Case 20- Innervation and nose Flashcards

1
Q

The three branches of the trigeminal nerve

A
  • V1- Opthalmic- exits the skull through the superior orbital fissure
  • V2- Maxillary- exits the skull through the foramen rotundum
  • V3- Mandibular- exits the skull through the foramen ovale
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2
Q

V1- Opthalmic division of the Trigeminal nerve

A
  • Goes to the orbit
  • Main branches= Nasociliary, Lacrimal, Frontal
  • Supply= Proprioception, touch, temperature and pain sensation from the forehead, cornea, upper eyelid and dorsal nose
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3
Q

V2- Maxillary division of the Trigeminal nerve

A
  • Goes to the Pterygopalatine fossa
  • Main branches- Zygomatic, infraorbital, superior alveolar and the ganglionic branches
  • Supply= Proprioception, touch, temperature and pain sensation from the lateral nose, upper teeth, hard palate, upper cheek
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4
Q

V3- Mandibular division of the trigeminal nerve

A

Goes to the infratemporal fossa. Has an anterior (mainly motor) and posterior (mainly sensory) trunk

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5
Q

Anterior division of the V3 mandibular division of the Trigeminal nerve

A
  • Buccal nerve which gives sensory innervation to the anterior cheek
  • Nerve to the masseter, medial and lateral pterygoids, temporalis provides motor innervation to the muscles of mastication
  • Tensor tympani supplies the middle ear and the tensor veli palatini supplies the soft palate
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6
Q

Posterior division of the V3 mandibular division of the Trigeminal nerve

A
  • Inferior alveolar nerve gives sensation to the lower jaw, lower teeth, chin. Exits the mental foramen as the mental nerve, goes along the mandible
  • Auriculotemporal nerve gives sensation to the temple. Encircles the middle meningeal artery
  • Lingual nerve gives sensation to the anterior 2/3rds of the tongue
  • Nerve to Mylohyoid gives motor innervation to the mylohyoid and the anterior belly of the digastric.
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7
Q

Sensory distribution of the Trigeminal nerve

A
  • Trigeminal (CNV) overview= anterior 2/3rds of the head, dura matter and cranial blood vessels
  • Ophthalmic division (V1)= forehead, cornea, upper eyelid and dorsal nose
  • Maxillary division (V2)= Lateral nose, upper teeth, hard palate, upper cheek
  • Mandibular division (V3)- Lower jaw, lower teeth, chin, posterior cheek, temple, anterior 2/3rds of the tongue
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8
Q

Route of sensory innervation

A
  • Small sensory fibres pick up Proprioception, Temperature, Pain, Touch. This is then detected by the main branches V1, V2, V3
  • This is sent to the Trigeminal ganglion then the Trigeminal root and the Ventrolateral pons
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9
Q

Trigeminal sensory nucleus

A
  • Mesencephalic- midbrain (proprioception, muscles of mastication and the tempero mandibular joint)
  • Principle sensory- Pons (touch/pressure)
  • Spinal nucleus- pain, temp
  • The spinal nucleus continues inferiorly into the spinal cord, receives afferents from the CNV as well as afferents from CNVII, IX, X and cranial nerves
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10
Q

Sensory innervation of the face

A
  • Trigeminal nerve to the Trigeminal sensory nucleus
  • Then to the Trigeminothalamic tract (ventral). Second order sensory fibres from the trigeminal sensory nucleus decussate. Terminates in the ventral posteromedial (VPM) nucleus of the thalamus.
  • Then goes to the VPM nucleus thalamus and then the Somatosensory cortex
  • Some fibres follow the dorsal trigeminothalamic tract to the ipsilateral VPM of the thalamus.
  • Additional fibres go to the cerebellum and establishes several reflex connections
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11
Q

Course of the facial nerve

A

The facial nerve passes through the internal acoustic meatus into the petrous temporal. It passes through the facial canal and then exits the skull via the stylomastoid foramen. It gives off 3 branches and enters via the Parotid gland

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12
Q

Branches of the facial nerve

A

• Posterior auricular nerve- muscles around the ear and occipital portion of the occipitofrontalis
• Posterior belly of digastric
• Stylohyoid
Terminal branches of the facial nerve= Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical
Nmonic= To Zanzibar By Motor Car

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13
Q

Muscles of facial expression

A
  • Origin- facial bones
  • Insertion- skin and superficial fascia, no deep fascia in the face
  • Innervation- facial nerve
  • Embryology- 2nd pharyngeal arch
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14
Q

Muscles used to raise the eyebrows

A

Occipitofrontalis- frontalis portion and occipital portion connected by an aponeurosis. The Frontalis portion raises eyebrows

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15
Q

Muscles used to close the eyes tightly

A

Orbicularis Oculi, sphincter of the eyelids. Has two portions the Orbital part (tight closure), Palpebral part (gentle closure/blinking)

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16
Q

Muscles used to bare the teeth

A
  • Zygomaticus major
  • Zygomaticus minor
  • Lavator anguli oris
  • Levator labii superioris
  • Levator labii superioris alaqeque nasi
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17
Q

