1. Gross Brain Overview: Part I
Basic Neuroscience
James H. Baños, Ph.D.

2. Overview Anatomical Directions Cranial Fossa Meninges
Pathology of the Cranial Fossa & Meninges

3. Anatomical Directions
Dorsal fin

4. Anatomical Directions
Dorsal fin

5. Anatomical Directions
Dorsal fin

6. Anatomical Directions
Dorsal
Ventral

7. Anatomical Directions
Dorsal
Caudal
Caudus = tail
Rostral
Rostrum = Stage or speaking platform
Ventral

8. Anatomical Directions
Dorsal-ventral and rostral-caudal are with respect to the neuraxis
Dorsal
Rostral
Caudal
Ventral

9. Anatomical Directions
But wait……we evolved

10. Anatomical Directions
But wait……we evolved…
Dorsal
Caudal
Rostral
Ventral
Dorsal
Rostral
Caudal
Ventral
Ventral
Dorsal
Caudal

11. Anatomical Directions
Rostral
Caudal
Caudal

12. Anatomical Directions
Dorsal
Ventral
Dorsal
Ventral

13. Anatomical Directions
Anterior-posterior and superior-inferior are in 3-D space
And do not respect the neuraxis.
Superior
Posterior
Anterior
Superior
Inferior
Anterior
Posterior
Inferior

14. Anatomical Directions
Medial-lateral can also respect either the midline, or some other
reference point
Lateral A B
Medial

15. Anatomical Directions
Just to keep it interesting:
Mesial = Medial

16. Anatomical Directions
Proximal
Distal

17. Ipsilateral vs. Contralateral
Ipsilateral -- On the same side, with respect to a reference point
Contralateral -- Opposite side, with respect to a reference point

18. Anatomical Planes Sagittal Plane Horizontal/axial Plane
Coronal Plane
Transverse Section

19. Coronal Plane
Corona = crown….but think
Statue of Liberty

20. Sagittal Plane
Mid-sagittal plane
Sagittal MRI

21. Horizontal Plane
AKA:
Axial plane
CT plane

22. Cranial Fossa

23. Cranial Fossa
Distinct areas of the skull base
Contain and support various parts of the brain
Contact point for the meninges

24. Cranial Fossa Anterior cranial fossa -- frontal lobes
Middle cranial fossa -- Temporal lobes
Posterior cranial fossa -- Cerebellum and
brain stem

25. Cranial fossa contain lumen, or holes for cranial nerves, arterial supply, and venous drainage

26. Meninges

27. Meninges Three layers covering the brain Support, protection
Dura mater
Arachnoid
Pia mater
Support, protection
Contain circulating CSF that supports the brain

28. Meninges

29. Dura Mater “Tough Mother” Thick, leathery outer covering
Adheres to inner surface of skull
Support, and forms sinus system (veinous drainage)
Pain sensitive
Has own blood supply -- Middle meningeal artery

30. Arachnoid Spongy/fibrous layer between the dura and pia
Collagenous connective tissue
Keep brain suspended in meninges
Subarachnoid space
Contains CSF

31. Pia Mater Innermost layer
Adheres almost indistinguishably to cortical surface, including sulci and gyri
Difficult to see grossly or remove

32. Dura Mater

33. Dura Mater
Middle meningeal artery

34. Arachnoid

35. Arachnoid

36. Pia and arachnoid together are sometimes referred to as the leptomeninges
CSF flows between the arachnoid and pia in the subarachnoid space

37. Dural Reflections

38. Also called dural septa
Dural Reflections
Also called dural septa
In certain places, the dura doubles on itself and forms a division or partition between parts of the brain
Falx cerebri
Tentorium cerebelli

39. Falx Cerebri
Extends down the longitudinal fissure, between the cerebral hemispheres
Forms the triangular-shaped superior sagittal sinus superiorly

40. Falx Cerebri

41. Falx Cerebri

42. Tentorium Cerebelli
Extends inward between the cerebellum and occipital lobes
Forms a “soft top” for the posterior cranial fossa
Brain stem passes through tentorial notch
Forms the transverse sinus posteriorly

43. Tentorium Cerebelli

44. Tentorium Cerebelli

45. Tentorium Cerebelli

46. Pathology of the Meninges

47. Meningitis Infection/inflammation of the meninges Can progress to
Bacterial
Viral
Can progress to
More widespread CNS infection
Hydrocephalus, if flow of CSF is blocked (e.g., purulent accumulation)

48. Bleeds Epidural Hematoma Rupture of middle meningeal artery
Blood accumulates between dura and skull
Mass effect compresses brain
Fed by arterial perfusion…can grow quickly

49. Bleeds
Epidural Hematoma
Mass
effect
Midline
shift

50. Bleeds Subdural Hematoma
Rupture of bridging veins from surface of cortex to veinous sinuses (e.g., superior sagittal sinus)
Accumulates more slowly (veins)
Still results in mass effect and compression of the brain
Older people particularly susceptible. Why?

51. Bleeds
Subdural Hematoma -- crescent shaped

52. Bleeds
Subdural Hematoma

53. Bleeds Subarachnoid Hemorrhage Rupture of cerebral vein or artery
Bleeding into the subarachnoid space
Blood hugs the surface of the brain (i.e., within the subarachnoid space). No mass effect
Can block flow of CSF and result in hydrocephalus

54. Bleeds
Subarachnoid Hemorrhage

55. Herniation Syndromes subfalcine cingulate herniation
Cingulate gyrus herniates below falx cerebri

56. Herniation Syndromes Uncal/Transtentorial Herniation
Uncus (medial temporal lobe) herniates medially over the edge of the tentorium cerebelli into the brain stem

57. Herniation Syndromes Tonsilar Herniation
Cerebellar tonsil herniates through the foramen magnum

58. Coming up next… Organization 3-D Orientation to Internal Structures
Developmental/Evolutionary
Morphology
3-D Orientation to Internal Structures