The spinal cord is a tubular structure composed of nervous tissue that extends from the brainstem and continuing distally before tapering at the lower thoracic/upper lumbar region as the conus medullaris. The spinal cord is anchored distally by the filum terminale, a fibrous extension of the pia mater anchoring the spinal cord to the coccyx. Protecting the spinal cord is the surrounding cerebrospinal fluid (CSF), supportive soft tissue membranes and meninges, and the osseous vertebral column. A basic knowledge of the structure and function of the spinal cord and spinal column is essential for healthcare providers as the recognition of characteristic clinical signs and symptoms is imperative for the appropriate treatment of patients presenting with a wide range of clinical symptoms.
Meninges and Spaces
After the 3rd week of development, there is a fusion of the neural folds into a tube (neurulation); the neural tube then closes completely at day 28 and forms the brain and the spinal cord.
The caudal neural tube's cross-sectional view initially appears diamond shaped, lined by neuroepithelial cells, which divide and multiply into neuroblasts that populate surrounding areas called the mantle zone, which eventually forms the gray mater. Divided neuroepithelial cells now form the ependymal lining of the central spinal canal with roles in CSF production.
The mantle zone differentiates into - basal plate, alar plate, and intermediolateral plate. More lateral parts form into the marginal zone which becomes the white mater with ascending and descending myelinated fibers.
The basal plates differentiate into the anterior or ventral gray horn. Multipolar neurons in the anterior horn are first-order neurons and give off motor fibers that exit the spinal segments and become myelinated by Schwann cells (derivative of neural crest cells).
The alar plates differentiate into the posterior or dorsal gray horn. They comprise second order pseudo-unipolar neurons, which receive sensory communication from first-order neurons derived from neural crest-derived dorsal ganglia.
The intermediolateral plates in cervical and thoracic regions are populated by pre-ganglion neurons which give off fibers exiting ventrally onto the sympathetic trunk.
Radiculo-medullary branches from the anterior and posterior spinal arteries and the costocervical trunk anastomose to supply the cervical region of the spinal cord. The thoracolumbar segments of the spinal cord receive extra arterial blood supply through radiculo-medullary branches of segmental arteries from the aorta; of note is the great radicular artery called Adamkiewicz artery. It has a variable origin arising anywhere between T9 and L5 vertebra.
There are 31 spinal nerve pairs (mixed) that arise from the intervertebral foramen on both sides of the vertebral column.
Nerves from the lower spinal segment exit terminal to the conus medullaris and form the cauda equina.
Ventral spinal nerve roots - make up the motor component of the spinal innervation with rootlets arising from the anterior horn of the spinal segment, sending motor impulses to muscles and joints, etc
Dorsal spinal nerve roots - make up the sensory component, with the dorsal ganglia sending sensory impulses via nerve rootlets to the posterior horn of spinal segments.
In general, the extent of disability depends on the level of injury and underlying degree of severity of the corresponding clinical pathology. For example, injuries at the levels of the cervical segment affect both upper and lower limbs while lesions from thoracic segments downwards affect the lower limb.
Spinal cord injury (SCI) patterns
Incomplete spinal cord injuries (SCIs)
|||Bican O,Minagar A,Pruitt AA, The spinal cord: a review of functional neuroanatomy. Neurologic clinics. 2013 Feb [PubMed PMID: 23186894]|
|||Huff T,Varacallo M, Neuroanatomy, Cerebrospinal Fluid . 2018 Jan [PubMed PMID: 29262203]|
|||Frostell A,Hakim R,Thelin EP,Mattsson P,Svensson M, A Review of the Segmental Diameter of the Healthy Human Spinal Cord. Frontiers in neurology. 2016 [PubMed PMID: 28066322]|
