Copy Right Hongqi ZHANG Department of Anatomy Fudan University 1. Systematic Anatomy. Nervous system Spinal cord. Dr.Hongqi Zhang ( 张红旗 )

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1 Systematic Anatomy Nervous system Spinal cord Dr.Hongqi Zhang ( 张红旗 ) zhanghq58@126.com 1

2 Spinal cord

3 Central nervous system (CNS) Brain Telencephalon Diencephalon Cerebellum Brain stem 1-Midbrain 2-Pons 3-medulla oblongata Spinal cord

border of L1 in adult at newborn at level of L3 Sexual difference: usually a little

4 Position of the Spinal Cord Position: Lies in vertebral canal, 45cm long approximately Upper end: Continuous with medulla oblongata at foramen magnum Lower end: at the lower border of L1 in adult at newborn at level of L3 Sexual difference: usually a little lower in female than in male Clinic significance: anaesthesia done usually at below the L1

5 Anaesthesia in the vertebral canal L1 Skin Subcutaneous fascia Supraspinal lig. Interspinal lig. Yellow lig. Lower end Of spinal cord Needle puncture Draw cerebrospinal fluid From the vertebral canal For lab examination

External Features of Spinal Cord External feature: A long cylindrical structure & slightly flattened anteroposteriorly Two enlargements Cervical enlargement

6 External Features of Spinal Cord External feature: A long cylindrical structure & slightly flattened anteroposteriorly Two enlargements Cervical enlargement corresponds to C 4 -T 1 of spinal cord Lumbosacral enlargement corresponds to L 2 to S 3 of spinal cord Filum terminale-only thin filament Conus medullaris Cauda equina

7 Lumbosacral enlargement Conus medullaris Filum terminale Cauda equina Conus medullaris and cauda equina

with ant.root (motor) 4 - Posterolateral sulcus - connect with post.

8 External Features of Spinal Cord Fissure and sulci 1 - Anterior median fissure 2 - Posterior median sulcus 3 - Anterolateral sulcus - connect with ant.root (motor) 4 - Posterolateral sulcus - connect with post.root (sense) 2 4 Post.root Spinal ganglion Post.branch 1 3 Ant.root Ant.branch

9 Segments of Spinal Cord A portion of the cord that gives rise to a pair of spinal nerve constitutes a segment. There are 31 segments 8 cervical ss 12 thoracic ss 5 lumbar ss 5 sacral ss 1 coccygeal s Segment - s

10 Relationship of SC Segments to Vertebral body In the third month of fetal life, the spinal cord occupies the entire length of the vertebral canal. After that time,there are some difference between spinal cord & vertebral canal in growth speed,that is, the vertebral canal grow faster than that of spinal cord, Spinal cord Vertebral canal Sc length = vertebral canal At 3rd fetal month

11 Relationship of SC Segments to Vertebrae At birth The inferior ends is below at the lower border of L1 in adult;at birth at level of L3, usually a little lower in female than in male. But each spinal nerve have to come out from their corresponding intervertebral foramina. Sc inf. end is higher Than that of canal L3 Sc inf. end is At the level of L 1 at adult After 3rd month At birth

12 More high level More almost horizental. More lower level More obliquity

13 Relationship of SC Segments to Vertebral Numbers Spinal segments Upper cervical region (C1~C4) Lower cervical and upper thoracic region (C5~8;T1-4) Vertebral levels (spines) Lie opposite the corresponding vertebrae One lower in number than corresponding vertebrae Middle thoracic region (T5~T8) Two lower in number than corresponding vertebrae Lower thoracic region (T9~T12) Three lower in number than corresponding vertebrae Lumber segments T10~T12 Sacral and coccygeal segments L1

14 Relationship of SC Segments to Vertebral Numbers Spinal segments Upper cervical region (C1~C4) Lower cervical and upper thoracic region (C5-8;T1~4) Middle thoracic region (T5~T8) Lower thoracic region (T9~T12) Lumber segments Sacral and coccygeal segments Vertebral levels (spines) = C1 ~ C4-1 = C4 ~ T3-2 = T3 ~ T6-3 = T6 ~ T9 = T10 ~ T12 = L1

