Neuroanatomy 1 SDL

Question 1

Define rostral

Answer 1

Rostral is taken from the Latin rostrum, to mean towards the nose/beak. Rostral therefore refers to the anterior (front) aspect of the head.

E.g. The forebrain is rostral to the midbrain.

Question 2

Define caudal

Answer 2

In this context, caudal refers to the posterior (back) of the head.

E.g. The hindbrain is caudal to the midbrain.

Question 3

What is the cephalic flexure?

Answer 3

Where the axis of the adult brain bends at an angle of about 100° between the midbrain and the diencephalon

Question 4

In the spinal cord and brainstem, what does the term ‘dorsal’ mean? What does it mean in the forebrain?

Answer 4

Spinal cord and brainstem –> means posterior

Forebrain –> means superior

Question 5

In which plane would you cut in order to make a transverse section of either brainstem or spinal cord?

Answer 5

Horizontal

Question 6

What is meant by the following terms in the context of the nervous system?

• grey matter:
• white matter:
• cortex:
• nucleus:
• tract:
• ganglion:

Answer 6

• Grey matter: mainly composed of neuronal cell bodies and unmyelinated axons
• White matter: mainly composed of myelinated axons
• Cortex: the cerebral cortex is the outermost layer of the brain, made up primarily of grey matter.
• Nucleus: cluster of neurons found in the CNS
• Tract: A nerve tract is a bundle of nerve fibers (axons) connecting nuclei of the central nervous system
• Ganglion: a cluster of neural bodies outside the central nervous system.

Question 7

Which subdivisions of the brain make up the forebrain or cerebrum?

Answer 7

cerebrum, thalamus, hypothalamus, pituitary gland

Question 8

Which subdivisions of the brain make up the brainstem?

Answer 8

midbrain, medulla and pons,

Question 9

The lobes of the brain

Answer 9

Question 10

What cortical landmarks which are used to subdivide the hemisphere into lobes?

Answer 10

• Longitudinal sulcus –> separates right and left hemispheres
• Central sulcus –> separates frontal lobe from parietal lobe
• Parieto-occipital sulcus –> separates parietal from occipital lobe
• Lateral sulcus –> separates temporal lobe from frontal and parieral lobe

Question 11

Are the cerebral lobes functional or descriptive subdivisions?

Answer 11

The lobes of the brain were originally a purely anatomical classification, but have been shown also to be related to different brain functions.

Question 12

What are the functions of the pre- and post-central gyri? And where are they located?

Answer 12

Precentral gyrus:

• Located anterior to central sulcus
• Function –> primary motor cortex

Postcentral gyrus:

• Located posterior to central sulcus
• Function –> primary somatosensory cortex

Question 13

What is the corpus callosum is composed of?

Answer 13

The largest fibre bundle in the brain, containing nearly 200 million axons. It is composed of white matter fibre tracts.

Question 14

What is the function of the corpus callosum?

Answer 14

Connects the right and left hemispheres - ensures both sides of the brain can communicate and send signals to each other

Question 15

Label these structures

Answer 15

Question 16

Label these structures

Answer 16

Question 17

Is the optic nerve part of the peripheral nervous system or part of the central nervous system?

Answer 17

t’s considered to be part of the central nervous system (CNS) as it is derived from an outpouching of the diencephalon during embryonic development.

Question 18

what do the 5 secondary vesicles give rise to?

Answer 18

Telencephalon

Diencephalon

Mesencephalon

Metencephalon

Mylencephalon

Olfactory tract

Olfactory bulb

Infundibulum

Optic nerve

Optic chiasm

Mamillary bodies

Cerebral peduncles of the midbrain

Pons

Cerebellum

Medulla oblongata

Question 19

What are the 3 layers of meninges that enclose the brain and spinal cord?

Answer 19

1. Dura mater
2. Arachnoid mater
3. Pia mater

Question 20

Describe the appearance of the dura mater

Answer 20

It is thick, tough and inextensible.

Question 21

Describe the appearance of the arachnoid mater

Answer 21

spiderweb-like appearance, is a thin, transparent membrane

Question 22

Describe the appearance of the pia mater

Answer 22

thin, translucent, mesh-like meningeal envelope

Question 23

What forms the dura mater in the cranial cavity?

Answer 23

1. Periosteal outer layer lining the inside of the skull
2. Meningeal fibrous inner layer

Throughout most of the cranial cavity, the two layers are tightly fused together.

Question 24

At some sites, though, the fibrous inner layer of dura separates from the periosteum to enclose what?

At two such sites of separation, the fibrous inner layer of dura projects into the cranial cavity to form what?

Answer 24

• Enclose blood-filled spaces - the dural venous sinuses - into which flows venous blood from the brain.
• At two such sites of separation, the fibrous inner layer of dura projects into the cranial cavity to form a dural reflection (sometimes called a fold or septum) which extends into the fissures between the major components of the brain.

Question 25

What is the name of the dural septum that extends down between the two cerebral hemispheres?

Answer 25

Falx cerebri: * The falx cerebri is a large, c**rescent-shaped fold of meningeal layer of dura mater** that descends vertically in the **longitudinal fissure** between the cerebral hemispheres of the human brain.

