Anatomy and localization of spinal cord disorders
- Andrew Eisen, MD, FRCPC
Andrew Eisen, MD, FRCPC
- Professor Emeritus
- University of British Columbia, Division of Neurology
Because it is the primary pathway of communication between the brain and peripheral nervous system, diseases that affect the spinal cord are clinically eloquent. Many of these disease processes have a predilection for targeting specific areas or tracts within the spinal cord. As a result, knowledge of spinal cord anatomy and recognition of typical common spinal cord syndromes are useful in the evaluation of a patient with a myelopathy and can allow for a more directed diagnostic evaluation.
The anatomy of the spinal cord and its vascular supply and clinical features of common spinal cord syndromes will be reviewed here. Diseases that affect the spinal cord are discussed separately. (See "Disorders affecting the spinal cord".)
SPINAL CORD ANATOMY
There are 31 spinal cord segments, each with a pair of ventral (anterior) and dorsal (posterior) spinal nerve roots, which mediate motor and sensory function, respectively. The ventral and dorsal nerve roots combine on each side to form the spinal nerves as they exit from the vertebral column through the neuroforamina (figure 1).
Longitudinal organization — The spinal cord is divided longitudinally into four regions: the cervical, thoracic, lumbar, and sacral cord. The spinal cord extends from the base of the skull and terminates near the lower margin of the first lumbar vertebral body (L1). Below that level, the spinal canal contains the lumbar, sacral, and coccygeal spinal nerve roots that comprise the cauda equina.
Because the spinal cord is shorter than the vertebral column, vertebral and spinal cord segmental levels are not necessarily the same. The C1 through C8 spinal cord segments lie between the C1 through C7 vertebral levels. The T1 through T12 cord segments lie between T1 through T8. The five lumbar cord segments are situated at the T9 through T11 vertebral levels, and the S1 through S5 segments lie between T12 to L1. The C1 through C7 nerve roots emerge above their respective vertebrae; the C8 nerve root emerges between the C7 and T1 vertebral bodies. The remaining nerve roots emerge below their respective vertebrae (figure 2).
- REXED B. SOME ASPECTS OF THE CYTOARCHITECTONICS AND SYNAPTOLOGY OF THE SPINAL CORD. Prog Brain Res 1964; 11:58.
- REXED B. A cytoarchitectonic atlas of the spinal cord in the cat. J Comp Neurol 1954; 100:297.
- Rathelot JA, Strick PL. Subdivisions of primary motor cortex based on cortico-motoneuronal cells. Proc Natl Acad Sci U S A 2009; 106:918.
- Kuypers H. Anatomy of the descending pathways. In: Handbook of Physiology: The Nervous System II, Brookhart J, Mountcastle VB. (Eds), American Physiological Society, Bethesda, MD 1981.
- Baker SN. The primate reticulospinal tract, hand function and functional recovery. J Physiol 2011; 589:5603.
- Riddle CN, Edgley SA, Baker SN. Direct and indirect connections with upper limb motoneurons from the primate reticulospinal tract. J Neurosci 2009; 29:4993.
- Wagner R, Jagoda A. Spinal cord syndromes. Emerg Med Clin North Am 1997; 15:699.
- BAKER AB. SPINAL CORD LOCALIZATION. J Lancet 1965; 85:269.
- Abdel-Azim M, Sullivan M, Yalla SV. Disorders of bladder function in spinal cord disease. Neurol Clin 1991; 9:727.
- Seftel AD, Oates RD, Krane RJ. Disturbed sexual function in patients with spinal cord disease. Neurol Clin 1991; 9:757.
- Biglioli P, Roberto M, Cannata A, et al. Upper and lower spinal cord blood supply: the continuity of the anterior spinal artery and the relevance of the lumbar arteries. J Thorac Cardiovasc Surg 2004; 127:1188.
- GILLILAN LA. The arterial blood supply of the human spinal cord. J Comp Neurol 1958; 110:75.
- Kawaharada N, Morishita K, Hyodoh H, et al. Magnetic resonance angiographic localization of the artery of Adamkiewicz for spinal cord blood supply. Ann Thorac Surg 2004; 78:846.
