Neuro Anatomy Flashcards
1
Q
What sensations are carried by the spinothalamic tract
A
Pain, temperature, crude touch
2
Q
Where are the spinothalamic tracts located
A
Anterior spinothalamic - anterior to ventral horn
Lateral spinothalamic - lateral to the grey matter
3
Q
What sensations are carried in the dorsal columns
A
Light touch, vibrations, joint position sense.
4
Q
What are the two dorsal column tracts
A
Fasciculus cunatus (lateral) Fasciculus gracilis (medial)
5
Q
What is the major descending motor pathway in the spine?
A
Lateral corticospinal (pyramidal tract)
6
Q
What is brown sequard syndrome and what is the distribution of neuronal symptoms
A
Hemisection if the spinal cord
Ipsilateral paralysis, loss of joint position, light touch and pressure/vibration
Contralateral loss of pain, temperature and crude touch
7
Q
What is the route of decent of the corticospinal tract
A
Cortex
Internal capsule
Medulla - decussates with majority crossing and descending as lateral corticospinal and minority (10%) remaining ipsilateral and descending as anterior corticospinal.
8
Q
What would be the effect of an infarct in the internal capsule
A
Contralateral paralysis
9
Q
What is the pathway of the spinothalamic tract
A
1st order neurones enter via the dorsal horn and synapse.
2nd order neurones decussate within a few spinal levels and ascend to the ventroposterior nucleus of the thalamus and synapse
3rd order neurones path to the somatosensory cortex
10
Q
What is the route of the dorsal column
A
First order neurones enter via the dorsal horn and ascend ipsilaterally in the Fasciculus cuneatus and gracilis and synapse in the medulla
Second order neurones decussate and ascend to the ventroposterior nuculus of the thalamus and synapse
Third order neurones pass to the somatosensory cortex.
11
Q
What is the blood supply to the spinal cord and where does it arise?
A
Anterior spinal artery arising from the vertebral arteries at foremen magnum
2 posterior spinal arteries arising from posterior inferior cerebellar artery at level of foremen magnum
12
Q
Which artery supplies most of the spinal cord
A
Anterior spinal artery
13
Q
What is the venous drainage of the spine
A
Posterior spinal vein
Posterior lateral spinal vein
Internal vertebral venous plexus in epidural space
14
Q
How is spinal arterial blood flow supported
Which is the key vessel in this
A
Radicular arteries arise from local vessels at each spinal level and feed the spinal arteries
The most important is the adamkiewicz artery from the lower thoracic upper segmental segmental arteries
15
Q
What nerves typically form the roots of the brachial plexus?
What variations are there?
A
Anterior primary rami of Spinal nerves C5-T1
Sometimes C4 or T2
16
Q
What are the segments of the brachial plexus termed
A
Roots - spinal nerves Trunks Divisions Cords Branches - end nerves
17
Q
What makes the brachial plexus vulnerable to injury
When are risks of injury?
A
It is superficial in the neck
Trauma, childbirth, GA,
18
Q
What are the trunks of the brachial plexus? Which roots form which?
Which nerve branch arises from which trunk?
A
Upper - c5+6
Middle - c7
Lower - c8+t1
Suprascapular nerve from the upper trunk
19
Q
What are the cords of the brachial plexus?
A
Lateral
Posterior
Medial
20
Q
Where does the radial nerve from from in the brachial plexus?
A
The posterior cord
21
Q
Where does the medial nerve arise in the brachial plexus
A
Combination of the medial and lateral cords
22
Q
Where does the ulnar nerve arise in the brachial plexus
A
From the medial cord
23
Q
Where does the musculocutanious nerve arise from in the brachial plexus
A
The lateral cord
24
Q
Where do the brachial plexus nerve roots emerge
A
Emerge from the intervertebral foremina then between scalenous anterior and saclenous medius. They pass inferior laterally across the first rib then posterior to the subclavian artery
25
What nerves arise directly from the brachial plexus roots
Nerve to scalene
Nerve to subclavian
Dorsal scapular nerve
Long thoracic nerve
26
Where are the brachial plexus divisions located
Anterior to the first rib posterior to the subclavian artery
27
Where are the brachial plexus divisions located
Beneath the clavicle and in the axilla around the axillary artery
28
What are the divisions of the brachial plexus (in relation to the trunks?)
