(Studying back mice… page under construction)
This web was born in March 2018, as a result of the study that we began in the summer of 2017.
*We have published a review about back mice (September 2021): you can access a free on line pdf in the following link of the Pain and Therapy Journal→ Historical Review of Studies on Sacroiliac Fatty Nodules (Recently Termed “Back Mice”) as a Potential Cause of Low Back Pain. Cañis Parera et al. Pain ther (2021).
In backmice.info we aim to provide as much information as possible on the pathology known as back mice. We want to share all the knowledge we have about this OVERLOOKED medical condition and everything related to it, hoping that it will help to move forward its research.
Even though back mice (Chapter 1) will be the main topic, you will also find information about other related issues, such as cluneal nerve entrapment (Chapter 2), knowledge about fatty tissue and fascia (Chapter 3), pain mechanisms (Chapter 4), and some historical errors to think about…
What are back mice?
Simply put, back mice could be described as palpable deep fatty nodules, easily felt by the skilled examinar. The nodules lay within the fascial layers in the so-called sacroiliac area, a defined triangulated area formed by the sacrum, the iliac crest and the midline .
These nodules have received many names, but Peter Curtis coined the name back mice in the 90’s. We will use the name back mice through out the webpage (partly because it’s king of amusing).
Back mice are easily felt as deep nodules by a lubricated skilled hand.
These nodules are often painless upon palpation, so most people are not awere of their existence.
Here you can see an ultrasound image of non-painful back mice (it is fibro-fatty tissue)
-> LINK to the video ULTRASOUND IMAGES OF NON-PAINFUL BACK MICE
Nevertheless, in some people they can be slightly tender or even excruciatingly painful upon examination, reproducing patient’s low back pain.
Some researchers suggested back mice could be caused by ‘fatty overgrowth’ that herniates through the deep fascial layer.
To better understand what these nodules exactly are it is necessary to understand how the fibro-fatty tissue, hence the fascial layers, are structured in the body.
Why so overlooked…
Unfortunately, there has been a coexistence of several factors that may explain why this entity has been NEGLECTED AND UNDERDIAGNOSED by mainstream medicine.
These are related to the fact that…
- many physicians do not palpate during physical examination and they lack proper palpation skills. Even if they do so, the lumps are easily missed without proper lubrication of the fingers.
- even though they palpate the painful nodules, somehow they confuse them with ‘conventional lipomas’ -which they are not- and it is widely believed that ‘conventional lipomas do not hurt’.
- nodules may be mistaken with ‘myofascial trigger points’.
- these nodules are neither visible in the Radiography nor in the Magnetic Resonance Imaging.
- fibro-fatty tissue and the fascia, has been neglected as being a causative pain agent in musculoskeletical disorders.
- many physicians are not familiar with the existence of the cluneal nerves entrapment.
Intrigued by chance…
Even though most physicians are completely unaware of the existence of back mice nowadays, they have indeed been studied throughout history by many physicians from around the world.
By chance, some of these researchers stumbled across this clinical condition and were intrigued by it like us…
- ->LINK to the story how we were intrigued by back mice, ‘my personal story’.
- ->LINK to the story about how Dr. H. Austin (one of our collaborators) operated on his first patient.
Similar stories to ours have been reported by many physicians in published articles. We recommend you the case of Dr Ries, Dr MacDermont, Dr Clavero-Núñez (in Spanish), and Dr Monnerot-Dumaine, among others.
Medical articles…
You can read a summary of all the articles we have found that studied and treated back mice throughout history in the following links:
→LINKS to ALL the published medical articles about back mice
*We have published a review about back mice (September 2021): you can access a free on line pdf in the following link of the Pain and Therapy Journal→ Historical Review of Studies on Sacroiliac Fatty Nodules (Recently Termed “Back Mice”) as a Potential Cause of Low Back Pain. Cañis Parera et al. Pain ther (2021).
Back mice may be related to cluneal neuropathy. In the link below you can access the list of all the articles that have studied this peripheral neuropathy.