15 Internal structure of spinal cord T C 1 - Gray matter 2 - White matter 3 reticular formation 1 L 2 S 3 C cervical;t tharacic;l lumbar;s sacral Central canal

16 Internal structure of spinal cord Fasciculus gracilis Fasciculus cuneatus Lat. spinothalamic tract Lat.corticospinal tract Nucleus proprius Gray matter Motor neuron of ant.horn White matter Spinal pia matar Spinal arachnoid Post.root Spinal ganglion Spinal n. Spinal dura matar. Ant.root

17 Gray matter of Spinal Cord Like a butterfly or letter H Consist of cell body,neuroglia and dendrite Located around the central canal Post. horn (column) Intermediate zone Post. gray commissures Ant. gray commissures Ant. horn (column)

18 Gray Matter of Spinal Cord Anterior horn (column) Posterior horn (column) Lateral horn (column) is present in the thoracic & upper lumber segments of the cord (T 1 -L 3 ) only Intermediate zone Ant. gray commissures Post. gray commissures

19 Gray Matter of Spinal Cord Posterior horn (column): 1- Marginal layer 2- Substantia gelatinosa Situated at the apex of posterior horn throughout the length of spinal cord. Receives fibers are associated with the senses cord. 3- Nucleus proprius Situated anterior to the substantia gelatinosa throughout the length of spinal cord. Concerns the sensations of pain and temperature 1 2 3

20 Gray Matter of Spinal Cord Posterior horn (column): Nucleus thoracicus (lable A) Situated at the base of posterior horn and extending from segments C8~L3. Associated with proprioceptive endings A

21 Intermediate zone Intermediolateral nucleus (labeled 1) Extends from segments T 1 ~L 3, Containing sympathetic preganglionic neurons Sacral parasympathetic nucleus : Extends from segments S 2 ~S 4, Containing parasympathetic preganglionic neurons Intermediomedial nucleus (labled A): Throughout the whole length of spinal cord.associated with receiving viscera afferent information 1

22 Anterior horn (column): Two groups of nuclei 1-Medial nuclear group: present in most segments of spinal cord, innervating axial (trunk) muscles 2-Lateral nuclear group: present only in cervical and lumbosacral enlargements, innervating limb skeletal muscles 1 2

23 Anterior horn (column): labeled with red color three kinds of neurons (motor neuron 2) α- motor neuron: large multipolar neuron, innervates skeletal muscles, producing contraction of muscles γ- motor neuron: smaller multipolar neuron, innervates intrafusal muscle fibers of neuromuscular spindles, regulating muscular tonus Interneuron Renshaw s cell: negative feedback

Ⅶ; Anterior horn is composed laminae Ⅷ and Ⅸ;

24 Rexed s lamina Posterior horn is formed by laminaⅠ to Ⅵ; Intermediate zone is corresponding to lamina Ⅶ; Anterior horn is composed laminae Ⅷ and Ⅸ; lamina Ⅹ is the gray matter around the central canal.

25 Important Subdivision of Spinal Cord Gray Matter laminae Ⅰ Ⅱ ⅢⅣ Ⅴ Ⅵ Ⅶ nuclei Posterior marginal nucleus Substantia gelatinosa Nucleus proprius Reticular nucleus Base of posterior column Thoracic nucleus Intermediomedial mucleus Intermediolateral nucleus Sacral parasympathetic nucleus ⅧⅨ Medial motor neuron column Lateral motor neuron column Ⅹ gray matter around central canal

26 White matter of spinal cord Organization Nerve fiber (tract) Around the grey matter Three parts Ant. Funiculus (A.F) Lat. Funiculus (L.F) Ascending & descending fiber Post. Funiculus (P.F) Ascending fiber only White commissure Ant.commissure of WM Post.commissure of wm Copy WM white Right Hongqi matter ZHANG Department of Anatomy Fudan University P.F L.F A.F

27 White Matter of Spinal Cord White matter contains three kinds of fibers: ascending, descending and fasciculus proprius Post. funiculus Post. white commissure Lat. funiculus Ant. funiculus Ant. white commissure

28 White matter of spinal cord Fiber tract: in CNS, fiber bundle which has similar origin, terminal, course and function. Ascending tract: to conduct the sensory impulse from the trunk and limbs to the brain. Descending tract. to convey the motor information from central nervous system to the trunk and limbs.

