2. Anatomy
External Structure:
• The spinal cord is a cylindrical elongated
structure flattened dorsoventrally, having a
length of 42–45 cm. It lies within the vertebral
canal extending from the atlas, continuous
with the medulla through the foramen
magnum, to the level of the 1st and 2nd lumbar
vertebra. Here it tapers into the conus
medullaris and terminates as the cauda equina.
3. • The cervical and lumbar enlargements of the
spinal cord provide the nerve roots innervating,
respectively, the upper and lower limbs.
• There are 31 pairs of spinal nerves, each having
dorsal sensory and ventral motor roots that exit
the cord (8 cervical, 12 thoracic, 5 lumbar, 5
sacral, 1 coccygeal).
• Three protective membranes, the meninges
including the dura mater, being the outer layer,
then the arachnoid, and the most inner one, the
pia, surround the cord .
4. • Cerebrospinal fluid flows between the
arachnoid and pia. Epidural fat is present in the
epidural space between the spinal canal and
dura mater.
5. • When clinical myelopathies develop, these
various disorders are classically categorized as
intramedullary, that is, intrinsic to the cord, or
extramedullary, occurring secondary to
disorders extrinsic to the cord.
• Extramedullary disorders are further
subdivided into those with either an intradural
extramedullary locus or a purely extradural site
of pathology.
6.
7. Internal Structure:
• White matter, consisting of myelinated fibers,
surrounds the butterfly or H-shaped gray
matter that contains cell bodies and their
processes within the cord’s center. These
include both primary ascending sensory fibers
and descending motor fibers.
8.
9. Vascular Supply
• One anterior and two posterior spinal arteries course the
length of the cord supplying the anterior two thirds and
posterior one third of the cord, respectively .
• Anterior spinal artery supplies the anterior horn,
spinothalamic tract, and corticospinal tract.
• Posterior spinal artery supplies the dorsal column and
dorsal gray matter
• Vertebral artery joins the anterior and posterior spinal
arteries to supply the cervical cord.
• Aortic segmental arteries provide the supply for the
remainder of the cord
10.
11. Spinal Cord Trauma
• This is the most widely studied example of
complete spinal cord transection and the
prototype of other acute transverse lesions
(vascular, demyelinative, compressive) giving rise
to paraplegia or quadriplegia with sphincteric
paralysis and sensory loss below the level of the
lesion.
• In cases of cervical spondylosis and/or a
congenitally narrow canal, an abrupt, forceful
extension of the neck can also severely damage
the cervical cord
12.
13. • The immediate effect of an acute transverse
lesion is dependent on its level. If at C1–C3,
death from respiratory paralysis is immediate.
• If it is lower, there is loss of all motor,
sensory, autonomic, and sphincteric function
below the level of the lesion. Or if at first the
loss of function is not complete, edema and
other secondary changes makes it so in a few
hours.
14. • The subsequent effects are divided into two
stages: the stage of spinal shock and the stage
of heightened reflex activity.
• Spinal shock is expressed by a loss of all reflex
activity below the level of the lesion, an atonic
bladder with overflow incontinence, atonic
bowel (paralytic ileus), gastric dilatation, and
loss of genital reflexes and vasomotor control.
15. • After 1 to 2 weeks, sometimes longer, spinal
flexor reflexes (Babinski signs, flexor spasms of
the legs) and then tendon reflexes begin to appear
in parts of the body supplied by the intact but
disconnected lower spinal cord segments.
• Simultaneously, bladder tone and gastric and
bowel function begin to recover. Gradually the
tendon reflexes become hyperactive, and the
bladder becomes spastic (frequency and urgency
of urination, small capacity of bladder with
automatic emptying).
16. • The paralyzed legs tend to remain in flexion or, if
the cord lesion is not complete, in extension. In
the latter case, there may be some return of motor
and sensory function below the lesion.
• The treatment of spine fracture and dislocation is
mainly orthopedic to reduce subluxation, assure
fixation of the spine, and by the immediate
administration of high doses of corticosteroids
17. Nontraumatic AcuteTransverse
Myelopathies
• Compressive: Tumor, Hemorrhage into the
spinal cord (hematomyelia) from an
arteriovenous malformation or epidural or
subdural hemorrhage(e.g from anticoagulant
drugs), or venous compression of the lower
cord by a dural fistula or AVM , Epidural
abscess( more often subacute in evolution),
spondylosis, acute disc herniation,…..etc
21. Cervical Spondylosis with Myelopathy
• This is perhaps the most frequently observed
myelopathy in general practice. It is essentially
a degenerative disease of the middle and lower
cervical vertebrae in which some combination
of degenerating and bulging disc(s), vertebral
and facet joint exostoses, and thickening of the
posterior longitudinal and yellow ligaments are
often engrafted on a congenitally narrow spinal
canal
22. • it compromises the cervical cord and roots by
compression and possibly by reduction of the
blood supply.
