Anatomy L1 and L2 Flashcards
Name the two major parts of the head.
Cranium and facial skeleton
How many bones make up the cranium?
8 bones
Name the bones making up the cranium.
Frontal (1) Parietal (2) Temporal (2) Occipital Ethmoid Sphenoid
Name the sutures of the skull and where they are found.
Coronal - between frontal and parietal bones
Sagittal - between parietal bones
Lambdoid - between parietal and occipital
Squamous - between temporal bone and parietal bone
What are the names of the two joints in the skull?
Bregma - joint between coronal and sagittal sutures
Lambda - joint between the sagittal and lambdoid sutures
What are fontanelles?
Unfused bone in infant’s cranium - allows for growth of brain to full size
Name the fontanelles.
Anterior (frontal) fontanelle
Posterior (occipital) fontanelle
Name the 5 layers of the scalp.
S - skin C - connective tissue (dense) A - aponeuroses (of scalp muscles) L - loose connective tissue P - periosteum
What is the sella turcica?
Bony depression in the sphenoid bone
Contains the hypophyseal fossa/pituitary fossa (contains the pituitary gland)
What part of the temporal bone is very thick/pyramid shaped?
Petrous part (pyramid shaped along the ridge)
What is the name of the big hole in the cranium?
Foramen magnum
Name the major divisions of the brain and what they consist of.
Forebrain - cerebral hemispheres, diencephalon (interbrain - thalamus and hypothalamus)
Brainstem - midbrain, pons and medulla
Cerebellum
Hindbrain - pons, medulla and cerebellum
Which brain contains 50% of neurons?
Small brain
.What is the front of the cerebrum called?
Anterior (rostral)
What is the back part of the cerebrum called?
Posterior (caudal)
What is the top of the cerebrum called?
Superior (Dorsal)
What is the bottom part of the cerebrum called?
Inferior (ventral)
Describe the orientation of the brainstem.
At an angle along the brainstem Superior (rostral) Posterior (dorsal) - near the cerebellum Anterior (ventral) Inferior (caudal)
What are gyri and sulci and what are their function?
Gyri = ridges
Sulci = valleys
Both present to increase the SA of the brain in order to accommodate more neurons.
What is the fissure called that’s found at the back of the brain?
Median longitudinal fissure
Name the 5 lobes of the cerebrum.
Frontal Parietal Temporal Occipital Insular
Central sulcus
Separates frontal lobe from parietal lobe of cerebellum
Lateral Sulcus
Separates the frontal lobe from the parietal lobe and temporal lobe
What separates the cerebrum from the cerebellum?
Transverse fissure
Where is the insular lobe located?
Deep beneath the lateral sulcus.
Covered by portions of the frontal, temporal and parietal lobes.
What separates the parietal lobe from the occipital lobe?
Parieto-occipital sulcus
What is the function of the corpus callosum?
Joins the two hemispheres of the brain.
Name the parts of the corpus callosum and their function.
Rostrum (beak)
Genu - connecting the anterior parts of the front lobe
Body - connecting the other parts of the frontal lobe
Splenium - connects the temporal and occipital lobes
What are the contents of the diencephalon?
Pineal gland - light/dark cycles
Thalamus
Hypothalamus
Pituitary gland
How does the brainstem anchor the cerebellum?
Via three cerebellar peduncles.
Why is the brain said to have a tabular structure?
Cranium is made up of separate tables of bone
Describe the tabular structure of the cranium.
Thick outer layer of compact bone = outer layer
Middle spongy layer = diploe
Inner thin layer of compact bone = inner layer
Where is the bone of the cranium the thickest and thinnest?
Thickest at the occipital and frontal regions
Thinnest at the temporal region
Calvaria
Top part of the skull
What fissure is between the hemispheres?
Longitudinal fissure
What is the falx cerebri?
Fold of dura running down between the hemispheres
Name the two layers of the dura mater.
Periosteal layer (adjacent to the skull) Meningeal layer (adjacent to the arachnoid)
What is the name of the sinus between the two layers of the dura mater?
Superior saggital sinus
Why does the meningeal layer extend inward to form flat partitions?
Subdivide the cranial cavity
Limit excessive movement of the brain within the cranium
What do the two layers of the dura separate to form?
Dural venous sinuses - superior sagittal sinus
Name the fold separating the two cerebral hemispheres.
Falx cerebri
Name the fold separating the two hemispheres of the cerebellum.
