Anatomy Flashcards
How much cerebral spinal fluid is circulating in you?
400-500mls
Where is CSF produced?
Choroid plexus of the ventricles
How is CSF reabsorbed?
Through the arachnoid granulations and into the dural venous sinuses
Which level should you do a lumbar puncture?
L3/L4
L4/L5 IV disc
Where does the subarachnoid space end?
Ends at the level of the S2 part of the sacrum
spinal cord ends at L1/L2
Where is the 3rd ventricle?
In the midline within the diencephalon
Where are the left and lateral ventricles?
In the cerebral hemisphere
What does the cerebral aqueduct connect?
The cerebral aqueduct connects the 3rd and 4th ventricles in the midline
Where is the 4th ventricle?
In between the cerebellum and pons
Circulation of CSF
1) secreted by choroid plexus
2) Right & left ventricles
3) 3rd ventricle
4) cerebral aqueduct
5) 4th ventricle
6) Mainly subarachnoid space (but some passes into the central canal)
7) reabsorbed from subarachnoid space via the arachnoid granulations
8) into the dural venous sinuses
Sensory supply to the dura mater?
CNV
Raised ICP and optic nerve
Raised ICP will compress optic nerve
It will also compress central artery and vein of retina
Visual symptoms of optic nerve compression and raised ICP
transient visual obscurations (graying-out of vision), transient flickering blurring of vision constriction of the visual field decreased colour perception
Which nerve might be damaged by tentorial herniation?
Occulomoter nerve (CNIII)
Which nerve supplies 4 extra-ocular muscles and eyelid and innervates the sphincter of the pupil (controls constriction of the pupil) etc?
Oculomotor
What will the eye look like if the oculomotor nerve is damaged?
“down and out”
-loose/slowness of pupillary light reflex, dilated pupils, ptosis, eye turned inferolaterally
Name two of the septa produced when the dura mater folds?
Falx cerebri
Tentorium cerbelli
Somebody has diploplia when looking down and they can’t move their eye infermedially, which nerve is damaged?
The trochlear nerve (CNIV)
Damage to which nerve results in paralysis of the superior oblique muscle?
Trochlear nerve (CNIV)
Eye cannot move laterally in horizontal plane (medial deviation of eye)
Damage to the abducent nerve
If you fracture your zygoma, what tends to happen to it?
It rotates medially
A thick fascial sling that holds the eye just above the floor of the orbit
The suspensory ligament of the eye
What lies in the infraorbital canal?
The infraorbital NVB
-This can be damaged in a zygoma fractue resulting in general sensory deficit of the facial skin
Infraorbital nerve
Large branch of V2
Supraorbital nerve
Large branch of V1
What does the superior oblique muscle do?
Intorsion of the eye
Depression in adduction
Abduction (weak)
Head tilt
CNIV
Painful third nerve palsy
Aneursym!!
What does the medial longitudinal fasciculus do?
It connects CNIII, CNIV and CNVI and carries information about which ways the eye should move
Which nerves supply the angle of the mandible?
CN2, CN3 spinal nerves
CNV1 and the eye
The upper eye lid
Cornea
The conjunctivae
The skin at the root/bridge/tip of the nose
CNV2 and the eye
the skin of the lower eyelid
the skin over the maxilla
the skin of the ala of the nose
the skin/mucosa of the upper lip
CNV3 and the eye
supplies: the skin over the mandible and temporomandibular joint (apart from the angle of the mandible – supplied by C2,3 spinal nerves)
The blink (corneal reflex)
CNV1 –> tigeminal ganglion –> trigeminal nerve (CNV) –> pons
Action potentials –> CNVII –> eyelid part of orbicularis oculi
Which nerve innervates the anterior surface of the eye so that it is sensitive to touch?
CNV1
Ciliary body
Helps the lens to focus
Which level do the presynaptic sympathetic axons leave the CNS?
exit the spinal cord in T1 spinal nerve and then…
ascend within the sympathetic trunk and then…
synapse in the superior cervical sympathetic ganglion
Which artery carries sympathetic axons into the orbit?
The opthalmic artery (an intracranial branch of the internal carotid artery) carries sympathetic axons into the orbit
Stellate ganglion
Inferior cervical ganglia and the 1st thoracic ganglia sometimes fuse to form the Stellate ganglion
CNIII
eye
CNVII
Submandibular and sublingual salivary gland
CNIX
Parotid salivary gland
CNX
the vagus nerves supply parasympathetic axons to the organs of the neck/chest & abdomen as far as the midgut
Where do the sacral spinal nerves carry parasympathetic axons to?
The sacral spinal nerves carry parasympathetic axons to the hindgut, PELVIS and perinium
Which nerve carries presynaptic parasympathetic axons to the ciliary ganglion?
CNIII
(somatic) motor to superior (SR), medial (MR) & inferior rectus (IR) and inferior oblique (IO)
(somatic) motor to levator palpebrae superioris (LPS)
presynaptic parasympathetic axons to the ciliary ganglion
Where does CNIII connect with the CNS?
connects with the CNS near the midline at the junction between the midbrain and the pons
What do the ciliary nerves supply?
The ciliary nerves supply autonomic axons to control the diameter of the iris (&pupil) and the refractive shape of the lens
-The long ciliary nerve forms the first part of the afferent limb of the blink (corneal) reflex
Vestibuloocular reflex
- turns the eyes in the opposite direction to a head movement (to stabilise the gaze on an object during head movements)
- CNS connections between CN VIII & CNs III, IV & VI
Purpose of the suspensory ligament of the lens?
connects the circumferences of the lens & the ciliary body
How do sympathetic axons course from the CNS to the organs of the head region?