- Lasjaunias P, Vallee B, Person H, et al. The lateral spinal artery of the upper cervical spinal cord. Anatomy, normal variations, and angiographic aspects. J Neurosurg 1985; 63:235.
- McCormick PC, Stein BM. Functional anatomy of the spinal cord and related structures. Neurosurg Clin N Am 1990; 1:469.
- Skalski JH, Zembala M. Albert Wojciech Adamkiewicz: the discoverer of the variable vascularity of the spinal cord. Ann Thorac Surg 2005; 80:1971.
- HADDEN SB. Diagnosis of spinal cord disease. Med Clin North Am 1951; 35:1765.
- Miller DH, McDonald WI, Blumhardt LD, et al. Magnetic resonance imaging in isolated noncompressive spinal cord syndromes. Ann Neurol 1987; 22:714.
- Offenbacher H. The diagnostic impact of magnetic resonance imaging on the evaluation of suspected spinal cord disease. Wien Klin Wochenschr 1992; 104:589.
- Morse SD. Acute central cervical spinal cord syndrome. Ann Emerg Med 1982; 11:436.
- Dickman CA, Hadley MN, Pappas CT, et al. Cruciate paralysis: a clinical and radiographic analysis of injuries to the cervicomedullary junction. J Neurosurg 1990; 73:850.
- Harrop JS, Sharan A, Ratliff J. Central cord injury: pathophysiology, management, and outcomes. Spine J 2006; 6:198S.
- Podnar S. Epidemiology of cauda equina and conus medullaris lesions. Muscle Nerve 2007; 35:529.
- Orendácová J, Cízková D, Kafka J, et al. Cauda equina syndrome. Prog Neurobiol 2001; 64:613.
- Valen B, Rolfsen LC. [The cauda equina syndrome]. Tidsskr Nor Laegeforen 2003; 123:643.
- Fraser S, Roberts L, Murphy E. Cauda equina syndrome: a literature review of its definition and clinical presentation. Arch Phys Med Rehabil 2009; 90:1964.
- Belinchón JM, Campos J, Merino J, et al. [Chronic spontaneous lumbar epidural hematoma]. Neurocirugia (Astur) 2005; 16:533.
- Cohen DB. Infectious origins of cauda equina syndrome. Neurosurg Focus 2004; 16:e2.
- Johnsson KE, Sass M. Cauda equina syndrome in lumbar spinal stenosis: case report and incidence in Jutland, Denmark. J Spinal Disord Tech 2004; 17:334.
- Kebaish KM, Awad JN. Spinal epidural hematoma causing acute cauda equina syndrome. Neurosurg Focus 2004; 16:e1.
- Lenehan B, Sullivan P, Street J, Dudeney S. Epidural abscess causing cauda equina syndrome. Ir J Med Sci 2005; 174:88.
- Wright MH, Denney LC. A comprehensive review of spinal arachnoiditis. Orthop Nurs 2003; 22:215.
- Baron EM, Young WF. Cervical spondylotic myelopathy: a brief review of its pathophysiology, clinical course, and diagnosis. Neurosurgery 2007; 60:S35.
- Do-Dai DD, Brooks MK, Goldkamp A, et al. Magnetic resonance imaging of intramedullary spinal cord lesions: a pictorial review. Curr Probl Diagn Radiol 2010; 39:160.
- Flanagan EP, Hunt CH, Lowe V, et al. [(18)F]-fluorodeoxyglucose-positron emission tomography in patients with active myelopathy. Mayo Clin Proc 2013; 88:1204.
- SPINAL CORD ANATOMY
- Longitudinal organization
- - Cervical cord
- - Thoracic cord
- - Lumbosacral cord
- - Cauda equina
- Cross-sectional anatomy
- - Dorsal horn
- - Ventral horn
- - White matter tracts
- Autonomic fibers
- Blood supply
- CLINICAL LOCALIZATION
- Segmental syndrome
- Dorsal (posterior) cord syndrome
- Ventral (anterior) cord syndrome
- Brown-Sequard (hemi-cord) syndrome
- Central cord syndromes
- Pure motor syndrome
- Conus medullaris syndrome
- Cauda equina syndrome
- Lhermitte's sign
- INFORMATION FOR PATIENTS