The Mouth and Face 3 Flashcards

1
Q

How does the hypoglossal nerve gain the interval between internal carotid artery and internal jugular vein?

A

It has to swing outwards very markedly.

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2
Q

What happens to the hypoglossal nerve at the level of the hyoid bone?

A

It loops around the external carotid artery at the point at which the occipital branch and the lingual branch of the external carotid artery arise.

It therefore comes to run very closely with the lingual artery just below the lower border of the digastric muscle.

In this part of its course, this nerve is quite superficial.

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3
Q

Which muscle does the hypoglossus nerve run?

A

It passes onto the outer aspect of the hypoglossus muscle where the muscle breaks up into twigs which supply all of the tongue musculature.

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4
Q

Where does the lingual artery lie in relation to the hypoglossus?

A

It passes deep to the hypoglossus at its posterior border.

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5
Q

What fibres hitch hike along the hypoglossal nerve for part of its course?

A

This nerve carries fibres from cervical segment C1 which hitch hike along it to the thyrohyoid and the geniohyoid.

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6
Q

What nerve is the lingual nerve a branch of?

A

It is a particularly important branch of the mandibular division of the trigeminal nerve.

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7
Q

Describe the path of the lingual nerve.

A
  • first lies on the lateral surface of the medial pterygoid muscle
  • then lies against the mandible next to the roots of the last molar tooth
  • from the mandible it enters the floor of the mouth with the styloglossus muscle
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8
Q

What is the lingual nerve the general sensory nerve to?

A

It is the general sensory nerve to the anterior 2/3rds of the tongue and the floor of the mouth, as well as to the gingivae on the lingual aspect of the teeth and alveolar bone of the mandible.

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9
Q

Where does the lingual nerve carry taste sensation from?

A

It carries special taste sensation from the anterior 2/3rds of the tongue.

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10
Q

Where does the lingual nerve carry parasympathetic neurones to?

A

Carries parasympathetic neurones to the submandibular and the sublingual glands.

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11
Q

How do special taste fibres leave the tongue?

A

They leave the tongue in the lingual nerve and pass back through the chorda tympani, which is a branch of the facial nerve, to go and join the facial nerve in the middle ear cavity.

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12
Q

How do parasympathetic preganglionic neurones that are destined for the submandibular and the sublingual glands leave the brain?

A

They leave the brain in the 7th cranial nerve and then they also go to the chorda tympani.

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13
Q

What is the path of the parasympathetic preganglionic nerves after they leave the chorda tympani?

A

They travel down the chorda tympani and join the lingual nerve but then they pass to their ganglion which is the submandibular ganglion which hangs from the lingual nerve.

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14
Q

Where does the submandibular ganglion lie?

A

It lies between the submandibular gland and the hypoglossus.

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15
Q

What happens within the submandibular ganglion?

A

Pre ganglionic fibres synapse.

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16
Q

Where do the postganglionic parasympathetic neurones go from from the submandibular ganglion?

A
  • salivary glands
  • mucous glands of the floor of the mouth
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17
Q

What is the course of the sympathetic fibres that pass through the submandibular ganglion?

A

The sympathetic fibres pass through the ganglion directly without synapsing and these are also involved in the secretomotor activity of the salivary and the mucous glands, and they are also vasoconstrictor in function.

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18
Q

What must we remove to see the deep muscles?

A

We must remove the

  • hypoglossus
  • submandibular gland
  • sublingual gland
  • 2 nerves
    • lingual nerve
    • hypoglossal nerve
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19
Q

What are the 2 deep muscles called?

A

These are called the genioglossus and the geniohyoid muscles.

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20
Q

What are the functions of these deep muscles (nonspecific)?

A

One of them moves the hyoid bone and one of them moves the tongue.

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21
Q

Where do the genioglossus and the geniohyoid muscles arise from?

A

They arise from little bony spines called the genial spines.

22
Q

Where are the genial spines?

A

These are on the inner aspect of the mandible near the midline.

