The spinal cord - Medulla spinalis The development of the neural tube in the area of the spinal cord The spinal cord - Medulla spinalis • length 40 - 50 cm, thickness 1cm • weight circa 30g • it is located within the spinal canal • it follows curvature of vertebral column Cranially: it continues as medulla oblongata, Borderline is decussatio pyramidum or detachment of 1st spinal nerve Caudally: conus medullaris (S apex lies at the level of intervertebral disc L1-2, $ body of L2) - filum terminale (25 cm, 1 mm) Caudal part of vertebral canal is filled with nerve roots- cauda equina (a horse s tail) N. glossopharyngeus (IX). N.varius (X) y N hypoglossus (XII) _ N. cervicalis I N. cervicalis II ^ N. cervicalis III-., M- cervicalis IV Fossa rhomboidea Arcus ant. (Atlas [C I] Radix dors, {c [sensorial Ganglia spinalis [sensorial N. cervicalis V -^^^ff' N. cervicalis VU^ 'j?jM m r. w„ ^WHS?/ [venebralts) «rvicafts VII -^^/f WEĽ cervicalis {C VII) N. cervicalis VIII__, Arcus vertebrae í Mfe' (venebraiiel N. thoracicus I ... 'horacicae {T I) N. thoracicus II -__j! N. thoracicus HI----, N- thoracicus IV ^_ sf (ŕvN 'Ar<;js vertebrae , » ,0s cosiale 1/ HIM.' / [Cos,3| |. V N. thoracicus V---^ N thoracicus VI N. thoracicus VII N. thoracicus VIII---asa N- thoracicus IX-N- thoracicus X- m m\ y^J H-Kľl* \ 1 0s COS —^Sf ß \[cos,a Radix dors, |pc (sensoria] [C Radix dors, (pi [sensoria] Dura mater spir Os cosiaiö i] IV Radix dors, [pc [sensoria] ( Arcus vertebrae (verie brali s] kjmbahs (L V) Cauda ec N. sacralis I, -Ganglion spinale [sensonum] N sacralis II N. sacralis N. sacralis IV n frr-— 0s sacrum :. • Y / [Sacraie; [Vertebrae sacrales 1 ■ V / i ■ J: Filum [erminale ext. / / v /; (duralel N. sacralis V / / ,J ^ J ' / \Os coccygis [Coccyx] N. coccygeus t 1J [Vertebrae coccygeae I ■ The spinal cord • It keeps structure of original neural tube with canalis centralis in the middle • At the level of spinal cord, there are realized simple unconditional reflexes 0 Motor neuron 0 Interneuron The spinal cord • thickness of the spinal cord is not the same in all sections - enlargements intumescentia cervicalis (C3-T2) intumescentia lumbalis (T9-L1) places where the nerves for limbs arise NERVES FUNCTIONS I_Breathing (C1 ■ 4) jnd head and n«ltmowm*nt(a) _ Heart rate (C*-$) and Jhoufd« movement (CS) tWrist and elbow movement (C6-7) j_Hand and finget movement (C7-T1) Sympaihclktone(Tl-IJ) (irxludirsg temperature regulation) and trunk statu ity(T2-12) Ejaculation (Tu -12) ■»ndhip motion (12) Knee extension (l}) Foot motion (L4-S1) "and knee flexion (IS) The spinal segment •A section of the spinal cord from which arise fila radicularia (root fibers) of one pair of spinal nerves vrjTd to th» trjsi tu Seiwory root 9«>Cjfcon Eich fpnjl n*ev* hi a. cbrul (DKtfOOf) sensory root rajngfon »IKrl rl J (Wo 0« nerve crt MM Penile erection (S2-S4) and bowel and Madder activity (S2-S3) •Anterior root= radix anterior • posterior root= radix posterior - Ganglion spinale Structure of the spinal nerve ramus dorsalis •radix anterior: motor ^ . . S mixed ♦radix posterior: sensory \ SP|nal nerve . - Ganglion spinale ^ ramus .^ntrahs -a-c- mixed Posterior root Posterior horn (sensory) (interneurons and sensory axons) Anterior horn (somatic motor neurons) •Number of spinal segments corresponds to number of spinal nerves Cervical part (pars cervicalis): 8 segments (C1-8), C1 arises betweeen the occipital bone and atlas, nervi cervicales Thoracic part (pars thoracica): 12 segments (TM-12), nervi thoracic! Lumbar part (pars lumbalis): 5 segments (L1-5), nervi lumbales Sacral part (pars sacralis): 5 segments (S1-5), nervi sacrales Coccygeal part (pars coccygea): 1 segment (Co1), nervus coccygeus •Longitudinal grooves Fissura mediana anterior Sulcus medianus posterior Sulcus