1. BRAINSTEM I Neuroscience 2005

2. LECTURE OVERVIEW Definition of Brainstem Brief Gross Orientation
Brief Cross Sectional Anatomy Orientation
Correlation of Gross and Cross Sectional Anatomy
Composite List of Brainstem Structures
Cranial Nerves (CN’s)
Introduction
Nucleus vs. Ganglion
Organization / Classification Based on Embryology
Spinal Cord vs. Brainstem
Skeletal mm: Branchial Arch vs. Somite Myotome
Correlation of Location and Function of CN’s

3. DIVISIONS of the BRAINSTEM
Midbrain
Pons
Medulla
(Terms “upper” and “lower” sometimes used)

4. LOCATION of BRAINSTEM Cranial Cavity CNS
Begins caudally at FORAMEN MAGNUM
Mostly infratentorial
CNS
Between spinal cord and diencephalon
Carpenter, Core Text of Neuroanatomy, 1991

5. Brainstem in situ
Nolte Text, p. 263

6. Grant’s Atlas of Anatomy

7. Median Saggital Plane
Haines Atlas
Haines Atlas
Nolte Text, p. 267

8. Haines Atlas, fig. 6-2

9. SERIAL SECTIONS
Haines Atlas

10. CLINCAL IMAGING vs. ANATOMY
WHICH WAY IS UP?
VENTRAL
DORSAL
Haines Atlas

12. CLASSICAL REPRESENTATIVE SECTIONS
MEDULLA
PONS
MIDBRAIN
Haines Atlas

13. Nolte Fig. 11-5

14. Nolte Fig. 11-6

17. Brainstem Structures:
Nolte Fig. 15-3
Brainstem Structures:
Name
Location
Function
Dev. Divisions
Mesen
Meten
Myelen

18. Cranial Nerves Telencephalon 1 Diencephalon 2 Midbrain 3 & 4 Pons
(not pictured)
Diencephalon 2
Midbrain
3 & 4
Pons
5 - 8
Medulla
9 - 12
Spinal Cord 11

19. Cranial Nerves (CN’s) HEAD AND NECK INNERVATION Components of CN’s:
Sensory
Special sensory
Motor (2 embryological types of skeletal mm)
Autonomic Motor:
Parasympathetics (sm. mm, glds)
- preganglionic
- head to the transverse colon
- where do the sympathetics to the head originate?
Neurons of origin in:
- NUCLEI
- GANGLIA
Clinical relevance:
- localization of lesions
- extent of damage / prognosis
- difficult to treat

20. CRANIAL NERVE NUCLEUS vs. GANGLION
OUTSIDE OF CNS
CLUSTER OF NEURONS
PSEUDOUNIPOLAR
SENSORY
WITHIN CNS
CLUSTER OF NEURONS
NOT PSEUDOUNIPOLAR*
SENSORY OR MOTOR
*except mesencephalic nucleus of V
Carpenter, Core Text of Neuroanatomy, 1991

21. SENSORY GANGLIA of CRANIAL NERVES
Langman’s Embryology
Carpenter, Core Text of Neuroanatomy, 1991

22. Cranial Nerve Nuclei

23. “WORM DIAGRAMS”
NOLTE
HAINES ATLAS

25. CLASSIFICATION OF CRANIAL NERVES
Based on:
A. Function
Motor
Somatic (skel. mm)
Visceral (sm. & card. mm & spec. skel. mm)
Sensory
Special Sensory
B. Embryologically Derived Location
Alar plate = sensory (lateral)
Basal plate = motor (medial)

26. SENSORY and MOTOR ORGANIZATION
Embryonic CNS Spinal Cord Brainstem
Langman’s Embryology

27. SPINAL CORD (body) BRAINSTEM (head*)
Motoneurons (EFF) :
somatic motor (skel. mm)
visceral motor (sm. & card. mm., glands)
Sensory neurons (AFF):
somatic sensory (skin, muscle, muc. mem., bone, and joint receptors)
visceral sensory (viscera)
Motoneurons (EFF):
somatic motor (skel. mm)
visceral motor (sm. &card. mm., glands)
branchial motor (skel. mm)
Sensory neurons (AFF):
somatic sensory ( skin, muscle., muc. mem., bone, and joint receptors)
visceral sensory (viscera)
special visceral (taste, smell)
special somatic (eye, ear)
*vagus and accessory nn. also to body

28. Somatic vs. Branchiomeric Skeletal Muscle
Somatic: from the myotomes (part of somites)
extraocular mm = CN III, IV, VI
tongue mm = CN XII
Branchial: from branchial arch* musculature
mm of mastication = CN V
mm of facial expression = CN VII
mm of the pharynx and larynx = CN’s IX, X, XI (ambiguus)
*also referred to as “pharyngeal arch”

29. Pharyngeal Arches
Pharyngeal = Visceral so skel. musc. from arches is a “special” kind of “visceral” muscle (SVE)
The term Pharyngeal Arch is used interchangeably with Branchial Arch
BRANCHIAL motor = SVE
Langman’s Embryology

30. BRANCHIAL ARCHES (PHARYNGEAL ARCHES)
Langman’s Embryology
1st = V musc. mast., ant. belly dig., mylohy., tensor tym., tensor palat.
2nd = VII musc. facial expr., stapedius, post. belly dig., stylohyoid, auricular
3rd = IX stylopharyngeus
4th = X Sup. Laryngeal Br. = cricothyroid, levator palat., pharyng. constr.
( 6th arch supplied by Recurrent Laryngeal Br. = intrinsic laryn. mm; also CN XI)

31. Langman’s Embryology
Nolte Text, p. 376
Gilman & Winans-Newman

32. Special Sensory
Somatic Sensory
Visceral Sensory
Visceral motor
Branchial motor
Somatic motor
Nolte Fig. 12-1

33. Haines Atlas

34. S G 12, 3, 4, 6 = tongue + eye mm (myotomes) E
G 5, 7, 9, 10 = skin + mucous mem. (prop. 3, 4, 6, 12) S
S 2, 8 = eye + ear A
G 9, 10 = int. organs V
S 7, 9, 10, 1 = taste, olf.
S G , 3, 4, 6 = tongue + eye mm (myotomes) E
G 3, 7, 9, 10 = parasymp.
S 5, 7 ambig. = branchial mm