Anatomic Landmarks

Question 1

what is the massa intermedia?

Answer 1

• aka thalamic adhesion
• is the bridging of each thalamus through the 3rd, which creates the hole in the the 3rd ventricle

Question 2

label, note important features

Answer 2

only portion of corona radiata seen right now are association fibers (which interconnect ipsilateral gyri) there are no internal capsule or lateral ventricles seen, indicating this cut is very rostral (pre-frontal cortex)

Question 3

lable, note important features

Answer 3

Question 4

how can the lateral ventricles localize relative position in the brain?

Answer 4

• anterior horn - in frontal & parietal lobes
• posterior horn - in occipital lobe
• inferior horn - in temporal lobe

Question 5

label, note important features

Answer 5

Question 6

label, note important features

Answer 6

uncus is seen on the ventral (inferior) surface of cerebram, pointing towards the mamillary bodies or optic chiasm. following the uncus, the change in the basic organization of cortex indicates the hippocampus

Question 7

label, note important features

Answer 7

• thalamus often in the same coronal cut as the tegmentum (and tentum), and is superior to both.
  
  • tegmentum (midbrain), from deep -> superficial: red nucleus, substantia nigra, crus cerebri

Question 8

label, note important features

Answer 8

• LV = lateral ventricles
• CN = caudate nucleus
• BG = basal ganglia
• T = thalamus: in between 3rd ventrical and IC
• Tegmentum: ventral midbrain that is in line with (inferior to) the thalamus:
  
  • from deep/superior/posterior to superficial/inferior/anterior:
    
    • red nuclei
    • substantia nigri
    • crus cerebri (cerebral peduncle)
• BP = basis pontis
• H = hippocampus (“geographically distinct”)

Question 9

label, note important features

Question 10

what structures form the walls of the 4th ventricle?

Answer 10

• lateral borders: cerebellar peduncles
• ventral border: brainstem (largely pons)
• dorsal border: cerebellum
• caudal (inferior) borders: medulla oblongota posterior ridges - gracile & cuneate tubercles

Question 11

label & note important features

Answer 11

caudal coronal cut

• four leave clover = orpora quadregemina (tectum)
• note how the cerebellar peduncles are
  
  • forming the lateral walls of the 4th ventricle
  • extending from arbor vitae and connect to:
    
    • superior - red nucleus (tegmentum)
    • middle - basis pontis
    • inferior - medulla oblongota

Question 12

what are the cerebral peduncles?

what forms them?

what are their key anatomic associations?

Answer 12

• cerebral peduncles are the external extension of the internal capsule.
• they form part of the tegmentum, and are made up of the
  
  • substantia nigra (deep)
  • crus cerebri (superficial)
    
    • note: crus cerebri are immediatley lateral to mammary bodies in transverse cut

Question 13

which cerebellar peundcle connects to the midbrain?

Answer 13

superior cerebellar peduncle - connects to the red nuclei of tegmnetum (deepest portion)

Question 14

what is the vermis?

discuss the relationship of the vermis with the 4th ventricle?

Answer 14

• is a verticle partition with longitudinal fibers that separates the cerebellar hemisphere
• 4th ventricle:
• • in transverse cuts: is dorsal (posterior) to 4th ventricle
    
    • in coronal cuts that cuts that contain both the 4th ventricle & cerebellum: the vermis is above the 4th ventricle (shown here is a coronal cut)

Question 15

what portion of the cerebellum contain the deep cerebellar nuclei?

which of these nuclei is normally visible?

Answer 15

• contained within arbor vitae
• dentate nucleus it normally visible

Question 16

label, note impotant features

Answer 16

Question 17

label, note important features

Answer 17

trasnverse cut

• note longitudinal fissure
• very superior cut, no ventricles shown

Question 18

label, note important features

Answer 18

transverse cut

• internal capsule making “arrowhead” shape - anterior, genu, posterior
• note that this cut has two section of lateral ventricle - each bridged by corpus collosum

Question 19

label, note important features

Answer 19

transverse cut

• note how in a transverse cut, the basal ganglia appear lateral to thalamus, vs in a coronal cut, basal ganglia are inferior to thalamus
• no matter what: basal ganglia are lateral to IC, while caudate nucleus & thalamus are medial to IC

Question 20

label, note important features

Answer 20

• note how 3rd ventricle
  
  • is in between the thalamus
  • sits above the hypothalamus, which is inferior to t to the thalamus, forming the floor th ediencephalon

Question 21

label picture, note important features

Answer 21

transverse cut

• cerebral adeduct separating midbrain: tegmentum (ventral) vs tectum (dorsal)
  
  • `tegmnetum - sting ray structure
    
    • from deep / superior / posterior -> superficial / inferior / anterior
      
      • red nucleus
      • substantia nigra
      • crus cerebri
  • tectum - denoted by colliculi (rounded structures)
• pons - inferior to midbrain

Question 22

label picture, note important features

Answer 22

transverse cut

• superior cerebellar peduncle joining the red nuclei, the most dorsal & superior part of tegmentum

Question 23

label picture, note important features

Answer 23

transverse cut

• basis pontis (pons):
  
  • pontine nuclei: interdigate with middle cerebral peduncle at lateral pons
  • middle cerebral peduncle: comes from arboe vitae
  • corticlospinal tracts: near ventral surface of basis pontis, tracts perpendicular to surrounding tissue (are running vertically)
• 4th ventricle:
  
  • ​very narwow in the transverse cut - is ventral to vermis
  • vs in certain coronal cuts - is below vermis

Question 24

label picture, note important features

Answer 24

transverse cut

• pons interfacing with cerebellum
  
  • middle peduncle - exending from arbor vitae and interfacing with pontine nuclei
  • dentate nucleus - only visible nuclei of the 4 that comprise the arbor vitae

Question 25

lable, note important features

Answer 25

transverse cut - inf pons & sup medulla? * pons: basis pontis connecting with middle cerebellar peduncle * medulla: dermarcated by inferior olive boies\* * **inferior olive bodies:** ventral feature that is _lateral / dorsal_ to pyramids * **pyramids**: **made of corticospinal tracts** (extending down from pons) * **inferior cerebellar peduncle:** interdigitating with medulla

Question 26

describe the layout of the features on the dorsal surface of the medulla.

Answer 26

* superiorly: * gracile nuclei - medial * cuneate nuclei - lateral * accessory cuneate nuclei - lateral to cuneate * inferiorly: * spinal trigeminal nucleus - _inferolateral to cuneate_

Question 27

what is meant by the "closed" medulla? list & descrbibe the features seen in the closed medulla

Answer 27

closed medulla = caudal medulla: at the level of the central canal * ventral: * pyramidal tracts (corticospinal tracts) - most ventral, extend inf beyond olive bodies * olive bodies - lateral to pyramidal tracts * inferior olive nuclei - superior to pyramids * dorsal: * gracile nuclei - medial * cuneate nuclei - lateral * accessory cuneate nuclei - lateral to cuneate * spinal trigeminal nucleus - _inferolateral to cuneate_