DESCENDING TRACTS OF SPINAL CORD: DESCENDING TRACTS OF SPINAL CORD
Descending tracts: Descending tracts PYRAMIDAL Corticospinal Corticonuclear EXTRAPYRAMIDAL Tectospinal Rubrospinal Reticulospinal Vestibulospinal Olivospinal
ANATOMICAL ORGANIZATION: ANATOMICAL ORGANIZATION First order neurons : cell body in cerebral cortex. Second order neurons: lower motor neuron in ant gray column or motor nuclei of cranial nerves.
CORTICOSPINAL TRACTS: CORTICOSPINAL TRACTS Voluntary, discrete, skilled movements especially those of distal part of limbs. They confer speed & agility to voluntary movements ( rapid skilled movements.)
PowerPoint Presentation: PYRAMIDAL TRACTS
MOTOR HOMUNCULUS: MOTOR HOMUNCULUS Face is situated inferiorly & that controlling lower limb is situated superiorly
PowerPoint Presentation: COURSE
PowerPoint Presentation: Facilitates the activity of flexors & inhibits the activity of extensor muscles.
LESIONS OF CORTICOSPINAL TRACTS: LESIONS OF CORTICOSPINAL TRACTS UPPER MOTOR NEURON Lesions above the pyramids : Contralateral paralysis Lesion below the pyramids : Ipsilateral paralysis. Features: Loss of performance of fine skilled voluntary movements. Babinski ᾿ s sign is present Tendon reflexes are exaggerated Superficial abdominal & Cremasteric reflexes are absent.
Applied Anatomy: Applied Anatomy Lesion in motor cortex – localized paralysis e.g. monoplegia . Lesion in Internal Capsule – Contralateral hemiplegia Contralateral paralysis of lower face and tongue may also be present . Lesion in Mid Brain – (Weber’s Syndrome) Contralateral hemiplegia involving also lower face & tongue. Ipsilateral paralysis of ocular ms supplied by 3 rd cranial nerve
PowerPoint Presentation: . Lesion in Pons – ( Millard Gubler Syndrome) Contralateral hemiplegia Ipsilateral paralysis of lateral rectus ms supplied by 6 th cranial nerve. Lesion in Medulla Oblongata – causes Medial medullary syndrome. Lesion in Spinal Cord – Brown sequard syndrome .