The direct or anterior pyramidal tract is motor; the impulse coming from the cerebral cortex passes down the spinal cord on the same side and thence to the anterior horn of the opposite side to supply mainly the muscles of the arm and trunk. The crossed or lateral pyramidal tract transmits motor impulses coming from the cortex which cross in the lower part of the medulla and descend on the opposite side. It supplies muscles on the same side as that on which the tract is. The direct cerebellar tract conveys impressions of equilibrium. The anterolateral tract (ascending tract of Gowers) conveys impressions of temperature and pain. The vestibulospinal tract - (descending tract of Lowenthal) is an indirect motor path.

Lissauer's tract is composed of ascending fibres from the posterior nerve-roots. The posterolateral (column of Burdach) conveys common sensation. The posteromedian (column of Goll) conveys muscular sense.

Fig. 489. - Diagram of the spinal cord in the lower cervical region, with its blood-vessels.

Pyramidal Tract

Motor paralysis below, spastic condition of paralyzed area; exaggerated reflexes; contractures; degeneration downward.

Posterior Columns

Sensory disturbances; ataxia; sensation of temperature and pain diminished; reflexes abolished; upward degeneration of postero-internal column.

Anterior Horn

Motor paralysis; muscle atrophy; reflexes abolished; degeneration descends and muscles show reaction of degeneration.

Posterior Horn

Sensory disturbances or anaesthesia, such as follows lesion of posterior column.

Anterior Root

Same as anterior horn.

Posterior Root

Anaesthesia, if complete J hyperalgesia and pain if irritative. Central Canal. - Painful and sensory impressions not properly recognized, while tactile or contact impressions are unaffected; joint dystrophies.

One Lateral Half

Brown-Sequard syndrome; complete loss of power below on the same side as lesion and slight loss of power below on opposite side; anaesthesia complete on opposite side below lesion.