anterolateralis Sulcus posterolateral is Sulcus intermedius posterior • sulcus anterolateralis (motor) • sulcus posterolateral is (sensory) Copyright © The McGraw-Hill Companies. Inc. Permission required for reproduction or display. Posterior root Posterior horn (sensory) (interneurons and sensory axons) \ ternary rood at ttw back o» ttw «»rul zonl \rrf*tin art tr*n cor> vtytd to tra brjin via Writ My» tnct% Srmory root rjancjhon Each iprul nwv* has a (tonal (port morí wmory root Cpnghcn «mich tl a ckAttr of wit cell Spinal Somatic sensory neuron Visceral sensory neuron Autonomic motor neuron Somatic motor neuron Posterior root ganglion Sensory nuclei ( r nuclei * Spinal nerve (sensory and motor) Anterior root (motor) Anterior horn (somatic motor neurons) The spinal cord - anterior view • Fissura mediana anterior • Sulcus anterolateralis- radix anterior The spinal cord: posterior view • Sulcus medianus posterior • Sulcus posterolateral is • radix posterior • S. intermedius posterior During the third month of intrauterinne development, the spinal cord fills whole lenght of the spinal canal. Later the vertebral column grows much faster than the spinal cord and the spinal cord of newborn usually ends at L3. Due the different speed of growth, the lumbar and sacral roots are extended to reach appropriate intervertebral spaces and they form cauda equina. The superior thoracic and cervical roots pass horizontally. 8 THJ^T v^(| cervikainisegm. hrudnisegm. lumb&lnisegm. sakr&nisogm. Internal structure of the spinal cord Grey matter (bodies of neurons) • Around the central canal, it has the shape of a butterfly • It protrudes into two horns- at the front: thicker and shorter cornu anterius, with motoneurons whose axons form efferent (motor) neural pathways at the back: thiner and longer cornu posterius, on whose neurons end axons of pseudounipolar neurons (of the spinal ganglia) of the afferent (sensory) pathways • Between both horns, there are interneurons (connective neurons) Posterior root Posterior horn (sensory) (interneurons and sensory axons) White matter (axons) • Located on surface, it is formed by bundles of myelinated axons, we distinguish following pathways: associative: connect two different places of the same spinal segment on the same side comissural: connect right and left half of the same segment projective: go ascending or descending through the spinal cord and enter the brain, there are two types (according direction of course): • descending: pass within anterior part of spinal cord and continue as motor pathways • ascending: pass within anterior part of spinal cord anf they are continuation of sensory pathways s«<»icry roots n on b*cfc of th» sp«»l o Imfxisti nt then c vtyfd to th» brim > nen* f*n> tract* Sensory root (jiogUoo E>Ch Vf»r«l rtfr * A>\J (post* sensory root OJtjtion w*»d iknlti otrttrv Motor nc*vf root «* *. .. - «■ The spinal cord - crossection Grey matter (substantia grisea) • canalis centralis • cornu anterius • cornu posterius White matter {substantia alba) • funiculus anterior • funiculus lateralis • funiculus posterior The pathways within spinal cord- white matter • Ascending (afferent) sensory - somatosensory and viscerosensory information converge within spinal nerves • Descending (efferent) motor - somatomotor - visceromotor (autonomous) • Crossing of tracts HI (damage can cause contralateral paralysis,) • rfctwti IVr*»>fMaf-a Crossection - white matter of spinal cord and its tracts 1 - fasciculus gracilis /Golli/ 2 - fasciculus cuneatus /Burdachi/ (jen v oblasti horních Th a C segmentu) 3 - tractus spinoccrebellaris posterior 4 * tractus spinoccrebellaris anterior 5 - tractus corticospinal is lateralis 6 - tractus spinotectalis 7 - tractus rubrospinal is 8 - tractus spinoolivaris 9 - tractus