1. Cranial Fossa: Brain and Spinal Cord PA 481 A&P Tony Serino, Ph.D. Biology Dept. Misericordia Univ.

2. Central Nervous System (CNS) Gray vs. White matter Protection of CNS –Meninges –CSF flow Brain –Development –Selected structures Spinal cord –Selected structures

3. Cranial Fossa Anterior Middle Posterior

4. CNS (Central Nervous System) Brian and spinal cord Displays gray and white matter –Gray matter are areas of CNS with many cell bodies of neurons present (little myelinated nerve fibers) –White matter are area of CNS with few cell bodies but many myelinated nerve fibers Protected by bone and membranes

5. Gray and White Matter Since the cerebrum and cerebellum outgrow their cores, gray matter ends up on outside of both structures.

6. Meninges Dura Mater –outermost; tough, fibrous CT –In brain, divided into two layers (periosteal and meningeal) –In spine, only one layer with fat filled space above the layer called the epidural space Arachnoid –middle; web-like appearance –Potential space between Dura and arachnoid is the subdural space Pia Mater –innermost, delicate membrane fused with CNS surface –Space between Pia and Arachnoid is the subarachnoid space

7. Meninges of the Spinal Cord Pia mater Arachnoid Dura mater Meninges Centrum Epidural space Subdural space Subarachnoid space Dorsal Root Ganglion

8. Brain Meninges

9. Extensions of Dura Mater hold brain in cavity Sellar diaphragm (not shown)

10. Venous Sinuses of Cranium Superior Sagittal Inf. Sagittal Straight Cavernous Sigmoid Transverse

11. Lateral Venous Lacunae Arachnoid villi

12. Maxillary A. Middle Meningeal A. Middle Meningeal Artery

13. Brain Ventricles

14. Choroid Plexus

15. CSF (cerebral-spinal fluid) Flow

16. Hydrocephalus Blockage of CSF flow can lead to severe brain and/or head enlargement. In an adult, such swelling would be fatal.

17. Brain Development Structures Functional Areas

18. Neural Tube forming

19. Neural Tube

20. Brain Vesicles

21. Flexures and Cerebral Cortex Growth

22. Major Divisions of Brain Brain Stem = midbrain + pons + medulla

23. Brain Anatomy (req’d)

24. Projections vs. Commissures

25. Functional Anatomy of Brain

26. Functional Areas of Cerebrum

27. Primary Motor and Somatosensory Gyri

28. Basal Nuclei: cerebral nuclei Putamen and Globus Pallidus Subthalamic nuclei and the Substantia nigra are usually included

29. Reticular Formation Extends along length of brain stem; used in maintaining alertness while awake; also includes motor nuclei such as centers for Cardiac, Respiratory and Vasomotor control.

30. RAS receives inputs from eye, ear and genral sensation to maintain alertness

31. Limbic System: functional system; responsible for emotion and memory Cingulate Gyrus Fornix Mammillary body

32. Hypothalamus Control of Pituitary

33. Posterior Pituitary

34. Anterior Pituitary

35. Pineal Gland Plays a major role in circadian rhythm control through its sympathetic connection to the hypothalamus Melatonin increases at night and decreases during daylight Implicated in the control of major life changes (such as the onset of puberty and adulthood

36. Internal Carotid Artery

37. Blood Supply (Circle of Willis) Vertebral A. Internal Carotid A. Ant. Communicating Post. Communicating Ant. Cerebral Post. Cerebral Middle Cerebral Basilar A.

38. Cranial Nerves

39. CN I: Olfactory Nerve covered by meninges and contain glial cells Cribiform plate damage after trauma could lead to CSF leakage (runny nose after head trauma) Pathway: Bulb  tract  med and lat. stria  prepiriform and amygdala

40. CN II: Optic Nerve Covered by meninges Leaves by optic canal Pathway: nerve  chiasma  tracts  lat. geniculate and sup. colliculus  optic radiation to occipital lobe

41. Superior Orbital Fissure Midbrain Pons Oculomotor N. (III) Ciliary ganglion Inferior Rectus muscle Inferior Oblique muscle Superior Rectus muscle Medial Rectus muscle Levator Palpabrae muscle Parasympathetic Motor fibers Originates from brain stem: midbrain Leaves via sup. orbital fissure Path: occulomotor nucleus  muscles : levator palpebrae, sup., medial, inf. rectus, and inf. oblique. Separate branch from Edinger- Westphal nuclues  ciliary ganglion  parasym innervation to iris sphincter and ciliary muscle. Palsy –leads to ptosis, diplopia, dilated pupil; gaze is “down and out”; pupil involvement usually due to increase cranial pressure due to surface location of fibers in nerve CN III: Occulomotor Nerve

42. CN IV: Trochlear Nerve Originates from brain stem: midbrain Complete decussation in midbrain Nucleus to Sup. oblique, runs the longest distance in cranial vault Passes through sup. orbital fissure In injury, affected eye is higher and deviated medially, head tilts away from lesion; hardest to diagnose

43. CN V: Trigeminal Nerve

44. CN VI: Abducens Nerve Originates from brain stem: pons  goes to lateral rectus m. Passes through sup. orbital fissure Injury: affected eye deviates medially (crosseyed look) patient may turn head to compensate

45. CN VII: Facial Nerve

46. CN VIII: Vestibulocochlear Nerve

47. CN IX: Glossopharyngeal Nerve

48. CN X: Vagus Nerve

49. CN XI: Accessory Nerve

50. CN XII: Hypoglossal Nerve