29 White matter of spinal cord Nomenclature : Course: pyramid tract Origin and terminal : Corticospinal tract. Spinothalamic tract Appearance of the tract: Fasciculus gracilis General: lateral corticospinal tract. Fasciculus proprius: both origin & termination of the fascisulus are in the spinal cord.with two direction (ascending & descending), the function take part in different segment reflex.

30 Major Ascending or sensory Tracts Fasciculus cuneatus Fasciculus gracilis Pos. spinocerebellar tract Ant. spinocerebellar tract Spinothalamic tract Lat.Spinothalamic tract(rough tonch) Ant.Spinothalamic tract(pain,temperature,sensation) Red color means important

31 Fasciculus cuneatus Fasciculus gracilis Fasciculus gracilis and fasciculus cuneatus

32 From pain and temperature And some touch receptors Spinothalamic tract Lateral and anterior spinothalamic tract

33 Summary-ascending tracts Tract Site of origin Funiculu s Fasciculus gracilis Fasciculus cuneatus Posterior spinocerebellar tract Spinal ganglia below segment T5 Spinal ganglia above segment T4 Homolateral nucleus thoracicus Posterior Termination Gracile nucleus Cuneate nucleus Function Conscious proprioceptive (vibratory sense, and muscle joint sense) and fine touch sensation of trunk and limbs Lateral Cerebellum Unconscious proprioception from limbs and trunk Anterior spinocerebellar tract Contralateral Laminae Ⅴ~Ⅶ Lateral Spinothalamic tract Laminae Ⅰ, Ⅳ~Ⅶ Lateral Dorsal thalamus Pain, temperature and crude touch sensation of trunk and limbs anterior Spinothalamic tract anterior

34 Descending Tracts Fasciculus proprius Lateral corticospinal tract Rubrospinal tract Medial longitudinal fasciculus Reticulospinal tract Vestibulospinal tract Tectospinal tract Anterior corticospinal tract Red color means important content

Lateral and anterior corticospinal tract Coranal section of cerebrum horizental section of cerebrum horizental section of midbrain horizental

35 Lateral and anterior corticospinal tract Coranal section of cerebrum horizental section of cerebrum horizental section of midbrain horizental section of pons Lateral corticospinal tract Anterior corticospinal tract horizental section of medulla ablongata horizental section of spinal cord

36 Summary - descending tracts Tract Site of origin Funiculus Termination Function Lateral corticospinal Anterior corticospinal Cerebral cortex Lateral Laminae (Ⅳ~Ⅸ) anterior horn Cerebral cortex Anterior Motor neurons & interneurons Rubrospinal Red nucleus Lateral Laminae (Ⅴ~Ⅶ) anterior horn Motor neurons & interneuron (for flexor) Vestibulospinal Reticulospinal Homolateral vestibular nuclei Reticular formation Anterior Anterior & lateral Laminae (Ⅶ~Ⅷ) anterior horn Motor neurons & interneuron (for extensor) Laminae (Ⅶ~Ⅷ) Voluntary movement of skeletal muscle of trunk and limbs Facilitates activity of flexor muscles Facilitates activity of extensor muscles Control Voluntary movement of skeletal muscle of trunk & proximal extremity

