Case 5 anatomy Flashcards
the cribriform plate is part of which bone?
ethmoid bone
where does the optic nerve terminate?
in the lateral geniculate nucleus
where does the trochlear nerve arise from?
the dorsal surface of the midbrain
describe the course of the trochlear nerve
- Arises from the dorsal surface of the midbrain
- Passes anteriorly around the brainstem
- Pierces the dura mater at the margin of the tentorium cerebelli
- Passes in the lateral wall of the cavernous sinus
- Exits the skull through the superior orbital fissure and enters the orbit
which nerves arise from the midbrain?
- oculomotor
- trochlear
which nerves arise from the pons?
trigeminal
where do you find the trigeminal ganglion?
on the anterior surface of the petrous temporal bone
describe the course of the ophthalmic branch
- Passes forwards in the lateral cavernous sinus
* Divides into three branches which exit the skull through the superior orbital fissure to enter the orbit
where does the maxillary branch exit the skull? where does it go next?
through the foramen rotundum
- Enters the pterygopalatine fossa
- It gives off numerous branches within the pterygopalatine fossa
what’s the terminal branch of the maxillary nerve? where does it go?
Its terminal branch, the infraorbital nerve, exits the fossa through the inferior orbital fissure to enter the orbit
where does the mandibular branch exit the skull?
through the foramen ovale
where does the manibular branch give off its branches?
in the infratemporal fossa
what are the branches of the ophthalmic branch?
- Frontal
- Nasociliary
- Lacrimal
(FML)
what are the branches of the maxillary branch?
- Infraorbital
- Zygomatic
- Nasopalatine
- Greater palatine
- Lesser palatine
- Anterior superior alveolar
- Middle superior alveolar
- Posterior superior alveolar
what are the branches of the mandibular branch?
- Meningeal
- Deep temporal
- Auriculotemporal
- Masseteric
- Nerve to medial pterygoid
- Buccal
- Incisive
- Lingual
- Inferior alveolar
- Mental
- Nerve to mylohyoid
what is the sensory distribution of the different branches of the trigeminal nerve?
- Ophthalmic = forehead and backwards, eyebrows and medial part of nose
- Maxillary = up to forehead, over cheek bone, lateral parts of nose
- Mandibular = up to forehead, across side of cheeks, over chin
what are the muscles that the mandibular division provides innervation to?
8 muscles:
• Four muscles are the muscles of mastication; masseter, temporalis, medial pterygoid and lateral pterygoid
• Anterior belly of digastric, mylohyoid, tensor tympani, tensor veli palatini are also innervated by mandibular nerve
what does the tensor veli palatini do?
tenses the soft palate
what innervates the stapedius muscle?
facial nerve
which nerves arise from the pons-medullary junction?
abducent, facial and glossopharyngeal nerves
describe the pathway of the abducent nerve
- Arises from the brain stem at the pons-medullary junction
- Traverse the pontine cistern of the subarachnoid space
- Pierces the dura mater at the clivus
- Passes through the cavernous sinus parallel to the internal carotid artery
- Exits the skull through the superior orbital fissure and enters the orbit
which cranial nerve runs parallel to the internal carotid artery in the cavernous sinus?
abducent nerve
what are the functions of the facial nerve?
- motor innervation to the muscles of facial expression
- taste sensation from the anterior 2/3 of the tongue
- cutaneous sensation for the external ear
- parasympathetic innervation to the nasal glands, lacrimal gland, and submandibular & sublingual salivary glands
which cranial nerve nuclei is the facial nerve associated with?
4
• Trigeminal – the nucleus where facial nerve fibres carrying general sensation terminate
• Rostral end of nucleus solitarius – the nucleus where facial nerve fibres carrying taste sensation terminate
• Facial motor nucleus – the nucleus where lower motor neurones supplying the muscles of facial expression arise
• Superior salivatory nucleus – the nucleus where preganglionic parasympathetic fibres to the lacrimal, nasal, submandibular and sublingual glands arise
what is the facial nerve composed of?
the facial nerve proper and the nervus intermedius:
- The facial nerve proper is the somatic motor component which supplies the muscles of facial expression
- The nervus intermedius is composed of the sensory and parasympathetic components
what ganglion is associated with the facial nerve?
geniculate nucleus
through what does the facial nerve leave the skull? (which fibres?)
stylomastoid foramen - general sensory and motor fibres
describe the course of the facial nerve and branches that it gives off
- Passes through the posterior cranial fossa
- Enters the petrous temporal bone through the internal auditory meatus
- As it passes through the facial canal it swells to form the geniculate ganglion
- The greater petrosal nerve and the nerves to the stapedius and the chorda tympani are given off
- The general sensory and motor fibres exit the skull through the stylomastoid foramen
what does the greater petrosal nerve do? what fibres does it transmit?
