1. Brainstem Anatomy

2. General Organization

3. General organization Sensory cranial nerve nuclei are lateral Sensory cranial nerve nuclei are lateral Motor cranial nerve nuclei are medial Motor cranial nerve nuclei are medial Visceral motor and visceral sensory nuclei are intermediate Visceral motor and visceral sensory nuclei are intermediate

4. Pyramidal decussation Medullary pyramid CN IX CN X CN XII Inferior olive Obex Tubercuum gracilis Tubercuum cuneatus 4 th ventricle

5. Tracts Depending on direction of fibers, cut in long section or cross section. Depending on direction of fibers, cut in long section or cross section. Most tracts are in cross section because they run from rostral to caudal (“descending”) or caudal to rostral (“ascending”). Most tracts are in cross section because they run from rostral to caudal (“descending”) or caudal to rostral (“ascending”). Image of the brainstem of a Brainbow mouse, by Jean Livet of Harvard UniversityBrainbow mouse

7. Sympathetics to eye Sympathetic chain Superior cervical ganglion T1 T2 T3 Hypothalamospinal tract *Damage will produce Horner’s syndrome: anhidrosis, meiosis (small pupil); minor ptosis (drooping of the upper lid)

8. Pyramidal Decussation

9. Pyramid Pyramidal decussation Spinal tract of trigeminal Spinal nucleus of trigeminal Cervical motor neurons Fasciculus cuneatus Fasciculus gracilis Nucleus gracilis Central canal Lateral corticospinal tract Spinal accessory motor neurons Anterolateral system

10. Pyramidal Decussation

11. Pyramid Pyramidal decussation Lateral corticospinal tract Spinal tract of trigeminal Spinal nucleus of trigeminal Cervical motor neurons Fasciculus cuneatus Fasciculus gracilis Nucleus gracilis Central canal Nucleus cuneatus Anterolateral system Spinal accessory motor neurons

12. Caudal Medulla

13. Pyramid Medial lemniscus Internal arcuate fibers Spinal tract of trigeminal Spinal nucleus of trigeminal Fasciculus cuneatus Nucleus gracilis Central canal Nucleus cuneatus Central gray mater Medial Longitudinal fasciculus Anterolateral system

14. Caudal Medulla

15. Pyramid Medial lemniscus Internal arcuate fibers Spinal tract of trigeminal Spinal nucleus of trigeminal Fasciculus cuneatus Nucleus gracilis Central canal Nucleus cuneatus Central gray mater Medial longitudinal fasciculus Hypoglossal nucleus Inferior olivary nucleus Anterolateral system

16. Mid-Medulla

17. Mid-Medulla Pyramid Medial lemniscus Internal arcuate fibers Spinal tract of trigeminal Spinal nucleus of trigeminal Fasciculus cuneatus Nucleus gracilis Solitary nucleus & tract Nucleus cuneatus Obex Medial longitudinal fasciculus Hypoglossal nucleus Inferior olivary nucleus Anterolateral system Dorsal motor nucleus of vagus Ext. cuneate n.

18. Mid-Medulla

19. Mid-Medulla Pyramid Medial lemniscus Internal arcuate fibers Spinal tract of trigeminal Spinal nucleus of trigeminal Solitary nucleus & tract Nucleus cuneatus Obex Medial longitudinal fasciculus Hypoglossal nucleus Inferior olivary nucleus Anterolateral system Dorsal motor nucleus of vagus Ext. cuneate n. Inf cerebellar peduncle

20. Mid-Medulla

21. Mid-Medulla Pyramid Medial lemniscus Spinal tract of trigeminal Spinal nucleus of trigeminal Solitary nucleus & tract Vestibular nucleus Medial longitudinal fasciculus Hypoglossal nucleus Inferior olivary nucleus Anterolateral system Dorsal motor nucleus of vagus Ext. cuneate n. Inf cerebellar peduncle

22. Rostral Medulla

23. Pyramid Medial lemniscus Spinal tract of trigeminal Spinal nucleus of trigeminal Choroid plexus Vestibular nucleus Medial longitudinal fasciculus Cerebellar cortex Inferior olivary nucleus Anterolateral system 4th ventricle Inf cerebellar peduncle

24. Rostral Medulla

25. Pyramid Medial lemniscus Spinal nucleus & tract of trigeminal Vestibular nucleus Medial longitudinal fasciculus Dentate nucleus Inferior olivary nucleus Anterolateral system 4th ventricle Inf cerebellar peduncle Dorsal cochlear n

26. Caudal Pons

27. Pontine nuclei Trapezoid body Anterolateral system Facial nerve Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus 4th ventricle Middle cerebellar peduncle Facial nucleus Abducens nucleus Abducens nerve Raphe nucleus

28. Mid to Rostral Pons

29. Pontine nuclei Anterolateral system Superior cerebellar peduncle Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus 4th ventricle Middle cerebellar peduncle Trigeminal nerve Trigeminal nuclei

30. Mid to Rostral Pons

31. Pontine nuclei Anterolateral system Superior cerebellar peduncle Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus Raphe nuclei Middle cerebellar peduncle

32. Rostral Pons

33. Pontine nuclei Anterolateral system Superior cerebellar peduncle Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus Raphe nuclei Lateral lemniscus Cerebral aqueduct

34. Pontomesencephalic Junction

35. Pontine nuclei Anterolateral system Superior cerebellar peduncle Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus Inferior colliculus Lateral lemniscus Cerebral aqueduct

36. Pontomesencephalic Junction

37. Pontine nuclei Anterolateral system Superior cerebellar peduncle Medial longitudinal fasciculus Corticofugal fibers Medial lemniscus Inferior colliculus Periaqueductal gray Cerebral aqueduct

38. Mesencephalon

39. Mesencephalon Cerebral peduncle Anterolateral system Superior cerebellar peduncle Substantia nigra Medial lemniscus Superior colliculus Periaqueductal gray Cerebral aqueduct Medial geniculate Red nucleus Oculomotor nucleus and nerve

40. Rostral Mesencephalon

41. Cerebral peduncle Anterolateral system Superior cerebellar peduncle Substantia nigra Medial lemniscus PinealPeriaqueductal grayCerebral aqueductPretectal n Red nucleus Oculomotor nerve Thalamus

42. Atlas of brain stem anatomy