척수 (spinal cord) 원기둥모양, vertebral column 의 spinal canal (vertebral canal) 속에위치 척수의보호 척추뼈와인대, meninges, CSF 범위 위 : foramen magnum 에서숨뇌와연결 아래 : 성인 ; L1 척추뼈의아래모서리소아 ; L3 척추뼈의위모서리 척수팽대 Spinal enlargements 1. Cervical enlargement: C3-T2, brachial plexus 2. Lumbar enlargement: L1-S3, lumbosacral plexus 척수원뿔 (conus medullaris) 척수종말끈 (filum terminale) 척수 원통형구조 cylinderical structure ( 길이 : 43-45 cm, 직경 : 1-1.5 cm) 남 : 45cm 여 : 42cm 평균직경 : 1cm 척수팽대 Spinal enlargements 1. Cervical enlargement: C3-T2 2. Lumbar enlargement: L1-S3 말총 (cauda equina) 목신경 cervical nerves ---------8쌍가슴신경 thoracic nerves------ 12쌍허리신경 lumbar nerves ------- 5쌍엉치신경 sacral nerves -------- 5쌍꼬리신경 coccygeal nerves ----- 1쌍 31쌍 그림 5-3 요추신경 : 아래로내려갈수록굵어지나, 추간공은좁아진다. L5 가가장굵지만추간공은가장좁다 : HIVD 시에압박가능성이가장높다 1
척수의고랑과틈새 Sulcus and fissure 앞정중틈새 anterior median fissure 앞외측고랑 anterolateral sulcus (ant. Roots) 뒤정중고랑 posterior median sulcus 뒤외측고랑 posterolateral sulcus(post. Roots) 뒤중간고랑 posterior intermediate sulcus Ant & post root spinal nerve ant primary division (APD) & post primary division (PPD) 그림 5-1 2
그림 5-2 척수의내부구조 1. 백색질 White matter (1) 앞쪽섬유단 anterior funiculus = ant. white column (2) 뒤쪽섬유단 posterior funiculus = post. white column 1. gracile fasiculus ( 널판다발 ): 척수의전장에걸쳐분포 2. cuneate fasicleus ( 쐐기다발 ): 가슴분절의중간부분부터 gracile fascilus의가쪽에분포 (3) 외측섬유단 lateral funiculus = lat. white column (4) 백색질맞교차 white commisure (5) 뒤가쪽로 dorsolateral tract (tract of Lissauer) 2. 회색질 Gray matter (1) 앞쪽뿔 Anterior horn : motor cell (A, Aγ) (2) 뒤쪽뿔 Posterior horn (3) 가쪽뿔 Lateral horn : T1-L2 & S2-4 ; preganglionic sym-/parasympathetic neuron (4) 회색질맞교차 Gray Commissure (5) 중간회색질구역 intermediate zone 3. 중심관 Central canal 3
Barr fig.5-4,5,6 * 단면의모양 1) 목부위에서는난원형 ( 가로 > 세로 ) 이지만허리부위부터는원형에가까움 2) 백색질의면적 (1) 아래쪽에서위쪽으로갈수록증가 (2) 목부분은백색질의면적이최대 3) 회색질의면적 (1) 목팽대및허리팽대부위가가장큼 (2) 가슴부위에서는회색질의발달이미약함 (3) 허리부위이하로내려갈수록백색질보다회색질이많아짐 4) Thoracic 과 lumbar segment 에는 lateral horn 도존재 회색질의세포구축학적층판배열 Cytoarchitectural lamination Laminae of Rexed ( 척수층판 ) Dorsal horn : I, II, III, IV, V, VI Intermediate zone : VII, X Ventral horn : VIII, IX 그림 5-7 Nucleus of Onuf: 남성, pelvic floor sphincter 4
척수신경의연결 Dorsal horn 1. 가쪽섬유군 Lateral division (1) Unmyelinated C or A delta fibers (2) Substantia gelatinosa (Lamina II) 와연접 ( 일부는 dorsolateral tract (of Lissauer) 를거쳐인접척수분절 ( 상하 2-3) 로들어감 (3) Lamina I, IV, V, VI 에서나온 axon 이 spinothalamic tract( 통각및온각 ) 가됨 2. 안쪽섬유군 Medial division (1) Myelinated A fibers 로 dorsal funiculus 의 F. gracilis and cuneatus 가됨 (Discriminative sense, Proprioception 담당 ) (2) 일부는 lamina IX 에서 motor neuron 과연결하여 stretch reflex 를일으킴 5
그림 5-8 Barr fig.5-10 그림 5-9 6
