It is well known that whales in captivity suffer from dorsal fin bending.
However, the mechanisms behind this change are poorly
understood. Humans can suffer from similar symptoms either after a period of
immobilization or after suffering a brain lesion. Therefore, we here speculate
whether the bent dorsal fins are reflecting contracture development in whales.
References
[1]
Alves, F., et al. (2018) The Incidence of Bent Dorsal Fins in Free-Ranging Cetaceans. The Journal of Anatomy, 232, 263-269. https://doi.org/10.1111/joa.12729
[2]
O’Dwyer, N.J., Ada, L. and Neilson, P.D. (1996) Spasticity and Muscle Contracture Following Stroke. Brain, 119, 1737-1749. https://doi.org/10.1093/brain/119.5.1737
[3]
Baker, J.H. and Matsumoto, D.E. (1988) Adaptation of Skeletal Muscle to Immobilization in a Shortened Position. Muscle & Nerve, 11, 231-244. https://doi.org/10.1002/mus.880110308
[4]
Born, C.T., Gil, J.A. and Goodman, A.D. (2017) Joint Contractures Resulting from Prolonged Immobilization: Etiology, Prevention, and Management. Journal of the American Academy of Orthopaedic Surgeons, 25, 110-116. https://doi.org/10.5435/JAAOS-D-15-00697
[5]
Trudel, G. and Laneuville, O. (2014) Quantitative and Temporal Differential Recovery of Articular and Muscular Limitations of Knee Joint Contractures; Results in a Rat Model. The Journal of Applied Physiology, 117, 730-737. https://doi.org/10.1152/japplphysiol.00409.2014
[6]
Hagglund, G. and Wagner, P. (2011) Spasticity of the Gastrosoleus Muscle is Related to the Development of Reduced Passive Dorsiflexion of the Ankle in Children with Cerebral Palsy: A Registry Analysis of 2796 Examinations in 355 Children. Acta Orthopaedica, 82, 744-748. https://doi.org/10.3109/17453674.2011.618917
[7]
Tedroff, K., et al. (2011) Does Loss of Spasticity Matter? A 10-Year Follow-Up after Selective Dorsal Rhizotomy in Cerebral Palsy. Developmental Medicine & Child Neurology, 53, 724-729. https://doi.org/10.1111/j.1469-8749.2011.03969.x
[8]
Pingel, J., Bartels, E.M. and Nielsen, J.B. (2016) New Perspectives on the Development of Muscle Contractures Following Central Motor Lesions. The Journal of Physiology, 595, 1027-1038. https://doi.org/10.1113/JP272767
[9]
Tabary, J.C., et al. (1972) Physiological and Structural Changes in the Cat’s Soleus Muscle Due to Immobilization at Different Lengths by Plaster Casts. The Journal of Physiology, 224, 231-244. https://doi.org/10.1113/jphysiol.1972.sp009891
[10]
Colver, A., Fairhurst, C. and Pharoah, P.O. (2014) Cerebral Palsy. Lancet, 383, 1240-1249. https://doi.org/10.1016/S0140-6736(13)61835-8
