The Skull Flashcards
Name the five major holes in the sphenoid bone
foramen rotundum foramen ovale foramen spinosum superior orbital fissure optic foramen
what passes through the foramen rotundum?
Vii (Maxillary branch)
.. it then goes through the pterygopalatine fossa.
what passes through the foramen ovale?
Viii (mandibular branch)
what passes through the foramen spinosum?
middle meningeal artery
what passes through the superior orbital fissure?
oculomotor nerve (III),
trochlear nerve (IV),
abducens (VI)
and lacrimal, frontal and nasociliary branches of ophthalmic nerve (V).
what passes through the optic foramen?
optic nerve (II)
what lies between the lesser sphenoid wing and the sphenoid body?
the optic foramen
what travels through the stylomastoid foramen?
stylomastoid artery and the facial nerve
what travels through the carotid canal? (2)
internal carotid artery
carotid plexus of nerves
What travels through the internal auditory meatus?
facial nerve (VII) vestibulochochlear nerve (VIII) labyrinthine artery
what is nerve II? Where does it exit + bone?
Optic nerve Optic foramen (sphenoid bone)
What is nerve III? Where does it exit + bone?
oculomotor nerve
superior orbital fissure
located between the greater and lesser sphenoid wings
What is nerve IV? Where does it exit + bone?
trochlear nerve
superior orbital fissure
located between the greater and lesser sphenoid wings
what are the three branches of the trigeminal nerve?
V1 - opthalmic nerve
V2 - Maxillary nerve
V3 - Mandibular nerve
What does the opthalmic division (V1) of the trigeminal nerve exit?
superior orbital fissure
Where does the maxillary division (V2) of the trigeminal nerve exit?
foramen rotundum
Where does the mandibular division (V3) of the trigeminal nerve exit?
foramen ovale
What are the three branches of the opthalmic (V1) trigeminal nerve?
lacrimal nerve
frontal nerve
nasociliary nerve
What does the trochlear nerve supply?
superior oblique eye muscle. It is a tiny thread-like nerve.
What is the VIII nerve?
vestibulochochlear nerve
What is the IX nerve?
glossopharyneal nerve
Where do nerves IX, X, XI all emerge from?
jugular foramen
What is the XII nerve? What does it innervate?
hypoglossal nerve.
Most of the tongue muscles (intrinsic and extrinsic)
What is the lingual nerve a branch of?
mandibular division of trigeminal
What does the brainstem consist of?
Midbrain
Pons
Medulla oblongata
What part of the brainstem does cranial nerve V orginate?
Pons
What does the abducens nerve innervate?
Lateral rectus muscle of the eye
What sensory input does the facial nerve have?
From the anterior 2/3 of the tongue (taste sensation).
What nerve is responsible for taste at the posterior 1/3 of the tongue?
IX – glossopharyngeal nerve
What nerve has a secretory function for the parotid gland?
IX – glossopharyngeal nerve
IX is primarily a sensory nerve. Where do the afferent fibres arise from?
- General sensation in the oropharynx, posterior 1/3 of tongue, eustachian tube, middle ear.
- taste buds of the pharynx and posterior 1/3 of tongue.
- chemoreceptors in the carotid body, and baroreceptors in the carotid sinus.
Name the four structures that pass through the jugular foramen.
Nerves IX - glossopharyngeal X - vagus XI - accessory and the jugular vein
What are the three branches of the opthalamic nerve?
lacrimal
frontal
nasociliary
what innervates the lacrimal gland?
zygomatic branch of the maxillary nerve
(contains the parasympathetic secetomotor fibres)
NB. maxillary branch also leads into the posterior superior alveolar nerve
what nerve joins up with the lacrimal nerve?
zygomaticotemporal branch of the maxillary nerve
what does the frontal nerve (branch of the opthalamic nerve) branch into ? (2)
supraorbital nerve
supratrochlear nerve
what do the supraorbital and supratrochlear nerves supply?
the orbital cavity
frontal air sinus
skin of the forehead and scalp
what does the maxillary branch of cranial nerve V supply?
the skin of the face and the side of the nose
what are the branches of the maxillary nerve? (6)
meningeal branch zygomatic branch ganglionic branch posterior superior alveolar nerve middle superior alveolar nerve anterior superior alveolar nerve
what are the functions of the facial nerve?
facial expression
lacrimation
salivation
taste sensation (anterior 2/3 of the tongue), floor of the mouth, and the palate.
Does the facial nerve have a motor or sensory root?
both
two nerves enter the internal auditory meatus of the petrous part of the temporal bone. Which are they?
vestibulocochlear nerve and facial nerve
what two nerves activate the salivary glands?
glossopharyngeal nerve (IX) facial nerve (VII)
what nerve supplies taste sensation to the anterior 2/3 of the tongue?
Facial nerve
what nerve supplies taste sensation to the posterior 1/3 of the tongue?
glossopharyngeal nerve
what happens when the chorda tympani is cut?
permanently reduces secretion of not only the submandibular salivary gland, but also the parotid gland.
what innervates the posterior belly of the digastric muscle?
the digastric branch of the facial nerve
where is the geniculate ganglion and which cranial nerve does it belong to?
petrous part of temporal bone
facial nerve
Is the facial nerve motor or sensory?
both
what are the names of the five motor branches of the facial nerve (VII)
temporal zygomatic buccal mandibular cervical (innervates neck muscles)
what are the extrinsic muscles of the tongue? (4)
styloglossus
palatoglossus
hyoglossus
genioglossus
Which nerve emerges from the parotid gland?
facial nerve
Orbicularis Oculi consists of two parts – what are they?
Palpebral part (loosely closed eyelid) Orbital part (Strongly closed eyelid)
What are corticospinal tracts?