37 Summary - descending tracts Tract Site of origin Funiculus Termination Function Medial longitudinal fasciculus Tectospinal Fasciculus proprius Vestibular nuclei Superior colliculus Spinal cord Anterior Laminae (Ⅶ~Ⅷ) Anterior horn cell Coordinate of head and eye movement Anterior Laminae(Ⅵ~Ⅷ) Reflex head turning Anterior, lateral & posterior Spinal cord Intrinsic reflex mechanism of spinal cord

Main functions of spinal cord Conduction of excitations bridge; brain - periphery Sensory impulse to brain Motor impulse to periphery Reflex Somatic reflex (skeletal m

38 Main functions of spinal cord Conduction of excitations bridge; brain - periphery Sensory impulse to brain Motor impulse to periphery Reflex Somatic reflex (skeletal m contration) superficial and deep reflex Tendon (stretch reflex ) arc Flexor reflex Abdominal reflex Visceral reflex (sm,cardiac m,gland) Defecation reflex Carotid reflex

39 Spinal cord transverse section lesion Complete spinal cord transection results in the immediate Loss of all neural function below the level of the lesion.there is a complete lose below the level of the lesion of : All somatic sensation All motor function All visceral sensation All reflex activity All muscle tone,etc Spinal shock: last for 1~6 weeks

Hemisection of the spinal cord (brown-sequard syndrome) sensation

2-Fasciculus cuneatus 3 3-Spinothalamic tract motor 4 Injured

corticospinal tract Right:deep sensation,limb paralysis Copy Right

40 Hemisection of the spinal cord (brown-sequard syndrome) sensation 2 1 Injured main sensory fasiculus: 1-Fasciculus gracilis 3 2-Fasciculus cuneatus 3 3-Spinothalamic tract motor 4 Injured motor fasiculus: 4 - Lat.corticospinal tract Ant.corticospinal tract Right:deep sensation,limb paralysis Copy Right Left Hongqi :superficial ZHANG Department sensation disfunction of Anatomy Fudan University

41 Hemisection of the spinal cord Brown-sequard syndrome Result in: The ipsilateral motor neuron paralysis below the level of lesion Resulted from damage to the ipsilateral corticospinal tract. Loss of the ipsilateral deep sensation (proprioceptive,vibratroy and two point discrimination sense)below the level of lesion. resulted from damage to the fasciculus gracilis and fasciculus cuneatus. Loss of the contralateral superficial sensation (pain & thermal Sense)below the level of lesion. resulted from damage to the lateral spinothalamic tract.

42 Lesion of anterior horn of the spinal cord It causes ipsilateral lower motor neuron paralysis in the segments of the lesion (resulting from damage to lower motor neurons)such as infantile paralysis (Poliomyelitis). Usually it is caused by poliomyelitis virus Motor neuron

43 Meningocele cleft spine Meningocele

46 FIGURE At upper thoracic and all cervical levels the dorsal funiculus is further subdivided, as shown here This view also shows the named sulci, fissures and septi, as well as the Copy course Righttaken Hongqi by entering ZHANG Department and departing of axons. Anatomy Fudan University

answer 9 1 - intermediolateral cell column 2 - dorsal

47 answer intermediolateral cell column 2 - dorsal funiculus 3 - lateral funiculus 4 - ventral funiculus

FIGURE 3.1.4 Most of the structures labeled on these slides are ones you have identified in earier views of this module.

48 FIGURE Most of the structures labeled on these slides are ones you have identified in earier views of this module. Try to reconcile the appearance of the structure here with that in views of the brain's surface. All the sections, except the 3 spinal cord ones, are clickable. Clicking on one leads you to enlarged view of the section.

49 The end! Hardworking Harvest

The Spinal Cord. The Nervous System. The Spinal Cord. The Spinal Cord 1/2/2016. Continuation of CNS inferior to foramen magnum.

The Spinal Cord. The Nervous System. The Spinal Cord. The Spinal Cord 1/2/2016. Continuation of CNS inferior to foramen magnum. The Nervous System Spinal Cord Continuation of CNS inferior to foramen magnum Simpler than the brain Conducts impulses to and from brain Two way conduction pathway Reflex actions Passes through vertebral