1. Visceral motor nuclei (in thoracolumbar region) (1) Lamina VII 의 Intermediolateral nuclei 에위치함 (2) Sympathetic preganglionic fibers 를내보냄 (3) Anterior root - Spinal nerve - White communicating ramus 를거쳐 sympathetic ganglion 에서연접 -Postganglionic fibers (4) Postganglionic fibers a. unmyelinated fiber 로 gray communicating ramus 를통하여내장기의민무늬근섬유와연결됨 b. 다시척수신경에합류 - 혈관, 땀샘, arrector pili muscle 등에분포 2. Visceral motor nuclei (in Sacral region) (1) Lamina VII 의 Intermediolateral nuclei 에위치함 (2) Parasympathetic preganglionic fibers 를내보냄 (3) 중간에연접없이장기까지가서 postganglionic fiber 와연접 7
척수신경로 ( 오름, 내림신경로 ) 그림 5-10 일반감각계통 (General Sensory system, Ch 19) 8
오름신경로 1. 해부학적구성 1) 주요구성원 1st-order neuron 2nd-order neuron 3rd-order neuron cerebrum (Soma in sp. ganglion) (Soma in sp. cord) (Soma in brain) 2) 곁가지 (Branches) (1) To motor neurons : 반사적근육운동에관여 (2) To reticular formation 2. 종류 ( 기능 ) 1) 의식적감각정보 (Conscious sensory information) (1) 감각을 ( 시상을통하여 ) 대뇌로전달 (2) Spinothalamic tracts, Fasciculus gracilis and cutaneous (dorsal column-medial lemniscus system) 2) 비의식적감각정보 (Unconscious sensory information) (1) 감각을소뇌로전달 ( 근육작용의조율 ) (2) Spinocerebellar tracts and Cuneocerebellar tract, Spino-olivary tract 3) 기타의감각정보 (Other sensory information) (1) Spinotectal tract: 중간뇌로전달되어척수시각반사 (spinavisual reflex) 에관여함 (2) Spinoreticular tract: 그물구성체로전달되어상행그물활성계 (ascending reticular acivating system) 의구성원이됨 통각, 온도감각, 단순촉각, 압각을전달하는 Spinothalamic system 그림 19-1 9
내림신경로 1. 해부학적구성 (anatomical organization) 1) 주요구성원 1st-order neuron (Upper motor neuron) 2nd-order neuron (Inter neuron) (in brain) (in spinal cord or brain stem) 3rd-order neuron (Lower motor neuron) (in spinal cord) 2) 곁가지 (branches) (1) To cortex : inhibit activity in adjacent regions of the cortex (2) To subcortical regions (basal ganglia, red nucleus, olivary nuclei, reticular formation) : 대뇌의운동정보를접수하여척수와연결된고유신경로를통하여내려보냄 2. 종류 ( 기능 ) 1) 겉질척수로 (corticospinal tracts) : 속도가빠른개개의숙련된수의운동 (voluntary, rapid, discrete, skilled movements) 2) 피라밋바깥로 (extrapyramidal, subcortical descending tracts): 단순한기본동작 (simple basic voluntary movements) 및반사작용 3) 내림자율신경로 (descending autonomic tract) : 내장운동을조율 운동계통 (motor system) 그림 23-1 10
뇌줄기의표면 1. Medulla oblongata 1. 다리뇌와의경계 : 뒷면 : :stria medullaris 앞면 : ponto-medullary (inf. potine) sulcus 척수와의경계 : rootlets of first cervical spinal n. 2. 앞면 Anterior surface (1) Pyramid (2) Olive (3) Preolivary sulcus : rootlets of XII Postolivary(posterolateral) sulcus : rootlets of cranial nerve IX, X, XI (4) Pontomedullary junction: roots of cranial nerve VI, VII, VIII 3. 뒤면 Posterior surface (1) Gracil tubercle( 널판다발결절 ) & cuneate tubercle( 쐐기다발결절 ) (2) 제 4 뇌실 ( 아래쪽 1/2) 의바닥 : (3) Inferior cerebellar peduncle( 아래소뇌다리 ) 그림 6-1 2. Pons 1. 좌우소뇌반구를잇는 bridge 모습에서유래중간뇌와의경계 : 앞 : superior pontine sulcus 뒤 : trochlear nerve 2. 앞면 (1) Basilar sulcus: basilar groove for basilar artery (2) Trigeminal nerve roots : medial motor & lateral sensory 3. 뒤면 (1) 제 4 뇌실 ( 위쪽 1/2) 의바닥 : median sulcus ( 정중고랑 ), medial eminence ( 안쪽융기 ), facial colliculus ( 얼굴신경둔덕 ), sulcus limitance ( 경계고랑 ), (2) 제 4 뇌실가쪽벽 : Inf. & sup. cerebellar peduncles 그림 6-3 11
