Understanding the Brainstem and Its Components

1. The brainstem

2. The brain • Telencephalon 端脑 • Diencephalon间脑 • Cerebellum 小脑 • Brain stem 脑干

3. The brain stem Consists of • Midbrain • Pons • Medulla oblongata

4. Medulla oblongata延髓 Ventral surface • Pyramid锥体: contain pyramidal tract (corticospinal tract) • Decussation of pyramid锥体交叉: formed by crossing fibers of corticospinal tract • Olive橄榄: produced by underlying inferior olivary nucleus • Anterolateral sulcus前外侧沟: rootlets of hypoglossal nerve emerge from it • Retroolivary sulcus橄榄后沟: rootlets of glossopharyngeal, vagus and accessory nerves emerge from it

5. Medulla oblongata Dorsal surface • Lower portion • Gracile tubercle • produced by underlying gracile nucleus • Cuneate tubercle • marks the site of cuneate nucleus • Inferior cerebellar peduncle Obex Upper portion: forms the lower half of rhomboid fossa

6. Pons 脑桥 Ventral surface • Basilar part基底部 • Basilar sulcus 基底沟 • Bulbopontine sulcus 延髓脑桥沟: from medial to lateral, the abducent, facial and vestibulocochlear nerves appear • Middle cerebellar peduncle小脑中脚 • Trigeminal nerve 三叉神经 • Pontocerebellar trigone 脑桥小脑三角: the junction of medulla, pons and cerebellum

7. Pons Dorsal surface • Superior cerebellar peduncle • Superior medullary velum • Trochlear nerve

8. Midbrain 中脑 Ventral surface • Crus cerebri 大脑脚底 • Interpeduncular fossa 脚间窝oculomotor nerves emerge from medial of crus cerebri • Posterior perforated substance 后穿质

9. Midbrain中脑 Dorsal surface • Superior colliculus constitute centers for visual reflexes • Inferior colliculus associated with auditory pathway • Brachium of superiorcolliculi • Brachium of inferior colliculi

10. Fourth ventricle 第四脑室 Central canal →fourth ventricle →mesencephalic aqueduct→third ventricle Position • Situated ventral to cerebellum, and dorsal to pons and cranial half of medulla

11. Boundaries • Inferolateral: gracile and cuneate tubercles, inferior cerebellar peduncle • Superolateral: superior cerebellar peduncle • Lateral recess

12. Features • Median sulcus 正中沟 • Sulcus limitans 界沟 • Vestibular area前庭区 overlies vestibular nuclei • Acoustic tubercle听结节overlyingdorsal cochlear nucleus • Medial eminence 内侧隆起 • Striae medullares 髓纹

13. Facial colliculus • : overlies nucleus of abducent n. and genu of facial nerve • Hypoglossal triangle : verlyinghypoglossal nucleus • Vagal triangle: overlies dorsal nucleus of vagus nerve • Funiculus separans • Area postrema • Locus ceruleus

14. Roof • Anterior part: formed by superior cerebellar peduncle and superior medullary velum • Posterior part: formed by inferior medullary velum and choroid plexus of fourth ventricle • Three apertures • Median aperture of fourth ventricle第四脑室正中孔 • Two lateral apertures of fourth ventricle 第四脑室外侧孔

15. Tela choroidea and choroid plexus

16. Internal structures Gray matter • Cranial nerve nuclei • Relay nuclei

17. General somatic motor nuclei一般躯体运动核 • Nucleus of oculomotor n. • Nucleus of trochlear n. • Nucleus of abducent n. Nucleus of hypoglossal n.

18. Generalsomatic motor nuclei

19. Special visceral motor nuclei • Motor nucleus of trigeminal n • Nucleus of facial n. • Nucleus ambiguus • Accessory nucleus

20. Special visceral motor nuclei

21. General visceral motor nuclei 一般内脏运动核 • Accessory oculomotor nucleus 动眼神经副核 • Superior salivatory nucleus 上泌涎核 • Inferior salivertory nucleus 下泌涎核 • Dorsal nucleus of vagus n. 迷走神经背核

22. General visceral motor nuclei

23. Visceral sensory nuclei ( general and special ) • Nucleus of solitary tract孤束核

24. Visceral sensory nuclei ( general and special )

25. General somatic sensory nuclei • Mesencephalic nucleus of trigeminal n. 三叉神经中脑核 • Pontine nucleus of trigeminal n. 三叉神经脑桥核 • Spinal nucleus of trigeminal n. 三叉神经脊束核

26. General somatic sensory nuclei

27. Special somatic sensory nuclei • Cochlear nuclei 蜗神经核 • Vestibular nuclei 前庭神经核

28. Special somatic sensory nuclei

29. Relay nuclei 传导中继核 • Gracile nucleus 薄束核 • Cuneate nucleus 楔束核 • Inferior olivary nucleus 下橄榄核 • Superior olivery nucleus 上橄榄核 • Pontine nucleus 脑桥核 • Nucleus of inferior colliculus下丘核 • Gray matter layers of superior colliculus 上丘灰质层 • Red nucleus 红核 • Substantia nigra 黑质 • Pretectal area 顶盖前区

30. Non-cranial nerve nuclei

31. White matter Ascending tracts • Medial lemniscus 内侧丘系 • Spinal lemniscus脊髓丘系 • Trigeminal lemniscus 三叉丘系 • Lateral lemniscus外侧丘系

32. Medial lemniscus 内侧丘系

33. Spinal lemniscus 脊髓丘系

34. Trigeminal lemniscus 三叉丘系

35. Descending tracts • Corticospinal tract皮质脊髓束 • Rubrospinal tract 红核脊髓束 • Tectospinal tract 顶盖脊髓束 • Vestibulospinal tract 前庭脊髓束 • Reticulospinal tract 网状脊髓束

36. Lateral lemniscus 外侧丘系

37. Reticular formation of brain stem • Ascending reticular activating system (ARAS) 上行网状激动系统 • Motor central and vital centres • Reticulospinal tract • Cardiovascular center and respiratory center • Serotonergic rapheal nuclei

38. The characters of internal structure of brain stem

39. Medulla oblongata Lower part (closed part) • Two decussations– • Decussations of medial lemniscus • Decussations of pyramid

40. Medulla oblongata Upper part (open part) • Appearance of inferior olivary nuculeus and inferior cerebellar peduncle • Enlargement of central canal to form the fourth ventricle floor

41. Pons • Tegmentum of pons脑桥被盖directed upward continuation of medulla oblongata • Basilar part基底部 contain both longitudinal and transverse fibers intermixed with pontine nuclei

42. Midbrain • Rectum of midbrain中脑顶盖: includes superior and inferior colliculi • Cerebral peduncle 大脑脚 • Tegmentum 被盖: contain ascending tracts, central gray matter, recticular formation and so on • Substentia nigra 黑质 • Crus cerebri 大脑脚底: • Pyramidal tract锥体束－middle three-fifths of the crus: • Frontopontine tract额桥束medial one-fifth: • pariatotempopontine tract 顶颞桥束lateral one-fifth