Muscles used to blow out cheeks with closed lips

A
  • Blow out cheeks- Buccinator is a muscle of the cheek which lies at deeper level than other facial muscles
  • Closed lips: Orbicularis Oris is a sphincter of the mouth which narrows the mouth and closes the lips (most contracted when whistling)
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18
Q

Buccinator muscle

A
  • Deeper to other facial muscles. Attachments:
  • Anterior- Orbicularis oris
  • Posteriorly- Pterygomandibular raphe
  • Superior: Maxillary alveolar margins
  • Inferior: mandibular alveolar margins
  • Parotid duct pierces buccinator
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19
Q

Muscles used in a Grimace

A

Plastyma: large, flat superficial muscle

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20
Q

Facial nerve

A
  • Facial motor nucleus has two components, superior and inferior
  • Bilateral due to superior portion of facial nucleus which innervates the forehead
  • Contralateral single innervation to the inferior portion which innervates the rest of the face
21
Q

LMN lesion of CNVII

A

Removes messages from both the superior and lower motor nucleus so the entire one side of face will be paralysed.

22
Q

UMN lesion of CNVII

A

Loss of fibres to the superior motor nucleus. You will still get fibres from the ipsilateral side so there is still movement in the forehead. Only loss of movement in the lower face on one side. Is forehead sparing

23
Q

Anatomical sieve of facial pain

A
  • Eye- orbital cellulitis, glaucoma
  • Upper respiratory- sinusitis, infections
  • Ear- Otitis media/externa
  • Teeth- Dental abscess
  • Bone- TMJ pain, mastoiditis
  • Parotid gland- mumps, calculi
  • Soft tissue- cell
24
Q

Surgical sieve of facial pain

A
  • Neoplastic
  • Headaches- cluster/migraines /overuse of medication
  • Vascular- Temporal arteritis
  • Neurological- trigeminal neuralgia, herpes zoster, post-herpetic neuralgia
  • Atypical or idiopathic- may be related to stress or depression
25
Q

Trigeminal neuralgia- facial pain

A
  • Pain in the region of 1 or more divisions of the trigeminal nerve, rare but most frequent facial neuralgia
  • Peaks in 50-60, increases with age
  • Site- unilateral, V2/V3 distribution
  • Character- episodic, severe, sharp, shock like pain. Lasts secs-mins
  • Precipitating symptoms- light tough, washing face, cold wind, eating
  • Associated symptoms- none
  • Impact of pain- decreased quality of life including weight loss, isolation and depression
  • Majority of cases are due to nerve compression which is usually vascular i.e. due to a sagging cerebellar artery
26
Q

Post herpetic neuralgia- facial pain

A
  • In 10% of patients with herpes zoster (shingles)
  • Site- distribution of shingles rash
  • Character- burning, aching, sometimes sharp
  • Precipitating symptoms- vesicular rash and pain
  • Associated symptoms- hypersensitivity over shingles scar
  • Impact of pain- can be debilitating, depression, insomnia and social isolation
27
Q

The nasal cavity

A
  • Piriform in shape
  • It is wider below and is covered superior by the nasal bones
  • The cavity is divided into a left and right side by the medial wall
  • There are respiratory and olfactory regions
28
Q

Boundaries of the nasal cavity- Anterior, Posterior, Roof, Floor

A
  • Anterior- Cartilaginous region of the nose
  • Posterior- Nasopharynx
  • Roof- Nasal bone, Frontal bone, Cribiform plate of the ethmoid bone, Sphenoid bone
  • Floor- Palatine process of the maxilla, Horizontal plate of the palatine bone
29
Q

Boundaries of the nasal cavity- Medial, Lateral wall

A
  • Medial wall- Perpendicular plate of the ethmoid bone, Nasal crest of the maxilla, Nasal crests of the palatine bone, Vomer, Septal cartilage
  • Lateral wall= Nasal bone, Frontal bone, Ethmoid bone (Superior/Middle conchae), Inferior conchae, Sphenoid bone, Nasal cartilage, Maxilla and the Palatine bone
30
Q

Nose- Conchae, Recesses

A

The Conchae are bony projections. The superior and middle conchae are connected. The recesses:
• Spheno-ethmoidal recess- above the superior conchae
• Superior meatus- between the superior and middle conchae
• Middle meatus- between the inferior and middle conchae
• Inferior meatus- below the inferior conchae

31
Q

Paranasal sinus’s

A

Sinuses are air filled spaces within the bones. The Paranasal sinuses- Maxillary, Sphenoidal, Frontal, Ethmoidal. They are bilateral structures. They are lined with mucous membranes.

