# Detailed Assessment of Acrel Ganglion Through Cadaveric Dissection, Histology, and Ultrasonography

## TL;DR

This study investigates a mysterious structure in the wrist called Acrel’s 'pseudo-ganglion' using dissection, histology, and ultrasound to better understand its anatomy and clinical relevance.

## Contribution

The study provides a detailed anatomical and histological characterization of Acrel’s 'pseudo-ganglion' using multiple modalities.

## Key findings

- A ganglioform swelling was consistently found in all cadavers and matched ultrasound findings.
- Histology confirmed the absence of nerve cell bodies, supporting its classification as a 'pseudo-ganglion'.

## Abstract

Background

Acrel’s “pseudo-ganglion” is a ganglioform structure found on the floor of the fourth dorsal extensor compartment. The function of Acrel’s “pseudo-ganglion” is undetermined within published literature; however, recent histological studies suggest it to be devoid of nerve cell bodies and is, therefore, a “pseudo-ganglion." Advances in ultrasound technology have made it possible to better visualize nerves in vivo. This study aims to investigate any ganglioform structure at the termination of the posterior interosseous nerve, using ultrasound, cadaveric dissection, and histological studies.

Materials and methods

Twenty wrists from 10 formalin-fixed cadavers were dissected and examined. Standard haematoxylin and eosin staining of cadaveric samples was performed to check for the presence of any ganglionic cells and other cellular organizations. Ultrasound examination of the wrists of 10 live humans, using a GE LOGIQ e ultrasound system manufactured by GE Healthcare at Chicago, USA, with a 12L-RS transducer, was performed, looking for a non-compressible hypoechoic ovoid structure on the lateral side of the fourth extensor compartment, medial to Lister’s tubercle in accordance with the described location of Acrel’s “pseudo-ganglion."

Results

A ganglioform swelling was found in all cadavers, which corresponded to a non-compressible hypoechoic ovoid structure under ultrasonography, on the radial/lateral side of the fourth extensor compartment, and ulnar/medial to the dorsal/Lister’s tubercle. Standard haematoxylin and eosin staining from cadaveric samples showed the absence of any neuronal cells and inflammatory cells.

Conclusion

Understanding the termination of the posterior interosseous nerve under different modalities enabled us to gain knowledge about Acrel’s “pseudo-ganglion,” and this can aid in the assessment of various wrist pathologies linked to tendons around the wrist and their relation to this ganglioform swelling, named Acrel anglion. It may also help in refining clinical applications, being minimally invasive through the use of ultrasound and targeting that precise location.