Falx cerebelli
Name the fold separating the cerebrum and cerebellum.
Tentorium cerebelli
Which layer contains the meningeal blood vessels?
Periosteal layer of the dura mater
What is the function and composition of the grey matter?
Processing
Made up of cell bodies
Nucleus (CNS)
Ganglion (PNS)
What is the function and composition of white matter?
Communication
Made of axons with myelin
Name the three types of fibres of white matter in the brain.
Comissural fibres - between the hemispheres
Association fibres - within the hemisphere
Projection fibres - brain to spinal cord via internal capsule
What is the corpus striatum made of?
Caudate nucleus and lentiform nucleus
What is the lentiform nucleus made of?
Putamen and globus pallidus
What is the striatum made of?
Putamen and caudate nucleus
What is the pallidum made of?
Globus pallidus
What are basal ganglia made of?
Corpus striatum + subthalamic nuclei + substantia nigra
What makes up the internal capsule?
Fibres between the lentiform nucleus and thalamus/caudate nucleus
Name the parts of the internal capsule
Anterior limb (shorter) Genu Posterior limb (longer)
How do you distinguish the putamen from the globus pallidus?
Putamen is more lateral
Globus pallidus is more medial and paler
Name the capsules found in the brain.
Internal capsule External capsule (white matter) Extreme capsule (white matter)
What is the claustrum?
Thin layer of grey matter between the external capsule and extreme capsule
Describe the length of the spinal cord.
From the foramen magnum to the 1st/2nd lumbar vertebra
How many pairs of spinal nerves do we have?
31 pairs (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal)
What is the filum terminale?
Extends from the conus medullaris to the posterior surface of the coccyx.
What is the cauda equina and why is it present?
The collection of nerve roots at the inferior end of the vertebral canal.
After birth the vertebral column grows faster than the spinal cord.
Go over diagrams of spinal cord matter.
Notes
Name the two layers of the dura mater.
Periosteal layer
Meningeal layer
What sinus is between the two layers of the dura mater?
Superior sagittal sinus (venous blood)
What is the function of the middle meningeal arteries?
Supply blood to the dura and cranium
Where do the middle meningeal arteries arise from?
External carotid artery
What happens if the middle meningeal arteries are damaged?
An epidural (extradural) haematoma
How is the arachnoid mater connected to the pia mater?
Fine strands of connective tissue (arachnoid trabecula)
What is the function of the choroid plexus?
Produces CSF
What happens if injury occurs in the subdural space?
Subdural haemorrhage
What is the function of arachnoid villi and granulations?
Drain CSF from the subarachnoid space into the venous sinuses
What are arachnoid granulations?
Collections of arachnoid villi
What is meningitis?
Inflammation of the pia-arachnoid meninges
What causes meningitis and what are the symptoms?
Caused by virus/bacteria
Fever, headache, vomiting, stiff neck
How do you diagnose meningitis and what is its treatment?
DIagnose with lumbar puncture (L3/L4)
Treat with antibiotics
What is the difference between the meninges of the brain and spinal cord?
Spinal cord has no periosteal layer of the dura. Only the meningeal layer of dura mater is present.
What does the epidural space contain of the spinal meninges?
Fat tissue and venous plexus
Describe the stages of blood drainage of the brain.
Fine veins (brain) –> pial venous plexuses –> cerebral veins –> dural venous sinuses –> internal jugular vein –> heart
Where do the veins of the scalp drain into?
Drains into the dural venous sinuses via emissary veins
Where is the superior sagittal sinus found?
Between the two layers of dura mater
What is the function of the superior sagittal sinus?
Receives venous blood from the brain and scalp and CSF
Where does the superior sagittal sinus lie and what sinus does it join?
Lies along the superior margin of the falx cerebri
Joins the right transverse sinus
Where is the inferior sagittal sinus found?
Inferior margin of the falx cerebri
Where is the straight sinus found and what sinus does it join with?
Within the tentorium cerebelli
Joins the left transverse sinus
Where is the cavernous sinus found?
Adjacent to pituitary gland/fossa
What does the cavernous sinus enclose?
Internal carotid artery
Cranial nerves III, IV, V (2 divisions) and VI
Describe the draining of the superior and deep structures of the brain
Diagram in notes
Describe the draining of the inferior structures
Diagram
Why is there a danger of infection spreading from the scalp to the brain?