Anterior and posterior divisions of each trunk
29
What divisions form the posterior cord
| What branches does it produce?
Posterior divisions of all three trunks
Axillary nerve
Deltoid nerves
Radial nerve
30
What divisions form the lateral cord of the brachial plexus
| What branches does it produce?
Anterior divisions of upper and middle trunks
Lateral pectoral nerve
Musculocutanious nerve
Part of median nerve
31
What divisions form the medial cord in the brachial plexus
| What branches does it give off
```
Anterior division of the lower trunk
Medial pectoral nerve
Median cutaneous nerve to arm and forearm
Ulnar nerve
Contributes to median nerve
```
32
Where does the axillary nerve arise? What does it supply? Action of the muscles?
Posterior cord of Brachial Plexus
Sensation over sergeants patch
Motor to deltoid and teres minor
Arm abduction and external rotation
33
Where does the radial nerve arise? What does it supply? Action of the muscles?
Posterior cord
Sensation - dorsum of thumb and lateral 1.5 fingers, branches to posterior arm and forearm
Motor - triceps, wrist extensors
Arm and wrist extension
34
What is the route of the radial nerve
From the posterior cord descends posteriomedially then anteriolaterally passing anterior to lateral epicondyle. Crosses acf forming a superficial sensory and deep motor branch.
Superficial branch descends under brachioradialis. Deep branch descends to posterior compartment
35
Where does the musculocutanious nerve arise? What does it supply? Action of the muscles?
Lateral cord
Innervates arm flexors
Gives off sensory branch - lateral cutaneous nerve of the forearm
36
Where does the median nerve arise? What does it supply? Action of the muscles?
Lateral and medial cords of the plexus
Innervates for arm flexors and muscles of the thenar eminence + 1st and 2nd lumbericles
Sensation to lateral palmar aspect of hand
37
Route of median nerve
From the combination of lateral and medial cords travels with the artery into the arm
Passes between forearm flexors giving off palmar branch before going through carpel tunnel into hand
38
Where does the ulnar nerve arise? What does it supply? Action of the muscles?
Medial cord
Innervates flexor carpi ulnaris and half of flexor digitorum profundus + hypothenar eminance, lateral lumbericles and adductor pollicis
Sensation to dorsal and palmer side of the medial aspect of the hand
39
Route of the ulnar nerve
From the medial cord
Posterior to medial epicondyle
Cubital tunnel
Descends anterior compartment of forearm
Enters and superficial to carpel tunnel in ulnar tunnel
40
What nerve provides sensation to the shoulder, what is its origin roots?
Supraclavicular (C3-4)
41
What nerve provides sensation to the proximal lateral upper arm, what is its origin roots?
superior lateral cutaneous (c5-6), branch of the axillary
42
What nerves provides sensation to the axilla and proximal medial upper arm , what is its origin roots? What nerve supplies below it and posteriorly
Intercostobrachial T2
| Posterior cutaneous nerve of the arm c5-8, radial branch
43
What nerveS provides sensation to the distal lateral upper arm and posteriolateral element of the forearm, what are their origin roots?
Inferior lateral cutaneous nerve of the arm
Posterior cutaneous nerve of the forearm
All C6-8, branches of the radial
44
What nerve provides sensation to the medial forearm what is its origin roots?
Medial cutaneous nerve of the forearm
| C8-t1
45
What nerve provides sensation to the lateral forearm, what is its origin roots?
Lateral cutaneous nerve of the forearm
C5-6
Musculocutanious
46
What nerves provides sensation to the hand?