- Transmits general visceral efferent fibres? (superior salivatory nucleus)
- Provides presynaptic fibres to the pterygopalatine ganglion
- Postganglionic parasympathetic fibres from the pterygopalatine ganglion provide secretomotor innervation to the lacrimal and nasal glands
nerve to stapedius
- what fibres does it transmit
- what might a lesion lead to
- Transmits special visceral efferent fibres (facial motor nucleus)
- A lesion of the nerve to stapedius may result in hyperacusis (increased sensitivity to certain frequencies and volume ranges of sound)
chorda tympani
- what’s its course
- what fibres does it transmit
- Transmits both special visceral afferent fibres and general visceral efferent fibres
- Exits the tympanic cavity through the petrotympanic fissure
- Joins the lingual nerve in the infratemporal fossa
- Provides parasympathetic innervation to the submandibular and sublingual glands
what branches does the facial nerve give off after leaving the stylomastoid foramen?
- As the facial nerve exits the stylomastoid foramen it gives of general sensory fibres to supply a small area of skin around the concha of the auricle
- Close to the stylomastoid foramen it gives off motor branches to the stylohyoid muscle and the posterior belly of the digastric
- The remainder of the nerve passes forward to enter the substance of the parotid gland where it divides into the five main motor branches; temporal, zygomatic, buccal, mandibular, cervical
what fibres does the vestibulocochlear nerve transmit?
special somatic afferent fibres
what are the functions of the glossopharyngeal nerve?
- initiates the swallowing reflex in response to general stimulation of the oropharynx
- transmits both general and taste sensation from the posterior 1/3 of the tongue
- forms the afferent limb of the gag reflex
- transmits parasympathetic fibres to the parotid salivary glands
- provides motor innervation to the stylopharyngeus muscle
what are the cranial nerve nuclei that the glossopharygneal nerve are associated with?
5
• Trigeminal nucleus – the nucleus where glossopharyngeal nerve fibres carrying general sensation terminate
• Nucleus solitarius – the nucleus where visceral afferent fibres from the carotid sinus and bodies terminate
• Rostral end of nucleus solitarius – the nucleus where visceral afferent fibres carrying taste sensation terminate
• Inferior salivatory nucleus – the nucleus where preganglionic parasympathetic fibres to the parotid gland arise from
• Nucleus ambiguus – the nucleus where lower motor neurones supplying the stylopharyngeus arise from
which cranial nerves arise from the medulla?
glossopharyngeal, vagus, accessory (not spinal) and hypoglossal nerves
where does the glossopharyngeal nerve arise?
lateral aspect of the medulla between the olive and inferior cerebellar peduncle
describe the course of the glossopharygneal nerve
- Arises from the lateral aspect of the medulla between the olive and inferior cerebellar peduncle
- Passes through the posterior cranial fossa
- Exits the skull at the jugular foramen
- Follows the course of the stylopharyngeus muscle
- Passes between the superior and middle constrictor muscles to enter the oropharynx
which nerves pass though the jugular foramen?
glossopharyngeal, vagus and accessory nerves
where are the nerve cell bodies of the primary order neurons of the glossopharygneal nerve?
superior and inferior ganglia of the glossopharyngeal nerve are located near the jugular foramen
what’s the ganglion for the parotid gland?
otic ganglion
what are the functions of the vagus nerve?
- pharyngeal branches supply all the muscles of the soft palate except the tensor veli palatini and all the muscles of the pharynx except the stylopharyngeus
- laryngeal branches supply all the muscles of the larynx and provides sensory innervation to the larynx
- it’s therefore essential for the protective cough reflex
- provides parasympathetic innervation to the organs of the thorax and abdomen and conveys visceral afferent information from these regions
what are the muscles of the soft palate?
- tensor veli palatini
- levator veli palatini
- palatoglossus
- palatopharyngeus
- musculus uvulae
what are the cranial nerve nuclei that the vagus nerve is associated?
- Trigeminal nucleus – the nucleus where vagal fibres carrying general sensation terminate
- Nucleus solitarius – the nucleus where visceral afferent fibres from the thorax and abdomen terminate
- Rostral end of nucleus solitarius – the nucleus where vagal fibres carrying taste sensation terminate
- Dorsal motor nucleus of the vagus – the nucleus where preganglionic parasympathetic fibres to the organs of the abdomen and thorax arise from
- Nucleus ambiguus – the nucleus where lower motor neurons suppling the muscles of the soft palate, pharynx and larynx arise
describe the course of the vagus nerve
- Arises from the lateral aspect of the medulla between the olive and inferior cerebellar peduncle
- Passes through the posterior cranial fossa
- Exits the skull at the jugular foramen
- Passes through the neck in the carotid sheath
- Passes through the mediastinum behind the root of the lung
- Enters the abdomen through the oesophageal hiatus of the diaphragm