3. Midbrain 1. 사이뇌와의경계 : mammilary bodies( 유두체 ) 의바로아래부분 2. 앞면 (1) Cerebral peduncle ( 대뇌다리 ), interpeduncular fossa ( 다리사이오목 ), posterior perforated substance ( 뒤관통질 ) (2) Oculomotor nerve( 눈돌림신경 ) 3. 뒤면 (1) Superior colliculi and superior brachium (LGB) (2) Inferior colliculi and inferior brachium (MGB) (3) Trochlear nerve 뇌줄기의내부구조 1. 숨뇌 1. Level of pyramidal decussation 1) Pyramidal decussation ant. corticospinal tract lat. corticospinal tract 2) F & N gracilis F & N cuneatus 3) Spinal tract and nucleus of trigeminal n. (1) Extend caudally as far as C2 (2) Function : sense of pain, temp. of face 2. Level of decussation of medial lemniscus 1) Internal arcuate fibers (from N. gracilis and cuneatus) & decussation of medial lemniscus 2) Nucleus of spinal tract (CN V) 3) Spinal lemniscus : spinothalamic tracts & spinotectal tract 12
Ascending Pathway ( 오름신경로 ) 1. Dorsal column - Medial lemniscus system (DC-ML) 1. Discriminative touch ( 감별촉각 ) & proprioception ( 고유감각 ) 2. Post root (spinal cord) Gracile fasciculus ( 몸통의아래 & 다리 ) & cuneate fasciculus ( 몸통의위, 팔, 목 ) N. of gracile & cuneate internal arcuate fiber decussation medial lemniscus lateral division of VPI of thalamus corona radiata primary sensory area * DC-ML system 은중추신경내에서주행하며모든신체부분의공간적관계를유지하여대뇌피질의일차감각영역에신처부분의지도를그릴수있게한다. 2. Spinothalamic tract (anterolateral system) spinal lemniscus 1. lateral spinothalamic tract 1) 척수내위치등쪽회색질 (lamina I, IV, V, VI) 에서나온 axon 들이반대쪽으로건너가외측백색질을통하여상행함 ( 그림 1) 2) 기능 : 통각및온도감각 (pain, temperature) 3) 경로 Post root Posterolateral tract of Lissauer Gray Column (Lamina I, IV, V, VI) --x Lat. Spinothalamic tr. Spinal lemniscus VPL of Thalamus int. cap (post limb) Corona radiata Primary sensory area (cerebral cortex) 2. Anterior spinothamic tract 1) 척수내위치 : 앞쪽백색질 (anterior nerve root 안쪽 ) 2) 기능 : 단순촉각및압력감각 (light touch, pressure) 3) 경로 : Lat. spinothalamic tract 와유사함 13
내림신경로 1. corticospinal tract 1. 척수내위치 ( 그림 1) 1) 가쪽겉질척수로 (lateral corticospinal tract) : lat. funiculus 의뒤쪽을차지함 2) 앞쪽겉질척수로 (ant. corticospinal tract) : 앞쪽섬유단의안쪽 3) 척수의회색질 (lamina IV,VIII 및 IX) 에닿으며소수만이운동신경세포에직접연접 2. 기능 : 숙련된수의동작 (voluntary, discrete, skilled movements) 을조절 3. 경로 Pyramidal cells Corona radiata Cerebral peduncle (cerebral cortex) (midbrain) Pyramidal decussation -- Ant. CS tr. (15%) Spinal grey matter --x--- Lat. CS tr. (85%) Spinal grey matter 4. 피질척수로의가지 (branch) : cerebellar cortex, caudate nucleus, lentiform nucleus,red nucleus, olivary nucleus, reticular formation 5. Homunculus ( 운동소인 ) : 대뇌피질에존재하는운동신경원들의분포를그담당신체부위와의비율로표시한그림 14
Descending Spinal Tracts lateral pathway vs. ventromedial pathway 15
