1. Brain Anatomy and Physiology
Dr. Nevo Margalit – Neurosurgery
Tel Aviv Sourasky Medical Center

2. Scalp Skin Connective tissue (superficial fascia)
Epicranial aponeurosis (galea aponeurotica)
Loose areolar tissue
Pericranium
Occipitofrontalis muscle

3. Scalp

4. The Skull

5. The Skull

6. The skull

7. The Menings The 3 layers covering the brain
Dura: covers the brain and spinal cord. The venous sinuses run through the dura. 2 additional Parts of the dura are the Tentorium and the Falx Cerebri.
Arachnoid: Transparent, thin web structure. Creates a space around the brain called the sub arachnoid space where the CSF and the main blood vessels pass.
Pia: a very thin layer. Coats the brain and spinal cord and is inseparable from them.

8. Dura

10. Tentorium and Falx

11. Tentorium

12. Arachnoid

13. Arachnoid – Basal Cisterns

14. Parts of the Central Nervous System
2 hemispheres
Brainstem
Cerebellum
Spinal cord

15. Each hemisphere has lobes:
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Insular lobe
Limbic lobe

16. Lateral View

17. Insula

20. Gyruses and sulci Each lobe is composed of gyruses separated by sulci
The topography can be defined by histology, anatomical relationships or function

21. Map Brodmann

22. Gyruses and Sulci

23. Functional areas

24. Function 2

25. Function 3

26. f-MRI

27. The Motor Strip

28. Fibers

29. Ventricles and CSF

30. Ventricles and CSF
CSF is produced by the choroid plexus in the ventricles
The circulation is from the lateral ventricles to the third through the Monroe- aqueduct- IV ventricle- sub arachnoid space in skull and spine- absorption in sss and other sinuses through arachnoid granulations

31. CSF Pathways

32. CSF Pathways

33. Arteries of the brain

34. Arteries of the brain
Anterior circulation – internal carotid artery, from common carotid in the neck. Bifurcates to MCA and ACA
Posterior circulation – vertebral arteries that join to form the basilar artery that will then bifurcate to 2 PCA

35. Circle of Willis
Communication between 2 sides – anterior communicating (a-com)
Communication between anterior and posterior circulation – posterior communicating (p-com)
Many anomalies may exist

36. Arteries in the neck

37. Arteries in the subarachnoid space

38. Arteries of the brain

39. Physiology

40. Blood supply to the brain
The brain gets 15% of the cardiac output and 20% of the oxygen consumption
The brain tissue gets in average 50ml of blood per 100gr of tissue per minute. The gray matter receives about 3 to 4 times more then the white matter
Total blood supply to the brain is about ml per minute

41. Factors Affecting the blood supply
Autoregulation
Biochemical changes – O2 and CO2
Blood brain barrier - BBB

42. Autoregulation
Maintains a regular blood supply to the brain in changing blood pressures
The range is mm mercury
Possible mechanisms are the myogenic control, neurogenic and biochemichal control

43. CO2
The most important and powerful mechanism that controls brain blood flow
A change in 1mm PCO2 changes the flow in 4-5%
PCO2 of 70 gives a maximal vasodilatation. Above that the flow is pressure dependent

44. Hyperventilation Hyperventilation lowers the PCO2
It has a strong effect but it is limited in time
Could be dangerous if not regulated- ischemia
Can be regulated with a jugular bulb oximeter

45. BLOOD BRAIN BARRIER
The BBB is composed of the tight junctions in the endothelium cells of the blood vessels
Prevents passage of large molecules and even small ions like Na and Cl
Specific substances pass the BBB like glucose and amino acids

46. BLOOD BRAIN BARRIER
Because of the BBB, in the brain hydrostatic and oncotic pressures are not significant. The important parameter is the osmotic pressure
The BBB is damages in trauma, tumor, infarct, SAH and infection

47. BLOOD BRAIN BARRIER

48. Brainstem and Cranial Nerves

49. Brain stem Has 3 parts: midbrain, pons and medulla
Transports all the information to and from the brain
Centers for breathing and blood pressure
The origin or endpoint for cranial nerves
Contains the center of consciousness
Creates connections to the cerebellum

53. Nuclei in the brain stem

55. Cranial nerves 12 pairs of nerves
All cranial nerves except I and II originate from the brainstem
The nerves are sensory, motor or mixed
There are nuclei in the brainstem that are the origin or the endpoint of the cranial nerves

56. CN 1- Olfactory Nerve The sensation of smell Pure sensory nerve
From the nose to the forebrain
Very developed in some animals
Tested an odorous substance

60. CN 2 - Optic N Visual information from the eye to the brain
Pure sensory nerve
Belongs to the CNS and is not part of the PNS
Problems could result in field problem, acuity problem and more
Tested with a vision chart and field exam on confrontation

64. CN 3, 4, 6- occulomotor, trochlear and abbducence
Nerves that control the movement of the eyes and the constriction of the pupil
Pure motor nerves
Problems result in unsynchronized eye movements and/ or dilated pupil
Tested with the patient following a finger and with light

68. CN 5 – Trigeminal N The largest CN Sensory and motor
Sensation from the face eyes, mouth, and motor for mastication muscles
Tested with touch and pin on face

71. CN 7 – Facial N Motor nerve of the face and taste from the tongue
Motor and sensory
Tested with movement of the facial muscles

76. CN 8 – Vestibulocochlear N
The nerves for hearing and balance
Sensory nerves
The most common origin of a schwanoma
Tested by hearing test and balance function

79. CN 9 – Glossopharyngeal N
Sensation from the pharynx
Mainly sensory and small motor part
Problems result in aspiration
Tested with the gag reflex

81. CN 10 – Vagus N
Motor to the muscles larynx and pharynx and the parasympathetic of the body
Motor nerve
Problems result in hoarseness
Tested by opening mouth wide and saying “AH“

83. CN 11 – Accessory N Nerve to the trapezius and sternomastoid muscles
Motor nerve
Tested with shoulder raise or turning the head

85. CN 12 – Hypoglossal N Nerve to the muscle of the tongue Motor nerve
Tested with movement of the tongue