Presentation spinal cord

Origin: Termination Spinal cord in adult in child foramen megnum continous with medulla oblongata of brain Termination in adult at the lower boarder of L1 in child at the upper boarder of L3

Menings 1 dura mater Function’ Protection The spinal cord is surrounded by three membranes 1 dura mater 2 :arachnoid mater 3:pia mater : Function’ Protection Also by cerebrospinal fluid present in the subarachnoid space

In the cervical region inferiorly it gives origin to the brachial plexus lower thoracic region and lumber region it gives origin to lumbosacral plexus . superiorly the spinal cord is fusiformly enlarge the enlargement is referred as the cervical and lumber enlargement inferiorly the spinal cord tapers off into the conus medullaris from the apex of which a prolongation of pia mater the filum terminale descend to be attached to the posterior surface of the coccyx.

location The cord lie in midline anterior median fissure posterior median sulcus. Along the entire length of the spinal cord are attached 31 no of spinal nerves by the anterior or motor roots and Posterior root or sensory posterior root ganglion cells which gives rise to peripheral and center nerve fibber

Structure of spinal cord gray mater inner white mater Outer GRAY MATER On croos section the gray mater is seen H-shaped pillar with anterior column or horns posterior column or horns lateral gray column or horn (THORACIC AND LUMBER) united by gray commissure With central canal

Nerves cell groups in the anterior gray column Alpha efferent nerve large Multipolar It innervates the skeletal muscle Axon pass out in anterior roots of spinal nerves Gamma efferent Small Multipolar It innervates intrafusal muscle fibers of neuromuscular spindles Axon may pass out in anterior roots of the spinal nerves

(2) CENTRAL GROUP (3) LATERAL GROUP Nerve cell of the anterior gray column is divided into three basic groups (1) MEDIAL GROUP (2) CENTRAL GROUP (3) LATERAL GROUP

Medial group EXTENTION innervate muscle of neck, trunk, intercostal WHOLE SPINAL CORD innervate muscle of neck, trunk, intercostal abdominal

(2)Central group: (c) lumbosacral nucleus (L2 TO S1) EXTENTION cervical, lumber, sacral segments Three nuclei (a) phrenic nucleus (C3’4’5) INERVATE DIAGHPHRAM (b)accessory nucleus) (C5 OR 6) INNERVATION sternocliedomastoid and trapezius muscle (c) lumbosacral nucleus (L2 TO S1) unknwon distribution

Lateral group Extention Innervation cervical and lumbosacral segment Muscles (1) upper limb (2) lower limb

Nerve cells of the posterior gray column four nerve cell group 1 substantia gelatinosa 2 nucleus propius 3 nucleus dorsalis (clarks column) 4 visceral afferent nucleus First two extention through out the length of the cord other two lumber and thoracic segments

Substantia gelatinosa location apex of the posterior gray column composed Golgi type 2 neuron function receives afferent fiber associated with pain , temperature touch. Furthermore it receive input from the descending fibers from the supraspinal level .

Nucleus propius Location Below s g Function senses of position movement (proprioception) two points discrimination vibration

Nucleus dorsalis Location base of the posterior gray column extending C8 to L3 4 FUNCTION proprioceptive endings neuromuscular spindles and tendon spindle

Visceral afferent nucleus LOCATION lateral to the nucleus dorsalis EXTENTION T1 to L2 FUNCTION receiving visceral afferent information

Nerve cell group lateral gray column Extend T1 TO S4 Cells T1 TO L3 preganglionic sympathetic nerve fiber CELLS S 2,3,4 preganglionic parasympathetic fiber

The gray commissure and central canal LOCATION the anterior and posterior gray columns on each side are connected by a transverse gray commissure so that the gray column r in the central of the gray commissure is situated central canal. Superiorly above this it open into the cavity of the fourth ventricle continuous with the central canal of the caudal half of the medulla oblongata Inferiorly It is closed conus medullaris it expend into the fusiform terminal ventricle terminate below with in the root of the filum terminale It is filled with cerebrospinal fluid and is lined with epithelium called the ependyma

Anterior gray commisure IT resembles letter H posterior gray commissure The part of the gray commissure that is situated posterior gray canal Anterior gray commisure lie anterior to the canal

White mater lateral column posterior column anterior column It is divided into anterior lateral posterior white columns or finiculi. anterior column location lie on each side lie in between the midline and the point of emergence of the anterior nerve root . lateral column between the emergence of the anterior nerve root and the entry of the posterior nerve root the posterior column in between the entry of posterior nerve root and midline

Structure composition in centrral nervous system the white mater of spinal cord consist of a mixture of nerve fiber neuroglia blood vessel it surrounds the gray mater its white color is due to the high proportion of myelinated nerve fiber

Blood Supply of the Spinal Cord The spinal cord receives its arterial supply from three small, longitudinally running arteries: the two posterior spinal arteries and one anterior spinal artery. The posterior spinal arteries, which arise either directly or indirectly from the vertebral arteries, run down the side of the spinal cord, close to the attachments of the posterior spinal nerve roots. The anterior spinal arteries, which arise from the vertebral arteries, unite to form a single artery, which runs down within the anterior median fissure. The posterior and anterior spinal arteries are reinforced by radicular arteries, which enter the vertebral canal through the intervertebral foramina. The veins of the spinal cord drain into the internal vertebral venous plexus.

INJURIES

Injuries in children Children account for 1-10% of all spinal injuries. Motor vehicle accidents account for most injuries, followed by falls and sports. Most serious spinal injuries in children involve the cervical spine.

In children less than 8 years of age, most injuries are between the occiput and C2: Fulcrum of movement located at C2-3 in children, C5-6 in adults Significant ligamentous and joint capsule laxity Relatively large head and weak neck muscles Horizontal orientation of facet joints Incomplete ossicification of odontoid process

Injuries in adults

Terminology Plegia = complete lesion Paresis = some muscle strength is preserved Tetraplegia (or quadriplegia) Injury of the cervical spinal cord Patient can usually still move his arms using the segments above the injury (e.g., in a C7 injury, the patient can still flex his forearms, using the C5 segment) Paraplegia Injury of the thoracic or lumbo-sacral cord, or cauda equina Hemiplegia Paralysis of one half of the body Usually in brain injuries (e.g., stroke)

What are the differences between UMN and LMN. (e. g. , cauda equina vs What are the differences between UMN and LMN? (e.g., cauda equina vs. myelopathy)

Thoracic injuries (T2-L1) Paraparesis or paraplegia UMN (upper motor neuron) signs

Cauda equina injuries (L2 or below) Paraparesis or paraplegia LMN (lower motor neuron) signs Thigh flexion is almost always preserved to some degree

What is the difference between cauda equina and conus medullaris syndrome?