Gross appearance of the spinal cord :

cervical enlargement

lumbar enlargement

conus medullaris

cauda equina

filum terminale

Cross sectional anatomy of the spinal cord

pia mater

arachnoid mater

dura mater

anterior median fissure anterior root

spinal nerve

posterior median sulcus

posterior root

posterior root ganglion

gray matter

white matter

Cross sectional anatomy of the spinal cord

anterior root

spinal nerve

posterior root

posterior root ganglion

gray matter

white matter

The spinal cord is surrounded...pia mater which adheres tightly Arachnoid mater, which contains the blood vessels, dura mater dense strong fibrous membrane. The pia mater is thickened on each side of the sc to form...passes laterally and adheres to the arachnoid and dura... It anchors the spinal cord to the dura mater. ...the cord possesse a deep... And a shallow furrow post... Along the entire length of the sc....are attached 31 pairs of spinal nerves

posterior gray column

anterior gray column

gray commissure

lateral gray column (thoracic and upper lumbar)

Gray matter

Sixth thoracic segment

central canal

substantia gelatinosa

nucleus propius

nucleus dorsalis (C8 – L3/L4)

visceral afferent nucleus (T1 – L3)

Third lumbar segment

Posterior gray column

substantia gelatinosa

Third lumbar segment

Posterior gray column

- situated at the apex and is largely made up of golgi type 2 neurons which receives afferent fibers concerned with pain, temp and touch sensations.

Substantia gelatinosa - situated at the apex and is largely made up of golgi type 2 neurons which receives afferent fibers concerned with pain, temp and touch sensations. Nucleus propius – a group of large nerve cells anterior to the substantia present throughout the spinal cord and constitutes the main bulk of cells present in the posterior gray column. It receives fibers from the posterior white column associated with vibration sense, two point discrimination and sense of position and movement. Nucleus dorsalis (Clarke’s column) situated at the base of the posterior gray column and extends from the eighth cervical segment to the third or fourth lumbar segment. Most of the cells are comparatively large associated with propioceptive endings. Visceral afferent nucleus - medium size nerve cells lateral to nucleu dorsalis extends from first thoracic to third lumbar. There are 4...2 extend throughout, 2 are restricted to the T and L region 1. Substantia gelatinosa situated at the apex, is largely made up of golgi... 2. Nucleus propius - ant ..a group of large nerve cellsconstitue the main bulk of

cells....receives fibers from the posterior white column concerned with...vibration sense, two point discrimination,

3. Nucleus dorsalis- base extends from, most are large asso. With propioceptive endings 4. Visceral afferent medium size nerve cells

nucleus propius

Third lumbar segment

Posterior gray column

a group of large nerve cells constitue the main bulk of cells in the posterior gray column receives fibers from the posterior white column concerned with. vibration sense, two point discrimination, muscle joint sense

nucleus dorsalis (C8 – L3/L4)

Third lumbar segment

Posterior gray column

Anterior gray column

medial group for innervation of neck muscles

Sixth cervical segment

Lateral group for innervation of upper limb muscles

central group of cells (accessory nucleus)

innervate skeletal muscles of the neck and trunk including the intercostal and abdominal muscles

innervate the diaphragm (phrenic nerve) innervate sternocleidomastoid and trapezius muscle (accessory nerve)

innervate the skeletal muscles of the limb

Lateral gray columns

lateral gray column

Third sacral segment Sixth thoracic segment

preganglionic sympathetic outflow

(T1 – L2preganglionic

parasympathetic outflow (S2,S3,S4)

posterior white column

lateral white column

anterior white column

White Matter

Three kinds of Spinal Tracts

2. Descending tracts

3. Intersegmental

tracts

1. Ascending tracts

Ascending tracts

1. lateral and anterior spinothalamic tract (anterolateral system)

2. posterior white column tract : fasciculus gracilis and fasciculus cuneatus (lemniscal system)

3. spinocerebellar tract

Ascending pathway

Consists of three neurons: 1. first-order neuron - has its cell body in the posterior root ganglion 2. second order neuron - gives axons that decussates and ascends to a higher level in the central nervous system 3. third-order neuron - usually in the thalamus

Lateral spinothalamic tract

involved in pain and temperature sensation

Posterolateral tract Of Lissaauer lateral spinothalamic tract

lateral spinothalamic tract in spinal lemniscus

ventral posterolateral nucleus

pain and temperature sensation

involve in light touch and pressure

Posterolateral tract of Lissauer

sensations of light touch and

pressure

anterior spinothalamic tract

spinal lemniscus

Anterior spinothalamic tract

Posterior White Column tract

midbrain

medulla

nucleus cuneatus and gracilis

ventral posterolateral

nucleus

medial lemniscus

fasciculus gracilis and fasciculus cuneatus

posterior root ganglion

discriminative touch vibratory sense muscle joint sense

fasciculus gracilis contains long ascending fibers from sacral, lumbar and lower six thoracic spinal nerves

fasciculus cuneatus - upper six thoracic and all the cervical s spinal nerves

Fasciculus cuneatus

Posterior spinocerebellar tract

Anterior spinocerebellar tract

Spinothalamic tract

(anterolateral system)