Descending from the cortical motor centres to the spinal cord
What are corticobulbar/ nuclear tracts?
Descending from the cortical motor centres to the brainstem motor nuclei of the cranial nerves (III-XII)
Name three venous plexus in the brain
Cavernous sinus Pterygoid venous plexus (important one) Basilar plexus (sinus)
Aside from the muscles of facial expression, what other muscles does VII supply?
Posterior belly of the digastric muscle
Stylohyoid
Where does the common carotid artery bifurcate?
At the level of the upper border of the thyroid cartilage (C3-C4)
Cricoid cartilage - which level?
C6
Thyroid cartilage – which level
C4-C5
What structure does the internal carotid artery pass though?
Carotid canal in the temporal bone (no bifurcations in the neck)
What are the layers of the scalp?
S: Skin C: connective tissue A: Aponeurosis L: Loose Areolar tissue P: Periosteum (pericranium)
What does the frontal nerve of V1 (trigeminal - ophthalmic branch) divide into? (2)
Supratrochlear nerve
Supraorbital nerve
What is the lacrimal nerve a branch from?
Ophthalmic branch of the trigeminal nerve
What structures pass through the cavernous sinus?
ophthalmic division of the trigeminal nerve (Vi) maxillary division (Vii) oculomotor nerve (III) trochlear nerve (IV) abducens nerve (VI) - free within substance of sinus internal carotid artery
What are the primary functions of the vagus nerve?
supplies motor parasympathetic fibers to all the organs except the suprarenal (adrenal) glands, from the neck down to the second segment of the transverse colon.
what is ptosis?
a weak, droopy eyelid
what is miosis?
a constricted pupil
what is the name of the muscle(s) that raises the upper eyelid?
levator palpebrae superioris (striated muscle)
superior tarsal muscle (smooth muscle)
what innervates the levator palpebrae superioris?
oculomotor nerve, and the sympathetic n.s., for the superior tarsal muscle.
what nerve passes UPWARDS through the foramen magnum?
spinal aspect of the accessory nerve
(it then leaves via the jugular foramen)
spinal cord
vertebral artery
characteristics of foetal skull (5)
no mastoid process
only a ring of bone around the outer margin of the middle ear cavity
mandible is unfused at the symphysis
fontanelles present
face is very small because teeth not erupted + air sinuses not developed
why is there only mild ptosis with Horner’s syndrome?
Because the sympathetics only supply the smooth muscle in the superior tarsal muscle that supplies the superior tarsal plate..
why does a lesion at cranial nerve III cause more severe ptosis?
Because it supplies the striated muscle in the levator palpabrae superioris.
what is nystagmus?
involuntary jerky movement of the eyes
which way does the superior oblique move the eye?
Down and Out
BUT - tested by looking INWARDS and DOWNWARDS. This negates the effect of the lateral rectus and the inferior rectus.
what is special about the cricothyroid muscle? (3)
- only muscle that tightens the vocal cords.
- only muscle that lies on the outside of the larynx.
- has a different nerve supply to the rest of the intrinsic muscles (external laryngeal branch of the superior laryngeal nerve).
what nerve supplies most intrinsic muscles of the larynx?
recurrent laryngeal nerve
Somatic sensation (NOT taste) of the anterior 2/3 of the tongue belongs to which nerve? (also floor of the mouth)
The Lingual nerve.
This is a branch of the mandibular division of the trigeminal nerve.
What does the Lingual nerve also carry? (mandibular branch of trigeminal nerve)
the chorda tympani hitch hikes onto the this nerve and this is part of the facial nerve.
Thus, the lingual nerve carries both somatic and taste sensation.
what does the buccinator do, and what innervation?
compresses the cheeks during mastication.
not strictly a muscle of mastication, innervation is the facial nerve.
what three muscles arise from the styloid process?
styloglossus
stylohyoid
stylopharyngeus
what is the nerve supply to the muscles of the pharynx?
the cranial branch of XI accessory nerve that travels together with the vagus
what is the sensory nerve supply to the nasopharynx?
maxillary branch of cranial nerve V.
Similar to most of nose.
what is the sensory nerve supply to the oropharynx?
glossopharyngeal nerve (IX). Similar to back of tongue
what is the sensory nerve supply to the larnygeal part of the pharynx?
internal and recurrent branches of the vagus.
just like the larynx
what is the facial canal?
Z-shaped canal running through the temporal bone from the internal acoustic meatus to the stylomastoid foramen
name three major branches of the external carotid artery
superior thyroid (c4/ bifurcation level) facial artery (anterior to masseter muscle) lingual artery (travels behind superior aspect of larynx?)
name two terminal branches of the external carotid artery
maxillary
superficial termporal arteries
nb. these arteries divide off the external carotid artery inferior to zygomatic arch.
what artery arises from the same level as the superior thyroid artery but is posterior?
ascending pharyngeal artery
what artery arises from the same level as the facial artery but is posterior?
occipital artery
what are the boundaries of the posterior triangle?
What is the post important structure found there?
s.c.m. muscle
middle 1/3 of clavicle
trapezius
Accessory nerve
what is the anterior triangle of the neck subdivided into?
submandibular triangle
carotid triangle
muscular triangle
three types of intrinsic tongue muscles - what are they?
longitudinal
transverse
vertical fibres
All muscles of the tongue are supplied by the hypoglossal nerve, except for …… which is supplied by the ….
palatoglossus muscle Vagus nerve (motor accessory fibres from XI)
what is the structure that divides the anterior 2/3 of the tongue from the posterior?
sulcus terminalis
what nerve supplies motor innervation to all muscles of the larynx?
vagus nerve