23
Q

What is the path of the geniohyoid muscle?

A

It arises from the inside of the mandible at the front near the midline and it passes back to insert into the body of the hyoid bone.

24
Q

What is the position of the geniohyoid muscle advantageous for?

A

It is advantageous to pull the hyoid upwards and forwards.

25
Q

What is the forward movement of the hyoid bone, produced by the geniohyoid muscle, opposed by?

A

It is opposed by the stylohyoid muscle.

26
Q

What is the upward movement of the hyoid bone, produced by the geniohyoid muscle, opposed by?

A

It is opposed by the infrahyoid strap muscles.

27
Q

What is the nerve supply to the geniohyoid muscle?

A

It is supplied by the fibres from the cervical segment that have hitch hiked along the hypoglossal nerve.

28
Q

What does the genioglossus form?

A

This forms a great deal of the bulk of the tongue.

29
Q

Where does the genioglossus muscle arise from?

A

It arises from the inside of the mandible near the midline.

30
Q

Describe what happens to the genioglossus while passing from its point of origin?

A

It spreads widely to insert into the whole length of the undersurface of the tongue.

31
Q

What is the nerve supply to the genioglossus?

A

It is supplied by the hypoglossal nerve, like all of the tongue muscles.

32
Q

Where do the extrinsic muscles of the tongue take origin from?

A

They take origin from bone.

33
Q

What is the function of the extrinsic muscles of the tongue?

A

To move the tongue as a whole.

34
Q

What is the function of the intrinsic muscles of the tongue?

A

They alter the shape of the tongue.

35
Q

What are the extrinsic muscles of the tongue?

A
  • styloglossus
  • palatoglossus
  • hypoglossus
  • genioglossus
36
Q

What do the intrinsic muscles of the tongue form in the body of the tongue?

A

They form a weave of longitudinal, transverse and vertical muscles fibres in the substance of the body of the tongue.

37
Q

What passes between the muscle fibres of the intrinsic muscles of the tongue?

A

Fibrous septa pass between these fibres and they form a flexible framework for the dorsum and the tip of the tongue.

38
Q

What is the nerve supply to the intrinsic muscles of the tongue?

A

Except for the palatoglossus muscles, they are supplied by the hypoglossal nerve (12th cranial nerve).

39
Q

How can we detect lesions of the hypoglossal nerve?

A

By asking the patient to stick their tongue out. If there is damage to the hypoglossal nerve then the tongue will swing over to the side of the lesion.

40
Q

What does the structures and innervation of the tongue represent?

A

It represents its developmental history.

41
Q

What is the division between the anterior 2/3 and posterior 1/3 of the tongue marked by?

A

It is marked on the dorsum of the tongue by a faint V shaped line called the sulcus termin​alis.

42
Q

What is the foramen caecum?

A

At the apex of the V of the sulcus terminalis in the midline, there is a shallow pit called the foramen caecum.

43
Q

What does the foramen caecum represent?

A

It represents the origin of the thyroid gland in the floor of the primitive pharynx.

44
Q

What is the gustatory epithelium?

A

The mucous membrane of the tongue is firmly adherent to its surface and the mucous membrane is called the gustatory epithelium.

45
Q

What is the frenulum?

A

This is a median fold of mucous membrane beneath the tip of the tongue.

46
Q

What does the frenulum separate?

A

It separates the 2 submandibular orifices.

47
Q

What is the median glossoepiglottic fold?

A

Posteriorly there is a midline fold of mucous membrane that passes back to the epiglottis.

48
Q

What does the median epiglottic fold separate?

A

It separates the 2 valleculae.

49
Q

What does the gustatory mucous membrane of the anterior 2/3 of the tongue contain?

A

It contains 4 types of papillae:

  • circumvallate
  • fungiform
  • filiform
  • foliate
50
Q

Describe the cerumvallate papillae?

A
  • These are quite large and notable.
  • They are arranged along the sulcus terminalis
  • Each is 2mm diameter