Neuroanatomy Flashcards
2 Major Partitions of the Dura Mater
- Falx cerebri 2. Tentorium Cerebelli
Anterior Fossa
Contains the frontal lobes
Anterior Spinal Artery
(p. 219)
- originates from the vertebral arteries
- runs along the ventral surface of the spinal cord
Apraxia
- a deficit in higher-order motor planning and execution despite normal strength
- lesions to regions of the association cortex
Arachnoid Granulations
Reabsorbs CSF in the subarachnoid space.
Arachnoid mater
The 2nd meningeal membrane that adheres to the inner surface of the dura
Avascular Very thin and delicate
Attached to the 3rd membrain by cobweb-like strands of tissue
Closely follows the conformation of the outer layer of the brain and spinal cord
Blood vessles of the brain are distributed in the arachnoid mater and send branches through the pia to supply the outer layer of the cerebral hemispheres
CSF percolates over the surface of the brain within the subarachnoid space
Are migraines genetic?
Yes
About 75% of cases have a family history
Are migraines often unilateral?
Yes, but if they are always on the same side, you should get an MRI.
Astroglia
Gives structural support to and repair neurons
Atrium
Connects 3 parts of the lateral ventricle:
1) The body
2) The Posterior (Occipital) Horn
3) The Inferior (Temporal) Horn
Basis Pedunculi
- Where the internal capsule goes through the midbrain cerebral peduncles (aka, “feet of the brain”)
- The white matter in the ventral portion of the cerebral peduncles
- The middle 1/3 contains corticobulbar and corticospinal fibers with the face, arm, trunk, and leg axons arranged from medial to lateral
Bridging Veins
Traverse the subdural space.
They drain the cerebral hemispheres.
They pass through the subdural space en route to several large dural venous sinuses.
Cerebellum
- Motor coordination - skilled movements
- Control of muscle tone
- Equilibrium
- Postural reflexes
Cerebral Aqueduct
AKA - Aqueduct of Sylvius
Where the 3rd ventricle communicates with the 4th ventricle
Cerebrospinal fluid (CSF)
Crystal-clear, colorless, fluid composed largely of water Acts as a buffer to protect the brain and spinal cord Helps to provide constant pressure within the bony cavity under normal conditions
Choroid Plexus
Produces CSF
Lie inside the ventricles
Cistern
Areas where the subarachnoid space widens to form larger CSF collections
Cisterna Magna
AKA - Cerebellomedullary cistern
The largest cistern
Located beneath the cerebellum near the formen magnum
Cluster Headaches
- 5x more in men
- 1+/day every day for a few weeks then vanishes for months
- Severe headaches, constant boring sensation behind one eye
- Lasts 30-90 minutes
- Usually accompanied by unilateral autonomic sx (tearing, red eye, flushing, sweating, nasal congestion, or Horner’s Syndrome)
- Inhaled oxygen often effective in aborting attacks
Complicated Migraine
Accompanied by focal neurological deficits, such as:
- Sensory phenomena
- Motor deficits (hemiplegia)
- Visual loss
- Brainstem findings (basilar migraine)
- Impaired eye movement (ophthalmoplegic migraine)
Coronal sections
(aka frontal sections) Parallel to a vertical plane through both ears
Corpus callosum
Thick band of white matter that unites the two hemispheres of the brain
Corticospinal Tract Fibers Cross Over Where?
(p. 225)
- At the cervicomedullary junction (where the medulla and spinal cord meet)
- They cross over in the pyramidal decussation to enter the lateral white matter columns of the spinal cord, forming the lateral corticospinal tract (arm, trunk, leg; from medial to lateral)
- 85% of fibers cross over (pyramidal decussation)
- 15% continue into the ipsilateral spinal cord and enter the anterior white matter columns to form the anterior corticospinal tract (trunk)
Diencephalon
- Thalamus
- Epithalamus
- Hypothalamus
- Pineal body
- Third ventricle
Dorsal Grey Horns
- location where sensory nerve fibers synapse onto interneurons in the spinal cord
Dura mater
Tough, outermost layer. Closely attached to the inner surface of the skull. Consists of 2 fibrous layers: 1) Periosteal (outer), which is adherent to the inner surface of the skull & 2) Meningeal (inner), which forms folds that descend far into the cranial cavity. The two layers are fused except for at the falx cerebri and tentorium cerebelli.
Dural Venous Sinus
Large venous channels that lie enclosed within the two layers of dura.
They drain blood mainly via the sigmoid sinus to reach the internal jugular vein.
Ependymal Cells
Line the brain’s ventricles and produce CFS
Ependymal Cells
Line the walls of the ventricles
Epithalamus
- Not well understood
- Encompasses the pineal gland
Falx cerebri
A vertical partition b/t the major divisions of left and right cerebral hemispheres. Its narrow end is attached to the skull anteriorly. Its upper edge is attached to the vault of the skull in the midline Its lower edge arches over the upper edge of the corpus callosum to join onto the tentorium cerebelli
Foramen Magnum
The largest foramen at the base of the skull. It’s where the spinal cord meets the medulla (cervicomedullary junction)
Foramina
Holes, which allow cranial nerves, spinal cord, and blood vessels to enter and leave the intracranial cavity
Foramen Spinosum
Where the middle meningeal artery enters the skull.
Fossae
Compartments in the inner surface of the skull
Frequency of migraines
Several times per week to once every few years.
Ganglia
- collection of neuron cell bodies outside of the CNS
Great Radicular Artery of Adamkiewicz
(p. 220)
- a prominant radicular artery (anywhere from T5 to L3) that provides the major blood supply to the lumbar and sacral cord
Grey matter
Nerve-cell collections
Hematocrit Effect
When with mixed-density hematomas, the denser acute blood settles to the bottom
Hemiplegia or Hemiparesis
- Locations ruled out
- Corticospinal tract below the motor cortex above the medulla, b/c the face is spared
- Muscle or peripheral nerve
- Not below C5, b/c some arm muscles would be spared
- Locations ruled in
- Arm and leg area of motor cortex
- Corticospinal tract from lower medulla to C5
- Side of lesion
- Motor cortex or medulla (above pyramidal decussation) - contralateral
- Cervical spinal cord (below pyramidal decussation) - ipsilateral
- Associated features:
- Upper motor neuron signs
- Affect proximal more than distal muscles (“man in barrel”)
- Cortical lesions may be associated with aphasia or hemineglect
Horizontal sections
At right angles to the other two (coronal & sagittal)
How does CSF leave the ventricular system so it can percolate around the brain and spinal cord?
Through either:
1) The Lateral Foramina of Luschka
2) Teh Midline Foramen of Magendie
Humunculus
(p. 216)
- “little man”
- depicts localization of anatomical motor/senory functioning
- Generally:
- Lateral: tongue, face, hands
- Dorsal: arms, shoulders, torso
- Interhemispheric: legs, feet
Innervated areas that can cause headache pain are?
Blood vessels
Meninges
Scalp
Skull
Insula
Cortical area buried within the lateral sulcus Can only be seen when the lips of the fissure are drawn apart
Interpeduncular Cistern
Located on the ventral surface of the midbrain, between the cerebral peduncles.
The 3rd nerve (occulomotor nerve) exits the midbrain through here.
Internal Capsule
- internal portion of white matter tracks
- 3 parts:
- anterior limb - separates head of caudate from globus pallidus & putamen
- posterior limb - separates thalamus from globus pallidus & putamen; where the corticospinal tract lies
- genu - “knee”