Lateral Corticospinal Tract

tractus corticospinalis lateralis

The lateral corticospinal tract is the main voluntary motor pathway of the spinal cord. It carries the 85-90 percent of corticospinal fibres that crossed in the pyramidal decussation, so each tract controls the muscles on its own side of the body below the medulla. It is especially important for fine, skilled movements of the hands and fingers.

Anatomical Data

Structure & Connections

Location	Lateral funiculus of the spinal cord, along its whole length, medial to the dorsal spinocerebellar tract
Parts	Crossed corticospinal fibres Somatotopic layering (cervical fibres medial, sacral fibres lateral)
Connections	Primary motor and premotor cortex (origin) Internal capsule, cerebral peduncle, basilar pons and pyramid (route) Pyramidal decussation Ventral horn motor neurons and interneurons
Blood Supply	Anterior spinal artery (deep part); Posterior spinal arteries and pial plexus (superficial part)

Biomechanics

Function & Actions

Carries voluntary motor commands from the opposite motor cortex to spinal motor neurons, controlling skilled and precise movement.

Clinical Relevance

Clinical Notes

Damage to the lateral corticospinal tract causes upper motor neuron signs below the lesion on the same side: spastic weakness, brisk reflexes and an extensor plantar (Babinski) response. In Brown-Sequard syndrome, weakness is on the side of the cord lesion. It degenerates in motor neuron disease and hereditary spastic paraplegia.

Pathology

Common Injuries & Conditions

Brown-Sequard Syndrome

Hemisection of the cord causing same-side weakness and loss of vibration sense with opposite-side loss of pain and temperature.

Hereditary Spastic Paraplegia

Inherited degeneration of the longest corticospinal fibres causing progressive leg stiffness and weakness.

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