```
Medial dorsal and palmer surfaces (1.5 digits)
Lateral palmer and dorsal fingertips (3.5 digits) median
Lateral dorsal (except fingertips) (3.5 digits) radial
```
47
What nerves form the lumbar plexus
| What contributes in 50%
L1-3 and part of L4
| In 50% a branch of t12 is involved
48
How is the femoral nerve formed in the lumbar plexus
The dorsal divisions of L2,3 and 4
49
What forms the lateral cutaneous nerve of the thigh in the lumbar plexus
Dorsal divisions of L2 and 3
50
What forms the obturator nerve in the lumbar plexus
Ventral divisions of L2,3, and 4
51
What nerves are formed by the higher lumbar plexus (l1/2 +/- t12j
Subcostal
Iliohypogastric
Ilioinguinal
Genitofemoral
52
Where do the femoral and lateral cutaneous nerve of the thigh emerge in relation to musculature
Posteriolateral edge of the psoas
53
What lumbar plexus nerves arise on the medial border of psoas major
Obturator and accessory obturator
54
How does the genitofemoral nerve emerge from the lumbar plexus with respect to musculature
Pieces psoas appearing anteriorly to it
55
What is the route of the femoral nerve
Emerges lateral psoas
Runs inferiorly between psoas and iliacus
Passes beneath inguinal ligament into thigh
Lies lateral to the femoral artery (separated by iliac fascia ie NOT in femoral sheath)
Divides into terminal branches
56
What muscles does the femoral nerve supply with which branches
What sensation does it provide
Anterior division:
Sartorius
Intermediate and medial cutaneous nerve of the thigh (anterior and medial thigh)
Posterior division
Quadriceps
Nerves to recuts femoris and vastus (medialis, intermedius, lateralis)
Saphenous nerve
57
What is the route of the saphenous nerve
| What does it supply
Arises in femoral triangle
Descends lateral to the femoral vessels
Enters adductor canal
Crosses vessels to lie on medial side in front of lower adductor Magnus
In the lower adductor canal pieces fascia lata between sartorius and gracilis becoming subcutaneous.
Passes along tibial side of leg with great saphenous vein
Descends with vein to great toe.
Sensation to skin to front and medial leg and proximal medial foot.
58
What is the route of the o trust or nerve
| What does it supply
Arises medial border psoas at pelvic brim
Enters thigh via obturator canal dividing into a+p branches
Anterior provides articular branches to the hip and communicates with medial cutaneous nerve to the leg and saphenous nerve forming the subsartorial plexus supplying medial thigh sensation
Posterior branch provides articular branch to knee
59
What connects the lumbar and sacral plexuses
| Origins and route
The lumbosacral trunk (L4/5)
| From medial psoas runs over pelvic brim joining S1
60
What nerve roots form sacral plexus
S1 to S5 and coccygeal nerve
61
What are the main nerves from sacral plexus and their origin roots
The posterior cutanious nerve of the thigh - S1-3
The nerve to quadratus femoris from anterior rami L4-S1
Sciatic nerve - L4 to S3
62
What nerve provides sensation to the posterior thigh, leg and peroneum?
Posterior cutanious nerve of the thigh
63
What does the nerve to quadratus femoris supply?
Articular branch to hip joint
| Inner action to quadratus femoris and gemellius inferior
64
Route of sciatic nerve
Leaves pelvis through greater thoracic foramen
Enters buttock under glut maximum
Runs midway between greater trochanter of femur and ischial tuberosity
Passes into back of thigh and runs down to apex of popliteal fossa between semitendinous and biceps femoris tendons
Here divides into 2 - tibial nerve and common peroneal nerve (though this division can occur anywhere from the sacral plexus to the popliteal fossa)
65
Where do the tibial and common peroneal nerves sit in respect to the popliteal vessels
Superficial
Tibial initially lateral before crossing medially
Common peroneal runs laterally
66
What does the tibial nerve supply
Muscles and skin of calf sole of foot and toes
67
What is the posterior anastomosis of the tibial and peroneal nerve called
Sural nerve
68
Route and supply of common peroneal nerve and innervations
Winds around neck of fibula
Pierces peroneous longus
Divides into deep and superficial branches
Deep follows anterior tibial vessels into leg supplying anterior compartment muscles
Superficial pierces deep fascia in lower third of leg to lie in subcut tissue in front of ankle supplies skin over anterior lower leg and dorsum of foot. Supplies muscles of lateral compartment
69
What are potential variations to nervous supply of the leg
The lumbar plexus recieves a branch from t12 or more rarely l5
