Spinal Cord Anatomy PDF

SPINAL CORD  After the spinal cord ends, the Gross Anatomy nerves fan out into the cauda equina ("horse's tail"), which consists of spinal nerve roots. These nerves travel downwards within the vertebral canal to Super...

SPINAL CORD  After the spinal cord ends, the Gross Anatomy nerves fan out into the cauda equina ("horse's tail"), which consists of spinal nerve roots. These nerves travel downwards within the vertebral canal to Superior end of the Spinal Cord brachial region or lumbosacral region, there are some enlargements because the plexus Inferior end of the Spinal Cord Terminal Part of the Spinal Cord Filum Terminale Filum terminale internum (pars pialis) central canal 5-6mm Filum terminale externum (pars duralis) (coccygeal lig) Filum Terminale Enlargements of Spinal Cord C3 T2 L1 S3 Segments of the Spinal Cord 31 segments –8 cervical –12 thoracal –5 lumbar –5 sacral –1 coccygeal a pair of spinal nerve each segment  three and four coccygeal Spinal Nerves segments units and gives one spinal nerves one 8 CERVICAL coccygeal spinal nerves 12 THORACIC 5 LUMBAR 5 SACRAL 1 COCCYGEAL Spinal Nerves The largest → S1 The smallest →Co in 8% of cases, the dorsal root fibers are absent in the first cervical & the coccygeal segment The roots of spinal nerves C1 spinal nerve leaves the vertebral canal The C8 spinal nerve leaves the vertebral canal between C7-T1 vertebra CAUDA EQUINA Cauda Equina  All sensory information entering the spinal cord from the posterior lateral sulcus and the anterior lateral sulcus, all the ventral root arising all the motor information reach to the Topography of Spinal Cord target cells. and when you look at the anterior lateral sulcus you can see the ventral root  this white matter contains to these pathways, ascending and descending pathways, is located in the white matter. In Anterior median fissure- Anterolateral sulcus-Posterior median the gray matter, we have the glial cells and the neuron cells, neuron bodies are located sulcus-Posterior lateral sulcus- Posterior intermediate sulcus in the gray matter. And so the gray matter divides to the white matter Posterior Surface of the Spinal Cord funiculus gracilis and the funiculus cuneatus Meninges EPIDURAL SPACE DURAMATER SUBDURAL SPACE ARACHNOID MATER SUBARACHNOID SPACE (CEREBROSPINAL FLUID) PIA MATER  Subdural Space: Potential space between the dura mater and arachnoid mater. Meninges Contains small venous structures. spinal cord pia mater subarachnoid space arachnoid membrane subdural space dura mater epidural space Denticulate Ligament DENTICULATE LIGAMENT (18- 23) Denticulate Ligaments  All this funiculus contains the ascending and the descending pathways THE CROSS SECTION OF THE SPINAL CORD GRAY MATTER & WHITE MATTER HORNS or COLUMNS ANTERIOR & POSTERIOR HORNS GRAY COMMISSURE ant gray commissure post gray commissure CENTRAL CANAL LATERAL HORN T1-L2 or L3 S2-S4 THE CROSS SECTION OF THE SPINAL CORD posterior side of the central canal. These regions called gray commissure. These are gray commissure. Anterior part of the central canal is called anterior white commissure The Largest Gray Matter Contents of the gray matter  The medial portion of the spinal cord’s gray matter contains the central group of nuclei, including the Nerve Cell of Groups in the Anterior Gray Columns accessory nucleus and the phrenic nucleus. Accessory Nucleus: Located around the fifth cervical segment, it is associated with the accessory nerve (cranial nerve XI). This nerve innervates the sternocleidomastoid and trapezius three groups or columns: muscles, which are responsible for head and shoulder movements. medial Phrenic Nucleus: Found in the C3 to C5 spinal segments, it central controls the diaphragm, essential for breathing. lateral In contrast, the lateral gray matter is involved in the motor control of the Most segments of the medial part generally skeletal muscles of the limbs. relate with the skeletal muscles of neck and the trunk, intercostal muscles. Medial group segments related with the innervation of the Central Group smallest and is present in some cervical and lumbosacral segments in the cervical part C3-5 segments: phrenic nucleus in the upper five or six cervical segments: accessory nucleus. Accessory Nucleus smallest part of the central group and accessory nucleus is related with the accessory nerve generally we can see on the fifth cervical segment region accessory nucleus these are related with the central portion nucleus Nerve Cell Groups in the Posterior Gray Columns anterior part have medial, central, and