Descending Spinal Tracts The Lateral Pathways Voluntary movement under direct cortical control Components Corticospinal tract (=Pyramidal tract) Rubrospinal tract: Input: frontal cortex Output: primarily upper limb frontal cortex 의경우연합섬유를통해 corticospinal tract 으로도간다. 따라서 indirect cortico-rubro-spinal tract 은왜있는걸까? 실제로포유류의경우전반적으로 rubrospinal tract 이있기는하나사람의경우 corticospinal tract 에더많이치우친경향이있다. The Ventromedial Pathways Posture and locomotion under brain stem control The Vestibulospinal tract 몸이움직일때머리를어깨에맞추는행위 눈의시선고정 (VOR) 다리의 extensor근육을자극하여상체의자세유지 The Tectospinal tract 주위의환경을인지한상태에서하나의지점에서물체또는점이이동하였을때머리와눈을돌려서시선을맞추는행위 주자가 2루에달릴때투수가머리와눈을돌리는행위 The Pontine and Medullary Recticulospinal tract Pontine reticuospinal tract: anti-gravity Facilitating extensor m Medullary reticulospinal tract: Liberates the anti-gravity muscle from reflex control 16
뇌줄기의내부구조 1. 숨뇌 1. Level of pyramidal decussation 1) Pyramidal decussation ant. corticospinal tract 1/3 lat. corticospinal tract 2/3 2) F & N gracilis F & N cuneatus 3) Spinal tract and nucleus of trigeminal n. (1) Extend caudally as far as C2 (2) Function : sense of face 2. Level of decussation of medial lemniscus 1) Internal arcuate fibers (from N. gracilis and cuneatus) & decussation of medial lemniscus 2) Nucleus of spinal tract (CN V) 3) Spinal lemniscus : spinothalamic tracts & spinotectal tract 3. Level of the olives 1) Olivary nuclear complex (1) Inferior olivary nucleus (2) Accessory olivary nuclei : medial and dorsal 2) Vestibular nuclei (1) Inf., lat., med. vest n. (in med oblong) Sup. vest n. (in pons) 3) Cochlear nuclei (1) Ant. cochlear n. (2) Post. cochlear n. 4) Nucleus ambiguus ( 의문핵 ) (1) Motor nuclei for cranial n. IX, X, XI 5) Central gray matter (1) Hypoglossal nucleus (2) Dorsal nucleus of vagus (3) Inferior salivatory nucleus (4) Nucleus of tractus solitarius 17
Vestibulocochlear nerve (VIII) 1. vestibular nuclei (1) Inf., lat., med. vest n. (in med oblong) Sup. vest n. (in pons) (2) Concious balance of body (via cerebellar and cerebral connection) (3) Maintain head and eye movement for visual fixation on the object (4) 연결경로 ( 그림 11-13) Vestibular n. Vest nuc. 1. Inf. cerebellar peduncle Cb 2. Cerebral cortex (vestibular area) 3. Spinal cord (vestibulospinal tr.) 4. Median longitudinal fasciculus (MLF) Cranial n. III,VI, IV 2. Cochlear nuclei (1) Ant. cochlear n. (2) Post. cochlear n. (3) 연결경로 ( 그림 11-14) Spiral gang. Cochl n. Cochl nucleus Trapezoid body & sup. olivary nucleus Lateral lemniscus Inf. colliculus Inf. brachium Medial geniculate body (MGB) Auditory area (sup. temp gyrus) (Wernicke s area) 18
2. 다리뇌 (pons) 1. Transverse section through caudal part of pons 1) Medial lemniscus : most anterior part of tegmentum 2) Spinal lemniscus 3) 4) MLF (1) 넷째뇌실의정중면가까이위치함 5) Facial nucleus 6) Abducent nucleus 7) Post & ant cochlear nuclei 8) Spinal nucleus of trigeminal nerve 9) Pontine nucleus ( 다리뇌핵 ) (1) 대뇌로부터오는신경로를받아들여소뇌로연결하는중요한핵 Facial & Abducens nerve 1. Facial motor nucleus 1) 표정근육을지배하는 motor n. 2) Facial nucleus internal genu facial colliculus 밑에있는 abducens nucleus 을고리모양으로감아돈다 2. Abducens nucleus 1) lateral rectus m. 2) facial colliculus 아래에위치 3) 이신경핵에는 internuclear neuron 도위치하고있다. Internuclear neuron 의축삭들은반대쪽 MLF 을통해 medial rectus m. 을지배하는신경세포들이위치한 division of oculomotor nucleus 에연접 수평방향으로눈을움직일때가쪽곧은근과반대쪽안쪽곧은근이동시에수축 conjugate lateral eye movement ( 가쪽주시운동 ) 19
