Brain Atlas Flashcards
Dura Mater
Outermost covering
Arachnoid/Pia
Arachnoid layer is below dura mater and underlaid by the subarachnoid space where vessels and CSF travel
Arachnoid collapses onto pia mater postmortem
Pia mater is the innermost covering of the Brain tightly adhered to sulci and gyri
Arterial circle of Willis
Surrounds region of pituitary gland
Circle is fed by two internal carotid arteries and basilar artery
Caudal= caudal communicating arteries and rostral cerebral arteries form rostral end of circle
Rostral cerebral arteries
Between dorsal longitudinal fissure supplying the medial surface of the rostral cerebral cortex
Middle cerebral Artery
Supplies lateral surface of cerebral cortex
Caudal cerebral artery
Follows optic tract over thalamus to the longitudinal fissure
Dorsal Sagittal sinus
In the dura along dorsal midline
Transverse sinuses diverge from caudal end of the Sagittarius sinus in dura
Transverse sinus blood flow
In dura
Into the sigmoid and temporal
Sigmoid is continuous with the internal jugular vein and the temporal sinus is continuous with the internal maxillary vein
Dorsal longitudinal fissure
Separates into two hemispheres
Cruciate sulcus
Indentation near rostral part of frontal lobe and separates precruciate and postcruciate gyri
Precruciate: somatomotor for leg and arm and postcruciate: motor for face and somatosensory areas
In carnivores only
Rhinal fissure
Sulcus, runs longitudinally on ventrolateral aspect of brain and separates the olfactory bulb, tract and pyriform lobe (olfactory cortex)
Telencephalon
Optic to pons
Cerebrum, olfactory/pyriform lobe, hippocampus, corpus callosum
Lumen= lateral ventricles
Grows after other divisions so overlays diencephalon, mesencephalon
Only olfactory nerve
Diencephalon
Thalamus, hypothalamus and mammillary bodies
Lumen= third ventricle
Ends at interthalamic adhesion
Optic nerve
Mesencephalon
Crus cerebral, rostral and caudal colliculi
Lumen= mesencephalic aquaduct
Occulomotor and trochlear nerve associated
Midbrain, ends when the pons begins
Metencephalon
Cerebellum dorsal and pons centrally
Lumen= 4th ventricle
Includes some of the midbrain
Trigeminal is the only nerve associated with this division
Myelencephalon
Trapezoid bodies and pyramids, medulla
Until spinal cord
Lots of nerves associated
Brainstem
Mesencephalon and metencephalon but the pons only not cerebellum
Telencephalon boundaries
Olfactory bulbs to optic chiasm
Diencephalon boundaries
Optic chiasm to the intercrural fossa
Midbrain boundaries
Intercrural fossa to the rostral margin of pontine decussation
Pons boundaries
Rostral and caudal margin of the pontine decussation
Medulla boundaries
Rostral margin of trapezoid body and disappearance of pyramids, marks pyramidial decussation that occurs with the medulla-spinal cord junction
Abducens Nerve
CN 6
Emerge from junction of pons and trapezoid body
Facial and vestibulocochlear nerve
CN 7 and 8
Found together on lateral margin of trapezoid body
CN nerves
SSMMBMBSBBMM
Corpus Callosum
Largest commissure (axon) of telencephalon connecting the left and right hemispheres
Located ventral to this is the fornix
Rostral commissure
Within the fornix
Fornix= bundle related to hippocampus
Thalamus
Ventral to the fornix
Serves to relay all sensory information except smell to the cortex
Interthalamic adhesion is the middle of the thalamus connecting the two sides with the third ventricle surrounding it
Hypothalamus
Ventral to thalamus
Above the infundibulum of the pituitary
Endocrine, homeostatic and other survival functions
Mammillary bodies
Located caudoventral to hypothalamus
Affective emotional behaviors
Mesencephalic aquaduct
Narrow channel from third to fourth ventricle
Cerebellum
Dorsal structure that is caudal to the occipital cortex and above the brainstem