vestibulospinalis (med. et lat.) 10 - tractus tectospinal is 11 - tractus coticospinalis anterior 12 - tractus spinothalamics anterior 13 - tractus spinothalamics lateralis 14 - fibrae reticulospinales 15 - tractus spinoreticularis 16 - fasciculi proprii Protopathic sensibility: sensibility to strong stimulations such as pain, temperature, and some forms of touch Epicritic sensibility:the sensibility to gentle stimulations permitting fine discriminations of touch and temperature Proprioception: information from locomotor system Ascending tracts Modality: touch, pain, heat-cold, position (proprioception) Receptor: Exteroceptors, Interoceptors, Proprioceptors •First neuron: ganglion nervi spinalis •Second neuron: spinal cord Ibrain stem •Third neuron: thalamus (nuclei ventrobasales) •Ending: cerebral cortex, cerebellar cortex, brainstem 0 Interneuron Descending tracts Tractus corticospinalis = pyramidal tract main motor tract - voluntary movement 1st neuron - cerebral cortex(pyramidal cell) 2nd neuron - alfa-motoneurons —► spinal nerve Extrapyramidal tracts Involuntary movement Nuclei Ncl. Proprius Ncl. Thoracicus Ncl. Intermediolateralis Nell, motorii The arterial supply Longitudinal arteries: a. spinalis ant, (unpaired, anteriorly) a. vertebralis aa. spinales post (most often 4, posteriorly) transverse arteries: segmental branches a. spinalis ant a. radicularis ant. Veins of spinal cord Longitudinal veins Transverse veins ...into vv. intercostales posteriores THE SPINAL MENINGES Meninges of the brain and spinal cord • CNS (spinal cord and brain) is covered with several layers of coverings • Most superficial is a bony covering, that is formed by bones of skull and by vertebrae • Below the bony covering, there are meninges. They are fibrous coverings, which form following structures: •dura mater Cranial and spinal dura mater • arachnoid mater Cranial and spinal arachnoid mater • pia mater Cranial and spinal pia mater SPINAL DURA MATER • Covering fibrous membrane of the spinal cord • Within the spinal canal, there is a space between dura and the periosteum (known as epidural space), which is filled with fibrous tissue and venous plexuses • It doesn't enter the grooves and fissures on surface of the spinal cord Subarachnoid space Saccus durae matris spinalis •It extends from foramen magnum till body of S2 -(filum terminale externum) •The spinal cord and cauda equina •It is separated from walls of spinal canal using fibrous tissue •It continues onto surface of the spinal nerves within foramen intervertebrale Spaces around dura mater • spatium epidurale: Brain - virtual space Spinal cord - here it is present • spatium subdurale: virtual space Posterior spinal vein Internal vertebral plexus Drake: Gray's Anatomy for Students, 2nd Edition. Copyright © 2009 by Churchill Livingstone, an imprint of Elsevier, Inc. All rights reserved. SPINAL ARACHNOID MATER • Finer fibrous membrane • It covers the spinal cord below dura mater • It doesn't enter the grooves and fissures on the surface of the spinal cord • Between dura and arachnoid, there is subdural space, between arachnoid and pia mater subarachnoid space, that is filled with cerebrospinal fluid, which forms water pillow absorbing impacts against the brain SPINAL PIA MATER Very fine fibrous membrane, that contains numerous blood vessels It lies directly on the surface of the spinal cord and it permeates into all grooves and fissures Endorhachis - periosteum of spinal canal Spinal dura mater - outermost sheet of spinal meninges, it forms Saccus durae matris spinalis Spinal arachnoid - avascular membrane, it tightly touches the inner surface of dura mater Spinal Pia mater - intermost sheet of spinal meninges, it contains vessels Subarachnoid space Spatium epidurale - space between endorhachis