The lateral cutaneous nerve may be absent or travel a different course
The femoral nerve may branch in the psoas muscle and also may lie between the femoral vessels
The saphenous nerve may pierce the sartorius
The obturator accessory nerve may be present
The sciatic nerve may pierce or pass above piriformis and can branch anywhere from plexus to lower third of thigh
The superficial peroneal nerve may be absent
70
Which nerve root supplies the groin
L1
71
Which nerve root supplies upper anterior thigh
L2
72
Which nerve root supplies anterior knee
L3
73
Where do L4 and 5 provide sensation
L5 lateral lower leg
| L4 medial lower leg
74
Where is s1 sensation in the lower limb
Big toe, lateral foot and posterior calf
75
What nerve root provides sensation to posterior knee and thigh
S2
76
What area do s3-5 provide sensation too
Concentric rings to buttocks
77
Which nerves provide sensation to dorsum of foot
Superficial peroneal to most, deep peroneal to 1st web space
78
Which nerves provide sensation to sole of foot
```
Branches of sciatic:
Medial planter to distal medial
Lateral planter to distal lateral
Sural to proximal lateral
Calcaneal to heel
```
Saphenous nerve (from femoral) over medial maleolus and medial edge of foot
79
What nerve provides sensation to medial calf
Saphenous
80
What 3 nerves provide sensation to lateral calf
Common peroneal via lateral cutaneous nerve of leg
Superficial peroneal
Sural
81
What nerves provide sensation to posterior thigh
Mainly posterior cutaneous nerve of the thigh
| Proximally dorsal rami
82
What nerves provide sensation to lateral thigh
Subcostal proximal banded by iliohypogastric posteriorly
| Lateral cutaneous of thigh
83
What nerves provide sensation to anterior thigh
Femoral branch of genitofemoral proximally
| Medial and intermediate cutaneous nerves of the thigh (from femoral)
84
What nerve provides inner thigh sensation
Ilioinguinal proxmally
| Obturator
85
Where do the cranial nerves arise
I + II from forebrain
| Rest from brainstorming:
86
Type (s,m,b?) and function of olfactory nerve
S
| Smell
87
Type (s,m,b?) and function of optic nerve
S
| Vision
88
Type (s,m,b?) and function of occulomotor nerve
M
| Pupil constriction, accommodation, eye movement (up, down and medically), eyelid opening
89
Type (s,m,b?) and function of trochelar nerve
M
| Moves eye down and in
90
Type (s,m,b?) and function of trigeminal nerve
B
Sensation to face
Muscles of mastication
91
Type (s,m,b?) and function of abducens nerve
M
| Moves eye laterally
92
Type (s,m,b?) and function of facial nerve
B
Muscles of face expression, closes eyelids
Anterior 2/3 taste
Lacrimal, nasal, palate, submandibular and sublingual glands
93
Type (s,m,b?) and function of vestubulococlear nerve
S
Hearing
Balance
94
Type (s,m,b?) and function of glossopharyngeal nerve
```
B
Sensation and taste to posterior 1/3 of tongue, posterior pharynx
Motor for swallowing
Carotid sinus
Parotid gland secretion
```
95
Type (s,m,b?) and function of vagus nerve
B
Parasympathetic to eye, heart, gut, lungs, larynx
Sensation to airway
Motor to vocal cords
96
Type (s,m,b?) and function of accessory nerve
M
| Sternocleidomastoid and trapezius (turn head lift shoulders)
97
Type (s,m,b?) and function of hypoglossal nerve
M
| Tongue muscles
98
What way would the uvula move on a unilateral glossopharyngeal or vagus nerve palsy
Away from the effected side
99
What way does the tongue move on a unilateral hypoglossal nerve palsy
Towards the effected side
100
Where does the optic nerve exit the skull
Optic canal
101
What exits the skull through the supraorbital foramen
Subraorbital nerve from ophthalmic division of CNV
102
What exits the skull through the superior orbital fissure?
CN III, IV, VI and branches of V (nasociliary, frontal and lacrimal branches of ophthalmic division)
103
What passes out of the inferior orbital fissure
Maxillary and zygomatic nerves from maxillary division of cnv, infra orbital blood vessels
104
What passes through zygomatic foramen
Zygomatic nerve from maxillary division of cnv and zygomatic artery
105
What passes through the infraorbital foramen
Infraorbital nerve from maxillary division cnv
106
What passes through the mental foramen
Mental nerve from mandibular division cnv
107
What makes up the outer fibrous layer of the eye
Sclera and cornea
108
What comprises the vascular/muscular layer of the eye
The choroid posteriorly becoming the ciliary bodies and iris anteriorly
109
What comprises the neural layer of the eye
The retina
110
What are the cornea and sclera made from? Why are they different?
