Spinal Tracts

Reticulospinal Tract

(descending) Extrapyramidal motor tract responsible for facilitation or inhibition of voluntary and reflex activity through the influence on alpha and gamma motor neurons

Vestibulospinal tract

(descending) Extrapyramidal motor tract responsible for ipsilateral gross postural adjustments subsequent to head movements, facilitating activity of the extensor muscles, and inhibiting activity of the flexor muscles

Rubrospinal Tract

(descending) Extrapyramidal motor tract responsible for motor input of gross postural tone, facilitating activity of flexor muscles and inhibiting the activity of extensor muscles

Corticospinal tract (lateral)

(descending) Pyramidal motor tract responsible for contralateral voluntary fine movement.

Corticospinal tract (anterior)

(descending) Pyramidal motor tract responsible for ipsilateral voluntary, discrete and skilled movements

What do ascending tracts of the spinal cord involve/do?

Arises from cells of either spinal ganglia or intrinsic neurons within gray matter that receive primary SENSORY input. Relay sensory feedback to cerebrum and cerebellum

What do descending tracts of the spinal cord involve/do?

Involved with voluntary motor function, muscle tone, reflexes and equilibrium, visceral innervation and modulation of ascending sensory signals. The largest tract (corticospinal) originates in the cerebral cortex. Smaller tracts originate in the nuclei of the midbrain, pons and medulla oblongata.

Damage to corticospinal (pyramidal) tracts will result in these impairments:

Positive Babinski, absent superficial abdominal reflex, cremasteric reflex and loss of fine motor or skilled voluntary movement

Spino-olivary tract

(ascending) Ascends to the cerebellum and relays information from cutaneous and proprioceptive organs

Fasciulus cuneatus (posterior or dorsal column)

(ascending) Sensory tract for trunk, neck, and upper extremity proprioception, vibration, two-point discrimination and graphesthesia

Spinotectal tract

(ascending) Sensory tract providing afferent information for spinovisual reflexes and assists with movement of eyes and head towards a stimulus

Spinocerebellar tract (ventral)

(ascending) Sensory tract that ascends to the cerebellum, some fibers crossing with subsequent recrossing at the level of the pons for ipsilateral subconscious proprioception, tension in muscles, joint sense, and posture of the trunk, upper extremities and lower extremities

Spinoreticular tract

(ascending) The afferent pathway for the reticular formation that influences levels of consciousness

Spinothalamic tract (anterior)

(ascending) sensory tract for light touch and pressure

Spinothalamic tract (lateral)

(ascending) sensory tract for pain and temperature sensation

Fasiculus gracilis

(ascending) sensory tract for trunk and lower extremity proprioception, vibration, two-point discrimination and graphesthesia

Spinocerebellar tract (dorsal)

(ascending) sensory tract that ascends to the cerebellum for ipsilateral subconscious proprioception, tension in muscles, joint sense and posture of the trunk and LEs

Tectospinal Tract

(descending) Extrapyramidal motor tract responsible for contralateral postural muscle tone associated with auditory and visual stimuli

Damage to extrapyramidal descending tracts (reticulospinal, rubrospinal, tectospinal, vestibulospinal) may cause:

Significant paralysis, hypertonicity, exaggerated DTRs, clasp-knife