and saccus durae matris spinalis, it is filled with fat tissue and contains venous plexuses Spatium subdurale - just slitted space between dura mater spinalis et arachnoidea spinalis, which is enlarged just under some pathological condition (subdural hematoma) Spatium subarachnoideum - space between arachnoidea spinalis et pia mater spinalis, it contains the cerebrospinal fluid Layers within the spinal canal Periosteum = Endorhachis Spatium epidurale Dura mater spinalis Spatium subdurale Arachnoidea mater spinales Spatium subarachnoideum Pia mater spinalis Medulla spinalis Spinal cord Spinal nerve-<-- Denticulate ligament Clinical use Subarachnoid space Subdural space epidural anesthesia Spinal tap (spinal anesthesia), drug delivery Epidural anesthesia - spatium epidurale Spinal tap - spatium subarachnoideale • L3-L4, L4-L5 Spinal cord Epidural space with anesthesia CEREBRAL MENINGES CRANIAL DURA MATER Outmost covering, solid collagen tissue It covers the cranial cavity (it touches tightly the periosteum) Here is no real epidural space, it forms only under pathological conditions. It doesn't enter the grooves and fissures on surface of the brain, it enters only the largest fissures of the brain, where it emits its folds Cranial dura mater Cranial dura mater enters only the largest fissures of the brain, where it emits its folds: falx cerebri tentorium cerebelli falx cerebelli •Within all falxes and their attachments on the bones, there are passing sinuses ~ T^Sup. carabr "■■Skip margin of th« petr Middle cranial fossa Diaphragm of sella, Infundibulum falx cerebri: • Sickle-shaped fold • It arises from the whole cranial vault in the median plane from frontal to occipital bone and permeates into fissura longitudinalis cerebri • Along outer margin passes an important venous sinus (sinus sagittalis superior) • Near inner margin of falx cerebri, there passes another venous sinus (sinus sagittalis inferior) falx cerebelli: • Smaller sickle-shaped fold, that is located in the median plane • Is situated between cerebellar hemispheres • Attached on crista occipitalis interna • Within its attachment passes smaller venous sinus (sinus occipitalis) Falx Infundibulum Drake: Gray's Anatomy for Students, 2nd Edition. Copyright © 2009 by Churchill Livingstone, an imprint of Elsevier, Inc. All rights reserved. tentorium cerebelli: fold of dura mater • It is located in transversal plane, enters fissura transversa cerebri (fissure that separates cereberall hemispheres from cerebral hemispheres) • It is attached on the margins of sulcus sinus transversi on occipital bone and within its attachment passes large venous sinus (sinus transversus) (it continues both sides onto temporal bone as sinus sigmoideus Optti ntrx r Superior petrmat tittus Tentorium crrebeUt, free border / Left tram*me urns i Foramen magnum f 'unflurnce vf tinutet Straight smut SUBDURAL HEMATOMA Scalp Skull Dura mater Arachnoid mater Subarachnoid space Pia mater Bram Bleeding into the space between the dura mater and the brain itself EPIDURAL HEMATOMA Bleeding into the space between the dura mater and the skull Scalp Skull Dura mater Arachnoid mater Subarachnoid space Pia mater Brain CT scan of the head with subdural hematoma Subdural hematoma Illustration Arachnoid mater -avascular membrane -between dura mater and arachnoid-spatium subdurale -between arachnoid and pia mater-spatium subarachnoideale (cerebrospinal fluid) -it doesn't enter grooves and fissures Pia mater Spina bifida Pictures: Atlas der Anatomie des Menschen/Sobotta. Putz,R., und Pabst,R. 20. Auflage. München:Urban & Schwarzenberg, 1993 Netter: Interactive Atlas of Human Anatomy. Naňka, Elišková: Přehled anatomie. Galén, Praha 2009. Čihák: Anatomie I, II, III. Drake et al: Gray's Anatomy for Students. 2010