Cell body of presynaptic neurone in the CNS –>
ganglion of the cervical part of the sympathetic trunk –>
post synaptic axon to ganglion
Which level of the spinal cord do the presynaptic sympathetic axons leave from?
Leave from T1 spinal nerve and then ascend within sympathetic trunk and then synapse in the superior cervical sympathetic ganglion
..Then the postsynaptic sympathetic axons enter the internal and external carotid arteries etc…
Which nerve supplies the lacrimal gland?
CNVII
also supplies submandibular and sublingual salivary glands
Which nerve supplies the submandibular and sublingual salivary glands?
CNVII (also lacrimal gland)
Parasympathetic axons to hindgut, pelvis and perineum?
Sacral spinal nerves
parasympathetic axons to the organs of the neck/chest & abdomen as far as the midgut
Vagus nerve
(somatic) motor to superior (SR), medial (MR) & inferior rectus (IR) and inferior oblique (IO)
(somatic) motor to levator palpebrae superioris (LPS)
presynaptic parasympathetic axons to the ciliary ganglion
CNIII (the oculomoter nerves)
Which nerves pass through the superior orbital fissure?
Pneumonic : Lazy French Tarts Sit Nakedly In Anticipation
L: lacrimal nerve
F: frontal nerve (a branch of the ophthalmic nerve)
T: trochlear nerve (CN IV)
S: superior division of the oculomotor nerve (CN III)
N: nasociliary nerve (a branch of the ophthalmic nerve)
I: inferior division of the oculomotor nerve (CN III)
A: abducens nerve (CN VI)
Which nerve supplies the superior rectus and LPS?
Superior branch of CNIII
Which nerve supplies the lateral rectus?
CNVI
abducens
Which nerve supplies the MR, IR and IO? & Ciliary ganglion?
The inferior branch of CNIII
Where does CNIII connect with the CNS?
Junction between the pons and midbrain
What type of fibres does the long ciliary nerve contain?
Sympathetic motor and somatic sensory
-form the first part of the afferent limb of the blink reflex
What type of fibres are contained in the short ciliary nerve?
Parasympathetic and sympathetic
What do the ciliary nerves do?
Control the diameter of the iris (&pupil and the refractive shape of the lens)
The autonomic reflexes of the eye
-VESTIBULO-OCULAR REFLEX
-THE OCULOCARDIAC REFLEX
Maximal eyelid elevation
Pupillary light reflex
The accomodation reflex
Lacrimation
Pupillary light reflex
Adjusting light entry
The accomodation reflex
Far and near vision
The vestibulo-ocular reflex
ocular reflex
- turns the eyes in the opposite direction to a head movement (to stabilise the gaze on an object during head movements)
- CNS connections between CN VIII & CNs III, IV & VI
The oculocardiac reflex
reflex bradycardia in response to tension on the extraocular muscles or pressure on the eye
- CNS connections between CN V1 & CN X
Open eyes wider (get more light into the eye)
Focus on far objects
Emotional lacrimation
Sympathetic function
Allow orbicularis oculi to work?
Parasympathetic function
Get less light into the eye, focus on near objects, reflex lacrimation
-Allow orbiculairs oculi to work
Parasympathetic function
How do postsynaptic fibres reach levator palpebrae superioris?
levator palpebrae superioris via:
the superior cervical sympathetic ganglion
the internal carotid nerve the internal carotid plexus
axons carried on the ophthalmic artery…
and on its branches to the orbital structures
Non-physiologically dilated pupil?
Mydriatic pupil
The mobile insertion of the radially arranged dilator pupillae fibres?
Internal surface of the iri
The fixed origin of the radially arranged dilator pupillae fibres?
External circumference of the iris
part of Horner’s syndrome?
non-physiologically constricted pupil (miotic pupil)
Non-physiologically constricted pupil?
Miotic pupil
Drugs which might cause a pin point pupil?
Opiates
Fixed dilated pupil is a sign of which nerve pathology?
CNIII pathology
-inhibiting the pupillary constricting action of the parasympathetic axons in the ciliary nerve
Nerves in pupillary dilatation?
Dilator pupillae fibres
Nerves in pupillary constriction?
Sphincter pupillae fibres
Direct light reflex and consensual light reflex?
The sensory afferent limb of the reflex is the ipsilateral CNII (optic nerve)
The motor limb of the reflex is bilateral VIA CNsIII (OCULOMOTOR NERVES)
Where are the bodies of the parasympathetic CNIII axons located?
Edinger Westphal nucleus
What kind of muscle is contained in the levator palpebrae superioris?
Skeletal PLUS smooth muscle
The accommodation reflex —> response to the near
1) bilateral pupillary constriction (CNIII)
2) bilateral convergence (medial rotation of both eyes: CNIII)
3) Bilateral relaxation of the lens, the lens becomes spherical due to contraction of the ciliary muscles) (CNIII)
The ciliary muscles in far/near vision?
The ciliary muscles relax in far vision and contract in near vision
What do basal tears contain?
Lysosome
Nerves involved in reflex tears? (extra tears in response to mechanical or chemical stimulation)
(the ophthalmic nerve) from the cornea/conjunctiva
the efferent limb is parasympathetic axons originating from CN VII (the facial nerve)
How do CNVII axons reach the lacrimal gland?
branches of V1 and V2 carry the axons to the lacrimal gland
Primary headache syndrome
No obvious underlying cause for the headache
Secondary headache syndrome
Where the headache is a symptom of an underlying medical problem
