Neuroanatomy 2

Question 1

What does the SCALP consist of

clue is in the name

Answer 1

Skin
Connective tissue
Aponeurosis
Loose connective tissue
Periosteum

Question 2

What are the 3 meninges of the skull

Answer 2

Dura mater
Arachnoid mater
Pia mater

Question 3

What is the dura mater

Answer 3

Outermost meningial layer
Tough, fibrous membrane
Restricts movement of the brain

Question 4

2 layers of dura mater

Answer 4

Outer periosteal layer

Inner meningeal layer

Question 5

What is the Flax cerebri

Answer 5

Midline

Seperates the two cerebral hemispheres

Question 6

What is the tentorium cerebelli

Answer 6

Forms a roof over the posterior cranial fossa
Seperates cerebellum from occipital lobes
Free border = tentorial notch, for the passage of the midbrain

Question 7

What are the dural reflections and what are their purposes

Answer 7

Falx cerebri and tentorium cerebelli
Subdivides the cranial cavity
Protects and insulates the brain to reduce injury in response to trauma
Provides pathways fro blood vessels and nerves

Question 8

What are dural venous sinuses

Answer 8

Spaces the enclose venous blood

Drain venous blood from brain, skull bones, the orbit and the inner ear

Question 9

Dural venous sinuses in the falx cerebri

Answer 9

Superior and inferior sagitall sinuses

Question 10

Dural venous sinuses in the tentorium cerebelli

Answer 10

Straight sinus
Transverse sinus
Sigmoid sinus

Question 11

Course of sigmoid sinus

Answer 11

Leaves the skull though jugular foramen

Drains into IJV

Question 12

Where is the cavernous sinus located

Answer 12

Lateral to sphenoid bone

Question 13

What is the arachnoid mater

Answer 13

Middle meningeal layer
surround the brain loosely
Soft, translucent membrane
Seperated from dura by a subdural space

Question 14

What is the subarachnoid space

Answer 14

Seperates arachnoid and pia
conatins network of arachnoid trabeculae
Blood vessels and cerebrospinla fluid

Question 15

What is the pia mater

Answer 15

Innermost meningeal layer
Microscopically thin
Closely adherant to brain surface

Question 16

What is the extra-dural space

Answer 16

Potential space
Between bone and dura
usually the dura is firmly attached to the skull
contains meningeal arteries

Question 17

What is sub-dural space

Answer 17

Potential space

Between dura and arachnoid mater

Question 18

Subarachnoid space

Answer 18

Fluid filled space

Between the arachnoid and pia mater

Question 19

What is cerebrospinal fluid

Answer 19

Clear colourless fluid that surround the brain and spinal cord and has many important functions

Question 20

Functions of cerebrospinal fluid

Answer 20

Buiyancy
Protection
Clearing waste
Chemical stability

Question 21

What are the ventricles of the brain and their connections

Answer 21

Lateral ventricle (x2)
Third ventricle
Fourth ventricle
interventricular foramen (between lateral and third ventricle)
Aqueduct of midbrain (between the third and fourth ventricle)

Question 22

Name the parts of the lateral ventricles

and their association to the brain

Answer 22

Anterior horns (frontal lobe)
Body (parietal lobe)
Posterior horns (OCCIPITAL LOBE)
Inferior horns (temporal love)

Question 23

How is the choroid plexus formed and where is it located

Answer 23

Formed by an invagniation of the pia mater into ventricular lumen
located in the lateral, third and fourth ventricles

Question 24

What produces CSF

Answer 24

Choroid plexus

Question 25

What is CSF

Answer 25

Colourless fluid with little protein and few cells Total volume approx. 150ml Produced continuously, and replaces itself several times a day CSF must therefore be circulated and reabsorbed if it is continuously produced

Question 26

CSF circulation

Answer 26

Flows through the ventricular system into the fourth ventricle From there it enters the central canal of the spinal cord and the Subarachnoid space via 2 lateral apertures and 1 median aperture From the sub-arachnoid space, CSF is absorbed into the dural venous sinuses vai the arachnoid villi

Question 27

What are the arachnoid villi

Answer 27

Projections of the arachnoid later into the dural venous sinuses and sites of absorption Most commonly found in the superior sagittal sinus

Question 28

How does CSF absorption occur

Answer 28

CSF has higher hydrostatic pressure than venous blood | So absorbed in the venous blood though the villi

Question 29

What is hydrocephalus

Answer 29

Expansion of the ventricles

Question 30

What are the segments of the spinal cord

Answer 30

``` 8 Cervical segemnts 12 Thoracic segmants 5 Lumbar segmants 5 Sacral segments 1 Coccygeal segmants ```

Question 31

Where does the spinal cord terminate in adults

Answer 31

L1/L2

Question 32

What are the 3 spinal meningeal layers

Answer 32

Pia mater Arachnoid mater] Dura mater

Question 33

What seperates the dura mater from the bone in spina cord

Answer 33

adipose tissue

Question 34

Which root of the spinal nerve is motor (and which is sensory)

Answer 34

Ventral root = motor | Dorsal root = sensory

Question 35

How do they spinal nerves exit the vertebral canal

Answer 35

Via the intervertebral foramen - a hole between two adjacent vertebrae

Question 36

What ahppens to the spinal nerve when it exits the vertebral canal

Answer 36

Splits into the posterior ramus and anterior ramus

Question 37

What is a dermatome

Answer 37

area of skin supplied by one pair of spinal nerves

Question 38

Where do parasympathetic fibres arise from

Answer 38

Oculomotor, facial, glossopharyngeal and vagus nerve | S2 to S4 spinal segments

Question 39

Where do sympathetic fibres arise from

Answer 39

T1 to L2

Question 40

Features of the spinal cord

Answer 40

``` Outer white matter Inner grey matter Central canal Anterior median fissure Posterior median sulcus Posterolateral sulcus ```

Question 41

What areas is the white matter subdivided into

Answer 41

Dorsal funiculus Lateral funiculus Ventral funiculus

Question 42

What regions is the grey matter subdivided into

Answer 42

Dorsal horn Lateral horn Ventral horn

Question 43

What is the function of the dorsal horn

Answer 43

Main site of termination of primary afferent fibres

Question 44

What is the function of the lateral horn

Answer 44

Cell bodies of pre-ganglionic sympathetic fibres are located

Question 45

What is the function of ventral horn

Answer 45

Contain cell bodies of motor neurons that will leave the spinal cord through ventral root

Question 46

What is the function of the ascending tract

Answer 46

Carry impulses from pain, thermal, tactile, muscle and joint receptors to the brain

Question 47

What is the general sensation of the ascending tracts

Answer 47

Usually 3 neurons between the receptor and the cerebral cortex First order neuron - enters spinal cord on ipsilateral side second order neuron then crosses over to other side of spinal cord and ascends to the thalamus Third order neuron then leaves the thalamus and projects to the somatosensory cortex

Question 48

What is the descending tract

Answer 48

Originate form the cerebral cortex and brainstem Concerned with control of movement, muscle tone, spinal reflexes , spinal autonomic functions and modulation of sensory transmission to higher centres

Question 49

What is the corticospinal tract

Answer 49

Upper motor neuron leaves the pre-central gyrus and descends to the brainstem Majority of the fibres cross over when they reach the medulla oblongata Specifically they decussate at the pyramids Continues down spinal cord to the desired level as the lateral corticospinal tract here it synapses with a lower motor neuron, which will leave the spinal cord in a spinal nerve to innervate skeletal muscle