Collagen
Sclera collagen is in many directions and thus is opaque
Cornea collagen is organised into regular lamina and thus is clear
111
What is the junction between the cornea and sclera called, where is it on external anatomy
The limbus
| Between the iris and the white of the eye.
112
What is the choroid of the eye
A vascular layer
Nourishes the retina
Contains melanin absorbing light and preventing reflection
113
What is the function of the ciliary body in the eye
To change the shape of the lens facilitating focusing
Contraction causes fattening of the lens allowing focus on near objects
They also secrete aqueous humour from ciliary processes
114
What is the function of the iris. How does it achieve this?
Control pupil size and thus light entry.
Radial muscle fibres (dilator pupillae) which contract to dilate the pupil
Circular muscle fibres (sphincter pupillae) which contract to constrict the pupil.
115
Where are cone cells located in the eye?
Fovea (posterior pole in centre of macula)
116
Why is it important to appreciate that the central retinal artery is an end artery
It supplies the innermost retina and occlusion (if not very transitory) will cause permanent visual loss.
117
What is the function of aqueous humour in the eye
Provide oxygen and nutrients to the corneal endothelium
118
What is the pathway of aqueous humour in the eye?
Produced by the ciliary processes of the ciliary muscles, flows between the lens and iris through the pupil into the anterior chamber before draining into the trabecular mesh work into the canal of Schlemm.
119
Where in the eye is the trabecular mesh work and canal of schlemm
What do they do?
Anterior chamber
| Drain aqueous humour
120
What is the function of the lens of the eye?
| How does it achieve this?
Focus light onto the retina via refraction of the rays
Changes in tension on the suspensory ligaments via changes in papillary muscle contraction (contracted muscle = lax ligaments). As ligaments become lax lens curvature increases (becoming fatter) focusing on near objects.
121
What is in the posterior chamber of the eye? What is its function?
Vitreous humour
| Provides structural integrity and refracts light
122
What raises the risk of retinal detachment
Myopia
Age
Diabetes
123
What nerve provides visual sensation
Optic
124
What nerve provides tactile sensation to the eye
Ciliary nerves as branches of the ophthalmic division of trigeminal nerve
125
What is the motor supply to the eye
| What does each nerve do
Occulomotor nerve - sup, inf and medial recuts, inferior oblique + levator palpebrae superioris
Trochlear nerve - superior oblique
Abducent nerve - lateral rectus
126
What is the autonomic supply to the eye?
Sympathetic - post ganglionic fibres of the cervical plexus travel with long ciliary nerve - stimulation causes pupil dilation
Parasympathetic - post ganglionic fibres from ciliary ganglion travel with short ciliary nerve - cause pupil constriction. Pre ganglionic fibres are from the occulomotor nerve
127
Describe pathway of light from external to the eye to occipital lobe
Light from temporal vision hits nasal retina, passes back in optic nerve to optic chiasm and decussate joining pathways carrying light from nasal vision that hits temporal retina and remain ipsolateral.
These pathways then continue as the optic tract (carrying data from ipsolateral nasal visual field and contralateral temporal visual field) to the lateral geniculate nucleus of the thalamus.
The pathways then continue as the occipital radiation terminating in the primary visual cortex.
128
Describe the pupillary reflex
Light on retina stimulates optic nerve. In lateral geniculate nucleus of thalamus some afferents pass onto mid brain and synapse in ipsi and contra lateral Edinger westphal nuclei. Efferents return via ciliary ganglion causing pupil constriction.
129
What area is damaged if:
Left direct and right consensual pupillary reflex is lost
Right direct and left consensual pupillary reflex are intact
Left optic nerve
130
What area is damaged if
Left direct pupillary reflex is lost, right consensual reflex is intact
Right direct pupillary reflex is intact, left consensual reflex is lost
Left occulomotor nerve
131
What is the blood supply to the eye?
Ophthalmic artery, a branch of internal carotid , supplies the eye. It supplies the extra ocular muscles and the central retinal artery that supplies the eye is one of its branches.
132
What is the venous drainage of the eye?
4 posterior vortex veins draining into the superior and inferior ophthalmic veins passing out of the superior orbital fissure into the cavernous sinus.
