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Incomplete cord syndromes

Why damage to one part of the cord's cross-section gives a recognisable pattern. Brown-Séquard, central cord, anterior cord and posterior cord patterns, explained from the tracts and the blood supply.

Updated 2026-10-026 sources

Depth:

Why it matters

The tracts in the cord carry different functions, cross at different places and are fed by different arteries, so damage to one part of the cross-section produces its own pattern of loss [1, 2]. Reading the pattern is a way to understand the cord's anatomy.

What it is

An incomplete injury leaves some function below the level of damage; the standard examination calls an injury incomplete when there is sensory or motor sparing in the lowest sacral segments [3]. Four patterns follow from the anatomy [1, 4, 5, 2]:

  1. Hemisection (Brown-Séquard): damage to one half of the cord [1].
  2. Central cord syndrome: weakness affecting the arms more than the legs [4].
  3. Anterior cord syndrome: infarction of the front two-thirds of the cord [5].
  4. Posterior spinal artery infarction: damage to the back of the cord [2].

How it works

Hemisection. The lateral corticospinal tract and the dorsal column ascend or descend on the same side as the body they serve below the medulla, while the spinothalamic pathway crosses at the level of entry [1]. So below a hemisection, movement and fine touch are lost on the damaged side and pain is lost on the other side [1]. A published case describes this pattern after a tumour inside the cord [6].

Anterior cord. The anterior spinal artery supplies the anterior two-thirds of the cord [5]. Its loss typically causes motor deficits below the injury and impaired pain and temperature, while vibration and proprioception are preserved [5].

Posterior cord. The posterior spinal arteries, with the pial plexus, supply the posterior white columns and the back of the grey matter, so infarction in their territory typically presents with posterior column dysfunction [2].

Central cord. Central cord syndrome was first described in the 1950s after hyperextension injuries of stenotic cervical spines, with disproportionate weakness of the upper limbs [4].

Common misconceptions

Misconception: Central cord syndrome hits the arms because their fibres lie innermost in the corticospinal tract.

That lamellar explanation was the prevailing theory until recently; the current view is a diffuse injury that affects the hand and arm axons more because they are densest in the cervical corticospinal tract [4].

Check yourself

After a left hemisection at T10, which leg loses pain sensation?

The right leg: the spinothalamic pathway crosses at the level of entry, so the left half of the cord carries pain from the right [1].

Which sensations are spared in anterior cord syndrome?

Vibration and proprioception, carried in the posterior columns outside the anterior spinal artery's territory [5].

Read next

References

  1. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, et al.. 16.4 The Sensory and Motor Exams. Anatomy and Physiology 2e. OpenStax. 2022. https://openstax.org/books/anatomy-and-physiology-2e/pages/16-4-the-sensory-and-motor-exams
  2. Iwamoto M, Fukunaga A, Uehara T. Posterior Spinal Artery Infarction With Unilateral Lumbar Spinal Cord Lesion: A Challenge in Early Diagnosis. Journal of General and Family Medicine. 2026;27(3). doi:10.1002/jgf2.70122
  3. Snider B, Kirshblum S, Rupp R, Schuld C, Biering-Sorensen F, Burns S, et al.. International Standards for Neurological Classification of Spinal Cord Injury: Case Examples Reinforcing Concepts From the 2019 Revision. Topics in Spinal Cord Injury Rehabilitation. 2025;31(3):1-14. doi:10.46292/sci24-00049
  4. Shakil H, Santaguida C, Wilson JR, Farhadi HF, Levi AD, Wilcox JT. Pathophysiology and surgical decision-making in central cord syndrome and degenerative cervical myelopathy: correcting the somatotopic fallacy. Frontiers in Neurology. 2023;14. doi:10.3389/fneur.2023.1276399
  5. Alshehri A, Alanazi R, Dokhi HB, Alshalaan H, Alqahtani H, Alhamied N, et al.. Rare presentation of acute anterior cord syndrome due to fibrocartilaginous embolism in a pediatric patient following minor trauma. Surgical Neurology International. 2025;16:34. doi:10.25259/SNI_903_2024
  6. Kaballo MA, Brennan DD, El Bassiouni M, Skehan SJ, Gupta RK. Intramedullary spinal cord metastasis from colonic carcinoma presenting as Brown-Séquard syndrome: a case report. Journal of Medical Case Reports. 2011;5(1). doi:10.1186/1752-1947-5-342

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