Cracking fingers

Person pressing through the finger joints

MRI images of a cracking finger.

Cracking joints describes the overstretching of the finger joints by pulling on the fingers or by pressing the finger joints accompanied by cracking noises.

causes

One theory and investigation of researchers JB Roston and R. Wheeler Haines in 1947 to be smooth in the joint cartilage surfaces by a thin film of so-called joint fluid ( synovial fluid separated) from each other. If you overstretch the joint, a negative pressure is created in the joint capsule . Gases dissolved in the liquid are suddenly released ( cavitation ). At this point it cracks. The cavity, which is created by the negative pressure, remains for some time. After a few minutes, when the gas has been dissolved again, the process can be repeated.

This theory was supported in a scientific article published in 2015 and a. confirmed by Gregory N. Kawchuk. At the same time, a theory from 1971, according to which the cracking occurs when the bubbles burst, was refuted.

consequences

Most experts are of the opinion that some people “cracking their fingers” is a harmless habit for many decades. The widespread view that this leads to osteoarthritis has not yet been proven.

literature

A. Unsworth, D. Dowson, V. Wright: Cracking joints. A bioengineering study of cavitation in the metacarpophalangeal joint. In: Annals of Rheumatic Diseases. 1971 (30), pp. 348-358. PMID 5557778 , PMC 1005793 (free full text)
R. Brodeur: The audible release associated with joint manipulation. In: J Manipulative Physiol Ther. 1995; (3), pp. 155-164. PMID 7790795
MG Protopapas, TC Cymet: Joint cracking and popping: understanding noises that accompany articular release. In: Journal of American Osteopathic Association. Volume 102, 2002, pp. 283-287. PMID 12033758 full text (PDF; 42 kB)

Web links

Irene Berres: A cave in the joint: researchers solve puzzles about cracking fingers. on: spiegel.de , April 15, 2015.
Sarah Zhang: Scientists Still Don't Know Exactly Why Knuckles Crack . In: The Atlantic (online edition), March 29, 2018.

Individual evidence

^ JB Roston, R. Wheeler Haines: Cracking in the metacarpo-phalangeal joint. In: Journal of anatomy. 81. Pt 2 (1947), p. 165.
↑ Gregory N. Kawchuk, Jerome Fryer, Jacob L. Jaremko, Hongbo Zeng, Lindsay Rowe: Real-Time Visualization of Joint Cavitation . In: PLOS ONE . tape 10 , no. 4 , April 15, 2015, ISSN 1932-6203 , p. e0119470 , doi : 10.1371 / journal.pone.0119470 , PMID 25875374 , PMC 4398549 (free full text) - ( plos.org [accessed May 29, 2016]).
^ A. Unsworth, D. Dowson, V. Wright: Cracking joints. A bioengineering study of cavitation in the metacarpophalangeal joint. In: Annals of the Rheumatic Diseases . 30.4 (1971), p. 348.
↑ DL Unger: Does Knuckle Cracking Lead to Arthritis of the Fingers? In: Arthritis and Rheumatism. Volume 41, 1998, pp. 949-950. PMID 9588755 ( Ig Nobel Prize 2009)
^ J. Castellanos, D. Axelrod: Effect of habitual knuckle cracking on hand function . In: Annals of the Rheumatic Diseases . tape 49 , 1990, pp. 308–309 , doi : 10.1136 / ard.49.5.308 , PMC 1004074 (free full text).

[1] JB Roston, R. Wheeler Haines: Cracking in the metacarpo-phalangeal joint. In: Journal of anatomy. 81. Pt 2 (1947), p. 165.

[2] Gregory N. Kawchuk, Jerome Fryer, Jacob L. Jaremko, Hongbo Zeng, Lindsay Rowe: Real-Time Visualization of Joint Cavitation . In: PLOS ONE . tape 10 , no. 4 , April 15, 2015, ISSN 1932-6203 , p. e0119470 , doi : 10.1371 / journal.pone.0119470 , PMID 25875374 , PMC 4398549 (free full text) - ( plos.org [accessed May 29, 2016]).

[3] A. Unsworth, D. Dowson, V. Wright: Cracking joints. A bioengineering study of cavitation in the metacarpophalangeal joint. In: Annals of the Rheumatic Diseases . 30.4 (1971), p. 348.

[4] DL Unger: Does Knuckle Cracking Lead to Arthritis of the Fingers? In: Arthritis and Rheumatism. Volume 41, 1998, pp. 949-950. PMID 9588755 ( Ig Nobel Prize 2009)

[Castellanos-5] J. Castellanos, D. Axelrod: Effect of habitual knuckle cracking on hand function . In: Annals of the Rheumatic Diseases . tape 49 , 1990, pp. 308–309 , doi : 10.1136 / ard.49.5.308 , PMC 1004074 (free full text).