Fasciculus gracilis

Ascending tracts

Posterolateral tract

of Lissauer

Descending tracts

1. Corticospinal tract 2. Reticulospinal tract 3. Tectospinal tract 4. Rubrospinal tract 5. Vestibulospinal tract 6. Olivospinal tract

Consists of three neurons

cerebral cortex Descending

Pathway

1. first-order neuron : has its cell body in the cerebral cortex

2. Second-order neuron : internuncial neuron in the anterior gray column

3. Third-order neuron : the lower motor neuron in the anterior gray column

Corticospinal tract

concerned with voluntary, discrete,skilled movements

2/3 of the fibers arise from precentral gyrus 1/3 from the postcentral gyrus

fibers arise from axons of pyramidal cells in the fifth layer of the cerebral cortex

Fibers of the corticospinal tract arise from axons of pyramidal cells located in …. About 1/3 from primary motor cortex (area4), 1/3 secondary motor cortex(area6) 1/3 parietal lobe (areas 3,1,2) The descending fibers converge in the corona radiata then pass thru the posterior limb of the nternal capsule…continues thru the middle 3/5 of the basis peduncle of the midbrain

decussation of pyramid

lateral corticospinal tract

anterior corticospinal tract

corticospinal tract

Descending tracts

lateral corticospinal tract

anterior corticospinal tract

rubrospinal tract

vestibulospinal tract

tectospinal tract

fasciculus cuneatus

fasciculus gracilis

lateral corticospinal tract

cervical thoracic

lumbar

sacral

sacral

lumbar

thoracic

cervical

cervical thoracic

lumbar sacral

spinothalamic tract

Blood supply of the spinal cord

basilar artery

vertebral artery anterior spinal artery

posterior spinal artery

segmental spinal artery

anterior radicular artery

posterior radicular artery

Blood supply of the spinal cord

1. Anterior spinal artery 2. Posterior spinal arteries 3. Segmental spinal arteries anterior radicular arteries posterior radicular arteries 4. great anterior medullary artery of

Adamkiewicz

Arise from the aorta in the lower thoracic or upper lumbar. It may be the major source of blood supply to the lower two thirds of the spinal cord.

Clinical conditions involving the spinal cord

Clinical terms:

1. Paralysis - loss of motor function 2. Hemiplegia - paralysis of one side of

the body and includes the upper limb, one side of the trunk and the lower limb

3. Monoplegia - paralysis of one limb only

4. Paraplegia - paralysis of the two lower limbs

5. Quadriplegia - paralysis of all four limbs.

Complete cord transection

Affected structures 1. Anterior gray column

2. Corticospinal and other descending tracts 3. Ascending tracts

4. Descending autonomic tract

Clinical findings bilateral paralysis and muscle atrophy in the segment of the lesion bilateral spastic paralysis, loss of spinal reflexes loss of pain, temperature and touch, loss of discriminative touch, vibration sense ,muscle joint sense loss of bladder and bowel control

Anterior cord syndrome

Affected structures 1. anterior gray horn 2. anterior corticospinal tracts and other tracts but not the corticospinal tract 3. spinothalamic tract

Clinical findings bilateral paralysis in the segment of the lesion and muscle atrophy bilateral spastic paralysis bilateral paralysis of muscles innervated through anterior corticospinal tract bilateral loss of pain, temperature and impaired touch sensation below the level of the lesion.

Central cord syndrome

Affected structures: 1. Anterior gray column

2. Lateral corticospinal tract and

other descending tracts 3. Lateral and anterior spinothalamic

tract

sacral sacral

sacral

Clinical findings bilateral paralysis in the segment of the lesion and muscle atrophy bilateral spastic paralysis with sacral “sparing” bilateral loss of pain, temperature light touch and pressure sensations below the level of the lesion with sacral “sparing”

Brown-Sequard syndrome (hemisection of the cord)

Affected structures 1. Anterior gray column (one side) 2. Corticospinal and other descending tracts

3. Posterior white column (one side)

Clinical findings ipsilateral paralysis and muscle atrophy ipsilateral spastic paralysis, paralysis of voluntary movements, loss of spinal reflexes ipsilateral loss of tactile discrimination, vibratory sensation.

Affected structures 4. Lateral spinothalamic tract

(crossed)

5. anterior spinothalamic tract (crossed)

6. Posterior root of spinal nerve

Clinical findings Contralateral loss of pain and

temperature sensation two or three segments below the lesion

contralateral but not complete loss of tactile sensation

cutaneous anesthesia in the segment of the lesion

Brown-Sequard syndrome with a spinal cord lesion at the right 10th thoracic level.

loss of tactile discrimination, vibration sense

spastic paralysis

loss of pain and temperature sensation

impaired tactile sense

total loss of all sensations

hypotonic paralysis