→LINK to ALL the published medical articles about cluneal neuropathy
To better understand back mice, we need to study the fibro-fatty tissue and the fascial layers, which has been traditionally neglected. The reason why remains a puzzle to us. Sir William Copeman once said in 1954: ‘Since fibrositis lacks glamour it has been overlooked’ -back mice were named fibrositic nodules in the 50’s.
This is an altruistic project. We believe sharing is always a rewarding experience. So if you wish to contribute or correct something, make a remark or simply contact us,
don’t hesitate to write us to
contact@backmice.info
TERMS FOR USING OUR WEBSITE By visiting the backmice.info website, users agree to all of the following terms and conditions: WE DO NOT OFFER YOU MEDICAL ADVICE ON OUR WEBSITE. Our website provides only information about or related to a pathology that we are CURRENTLY STUDYING as a part of a PhD program. THE INFORMATION AT THIS WEBSITE IS NOT MEDICAL ADVICE AND YOU CANNOT USE OUR WEBSITE INFORMATION AS A SUBSTITUTE FOR SPECIFIC MEDICAL ADVICE. Always consult with professional physician or other qualified health care provider for specific personal recommendations. Never disregard professional medical advice or delay seeking such advice because of something you read this website.
There are still many questions to answer about the intriguing back mice:
What are back mice, the fibro-fatty lumbar nodules? How are they related to low back pain and other pain syndromes? Why are they sometimes tender other times asymptomatic? Why have the studies of W.S.C. Copeman and others been overlooked? Sometimes they are identified by nodules, others by trigger points, why? Why are the tender nodules sometimes just lobules under tension whereas other times they herniate? Why are them mainly BILATERAL? Why a bubble of fat? Do they become painful by oedema or hemorrhage, congestion or torsion? Does the edema respond to an hormonal response or sympathetic stimulus? Why can the painful edema be recurrent? Are they made from brown adipose tissue? Why can they sometimes be just cured by anaesthetic injection? Why is it sometimes necessary to remove them surgically? During surgical incision the tender nodules protrude, because of edema and tension, why? Subfascial fat herniation… why? What are the subfascial basic fat pads? Can the nodules cause cluneal nerve entrapment? Why are they related to fever or humid coldness? Why is fatty tissue so unknown? Why do NOT many physicians have the skills to palpated them? Why do they have so many names? …
LINK to the youtube video: are back mice real?
How to find back mice? (1 minut video)
How to infiltrate back mice? (1 minut video)
In the following video, you can see how to palpate and how to infiltrate simple lumbar “back mice” of a young patient who had right lumbar pain and referred pain to the posterior thigh since last 24 hours. The pain got worse with efforts or bending over.
She had past history of right lumbar pain some months ago, and some times she has lumbar pain randomly. When pressing the nodule the patient feels referred pain down the leg all the way to the knee. The pain disappears immediately after injecting 4ml 1% lidocaine. Pain relief lasted weeks.
Back mice is one of the many names of these intriguing nodules
Back mice is one of the many names that the LUMBAR FIBRO-FATTY NODULES have received (Back mice was a name proposed by Peter Curtis on the 90’s).
Many doctors got intrigued to study the mysterious painful nodules and it seems everyone chose a different way to named…
List of names and studies about these nodules during history:
- Rheumatic effusion or induration -Hautschwiele, Zellegewebesschwiele, Muskelschwiele or Knochenhautschwielen- (Froriep 1843)
- Swollen fibrous indurations (→Stockman 1904)
- Cellulalgic nodules or cellulite nodule (→LINK to french studies)
- Subcutaneous fatty nodes (→Sutro 1935)
- Epi-sacro-iliac lipoma (→Ries 1937)
- Sacroiliac nodules (→MacDermot 1942)
- Fibrositis of the back (→Copeman and Ackerman 1944) (→Mylechreest 1945), (→ other articles about fibrositis)
- Fibrositic nodules (→Pugh 1945)
- Herniation of subfascial fat (→Herz 1946) , (→Hench 1946), (→Hucherson and Gandy 1948) (→Herz 1952) (→Bonner 1954)
- Painful lipomas (→Rouhier 1951)
- Herniation or oedema of fat lobules (→Copeman and Ackerman 1947) , (→Copeman 1949) (→Clavero-Núñez 1945)
- Nodulation or herniation of fat (→ Moes 1947)
- Fibrolipomatous nodules (→Orr et al. 1948)
- Episacroiliac lipoma (→Hittner 1949), (→Katz 1950), (→ Sicard 1952), (→1952 Donati and Bidoni) (→Sheehan 1953), (→Monnerot 1955), (→Nocentini and Rosati 1956) (→Pace and Henning 1972) (→Rosati 1990), (→Beverley 2007).
