the insertion of the genioglossus?
Base of the tongue.
118
What is the action of the genioglossus?
Depresses the tongue and protrudes the tongue.
119
What is the innervation of the genioglossus?
Hypoglossal nerve.
120
What is the origin of the styloglossus?
Stylohyoid bone.
121
What is the insertion of the styloglossus?
Base and body of the tongue.
122
What is the action of the styloglossus?
Aid in swallowing, lifts and draws the tongue back, draws the hyoid apparatus and larynx rostrally.
123
What is the innervation of the styloglossus?
Hypoglossal nerve.
124
Licking is due to the combined action of what muscles?
Hyoglossus and genioglossus muscles.
125
Describe normal species differences in tongue color in dogs.
- Chows and shar peis have blue-black tongue
- Other species have normal pink tongue.
126
What are the clinical conditions that can cause a red tongue?
- Bacterial infection
- Diabetes
- Fever
- Urinary infection
- Hyperthyroidism
- Cancer
127
What are the clinical conditions that can cause a blue tongue?
- Circulatory problems
- Toxicosis
- Hepatitis/liver issues
128
What are the clinical conditions that can cause a yellow tongue?
- Jaundice
- Gastritis
129
What are the clinical conditions that can cause a pale tongue?
Anemia.
130
What are the clinical conditions that can cause a dark tongue?
Melanoma.
131
What are tongue ulcers usually due to?
Periodontal disease or kidney issues.
132
Describe macroglossia.
- Too large of a tongue in newborns
- Must tube feed newborns with this condition
- Results in lifelong feeding issues.
133
What are the characteristics of the tongue of a cat?
- Presence of hundreds of filiform papillae
- Produce secretions.
134
What are filiform papillae?
Projections on the surface of the tongue of a cat that are tiny white keratin protein spines; give the tongue its sandpaper-like texture and can be mechanical or gustatory in function.
135
Where is the parotid lymph node located in dogs and what does it drain?
Base of the ear under the cranial edge of the parotid gland; drains the dorsal head, orbit, muscles of mastication, and parotid gland.
136
What is the most easily palpable lymph node of the head region?
Mandibular lymph node at the ventral angle of the lower jaw.
137
What does the mandibular lymph node drain?
Oral cavity including teeth and tongue, muscles of mastication, all structures not drained by the parotid lymph node.
138
What is the largest lymph node of the head/neck?
Retropharyngeal lymph center.
139
What are the two groups of the retropharyngeal lymph center?
Medial and lateral.
140
Where are the retropharyngeal lymph nodes situated?
Between the larynx and the wings of the atlas; the last LN before the tracheal duct.
141
Describe the comparative differences of the retropharyngeal LN in different species.
In equine, they are of high clinical relevance, but in dogs, only the medial is consistent (large and elongated), lateral is sometimes dead or absent.
142
What does the retropharyngeal LN drain?
Deeper structures of the head such as the guttural pouch in equine.
143
What is the primary LN that drains the head in dogs?
Medial retropharyngeal lymph node.
144
What is retropharyngeal lymphadenitis?
Lateral LN becomes damaged, and affects the recurrent laryngeal nerve, resulting in laryngeal hemiplegia and roaring in equine.
145
What does the superficial cervical LN drain?
The neck region.
146
All of the lymph nodes of the head/neck region drain into where?
The tracheal duct.
147
The external jugular vein gives rise to what main branches?
Maxillary vein and linguofacial vein.
148
What branches does the linguofacial vein give off?
Lingual branch and facial branch.