PPRF : paramedian pontine reticular formation : center for lateral gaze 1. Longitudinal fiber bundle ( 세로섬유다발 ) 1) corticospinal fiber 2) corticopontine fiber 2. Transverse fiber bundle ( 가로섬유다발 ) 1) pontocerebellar fiber 3. Pontine nuclei * 대뇌와소뇌의연결 1) 정확하고효율적인수의운동이가능 2) 경로 대뇌겉질 corticopontine tract pontine nuclei pontocerebellar tract via middle cerebellar peduncle 소뇌겉질 dentate nucleus via sup. cerebellar penducle red nucleus & VL of thalamus 대뇌겉질 20
3. 중간뇌 (midbrain) Tectum ( 덮개 ) Cerebral peduncle ( 대뇌다리 ) Tegmentum ( 뒤판 ) Substantia nigra ( 흑색질 ) Basis peduncli ( 다리밑동 ) = Crus cerebri ( 대뇌섬유다리 ) 1. Tectum and asociated tracts 1) 아래둔덕 Inferior colliculus 2) 위둔덕 Superior colliculus 2. 중간뇌뒤판 Tegmentum 1) 도르래신경핵 Nucleus of trochlear n. - superior oblique of eye ball 2) Nuclei of oculomotor n. ( 눈돌림신경핵 ) 3) 섬유띠 Lemnisci : Medial, spinal, trigeminal, lateral 4) 안쪽세로다발 Medial longitudidnal fasciculus 5) 삼차신경중간뇌핵 Mesencephal nuc of trigeminal n. 6) Decussation of superior cerebellar peduncles 7) Substantia nigra 8) Red nucleus ; vascularity and iron-containing pigment 3. 대뇌다리 1) corticospinal tract & corticonuclear tract 2) corticopontine tract 1) Frontopontine fiber (medial) 2) Temporopontine fiber (lateral) 21
흑색질 (substantia nigra) 1. Copus striatum 과연결되어기능상바닥핵 2. Pars compacta 1) dopaminergic neuron 2) 세포질에 melanin pigment 을함유 3. Pars reticulata 4. Parkinson s disease 1) 운동기능장애 ; muscular rigidity ( 근경직 ), tremor ( 떨림 ), bradykinesia ( 운동완만 ), mask-like face ( 가면모양얼굴 ), shuffling gait 2) Degeneration of dopaminergic neuron 3) MPTP 4) Dopamine 의투여함으로써줄무늬체에대한흑색질의조절작용을대체할수있겠지만실제로 dopamine 은 BBB 을통과하지못하므로전구물질인 L-dopa 을투여한다. L-dopa 는치밀부분에남아있는신경세포들에의해도파민으로전환된다. L-dopa 을투여한다고해서신경세포가더이상소실되는것을막을수는없지만, 새줄무늬체에도파민을공급할수있을만큼의신경세포가남아있는한파킨슨병의운동기능장애는호전된다. 5) Therapeutic graft Trigeminal nerve Trigeminal sensory nucleus Skin of face and forehead, scalp, mucosa of the oral and nasal cavities, paranasal sinuses, and teeth trigeminal ganglion Main sensory nucleus ( 주감각핵 = pontine trigeminal, chief, superior sensory nucleus 삼차신경으뜸핵 ) Spinal nucleus ( 척수핵 ): pons~c2,3 Ventral trigeminothalamic tract: 주감각핵과척수핵에서기원한신경섬유가교차하는다발이다. Spinothalamic tract 와기능적으로같으며 medial division of ventral posterior of thalamus 에연접한다. Spinothalamic tract 은목아래쪽에서들어오는감각정보를전달하며 V5T 는반대쪽머리부위에서오는감각정보를전달한다. trigeminal lemniscus 감별촉각 22
Mesencephalic nucleus ( 중간뇌핵 ) Primary sensory neuron이 CNS에존재 Mesencephalic tract of trigeminal nerve 씹기근육의고유감각 Trigeminal motor nucleus 주감각핵안쪽에위치 Trigeminal ganglion 저작근 (masster, temporalis, lat., med. pterygoid m.), tensor typamni, tensor veli palatini, ant. belly of digatstric, mylohyoid m. Jaw jerk: 아래턱신경 중간뇌핵 운동핵 저작근 Jaw-opening reflex: 치아에통증을유발할정도의압박이가해지면저작근의수축이억제되어입이벌어진다. 23