Dr Jyoti Chopra Professor Department of Anatomy Vertebral Column

Houses and Protects spinal cord Supports weight Site for muscle attachments

Vertebral Column Part of the axial skeleton 33 vertebrae 7 Cervical 12 Thoracic 5 Lumbar 5 Sacral 4 Coccygeal Part of the axial skeleton 33 vertebrae 7 Cervical 12 Thoracic 5 Lumbar 5 Sacral 4 Coccygeal

Typical Vertebra 1. Body 2. Vertebral Arch a)Pedicles b)Laminae c)Processes Transverse Spinous Articular Superior Inferior 3. Spinal Foramen 1. Body 2. Vertebral Arch a)Pedicles b)Laminae c)Processes Transverse Spinous Articular Superior Inferior 3. Spinal Foramen

Intervertebral Foramen Superior and Inferior vertebral notch Superior and Inferior- pedicle Anterior- Intervertebral disc and vertebral body Posterior- Articular processes and joints Superior and Inferior vertebral notch Superior and Inferior- pedicle Anterior- Intervertebral disc and vertebral body Posterior- Articular processes and joints

Intervertebral foramina: Contents Spinal nerves Segmental arteries and veins embedded in areolar tissue Recurrent meningeal Branch Pressure on/ stretching of spinal nerves: Herniation of IV disc fracture of vertebral body Osteoarthritis of articular processes or joint

Intervertebral disc Fibrocartilaginous Extend from C2- sacrum as C1 has no vertebral body Thickest in cervical & lumbar region where movement of vertebral column are greatest Make upto 25% of length of column

Structure of Intervertebral disc Outer rim- anulus fibrosus fibrocartilage Concentrically arranged collagen fibers Collagen bundle pass obliquely and connects vertebral bodies Peripheral fibers attach to anterior and posterior longitudinal ligament

Structure of Intervertebral disc Central- Nucleus pulposus Contains mucopolysaccharide matrix About 80-90% water Normally under pressure Nearer to posterior margin Neither blood vessels nor nerves penetrate nucleus

Functions Changes shape, permit movement between vertebrae Structure deforms when pressure is put on vertebral column as in weight bearing Acts as a shock absorber Annulus totally encloses the nucleus and keeps it under constant pressure With age H2O content decreases and nucleus becomes more fibrocartilaginous, therefore less easily deformable and more easily damaged

Clinical Notes Nucleus, when under extreme pressure, can herniate or extrude in posterior or posterior-lateral direction Usually occurs in cervical or lumbar region Nucleus can put pressure on spinal nerve causing referred symptoms (motor and sensory) Can cause pressure on cord itself if true posterior

Curvature of Vertebral Column Primary curvature Secondary curvature

During later part of pregnancy Posterior lumbar concavity increases (Lordosis) Attempt to preserve centre of gravity In old age Intervertebral discs atrophy Loss of height Gradual return of continuous anterior concavity (Senile kyphosis)

Abnormal Curves of Vertebral Column Kyphosis Exaggeration of thoracic curve Caused by muscular weakness or structural changes in vertebral bodies/ intervertebral disc Lordosis Exaggeration of lumbar curve Caused by diseases of vertebral column like spondylolisthesis

Abnormal Curves of Vertebral Column Scoliosis Lateral deviation of vertebral column Common in thoracic region Caused by muscular or vertebral defects (poliomyelitis, congenital hemivertebra, short leg, hip disease)

Vertebral Canal Anterior- vertebral body, intervertebral disc, posterior longitudinal ligament Posterior- Laminae, ligamentum flavum Sides- pedicles, intervertebral foramen

Contents of Vertebral Canal Epidural space Spinal meninges Spinal cord with its nerve roots

Epidural Space Location: between spinal dura and periosteum of vertebral canal Contents: roots of spinal nerve, internal vertebral venous plexus, spinal arteries, areolar tissue Feature: minus atmospheric pressure.

Internal vertebral venous plexus Longitudinal, valveless vertebral venous plexus Communicates above with intracranial venous sinuses, segmentally with veins of thorax, abdomen and pelvis Anteriorly receives basivertebral vein

Internal vertebral venous plexus Pelvic venous blood enters in vertebral venous plexus specially if intra abdominal pressure raised Thus carcinoma of prostate metastasize to vertebral column and cranial cavity

Spinal pia mater Spinal dura arachnoid

Spinal Duramater Continuous superiorly through foramen magnum with meningeal layer of dura Inferiorly ends on filum terminale at lower border of S2 Extends along each nerve root and continues with epineurium Seperated from arachnoid mater by subdural space

Arachnoid mater Delicate impermeable membrane Inferiorly ends on filum terminale at lower border of S2 Seperated from pia mater by subarachnoid space

Pia mater Vascular membrane Closely covers spinal cord Inferiorly fuses with filum terminale Extends along each nerve root Ligamentum denticulatum- thickening on either side between the nerve roots Laterally attached to dura Helps in suspending spinal cord in middle of dural sheath

Subarachnoid Space Between arachnoid and pia mater Contents: cerebrospinal fluid (CSF) Features: pressure equal to the normal atmospheric pressure

Spinal Cord Terminates in adults- lower border of L1 In children- upper border of L3 Inferiorly taper in Conus medullaris Filum terminale- prolongation of piamater Attached to back of coccyx

Spinal cord – ventral view Anterior median fissure Anterolateral sulcus Anterolateral sulcus Ventral rootlets Ventral rootlets

Spinal cord dorsal view Posterior median sulcus- shallow furrow Posterolateral sulcus Dorsal rootlets

Roots of Spinal nerve

Spinal cord growth

Length of the roots increases progressively from above downwards Roots of lumbar and sacral nerves form leash of nerves- Cauda equina

Lumbar puncture Needle passes through- Skin Superficial fascia Supraspinous ligament Interspinous ligament Ligamentum flavum Areolar tissue containing IVVP in epidural space Duramater Arachnoidmater

Complications of Lumbar puncture Post lumbar puncture headache- Starts after hrs Due to leak of CSF if wide bored needle used Due to leak, downward displacement of brain, stretching of meninges- pain sensitive- headache Brain herniation- LP contraindicated in raised intracranial tension If done can lead to caudal displacement of uncus through tentorial notch or medulla through foramen magnum

subarachnoid anesthesia (spinal) epidural anesthesia

Development of Vertebral Column Paraxial mesoderm Divides in block of tissues- somites (4 th week) Somites- Ventromedial- sclerotome Dorsomedial- dermamyotome Mesenchymal cells of sclerotome migrate around notocord

Development of Vertebral Column Caudal half of each sclerotome fuses with cephalic half of succeeding sclerotome- form vertebral body Vertebral body- intersegmental Notocord degenerates but in intervertebral regions form nucleus pulposus Anulus fibrosus- scerotic mesenchyme of intervertebral region

Development of Vertebral Column Mesenchymal vertebral body- dorsal and lateral growth Dorsal growth- around neural tube, fuses with fellow of opposite side- neural arch Lateral growth- costal processes

Development of Vertebral Column Cartilagenous vertebrae Primary ossification centers- Centrum-2 Neural arch- 1 for each half Secondary ossification centers- Superior and inferior end of vertebral body Tip of each spinous process Tip of each transverse sprocess

Spina Bifida