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Gross Brain Overview: Part I

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Presentation on theme: "Gross Brain Overview: Part I"— Presentation transcript:

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

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