133
What is emmetropia
Normal vision uncorrected by glasses
134
How does the eye focus on a near object and why?
Contraction of ciliary muscle, more round lens meaning the more acute angled light from a near object is more bent focusing onto the retina.
135
What is myopia, why does it occur
| How is it corrected
Short sightedness
Long eyeball where distant objects focus infront of retina
Concave lens
136
What is hypermetropia, why does it occur
| Correction
Long sightedness
Short eyeball so near objects focus behind retina
Distant objects can focus on eyeball due to accommodate but with straining and ability to do so diminishes with age.
Convex lens
137
What is presbyopia
Due to ageing lens looses ability to accommodate
Near point gets further away so we have to hold objects further away to see them
Corrects with convex lens
138
What bones form the orbit - what parts?
```
Frontal - superior
Zygoma - inferiolateral
Maxilla - inferiomedial
Sphenoid - posteriolateral
Ethmoid - posteriomedial
Lacrimal - medial
Palatine - tiny posteriomedial fragment
```
139
What is a rough shape and volume of the orbit
Rough squat cone
| Around 30ml
140
How are the medial walls of the orbit aligned with respect to each other?
Parallel along the Sagittal plane
141
How are the lateral walls of the orbit aligned with respect to one and other
Around a 90degree angle
142
Where is the optic canal located in the orbit
Posterior at the apex
143
Where is the superior orbital notch
| What does it contain? What does it supply?
On superior orbital margin about 2cm from medial wall
| Superior orbital nerve supplying sensation to forehead
144
What may cause proptosis (protrusion of eyeball)?
Medial intervention (eg fluid from block)
Thyroid disease
Tumour
145
What can cause the eye to appear shrunken?
Age (periorbital fat loss)
| Atrophy (phtysis)
146
What are the medial and lateral junctions between the upper and lower eye lid called?
What os the gap between them called
M/L canthus
| Palpebral fissure
147
What are the internal and external continuations of the orbits periosteum
Internal - dura mater
| External - periosteum of skull
148
Where in the orbit is the lacrimal gland
Superior lateral to the eyeball behind the orbit rim
149
What layer covers the sclera and cuffs around penetrating structures such as muscles?
Clinical significance?
Tenons fascia
| Potential space for injection
150
Does Tenons fascia cover the cornea
No it starts at the limbus between the cornea and sclera
151
Where do the recus muscles of the eye originate?
The annulus of zinn - a fibrous ring surrounding the optic canal
152
What is the path of the recus muscles of the eye?
Widen forward from the annulus of zinc before inserting as a broad flat tendon on the sclera
153
What nerves supply the recus muscles
Superior medial and inferior - occulomotor
| Lateral - abducent
154
Where does the superior oblique muscle of the eye origionate, path and insert
Originates - sphenoid bone just superior and medial to annulus of zinn
Paths - anterior, superior and medial narrowing into a tendon before passing through a fibrocartilage ring called the trochlea, then turns posteriaterlally
Inserts beneath body of superior rectus behind the coronal equator of the eyeball
155
What innervates the superior oblique
The trochlear nerve
156
Origin, path and insertion of inferior oblique muscle of the eye
Origin - medial floor of of orbit near nasolacrimal canal
Path - passes laterally inferior to inferior rectus then curves superiorly
Inserts under lateral rectus behind the coronal equator of eye
157
What nerve innervates inferior rectus
Trochlear nerve
158
What eye movements would occur if the superior or inferior rectus muscles contracted without the corresponding oblique muscles
Why
Abduction of the eye (as well as looking up/down)
| The axis of the muscles is not on the sagital plane due to the angle of the orbit
159
What are 4 common methods of anaesthetising the eye
Topical
Sub-tenons block
Peribulbar block
Retrobulbar block
160
How is a sub-tenons eye block performed
Topicalise the eye
Dissection of tenons fascia
Insertion of blunt cannula into potential space
Injection - spread by hydrodissection
161
How is a peribulbar eye block performed?
Injection of la by sharp needle into the orbit (under the eyelids)
Avoids the muscle cone and relies on diffusion
162
How is a retrobulbar eye block performed?
| Advantage over peribulbar?
Longer Sharp needle into muscle cone
| Rapid onset