|||Lindeire S,Hauser JM, Anatomy, Back, Artery Of Adamkiewicz . 2018 Jan [PubMed PMID: 30422566]|
|||Jeanmonod R,Varacallo M, Geriatric Cervical Spine Injury . 2018 Jan [PubMed PMID: 29262191]|
|||Toney-Butler TJ,Varacallo M, Motor Vehicle Collision . 2018 Jan [PubMed PMID: 28722984]|
|||Varacallo M,Pizzutillo P, Osteoporosis, Spinal Cord Injury . 2018 Jan [PubMed PMID: 30252365]|
|||Devivo MJ, Epidemiology of traumatic spinal cord injury: trends and future implications. Spinal cord. 2012 May [PubMed PMID: 22270188]|
|||Chen Y,He Y,DeVivo MJ, Changing Demographics and Injury Profile of New Traumatic Spinal Cord Injuries in the United States, 1972-2014. Archives of physical medicine and rehabilitation. 2016 Oct [PubMed PMID: 27109331]|
|||Varacallo M,Pizzutillo P, Osteopenia . 2018 Jan [PubMed PMID: 29763053]|
|||Porter JL,Varacallo M, Osteoporosis . 2018 Jan [PubMed PMID: 28722930]|
|||Varacallo MA,Fox EJ, Osteoporosis and its complications. The Medical clinics of North America. 2014 Jul [PubMed PMID: 24994054]|
|||Varacallo MA,Fox EJ,Paul EM,Hassenbein SE,Warlow PM, Patients' response toward an automated orthopedic osteoporosis intervention program. Geriatric orthopaedic surgery & rehabilitation. 2013 Sep [PubMed PMID: 24319621]|
|||Donnally III CJ,Varacallo M, Fracture, Compression . 2018 Jan [PubMed PMID: 28846351]|
|||Tenny S,Varacallo M, Fracture, Odontoid . 2018 Jan [PubMed PMID: 28722985]|
|||Cornett CA,Vincent SA,Crow J,Hewlett A, Bacterial Spine Infections in Adults: Evaluation and Management. The Journal of the American Academy of Orthopaedic Surgeons. 2016 Jan [PubMed PMID: 26700630]|
|||Tenny S,Varacallo M, Chordoma . 2018 Jan [PubMed PMID: 28613596]|
|||Garg S,Dormans JP, Tumors and tumor-like conditions of the spine in children. The Journal of the American Academy of Orthopaedic Surgeons. 2005 Oct [PubMed PMID: 16224110]|
|||Al-Qurainy R,Collis E, Metastatic spinal cord compression: diagnosis and management. BMJ (Clinical research ed.). 2016 May 19 [PubMed PMID: 27199232]|
|||Donnally III CJ,Varacallo M, Lumbar Degenerative Disk Disease . 2018 Jan [PubMed PMID: 28846354]|
|||Donnally III CJ,Varacallo M, Lumbosacral Disc Injuries . 2018 Jan [PubMed PMID: 28846258]|
|||Alexander CE,Varacallo M, Lumbosacral Facet Syndrome . 2018 Jan [PubMed PMID: 28722935]|
|||Donnally III CJ,Varacallo M, Lumbar Spondylolysis And Spondylolisthesis . 2018 Jan [PubMed PMID: 28846329]|
|||Foris LA,Varacallo M, Spinal Stenosis And Neurogenic Claudication . 2018 Jan [PubMed PMID: 28613622]|
|||Alexander CE,Varacallo M, Lumbosacral Radiculopathy . 2018 Jan [PubMed PMID: 28613587]|
|||Donnally III CJ,Varacallo M, Basilar Invagination . 2018 Jan [PubMed PMID: 28846299]|
|||Hidalgo JA,Varacallo M, Arnold Chiari Malformation . 2018 Jan [PubMed PMID: 28613730]|
|||Ng KS,Abdul Halim S, Anterior spinal cord syndrome as a rare complication of acute bacterial meningitis in an adult. BMJ case reports. 2018 Oct 24 [PubMed PMID: 30361450]|
|||Liu J,Li Z,Ye R,Liu J,Ren A, Periconceptional folic acid supplementation and sex difference in prevention of neural tube defects and their subtypes in China: results from a large prospective cohort study. Nutrition journal. 2018 Dec 12 [PubMed PMID: 30541549]|
|||Diaz E,Morales H, Spinal Cord Anatomy and Clinical Syndromes. Seminars in ultrasound, CT, and MR. 2016 Oct [PubMed PMID: 27616310]|
|||Zeng Y,Ren H,Wan J,Lu J,Zhong F,Deng S, Cervical disc herniation causing Brown-Sequard syndrome: Case report and review of literature (CARE-compliant). Medicine. 2018 Sep [PubMed PMID: 30213001]|
|||Roth EJ,Park T,Pang T,Yarkony GM,Lee MY, Traumatic cervical Brown-Sequard and Brown-Sequard-plus syndromes: the spectrum of presentations and outcomes. Paraplegia. 1991 Nov [PubMed PMID: 1787982]|
|||Dave BR,Samal P,Sangvi R,Degulmadi D,Patel D,Krishnan A, Does the Surgical Timing and Decompression Alone or Fusion Surgery in Lumbar Stenosis Influence Outcome in Cauda Equina Syndrome? Asian spine journal. 2018 Nov 27 [PubMed PMID: 30472822]|