Lecture 4: Spinal Nerve-adele Flashcards
Gracile fasciculus (dorsal column) Cuneate fasciculus Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Cuneate fasciculus
Motor/sensory? Sensory
Origin? Lowe limb
Termination? Primary somatosensory cortex (leg area homunculus)
Fibres carrying-function (afferent- fine touch, proprioception from Lower limb. Go to the gracile nucleus of the medulla oblongata.
Decussate? In medial lemniscus at the medulla oblongata level. Then goes to the thalamus ➡post central gyrus
Cuneate fasciculus Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Cuneate fasciculus
Motor/sensory? Sensory
Origin? Upper limb➡ dorsal root ganglion
Termination? Primary somatosensory cortex (arm area homunculus) post central gyrus
Fibres carrying-function: afferent- fine touch, proprioception from upper limb go to the cuneate nucleus of posterior medulla.
Decussate? In medial lemniscus at medulla level then goes to the thalamus then post central gyrus
Spinothalamic tract (anterior and lateral tracts) Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Spinothalamic tract (anterior and lateral tracts)
Cuneate fasciculus
Motor/sensory? Sensory
Origin? Trunks and limbs
Termination? Post-central gyrus (primary somatosensory cortex)
Fibres carrying-function: afferent
Anterior-light touch sensation
Lateral-itch pain temp
After decussating➡ ascends via ventral or lateral spinothalamic tract which then heads to the VLP nucleus of to thalamus then if the primary somatosensory cortex
Decussate? From body ascends or descends 1-2 levels before synapsing in dorsal horn then decussates in anterior white commissure then goes to one of the 2 spinothalamic tracts to the VPL nucleus of the thalamus➡ post central gyrus.
Vestibulocerebellar Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Motor/sensory? Sensory Origin? Vestibular nuclei Termination? Cerebellum Fibres carrying-function: afferent➡ carries info about the position and movement of head. Enters cerebellum via the inferior cerebellar peduncle. Decussate?
Anterior spinocerebellar tract Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Motor/sensory? Sensory➡ anterior spinocerebellar travels in the anterior spinocerebellar tract
Origin? From the limbs, muscles, tendons and joints
Termination? Superior cerebellar peduncle➡ anterior lobe of the cerebellum.
Fibres carrying-function: afferent➡ whole limb movements and postural adjustments, unconscious coordination of motor activity.
Decussate? Ascend contra and ipsilaterally. Cross midline of spinal cord and the the pins (decussate twice)= ipsilateral. Then enter via superior cerebellar peduncle.
Posterior spinocerebellar Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Motor/sensory? Sensory➡ travels in the posterior spinocerebellar tract
Origin? Formal the limbs, muscles, tendons and joints
Termination? Inferior cerebellar peduncle➡ anterior lobe of the cerebellum
Fibres carrying-function: afferent➡ non conscious proprioception of individual muscles and caudal aspects of the body and legs
Decussate? Ascend ipsilaterally and enter cerebellum through inferior cerebellar peduncle
Reticulospinal Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Reticulospinal- lateral portion of reticulospinal tract and medial portion of reticular spinal tract.
Motor/sensory? Motor
Origin? Reticular formation in the pons (medial) and medulla (lateral)
Termination? Anterior horn of entire spinal cord➡ to extensor muscles
Fibres carrying-function: efferent➡ LATERAL INHIBITS voluntary extensor movement
MEDIAL FACILITATES voluntary extensor movement
Decussate?
Tectospinal tract Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Tectospinal tract (most anterior spinal tract near anterior median sulcus)
Motor/sensory? Motor
Origin? Colliculi in tectum of midbrain
Termination? Cervical anterior motor horn
Fibres carrying-function: efferent ➡ turns head in response to visual and auditory stimulus
Decussate?
Vestibulospinal tract Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Vestibulospinal tract- medial or lateral portions of the tract.
Motor/sensory? Motor
Origin? Medial/lateral vestibular nuclei of the pons
Termination? Ipsilateral anterior horn (medial terminates in cervical SC, and lateral terminates in the entire SC.)
Fibres carrying-function: Efferent➡ medial adjust the position of the head in response to changes in posture. Lateral ⬆ extensor muscle tone maintain upright posture and balance (mainly lower limb)
Decussate? DON’T DECUSSATE
Rubrospinal tract Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Rubrospinal tract
Motor/sensory? Motor
Origin? Red nucleus of the tegmentum in midbrain
Termination? Anterior horn of SC➡ upper arm
Fibres carrying-function: efferent➡facilitate contra lateral flexors of upper limb and inhibit extensors
Decussate? Ventral tegmentum (just near the substantia niagra)
Corticospinal tract Motor/sensory? Origin? Termination? Fibres carrying-function Decussate?
Corticospinal tract (lateral 90%, and anterior 10% CST)
Motor/sensory? Motor
Origin? Cerebral cortex pre central gyrus (motor homunculus from feet, legs, trunk, arm, head and neck sections) and post central sensory cortex.
Termination? Anterior horn ➡ lateral goes to limbs
Anterior goes to axial muscles
Fibres carrying-function: efferent ➡ fine voluntary movements of contra lateral upper and lower limbs (lateral CST) and axial muscles (anterior CST)
Decussate? Lateral CST- at decussation of the pyramids
Anterior- through anterior white commissure of spinal cord white matter.
