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27 Cards in this Set
- Front
- Back
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Where do the muscles of mastication originate from, with one exception? What is that exception?
What about their innervations? |
Masseter, temporalis, medial pterygoid, lateral ptyerygoid mm. and the rostral belly of digastricus m. all originate from the 1st pharyngeal arch. These muscles are innervated by the mandibular n. of trigeminal n.
The caudal belly of digastricus originates from the 2nd pharyngeal arch. This belly is innervated by the facial n. |
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What are the OIAI's of the temporalis m?
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O: Temporal fossa
I: coronoid process of the mandible A: Raise the mandible I: mandibular n. of trigeminal n. |
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What are the OIAI's of the masseter m.?
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O: zygomatic arch
I: caudal part of the mandible - ventrolateral surface, masseteric fossa, angular process A: Raise the mandible, draw the mandible to the active side I: Mandibular n. of trigeminal n. |
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What are the OIAI's of the medial pterygoid m.?
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O: pterygopalatine fossa
I: medial and caudal surfaces of the angular process of the mandible and ventral to the insertion of temporalis and lateral pterygoid mm. Action: Raise the mandible Innervation: Mandibular n. of trigeminal n. (CN V) |
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What are the OIAI's of the lateral pterygoid m.?
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O: A small fossa in the sphenoid bone – ventral to the alar canal, round foramen, and orbital fissure
I: Medial surface of the condyle of the mandible, ventral to the articular surface Action: Raise the mandible and moves it rostrally. (allows ruminants to ruminate) Innervation: Mandibular n. of trigeminal n. (CN V) |
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What are the OIAI's of the digastricus m.?
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O: Paracondylar (jugular) process of the occipital bone
I: Ventromedial border of the mandible to the level of the canine tooth Action: Open the jaws Rostral belly - Innervated by the mandibular n. of trigeminal n. (CN V) Caudal belly - Innervated by the facial n. (CN VII) |
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Does the digastricus m. insert farther rostrally in the dog or cat?
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Cat - this is why cats can open their mouths wider.
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What function do the lingual muscles serve? (2)
What are the extrinsic and intrinsic muscles? What embryonic structure do they originate from? What are they innervated by? |
Mastication and swallowing.
Extrinsic: genioglossus, hyoglossus, styloglossus mm. Intrinsic: Proper lingual mm. They originate from somites and are all innervated by the hypoglossal n. |
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What are the OIAI's of the styloglossus m.?
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O: Stylohyoid bone
I: Tongue Action: Retract the tongue Innervation: Hypoglossal n. (CN XII) |
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What are the OIAI's of the hyoglossus m.?
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O: Ventrolateral surface of the basihyoid and adjoining end of the thyrohyoid bone
I: Root of the tongue Action: Retract and depress the tongue Innervation: Hypoglossal n. (CN XII) |
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What are the OIAI's of the genioglossus m.?
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O: Intermandibular symphysis and adjacent body of the mandible
I: Midventral surface of the tongue; also inserts on the basihyoid and ceratohyoid bones Action: Depress the tongue, Caudal fibers draw the tongue forward, Rostral fibers curl the tip of the tongue downward Innervation: Hypoglossal n. (CN XII) |
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How many heads does styloglossus m. have?
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Three heads – short, rostral, and long
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What are the actions and innervations of the proper lingual mm.?
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Action: Protrude tongue, Fine tongue movements
Innervation: Hypoglossal n. (CN XII) |
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What is a good way to find the lyssa?
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Find where the two genioglossus m. meet, and you'll find the lyssa.
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What general function does the hyoid apparatus serve as a whole?
What about the basihyoid, stylohyoid, and thyrohyoid bones specifically? |
The hyoid apparatus suspends the larynx.
The basihyoid anchors the tongues. The stylohyoid attaches the hyoid apparatus to the skull (mastoid process) by way of the tympanohyoid cartilage. The thyrohyoid bone attaches to the larynx by the thyroid cartilage. |
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What are considered the hyoid muscles (there are seven of them)?
What is their action and innervation? |
Sternohyoideus m.
Sternothyroideus m. - (does not attach to the hyoid apparatus) Thyrohyoideus m. Mylohyoideus m. Geniohyoideus m. Stylohyoideus m. Ceratohyoideus m. Function in swallowing, lapping, and retching Innervated by various cervical and cranial nn. |
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What is the OIAI of sternohyoideus m.?
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O: Manubrium and first costal cartilage
I: Basihyoid bone Action: Draw the basihyoid bone and tongue caudally Innervation: Ventral branches of cervical spinal nerves, +/- Hypoglossal n. (CN XII) |
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If you stuck a pin through the bottom of a dog's mouth into the tongue, what muscle layers would it go through?
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mylohyoideus, geniohyoideus, genioglossus, proper lingual mm.
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What are the OIAI's of sternothyroideus m.?
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O: Manubrium sterni and first costal cartilage
I: Lateral surface of the lamina of the thyroid cartilage Action: Draw the hyoid apparatus, larynx, and tongue caudally Innervation: Ventral branches of cervical spinal nerves |
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What are the OIAI's of thyrohyoideus m.?
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O: Lamina of the thyroid cartilage
I: Caudal border of the thyrohyoid bone Action: Draw the hyoid apparatus caudally and dorsally Innervation: Ventral branches of cervical spinal nerves, Hypoglossal n. (CN XII) |
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What are the OIAI's of mylohyoideus m.?
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O: Medial side of the body of the mandible
I: Median fibrous raphe and the basihyoid bone Action: Support the tongue, Raise the floor of the mouth, Draw the hyoid apparatus cranially Innervation: Mylohyoid n. which is a branch of the Mandibular n. of trigeminal n. (CN V) |
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What is the only muscle that raises the tongue?
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The mylohyoideus m. Does so by contracting to the sides and drawing the floor of the mouth upwards.
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What are the OIAI's of geniohyoideus m.?
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O: Adjacent to the mandibular symphysis (chin)
I: Basihyoid bone Action: Draw the hyoid apparatus cranially Innervation: Hypoglossal n. (CN XII) |
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What are the OIAI's of stylohyoideus m.?
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O: Tympanohyoid cartilage and the proximal end of the stylohyoid bone
I: Basihyoid bone laterally Action: Raise the basihyoid bone Innervation: Facial n. (CN VII) |
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Why does CN7 innervate stylohyoideus m.?
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Because the stylohyoid foramen is where the facial nerve exits the cranium.
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What are the attachments, actions, and innvervation of ceratohyoideus m.?
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Dog – Courses between the thyrohyoid and ceratohyoid (and sometimes epihyoid) bones
Cat – Courses between the thyrohyoid, ceratohyoid and epihyoid bones Action: Decreases the angle formed by the thyrohyoid and ceratohyoid bones, and certaohyoid and epihyoid Innervation: Glossopharyngeal n. (CN IX) |
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Describe the really intricate "swallowing simplified".
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Jaws close
Tongue is raised (by mylohyoideus m.) to move bolus into the oropharynx Soft palate is raised (by levator velli palatini m.), intrapharyngeal ostium closes, hyoid apparatus and larynx are drawn rostrally, glottis closes Pharyngeal constrictor muscles contract (Crico, hyopharyngeus and one thyropharyngeus mm.) to propel food into the esophagus |