Question 26

What is the name of the dural septum that extends between the occipital lobes of the hemispheres and the cerebellum?

Answer 26

Tentorium cerebelli: * The tentorium cerebelli exists between and separates the **cerebellum and brainstem** from the **occipital lobes of the cerebrum**

Question 27

What is the function of the dural septae?

Answer 27

To separate the cranial cavity into compartments and protect the brain from displacement

Question 28

Which dural venous sinuses run along the lines of attachment of these two dural folds to the skull?

Answer 28

* The **straight, superior,** and **inferior sagittal sinuses** are found in the **falx cerebri** of the dura mater * They converge at the **confluence of sinuses** * The **superior petrosal sinuses** and the **transverse sinuses** are found in the tentorium cerebelli

Question 29

Label these structures

Answer 29

Question 30

What occupies space A? What is its function?

Answer 30

Subdural/subarachnoid space - contains CSF to: * Cushion the brain and spinal cord * To supply them with nutrients and remove waste Also, the major arteries of the brain run through the subarachnoid space.

Question 31

What are the arachnoid villi (also called arachnoid granulations) and what is their function?

Answer 31

**What:** Small protrusions of arachnoid mater into the outer membrane of the dura mater **Function:** permit one-way flow of CSF from the subarachnoid space to the venous circulation.

Question 32

Which vessel provides the arterial supply to the dura mater? Why is it of great clinical importance?

Answer 32

Middle meningeal artery --\> susceptible to injury in the pterion which can lead to an epidural haematoma

Question 33

Which two pairs of blood vessels provide the arterial supply to the brain?

Answer 33

Vertebral artery and internal carotid artery

Question 34

**Describe** the course of the vertebral and internal carotid arteries as they ascend to enter the skull.

Answer 34

Internal carotid: * originate at the bifurcation of the left and right common carotid arteries, at the level of **C4** * move superiorly within the **carotid sheath** * nter the brain via the **carotid canal** of the temporal bone. Vertebral: * arise from the subclavian arteries * ascend the posterior aspect of the neck, through holes in the transverse processes of the cervical vertebrae, known as **foramen transversarium.** * enter the cranial cavity via the **foramen magnum**

Question 35

Identify vessel A and B

Answer 35

A - vertebral artery B - ?

Question 36

**Indicate** which brain regions are supplied by each pair of vessels (represented by arrowheads). Note that each of these main branches give off small, penetrating branches along their course to supply the internal brain tissue.

Answer 36

Question 37

What does the posterior cerebral arteries supply?

Answer 37

The posterior aspect of cerebrum

Question 38

What does the middle cerebral artery supply?

Answer 38

Supplies lateral portions of cerebrum

Question 39

What do the anterior cerebral arteries supply?

Answer 39

Tucks under the midline portion of each cerebral hemisphere to supply its anterior and medial aspect

Question 40

Distribution (territories) of the anterior, middle and posterior cerebral arteries.

Answer 40

Question 41

Penetrating arterial branches, arising from around the arterial circle and passing into the substance of the brain, are often referred to as what?

Answer 41

Central or perforating arteries

Question 42

Branches arising from the middle cerebral artery are called what?

Answer 42

Striate arteries

Question 43

What do these striate arteries supply?

Answer 43

These supply structures inside hemisphere: * Deep nuclei * Deep grey matter (e.g. thalamus) * Internal capsule (major fibre bundle to and from cerebral cortex - deep white matter) * Supply includes major descending motor pathway

Question 44

Which two sets of veins drain blood from the brain?

Answer 44

Superficial and deep veins

Question 45

Where do the superficial veins of the brain run?

Answer 45

run over the surface of the hemispheres

Question 46

Where do the majority of the superficial veins drain into?

Answer 46

The superior sagittal sinus

Question 47

Where is the superior sagittal sinus located?

Answer 47

Lies along the superior edge of the falx cerebri

Question 48

Deep veins converge on the internal cerebral veins which eventually unite to form the what?

Answer 48

Great cerebral vein (of Galen)

Question 49

Fill in the missing words in the diagrammatic representation of the venous drainage of the brain

Answer 49

Question 50

What are the 3 main types of intracranial haemorrhages (ICH)?

Answer 50

1. Extradural (EDH) 2. Subdural (SDH) 3. Subarachnoid (SAH)

Question 51

A rupture of which vessel could lead to an extradural haemorrhage?

Answer 51

Middle meningeal artery

Question 52

A rupture of which vessel could lead to a subdural haemorrhage?

Answer 52

?

Question 53

A rupture of which vessel could lead to an subarachnoid haemorrhage?

Answer 53

?

Question 54

Subdural haemorrhage occurs most commonly in older / elderly people. Why?

Answer 54

Generalised cerebral atrophy and increased venous fragility

Question 55

What is a "berry" aneurysm? Suggest a few sites at which these might occur.

Answer 55

Abnormal dilations around the circle of Willis or at the points of arterial branching within the brain

Question 56

What are the consequences of rupture of a berry aneurysm?

Answer 56

Can lead to vascular stroke

Question 57

What is a Cerebrovascular Accident?

Answer 57

CVA = stroke

Question 58

How is a CVA caused?

Answer 58

These occur when a blood vessel is occluded, and brain tissue becomes infarcted.