- Hernia grasa (→1946 “El día médico”) (→1950 Dal Lago &Vera)(→1953 Nunziata)
- Pannicular hernia (→Ficarra 1952) (→Knight 1954) (→Ficarra 1955) (→Tong 1981)
- Sacroiliac lipomatosis (→Raymond 1952), (→Raymond 1960)
- Lipomatose kreuzbeinsyndrom (→Schmidt-Voigt 1953)
- Hernia of the panniculus adiposus (→Gomez 1957)
- Hernia of the sacral fascia (→Kanan 1959)(→Tibaudin 1959)
- Sacroiliac (episacral) lipoma (→Wollgast and Afeman 1961) (→1990 Grieve)
- Lipomes épi-sacro-iliaques (→Rimbaud 1953), (→Duval 1962)
- Hernia adiposa (→Sedwitz and Thomas 1963)
- Lipomata in sacroiliac region (→Singewald 1966)
- Copeman and Ackerman syndrome (→Baciu 1969)
- Lumbar fat herniation (→Faille 1978)
- Xanthoadipose nodules (→Ercegovac 1982)
- Non-fibrositic lumbar subcutaneous nodules (→Swezey 1991)
- Back mouse/mice (→Curtis 1993) (→ Fischer 1993), (→Earl 1995) (→Motyka 2000), (→Curtis 2000), (→Bond 2004), (→Curtis 2004), (→Bicket 2016), (→Tiegs-Heiden 2017) (Cañis-Parera et al. 2021)
- Iliac nodular disorder (→Kurnik 2003)
- Episacral lipoma (→Bond 2000), (→Erdem 2013)
- Fibro-fatty nodule (→Su Min Ko 2009)
- Sacroiliac fascial Lipocele (→Yang 2015)
- Nodolo di Copeman (→Farina 2017)(→Martinze-Nuñez 2020)
Other names for specific sacroiliac pain:
- Multifundus triangle syndrome (→Buwens 1955)
- Lumbodorsal subfascial fat fibrosis (→Dittrich 1963)
- Iliac crest pain syndrome (→Collée et al. 1991)
→LINK to ALL the published medical articles about back mice
→LINK to The history of the term “fibrositis“ (an old name for back mice was lumbar fibrositis and an old name for fibromyalgia was generalized fibrositis)
→LINK to the French studies about the “cellulite“ (an old name for back mice by French doctors was lumbar cellulite)
→LINK to the articles about the myofascial syndrome (another view for back mice)
→LINK to the articles about myogelosis [myogelose and muskelhärte] (another view for back mice)
The palpation technique to search for back mice
-The best patient’s position is standing with back slightly bending (semiflexion) and hands resting on the examination table.
-Leave the zone uncovered and apply some substance to your hands so that the fingers can slide. For example, in these cases, we are using some sterilizer.
-Begin to palpate the midline by pressing firmly on the spinal apophyses. Ask the patient for any focalized pain.
-If the patient has a lumbar painful side, start with the painless side. Palpate with the fingertips, doing continuous circular movements to find nodular spots.
-When the patient says that the area of the nodule is painful, do a second palpation, asking the patient to recognize the spot of maximum pain.
-Press firmly on the spot of maximum pain, and ask the patient if the pain has any radiation (to abdomen, inguinal region, gluteal region or leg).
-Sometimes they are only present in one side, other times they are bilateral.
-Some nodules are tender or painful and some are painless. Remember that this can change over time, and a painless nodule can become painful.
-If we mark the nodules, they usually stay between 5-7 cm from the midline.
In the following videos we’ll show how to palpate to search nodules in the sacroiliac region
Video 1. To illustrate how to do a palpation of the lumbar region (bilateral backmice)

(Page under construction)