Anatomy of spinal cordFunctions of spinal cord• Sensory• Motor• Autonomic functions
Sensory conductionAscending/ sensory tracts in spinal cord areA. Tracts in dorsal/posterior white columnB. Tracts in lateral white columnC. Tracts in ventral white column
Dorsal column pathwayIncludes• Fasciculus gracilis• Fasciculus cuneatus Sensations in it are (fine touch, pressure, tactile localization, tactile discrimination, vibration sensation, stereo gnosis)
Tracts in lateral white column1. Lateral spinothalamic tract(SGR)2. Ventral spinocerebellar tract3. Dorsal spinocerebellar tract Pain and temperature in SGR itching tickling and sexual sensations are carried by the spino thalamic pathway
Complete transverse cord lesion• Features• Loss of al forms of sensations below the segmental level of lesion• Narrow band of hyperesthesia or paresthesia at the upper margin of level of sensory loss• Radicular pain or segmental paresthesia may occur at the level of lesion
Continue…• In cervical lesion the pain radiate to arm, in thoracic lesion the pain is circumferential to chest or abdomen and in lumbar and sacral lesions pain radiate to legs
hemisection- brown sequard syndrome• Features• Loss of pain and temperature on the opposite side and the upper margin is usually 2 or 3 segments below the level of lesion• Loss of propriceptive sensation and motor deficit occur on the same side of lesion• Touch is not affected because it passes through the lateral column and dorsal column of both sided of the cord
Central spinal cord lesions (syringomyelic lesion)• Features• Dissociated sensory loss or suspended sensory loss is loss of pain and temperature at the level of lesion where the spinothalamic fibers cross in the cord. There is loss of pain and temperature on one or both sides over a number of dermatomes with normal sensation above and below and this is called suspended sensory loss because is has upper and lower level.
Continue…• Touch is preserved• There is sacral sparing in intramedullary lesion
causes• Syringomyelia• Trauma leading to hematomyelia
Posterior column syndrome (tabetic syndrome)• Features• Common complaints are paraesthesias in the form of tingling pins and needles, girdle and band like sensation• Unpleasant tight feeling over limb• Loss of position and vibration sense below the level of lesion• Pain touch and temperature is preserved
Continue….• Sensory ataxia• Positive romberg’s sign• Lightening pain occur which is penetrating occurring at right angle to skin• Lhermitte’s sign – electric shock like sensation from the neck travelling down along spine when the neck is suddenly flexed or extended this occurs in lesion of posterior column of cervical region
Disseminated/ multiple sclerosis-means widespread increase of connective tissue in the nervous systemFEATURES– widespread demyelinating disease of CNS- Nerve cells replaced by neuroglial cells- Delayed or blocked conduction
Sub acute combined degeneration of spinal cord• Demyelination of white fibers of spinal cord• Dorsal and lateral columns are affected• Seen in pernicious anemia patients
Complications of spinal cord transection• Patients develop negative nitrogen balance and catabolize large amounts of body proteins is due to immobilization1. Decubitus (postural ulcers) develop.2. Hypercalcemia/hypercalciurea and calcium stones in urinary tracts.3. Urinary stasis with paralysis of bladder.
• Therefore the prognosis in patients with transected spinal cord used to be very poor and death from septicemia uremia or inanition, coma and finally death.
treatment• Faster recovery and minimal loss of function after spinal cord injury is acquired by administration of large doses of glucocorticoids• As early as possible after injury• Administration of neurotropins• Implantation of embryonal stem cells at the site of injury
• Another possibility being explored is bypassing the site of cord injury with brain computer interfaces devices.• However these approaches are still a long way from routine clinical use.