This is because of the emissary veins drain into the dural venous sinuses
The facial skin around the nose and upper lip also drain (via the opthalmic veins) to the cavernous venous sinus
Describe what happens to the brain if interruption of blood flow occurs.
10s = unconsciousness
1-2min = impaired neural function
3-4 min = irreversible brain damage
Name the dual arterial supply of the brain
Internal carotid arteries
Go over the blood supply
diagram
What is the function of the circle of willis?
To equalize blood flow to various parts of the brain
Note only 20% of people have a complete circle
Name the vessels making up the circle of Willis
Anterior communicating artery joining the ACAs
Posterior communicating artery (x2) joining the ICA and PCA
What does the anterior cerebral artery supply (ACA)?
Supplies the medial aspect of the cerebral hemispheres (anterior 2/3 only)
What does the middle cerebral artery (MCA) supply?
Almost all the lateral surfaces of the cerebral hemispheres
small bit posteriorly is supplied by the PCA
What does the posterior cerebral artery (PCA) supply?
Posterior 1/3 of the medial aspect of the cerebral hemisphere
Occipital lobes, inferior temporal lobe regions, superior brainstem
What happens during a stroke?
Neurological dysfunction as a result of the reduction of blood supply to the brain
What usually causes a stroke?
Occlusion of a vessel by blood clot or cholesterol deposit
or
Bleeding from a ruptured vessel
What are the signs and symptoms of a stroke?
Depends on which blood vessels and branches are involved
What happens if the ACA is occluded?
Contralateral hemiplegia (one artery) or bilateral
Paralysis (two arteries) and impaired sensation
- greatest in the lower limb
What happens if the middle cerebral artery is occluded?
A severe contralateral hemiplegia and impaired sensation
Most marked in the upper limb and face
Severe aphasia (if the dominant hemisphere is affected)
What happens if the PCA is occluded?
Contralateral homonymous hemianopsia
Name the four ventricles of the brain.
Lateral (x2)
Third
Fourth
What do the ventricles contain?
CSF
What connects the third and fourth ventricle?
Cerebral aqueduct
How are the lateral ventricles connected to the third ventricle?
Via the interventricular foramen
Where are the apertures found and what are their names/function?
Found in the fourth ventricle - lateral and median apertures
Allow CSF to drain from the fourth ventricle into the cisterna magna (subarachnoid space)
Where is the CSF produced and what is its function?
Produced in the choroid plexuses
Protects and nourishes the brain
State the pathway of flow of CSF.
1 - Lateral ventricles to 3rd ventricle via the interventricular foramen
2 - 3rd ventricle into the cerebral aqueduct
3 - cerebral aqueduct into the fourth ventricle
4 - fourth ventricle via lateral and median apertures into the cisterna magna (subarachnoid space)
5 - fills the subarachnoid space to bath the external surface of the brain
6 - enters venous sinuses at arachnoid granulations (villi)
What forms the BBB?
Tight junctions between endothelial cells of capillaries
What is the function of the BBB?
Selective for nutrients (glucose, essential amino acids, electrolytes)
Keeps out certain chemicals and drugs
A PROTECTIVE MECHANISM TO MAINTAIN A STABLE ENVIRONMENT FOR THE BRAIN
Ineffective against fats, fatty acids, oxygen and carbon dioxide
What substances affect the brain?
Nicotine, alcohol, anesthetics
What is hydrocephalus?
Excessive amount of CSF in the ventricular system due to increased production of fluid or disturbances in its circulation/absorption into the venous sinuses
What happens if the bridging veins are injured?
Subdural haematoma
Where is the suprorbital margin found?
Ridge above the eye socket (orbit)
Where is the supraciliary ridge found?
Above the supraorbital margin
Where is the sphenoid bone found and what are its parts?
Found behind the eye
Greater wing, body, lesser wing
Name the two parts of the temporal bone.
Squamous part
Petrous part
Where is the mastoid process found?
Protrusion of temporal bone anterior
Where is the external acoustic meatus found and what does it look like?
Round bit near temporal bone
Where is the external occipital protuberance found?
Back surface of the occipital bone
Which lobe is in the anterior cranial fossa?
Frontal lobe
Which lobe is in the middle cranial fossa?
Temporal lobe
What is in the posterior cranial fossa?
Brainstem and cerebellum
What is the difference between the putamen and globus pallidus making up the lentiform nucleus?
Putamen = darker, more lateral in coronal section
Globus pallidus = paler, more medial in coronal section
