Overview Of Nervous System & Spinal Cord External Features & Scalp

Question 1

Describe the CNS embryological classifiction (with mentioning cavity of each)

Answer 1

Forebrain (prosencephlon): median diencephalon (3rd ventricle) + 2 telencephalons (2 lateral ventricles)
Midbrain (mesencaphalon, cerebral aqueduct of Sylvius)
Hind brain (rhombencephalon, 4th ventricle)

Question 2

Describe arrangement of grey and white matter throughout CNS

Answer 2

Spinal chord, white matter surrounds H-shaped grey matter
Brain stem, scattered nuclei of grey matter in white matter
Cerebral hemispheres, deep nuclei & on the surface forming cortex

Question 3

State functions of the CNS

Answer 3

1. Maintenance of homeostasis
2. Recieving and integrating sensory information
3. Integrating information
4. Controlling muscles and glands
5. Maintaining mental activity

Question 4

Describe site & length of spinal cord

Answer 4

S: occupies upper 2/3 of vertebral column, begins a atlas vertebra as continuation of medulla oblongata, ends at level of disc between L1&2 at birth it ends at L3.
45 cm

Question 5

Mention the enlargements of the spinal chord

Answer 5

1. Cervical enlargement gives origin to brachial plexus (C4 to T1)
2. Lumbar enlargement gives origin to lumbar and sacral plexuses (L1 to S4)

Question 6

The tapering lower end if s.c. Is called …., a filament of … mater extends from its end then attaches to …., this is called….

Answer 6

Conus medullaris
Pia
Back of coccyx
Filum terminale

Question 7

…..&…..divide the spinal cord into rt & lt halves

Answer 7

Anterior median fissure
Posterior median septum

Question 8

Locate pseudounipolar neurons

Answer 8

In posterior root ganglion carried by posterior root of spinal nerves

Question 9

All ant rami form plexuses except ……

Answer 9

The 12 thoracic

Question 10

Mention the ant rami sending white ramus communicants

Answer 10

12 thoracic + upper 2 lumbar

Question 11

Both rami of …are purely motor

Answer 11

C1

Question 12

Write short note on recurrent meningeal nerve

Answer 12

It is the first branch of mixed spinal nerve after leaving IVF & re-enters through it to supply dura, periosteum, b.v. & IV discs. Plays a role in referred pain and occipital headache

Question 13

All sacral & coccygeal segments are located opposite….

Answer 13

L1

Question 14

Describe direction of spinal nerves

Answer 14

C1-2, horizontal
C3-T12, oblique
L1-Co, vertical

Question 15

Describe exit of spinal nerves from the vertebral canal

Answer 15

C1-7 above corr disc
C8 below C7
T1-L5 below corr disc
S1-4 pass via ant & post sacral foramina
S5 & Co sacral hiatus

Question 16

Mention the structure occupying the lower 1/3 of vertebral canal

Answer 16

Cauda equina

Question 17

GR: 4th & 5th lumbar nerves are most liable to compression

Answer 17

As the size of spinal nerves inc in downwards direction while the size of intervertebral foramina dec

Question 18

….is largest spinal nerve

Answer 18

S1

Question 19

The dura & arachnoid end at ….

Answer 19

S2

Question 20

Mention contents of subarachnoid space

Answer 20

CSF
Filum terminale
Ligamentum denticulatum (21 teeth)
Subarachnoid septum extends from post med septum

Question 21

Site & uses of lumbar puncture

Answer 21

S, above or just below the tip of 4th lumbar spine
U, diagnostic; to measure pressue, sample or inject air for contrast in C-ray
Therapeutic, relieve inc intracranial tension or inject abx or spinal anesthesia

Question 22

Describe the extent of the scalp

Answer 22

Ant: supra-orbital margin
Post: external occipital protuberance and highest nuchal line
Lat: superior temporal line

Question 23

Mention the result if density of CT of the 2nd layer

Answer 23

1. Infections tend to remain localized causing pain
2. Wounds do not gap
3. Injury to vessels leads to profuse bleeding as walls are adherent to CT septa thus can’t contract or retract

Question 24

Describe attachment of epicranial aponeurosis

Answer 24

Ant: frontal bellies of occipito-frontalis
Post: occipital bellies of o.f.
Lat: sup temporal line

Question 25

GR: wounds reaching aponeurotic layer gap

Answer 25

Due to muscle contraction

Question 26

Compare frontal bellies & occipital bellies of o.f.

Answer 26

F: Origin: wider partly united in midline; each arises the skin of eyebrows Insert in epicranial aponeurosis Supplied by temoral branch of facial nerve Pull scalp forwards and raise eyebrows O: Origin: narrower separated from each other by an extension of epicranial aponeurosis, each arises from lat 2/3 of the highest nuchal line Inserted as before Post auricular branch of facial nerve Pull scalp downwards

Question 27

GR: Black eye occurs with injury of 4th scalp layer

Answer 27

As it is composed of loose areolar CT allowing spread of blood below the aponeurosis, it cannot spread to the neck due to attachment of occipital bellies to bone, but it can spread forward since the frontal bellies is not attached to bone thus the blood collects in the eyelid.

Question 28

What happens in case of injury of vessels of 5th layer

Answer 28

Collection of blood (hematoma) that takes the shape of bone.

Question 29

Mention arteries of the scalp

Answer 29

1. Supraorbital & supratrochlear 2. Superficial temporal artery 3. Posterior auricular artery 4. Occipital artery

Question 30

Mention branches originating from ICA & areas they supply

Answer 30

Supraorbital & supratrochlear Skin of forehead, s.o. supplies skin till level of the vertex

Question 31

Enumerate branches of each: 1. Superficial temporal art 2. Post auricular 3. Occipital art

Answer 31

1. Transverse facial, auricular, middle temporal, glandular to parotid & terminal (frontal & parietal) 2. Auricular, occipital, stylomastoid 3. Auricular, occipital, mastoid, sternomastoid, descending, muscular & meningeal

Question 32

Superficial temporal art supplies ….

Answer 32

Skin of temple & side of scalp

Question 33

….ascends above post belly of digastric while ….ascends below it ….

Answer 33

Posterior auricular art Occipital art

Question 34

Supraorbital & -trochlear veins unite to form ....., which drains into....forming......that ends in.....

Answer 34

Facial vein Ant division of retromandibular vein Common facial vein IJV

Question 35

Retromandibular vein is formed from....

Answer 35

Union of superficial temporal and maxillary veins

Question 36

Describe course of posterior auricular vein

Answer 36

Unites with post division of retromandibular vein forming EJV

Question 37

Occipital vein drains into .....

Answer 37

Suboccipital venous plexus

Question 38

What is the importance of emissary veins?

Answer 38

They help to reduce venous pressure inside the cranial cavity

Question 39

Mention nerves in front of the auricle

Answer 39

Sensory: Supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal Motor: temporal branch of facial nerve

Question 40

Mention nerves behind the auricle

Answer 40

Sensory: Greater auricular, lesser occipital, greater occipital, third occipital nerves. Motor: posterior auricular bracg of facial nerve

Question 41

Nerves which originate from C2 only

Answer 41

Lesser occipital, greater occipital

Question 42

The skin up to vertex on the front is supplied by ....., while on the back ....

Answer 42

Supraorbital Greater occipital

Question 43

Describe lymph drainage of scalp

Answer 43

Pre-auricular, parotid LNs Post-auricular, mastoid & occipital LNs