J Korean Soc Spine Surg.  2013 Dec;20(4):210-214. 10.4184/jkss.2013.20.4.210.

Anatomical and Pathophysiological Features of Cauda Equina

• Kim DY
• Lee KB

• KMID: 1896953
• DOI: http://doi.org/10.4184/jkss.2013.20.4.210

Abstract

STUDY DESIGN: Review of literature on anatomical and pathophysiological features of cauda equina.
OBJECTIVES
To look into the anatomical and pathophysiological features of cauda equina and support their basic knowledge of treating cauda equina syndrome. SUMMARY OF LITERATURE REVIEW: Cauda equina has different anatomical and pathophysiological features to peripheral nerve.
MATERIALS AND METHODS
Review of literature.
RESULTS
When compressing to cauda equina, the pathophysiologic mechanism develop as follows; increasing the vascular permiablity of nerve root, intraneural edema, and subsequent blood and nutritional impairment. Nerve root injury develops through this pathophysiologic mechanism.
CONCLUSIONS
Cauda equina has an extensive ateriovenous anastomosis and guaze-like pia mater, which supply blood and neutrition to it. These anatomical features prevent it from complete cauda equina syndrome when compressing to it under arterial blood pressure.

Keyword

Cauda equina; Anatomy; Pathophysiology

MeSH Terms

Arterial Pressure
Cauda Equina*
Edema
Peripheral Nerves
Pia Mater
Polyradiculopathy

Figure

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  Fig. 1. Intradural arrangement of cauda equina. The most caudal roots (black arrow) is located in central and posterior position, and the most cephalad roots (asterix) is located in lateral and anterior position. In addition, motor fiber is located in medial and anterior to sensory fiber (Photography by Shinich Kikuchi, MD, PhD).

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  Fig. 2. Photo showing the differences between spinal nerve root (asterix) and cauda equine (black arrows). Cauda equina has no connective tissue, adipose tissue, perineurium, epineurium, and endonurium (VR: ventral root, DR: dorsal root, DRG: dorsal root ganglion, Photography by Shinich Kikuchi, MD, PhD).

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  Fig. 3. Inter- and intrafascicular arteries showing compensating coils to allow interfascicular movement (1:Radicular artery, 2: interfascicular artery, 3: intrafascicular artery). Cited from Parke WW, Watanabe R, Spine (Phila Pa 1976). 1985;10:508-15.

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  Fig. 4. Graphic complilation showing the structure of a typical lumbosacral nerve root derived from data obtained by injection studies. 1. Fas-cicular pia; 2. Inter- and intrafascicular arteries 3. Longitudinal radicular artery; 4. Large radicular vein; 5. Arteriovenous anastomosis; 6. Collateral radicular artery; 7. Gauzelike pia-arachnoid that permits percolation of CSF to assist in metabolic support. Cited from The Spine Fifth Ed. Page 49 Figure 2-42.

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