GEN2305 Summary
Case 1 Learning goals
1. Recap of the general anatomy of the brain (not discussed unless there are specific
questions)
Nervous system is composed of the central nervous system and the peripheral nervous
system. The central nervous system is composed of the brain, brainstem, and spinal cord.
The peripheral nervous system is all the nerves in the periphery. The peripheral nervous
system is furthermore composed of the somatic and the autonomic nervous system. The
autonomic is composed of the afferent and efferent nerves. The efferent nerves are seen as
the sympatic (action) and parasympatic (rest). The somatic is the free will, this controls the
afferent (sensory) and efferent (motor) nerves.
The general organization of the brain itself is as follows: The Forebrain, Midbrain and
Hindbrain. These compartments can be divided into the embryologic composition of the
Telencephalon, Diencephalon, Mesencephalon, Metencephalon, Myelencephalon.
Brain medial structures: Pineal gland, Tectum and Tegmentum. Other ones are logical.
- Meninges
The brain from the outside to the inside. First you have the skin, then the peritoneum, after
this there is bone and under the bone the Dura Mater will start. The Dura Mater has two
layers, the periostale layer against the bone and the meningeal layer. These two layers allow
sinuses to form. The dura mater is tough and inflexible. It surrounds the brain and the spinal
cord. Under the dura mater is the arachnoid membrane, it is the membrane in between the
dura and the pia. Under this there is a spider web like space called the subarachnoid space.
In the subarachnoid space blood vessels are located. The layer directly on top of the brain is
the pia mater. It is also located in the brain and spinal cord but not in the sulci. It is a thin
layer with blood vessels.
- Function of brain areas
Frontal lobe the frontal lobe is located on the front of the brain superior of the lateral
fissure and rostral of the central sulcus. It is involved with the higher cognitive functions like
the executive functions, memory, language, motivation, problem solving, decision making
and personality. Then we have the parietal lobe, this is located caudally of the central sulcus
and superior of the lateral sulcus. Also, the parieto-occipital sulcus separates it from the
occipital lobe rostrally. It is involved in sensory association and sensory processing but also
in the eye-hand coordination and spatial recognition. Then we have the temporal lobe, this
is located inferior of the lateral sulcus and anterior of the occipital lobe. It is involved in
emotion and memory, talk, but also in smell, taste perception, aggression, and sexual
behavior. Then finally, we have the occipital lobe which is located caudally of the parieto-
occipital sulcus and its main function is to control view, process the vision and recognize
objects.
The brain has specific regions like the Broca and Wernicke area. The Broca area is motor
function of the mouth, and the Wernicke area is for the sensory part (word remembering).
- Connections between hemispheres
There are three connections between the hemispheres: the corpus callosum, the commisura
anterior, and the commisura posterior. The corpus callosum is seen when you look
superiorly (dorsally) onto the brain, there you can see white matter which is the corpus
callosum.
, - Cirkel van willis + Cranial nerves (Zie schrift)
The brain is mainly supplied by the internal carotid artery and its branches. These branches
are the a. cerebri media, and a. cerebri anterior. Parts of the brain in the posterior cranial
groove are supplied with blood from the a. vertebralis. These arteries are connected via the
circle of Willis. Which guarantees blood flow in the brain when one artery is occluded or has
limited blood flow.
Venous drainage does not follow the arterial supply. In the superior sagittal sinus, we can
see granulations of the arachnoid layer. This is so that the toxics and waste products from
the brain can go to the kidney. Cerebrum, cerebellum, and brainstem are drained by various
veins which empty in the dural venous sinuses. These lie between the periostal and
meningeal layer of the dura mater. All dural venous sinuses drain into the internal jugular
vein.
, 2. What are different types of paralysis?
Clinically we can see paralysis or paresis, paralysis is that you cannot move or feel in the
limb. Paresis is partial damage causing weakness of the limb.
We have different types of paralysis, when you have both an arm and leg on one side of the
body that is paralyzed this is called hemiplegia. When one limb on one given side is
paralyzed, it is called monoplegia. Then we have quadriplegia, diplegia, and paraplegia.
Diplegia is a paralysis of both arms. Paraplegia is a paralysis of both legs. Quadriplegia is the
paralysis of all limbs.
Then there are different types of palsies. Central facial palsy is the weakening of muscles of
the face by a lesion in the cortex. Weakness in the muscles that regulate breathing,
swallowing, speech and chewing is a pseudobulbar palsy.
The upper motor neuron syndrome is a moderate to large lesion of the motor cortex, in the
pyramidal tracts, corticospinal tract and/or corticobulbar tract. It is characterized by a
paralysis of the contralateral limbs, hyperreflexia, hypertonia, and a Babinski sign. A Lower
motor neuron lesion is anywhere along the nerve fibers between the anterior horn of the
spinal cord and relevant muscle tissue. It is thus in the periphery; this leads to peripheral
paresis, which is characterized by lower tone, lower power and hyporeflexia. With a normal
Babinsky reflex.
Anterior cerebral artery syndrome is caused by interruption of blood flow in the trunk of the
middle cerebral artery or anterior cerebral artery. This damages the precentral gyrus and
results in contralateral paralysis.
We can differentiate different degrees of paralysis: Flaccid paralysis is a neurological
condition characterized by weakness or paralysis and reduced muscle tone without other
obvious cause. The muscles will get limp and atrophy can occur. This abnormal condition
may be caused by disease or by trauma affecting the nerves associated with the involved
muscles. It can be ascending when it starts in the legs and travels towards the arms. Or
descending when it starts proximal and starts to progress distally.
Spastic is also a possibility, here the muscles are tight, hard, and jerk around oddly (spasms).
Complete paralysis is when you can’t move muscles at all.
Partial is when there is still control of some of the muscles, most of the times this is called
paresis.
Temporary and permanent paresis some movement will return overtime, other might never
return.
a. Stages, progression
The corticospinal tract controls the voluntary movements of both the contralateral upper
and lower limbs. Depending on the extent of the lesion the functions are lost when the tract
is damaged. After a stroke, first the affected muscles lose their muscle tone. After several