• Clinically, the syndrome consists of a triad of (1)
painful, stiff neck with limitation of the range of
movement; (2) radicular pain and numbness and
reduced reflexes in an arm; and (3) symmetric or
asymmetric spastic paraparesis and ataxia with
signs of lateral and posterior column affection.
23. • Diagnosis is made by MRI or CT
myelography and by the exclusion of other
spinal cord diseases.
• The main differential diagnostic considerations
are demyelinative disease and subacute
combined degeneration and there is a
superficial resembance to amyotrophic lateral
sclerosis.
• Treatment: analgesia, soft collar and surgery
24.
25. Demyelinative Myelopathy
• Among young adults in northern climates, multiple
sclerosis is the most frequent cause of symmetric or
asymmetric paraparesis with hyperreflexia and
sensory ataxia. About one-third of patients with
multiple sclerosis, including older adults, exhibit
this essentially spinal form of the disease. A history
of earlier attacks of neurologic disorder and the
presence of nonspinal findings referable to white
matter (optic atrophy, nystagmus, internuclear
ophthalmoplegia, ataxia) and cerebral white matter
lesions on MRI are helpful in diagnosis.
26.
27. Spinal Cord Tumors
1. Intramedullary: are mostly ependymomas,
less often astrocytomas
2. Extramedullary intradural: are most often
neurofibromas or meningiomas
3. Extradural tumors usually prove to be
metastatic carcinomas, lymphomas,
plasmacytomas, or chordomas
28. • Radicular pain in combination with
asymmetric or symmetric sensory and motor
tract involvement and variable sphincteric
dysfunction, evolving over weeks or months,
constitutes the prototypical syndrome.
• Some of the ependymomas progress slowly
over months or years, whereas the time course
of epidural lymphomas and metastatic
carcinomas is measured in days or weeks.
29. • Radicular symptoms are prominent with
neurofibromas but may occur also with
meningiomas and other tumors. Back pain and
percussion tenderness are the usual features of
compression by metastatic tumor.
• The treatment of most spinal tumors, even the
intramedullary ones, is surgical excision with
radiation therapy.
33. Epidural Abscess
• Skin infection in the region of the back or a bacteremia
may permit seeding of the epidural space or a vertebral
body, which in turn gives rise to an osteomyelitis with
extension to the epidural space.
• Rarely, infection is introduced by a lumbar puncture
needle or laminectomy.
• Fever and local pain and tenderness in the back, not
necessarily confined to the lumbar spine, are followed
within a few days by radicular pain and a rapidly
progressive paraparesis and sensory loss in the lower
parts of the body, with sphincteric paralysis.
34. • These clinical findings call for immediate
investigation with MRI or CT myelography,
followed by laminectomy and drainage, and
the administration of appropriate antibiotics in
high doses.
• Laminectomy must be performed before
paralysis becomes established if permanent
damage to the cord is to be avoided.
35.
36. Subacute Combined Degeneration
(SCD) of the Cord
• This is the name applied to the spinal cord disease
resulting from a deficiency of cobalamin (vitamin
B12)
• It begins with symptoms and signs of posterior
column disorder (paresthesias of hands and feet,
instability of stance and gait, impaired vibratory
and position senses), followed after some weeks
by a symmetric ataxic paraparesis with either
increased or decreased tendon reflexes and
Babinski signs
37. • The spinal cord lesion may precede the macrocytic
anemia by months or a year or more, particularly in
patients taking folic acid or those with iron deficiency.
• A megaloblastic anemia is an important clue to the
diagnosis of vitamin B12 deficiency.
• Diagnosis is straightforward when vitamin B12 levels
are low
• In the early and moderate deficiency state, the
administration of parenteral vitamin B12 (initially 1000
μg every 1–2 weeks and later monthly) can reverse the
disorder.
38.
39. Syringomyelia
• This syndrome is central cavitation of the spinal
cord, predominantly cervical, and often of
undetermined cause or occurs as a late
complication of spinal cord trauma.
• Clinically, syringomyelia is distinguished by
segmental weakness and atrophy of the hands and
arms with loss of tendon reflexes and a segmental
loss of sensation of dissociated type (i.e., loss of
pain and temperature sense and preservation of
the sense of touch and pressure) in a “cape”
distribution over the neck, shoulders, and arms.
40. • Later in the illness there is weakness and
ataxia of the legs from involvement of
corticospinal tracts and posterior columns.
Pain in the neck and arms, kyphoscoliosis, and
lower brainstem signs (syringobulbia) are
frequently associated.
• Tratment is surgery
41.
42. Ventral (Anterior) Cord Syndrome
• With infarction in the territory of the anterior
spinal artery (occlusion of the anterior spinal
artery itself or, more often, its extraspinal
tributaries), damage is limited to the anterior two-
thirds of the spinal cord. Tumor invasion and
inflammatory myelitis may have a similar effect.
There is paraplegia or quadriplegia, bilateral loss
of pain and temperature sensation below the
lesion, and sparing of posterior column (joint
position and vibration) sense.