lateral nuclei, and the posterior have four nerve cell groups. four nerve cells groups: –substantia gelatinosa –nucleus proprius –nucleus dorsalis (Clark’s column) –visceral afferent nucleus Nerve Cell Groups in the Posterior Gray Columns Substantia gelatinosa group: apex of the posterior horn pain, temperature & touch It's located at the apex of the posterior cord. Nerve Cell Groups in the Posterior Gray Columns Nucleus proprius anterior to the substantia gelatinosa senses of position & movement (proprioception), two point discrimination and vibration Nerve Cell Groups in the Posterior Gray Columns located only here, until you do the Nucleus propius, we can see this nucleus. And this nucleus is just located in Nucleus dorsalis (Clarke’s the C8 or L3 regions column) base of the posterior gray column C8-L3 or L4 proprioceptive endings (neuromuscular spindles and tendon spindles) Visseral Afferent Nucleus Lateral to the nuc dorsalis  Nerve Cell of Groups in the Lateral Gray Columns On the autonomic nervous system, all the sympathetic fibers is originate from these preganglionic fibers intermediolateral group of cells →form lateral horn T1- L2 or L3→preganglionic sympathetic outflow S2-S4→ preganglionic parasympathetic outflow they defined 10 lamina on the spinal cord and he think that all these neurotypes located the same region and they are responsible for the same function PARTS OF WHITE MATTER POSTERIOR White Column (Funiculus) LATERAL White Column (Funiculus) ANTERIOR White Column (Funiculus) ANTERIOR WHITE Commissura  myelinated nerve fibers should all carry information, all the fibers carry Contents of white matter information in the white matter. neuroglia blood vessels myelinated nerve fibers  Roots of the Spinal Nerve DORSAL ROOT (SENSORY) VENTRAL ROOT (MOTOR) DORSAL ROOT GANGLION (SPINAL GANGLION) (cell bodies of first order neuron) intermediate sulcus and this sulcus and divides to the posterior finiculus the posterior finiculus have two pathways fasciculus gracilis and fasciculus cuneatus Branches of the Spinal Nerves Ventral Ramus Dorsal Ramus CONTENTS OF TYPICAL SPINAL NERVES GSA (pain,temperature, touch pressure & proprioception) GSE It's related with the somatic regions, muscles, tendons, or GVA organ to spinal cord and also we have another fibers general visceral afferent this information coming from the joints. GVE general visceral afferent fibers these fibers carrying information from the spinal cord or body to organ DERMATOM Important Dermatom Areas C6 thumb C7 index & middle finger C8 ring & little finger T4 nipple before puperte in the female, male T7 superior to the xiphoid process T10 umblical region L1 superior to the inguinal lig, proximal part of external genital organs Important Dermatom Areas S3 distal part of external genital organs L4 medial border of the foot & S1 lateral border of the foot and little toe S5-Co1 anus Arterial Supply of the Spinal Cord pair of post spinal arteries (vertebral a. or PICA) anterior spinal artery (vertebral a.) reinforced by segmental arteries. –ascending cervical,deep cervical (subclavian a) –posterior intercostal a (thoracic aorta) –lumbar a (abdominal aorta) –lateral sacral, iliolumbar a (internal iliac a) generally on the left side it enters to the spinal cord and it's the major auricular arteries it's originated from the lumbar arteries and it's supplied to the lower two-thirds of the spinal cords. this internal vertebral venous plexus and also intervertebral vein and this vein passing through the intervertebral foramen and then externally we can see the external vertebral venous plexus and Herniation is important. Generally, it's occurred in the movement regions and unmovable region. For example, cervical regions is mobile and thoracic regions unmovable. So between the joint of these two regions, we can see the herniation. generally posterior lateral side of the annulus fibrosus we can see there is a tear and this tear regions the annulus fibrosus drains to the external region generally Clinical Notes A herniated intervertebral disc, primary or secondary vertebral tumor, or a fracture dislocation can press on the spinal nerve roots in the intervertebral foramina A lesion of one posterior spinal nerve root will produce pain in the area of skin innervated by that root and in the muscles that receive their sensory nerve supply from that root A lesion of an anterior root will result in paralysis of any muscle that is supplied exclusively by that root and a partial paralysis of any muscle that is supplied partially by that root.