Yet another perineural layer: so what?

Reina, Miguel Ángel; Boezaart, André P.; Nin, Olga C.; Zasimovich, Yury; Sala‐Blanch, Xavier

doi:10.1136/rapm-2019-100765

Cited by 6 publications

(6 citation statements)

References 3 publications

(5 reference statements)

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“…In other instances they enclosed the entire nerve endings. Within the nerves, other delicate collagen membranes, the circumfascicular collagen layer, surrounded each of the fascicles close to the perineurium, as previously shown (Reina, Boezaart, Nin, et al, 2020; Reina, Boezaart, Tubbs, et al, 2020). These circumfascicular membranes and perineurium layers were in tight contact with each other, not separated by any adipose tissue.…”

Section: Resultssupporting

confidence: 64%

“…Inside the nerves, another layer, the circumfascicular collagen layer, encloses each fascicle (Reina, Boezaart, Nin, et al, 2020; Reina, Boezaart, Tubbs, et al, 2020). This layer is in close contact with the perineurium, which is a cellular layer (Figure 8).…”

Section: Discussionmentioning

confidence: 99%

“…This layer is in close contact with the perineurium, which is a cellular layer (Figure 8). The circumfascicular collagen layer is the innermost network of collagen fibers surrounding the fascicles and completes the complex of network membranes, the final step in conveying stimuli to axons (Reina, Boezaart, Nin, et al, 2020, Reina, Boezaart, Tubbs, et al, 2020). The needling effect that pulls the conglomerate of collagen membranes also forcibly pulls on the nerve endings, stimulating them despite the distance from the tip of the needle.…”

Section: Discussionmentioning

confidence: 99%

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Microscopy of structures surrounding typical acupoints used in clinical practice and electron microscopic evaluation of acupuncture needles

et al. 2022

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Although the general functionality and structures of acupoints have been studied, there has been little insight into their underlying morphology and physical characteristics. We describe the microanatomical structures surrounding acupoints, the electron microscopic appearance of the needles, and the physical effects of acupuncture needling on the fascia. We injected heparinized blood solution through thin needles at seven known and commonly used “sweat acupoints” in eight fresh, unembalmed, cryopreserved human cadavers to mark the needle positions, and later, during histological examination, to identify them. After the solution was injected, samples were dissected and prepared for histological examination. We examined 350 cross‐sections of five different paraffin wax sections from each acupoint microscopically. Acupuncture needles were photographed and superimposed on the cross‐sectioned tissues at similar magnifications. Needles were also examined under a scanning electron microscope to judge the roughness or smoothness of their surfaces. A greater conglomeration of nerve endings surrounded the acupoints than in tissues more than 1–3 cm distant from them. Nerve endings and blood vessels were in close contact with a complex network of membranes formed by interlacing collagen fibers, and were always enclosed within those collagen membranes. Nerve endings were found within hypodermis, muscles, or both. Scanning electron microscopy demonstrated the three‐dimensional shapes and sizes of the needles, and the degree of roughness or smoothness of their polished external surfaces. We demonstrate a delicate arrangement of nerve endings and blood vessels enclosed within complex collagen membrane networks at acupoints within the hypodermis and muscle. This arrangement could explain why needling is an essential step in the acupuncture process that provides favorable outcomes in clinical practice.

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Section: Resultssupporting

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Microscopy of structures surrounding typical acupoints used in clinical practice and electron microscopic evaluation of acupuncture needles

et al. 2022

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“…Inside each cord were 25–30 fascicles but the number, shape, and size varied every 4–5 mm, as shown in Figure 2. Each fascicle in the cord had its own perineurium covered by interlacing collagen fibers, which our group previously described as the “circumfascicular collagen fiber network” (Reina et al, 2020; Reina, Boezaart, Nin, Zasimovich, & Sala‐Blanch, 2020). The topograms (maps) of the fascicles of the three cords shown in Figure 2 were different.…”

Section: Resultsmentioning

confidence: 99%

“…We therefore propose the following: Similar to the dura mater at the brachial plexus level where the roots become trunks, which form septae that later close and engulf the cords as epineuria (Reina et al, 2015), the circumneurium that originates from the adventitia of the blood vessels in the neurovascular bundle (Reina et al, 2015; Reina et al, 2020) forms septae at the level of the transition from the brachial plexus trunks to the cords. More distally, these septae form the circumneuria of the individual cords.…”

Section: Discussionmentioning

confidence: 99%

A reliable septum exists between the lateral cord and medial and posterior cords in the costoclavicular region: Clinical and microanatomical considerations in brachial plexus anesthetic blockade

et al. 2020

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Background and Objectives The ultrasound‐guided proximal infraclavicular costoclavicular block (PICB) appears popular but its results are inconsistent. We sought an accurate demonstration of septae formed between the brachial plexus cords. Methods We performed in‐plane, lateral‐to‐medial PICBs on 120 patients and recorded images. Once the most superficial lateral cord component was entered, a 0.4–0.6 mA current was applied to confirm needle placement; 5 ml of local anesthetic (LA) solution was then injected and its spread was observed and recorded. As the needle was advanced, the presence or absence of a hyperechoic linear structure was noted before the deeper compartment was reached, specifically looking for the possible displacement of such a septum. Results Upon initial scanning, a septum was observed in 67 of the 120 patients (46.2%). However, there was clear displacement of a linear septum between the lateral cord compartment and the medial and posterior cord compartments that prevented spread between the compartments in 94.16% of patients. Piercing the septum evoked motor responses from the medial or posterior cord. The same anatomical regions were studied microanatomically by analyzing cross‐sections obtained with the same approach angle as the ultrasound probe. Conclusions Intraplexus fascial septae that bundled the medial and posterior cords into one compartment and separated them from the lateral cord were demonstrated and confirmed microanatomically. This suggests the need for two separate injections (or two separate catheter placements for continuous peripheral nerve blockade) into the superficial and deep compartments to ensure LA spread around all three cords of the brachial plexus at this level.

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Nerve block, nerve damage, and fluid injection pressure: overturning the myth

McLeod,

Reina

2024

British Journal of Anaesthesia

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Yet another perineural layer: so what?

Cited by 6 publications

References 3 publications

Microscopy of structures surrounding typical acupoints used in clinical practice and electron microscopic evaluation of acupuncture needles

Microscopy of structures surrounding typical acupoints used in clinical practice and electron microscopic evaluation of acupuncture needles

A reliable septum exists between the lateral cord and medial and posterior cords in the costoclavicular region: Clinical and microanatomical considerations in brachial plexus anesthetic blockade

Nerve block, nerve damage, and fluid injection pressure: overturning the myth

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