32
Q

Functions of the Paransal sinus’s

A
• Warm and humidify inspired air
• Reduce the weight of the skull
• Speech-resonance of the voice
• Mucus production
They all drain into the lateral wall of the nasal cavity
33
Q

Frontal sinuses

A
  • Anterior structures
  • Lie between the two glabellae i.e. between the eyebrows
  • They sit on top of the nasal cavity
  • Drain into the hiatus semilunaris- part of the middle meatus
34
Q

Ethmoidal sinus

A
  • Relatively small
  • Also called the anterior, middle and posterior ethmoidal air cells
  • They sit on top of the nasal cavity
  • Close proximity to the orbit (between the eyes)
35
Q

Ethmoidal sinus drainage

A
  • Anterior -> Hiatus semilunaris
  • Middle -> Ethmoidal bulla
  • Posterior -> Superior meatus
36
Q

Maxillary sinus

A
  • Between the upper teeth and orbit (eye)
  • Lateral to the nasal cavity
  • Drains into the hiatus semilunaris
  • The drainage point is high on the medial wall of the sinus, normally infected due to the point of drainage as the maxillary sinus has to be full of mucus before it drains when the head is erect. When lying down it only drains medially so only the upper sinus drains
37
Q

Sphenoidal sinus

A
  • Located below the sella turcia (houses the pituitary gland)
  • It sits superoposteriorly to the nasal cavity (behind)
  • Drainage is to the sphenoethmoidal recess
38
Q

Blood supply to the nose

A
  • Internal Carotid -> Ophthalmic artery -> Anterior/Posterior Ethmoidal artery
  • External carotid -> Maxillary artery -> Sphenopalatine / Greater palatine artery
  • External carotid -> Facial artery -> Labial and nasal branches
39
Q

Blood supply to the lateral wall of the nose

A
  • Internal carotid -> Ophthalmic artery in the orbit (superior to nasal cavity) -> Anterior Ethmoidal and Posterior Ethmoidal
  • External carotid artery -> Maxillary artery -> Sphenopalatine artery (in the nasal cavity) and the Greater palatine artery (outside the nasal cavity before going through the maxilla to supply the nose)
  • External carotid -> Facial artery -> Lateral nasal artery (lateral)
  • Main arteries which supply the lateral wall of the nose= Anterior Ethmoidal, Posterior Ethmoidal, Sphenopalatine, Greater palatine and the Lateral nasal
40
Q

Blood supply to the medial wall of the nose- there are septal branches of:

A
  • Anterior ethmoidal artery
  • Posterior ethmoidal artery
  • Sphenopalatine artery
  • Greater palatine artery
  • Facial artery -> Superior labial artery (medial)
41
Q

Medial wall- Epistaxis

A
  • On the medial wall there is an anastomosis of most of the major arteries that supply the nose
  • It is known as Little’s are or Kiesselbach’s plexus
  • Common site of nose bleeds (Epistaxis)
42
Q

Nerve supply to the nose- Ophthalmic

A

Ophthalmic division VI (exits the skull via the superior orbital fissure-> Nasocillary branch -> Anterior ethmoidal

43
Q

Nerve supply to the nose- Maxillary division V2

A
  • Exits the skull via the foramen rotundum
  • Infraorbital fissure -> Infraorbital canal -> Infraorbital nerve and the Ant.Sup. alveolar nerve
  • Pterygopalatine ganglion (in the Pterygopalatine fossa) goes through the Sphenopalatine foramen to form the Nasopalatine nerve
  • Pterygopalatine ganglion goes through the Palatine canal to form the Greater palatine nerve
44
Q

Nerve supply to the medial wall

A
  • CNVI -> Nasocilary branch -> Anterior ethmoidal
  • CNV2 -> Nasal branches of the pterygopalatine ganglion via the sphenopalatine foramen -> Nasopalatine nerve
  • The Olfactory nerves go through the Cribiform plate
45
Q

Nerve supply to the Lateral wall of the nose

A
  • Top near the front of the head= Nasociliary branch (CNVI) -> Anterior ethmoidal -> External nasal branch.
  • Bottom near the front of the head= Infraorbital (CNV2) -> Nasal branch and branch of anterior superior alveolar nerve
  • Right (near the back of the head)= Pterygopalatine ganglion (CNV2) -> Posterior superior: from nasal branches via the sphenopalatine foramen -> Posterior inferior: from greater palatine nerves
46
Q

What does the ICA and ECA supply

A

Arteries supplying the scalp are branches of either the external carotid artery or the ophthalmic artery which is a branch of the internal carotid artery. The Internal Carotid artery supplies the brain, forehead and eyes.

47
Q

Venous drainage of the scalp and face

A
  • Supratrochlear vein and Supraorbital vein -> Anterior facial vein -> Common facial vein -> IJV
  • Superior division of the Maxillary vein and the Temporal vein -> Retromandibular vein -> Anterior division -> Common facial vein -> IJV
  • Superior division of the Maxillary vein and the Temporal vein -> Retromandibular vein -> Posterior division and the Posterior Auricular vein -> External jugular vein -> Subclavian vein
  • The Occipital veins drain into the Suboccipital plexus of veins
48
Q

Epistaxis- nose bleeds

A
  • Bimodal age distribution, 2-10 years and 50-80 years
  • 60-70% have had epistaxis once in lifetime- 10% sought medical help

Cause of Epistaxis
• Major trauma- nasal fracture involves major vessels
• Microtrauma- Little’s area of septum

49
Q

Anosmia

A

Caused by problems with the Olfactory nerve