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Hindlimb joint angle changes and action of the primary ankle extensor muscles during posture and locomotion in the Striped skunk ( Mephitis mephitis )
Author(s) -
Goslow G. E.,
Van De Graaff Kent M.
Publication year - 1982
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/jzo.1982.197.3.405
Subject(s) - ankle , anatomy , biology , treadmill , lever , hindlimb , physics , quantum mechanics , physiology
Knee (femorotibial), ankle (talocrural) and metatarsophalangeal joint angles during posture and locomotion were determined for the adult Striped skunk, Mephitis mephitis . Cinematography of animals moving overground and cineradiography of animals walking on a treadmill are the basis for joint angle measurements. These data allowed for the documentation of muscle length change of the primary ankle extensors, soleus, medial and lateral gastrocnemius and plantaris during stepping. Whole muscle length—active tension curves were determined on anaesthetized skunks. Appropriate moment arms were measured over the physiological range of knee and ankle angles. This study provides some mechanical and musculoskeletal data of the ankle of M. mephitis and provides for comparison and contrast to similar data for the domestic cat. Major findings include: (1) the length—active tetanic tension curves of the ankle extensors tend to be broad over a wider range of lengths in M. mephitis than in the cat, (2) the range of lengths at which the ankle extensors are actively used is relatively narrow in both species, (3) as both animals walk faster the working range of the muscles is closer to the maximum in situ length, (4) a broader range of ankle joint angles exists for M. rnephitis than for the cat at which the length—active tension curve and moment arm curve interact to provide maximum or near maximum torque, and (5) in general, the stance phase of the skunk is initiated at muscle lengths (relative to standing length) that are much shorter than those of the cat which may result in greater elastic storage for the cat durine E 2 . These data coupled with an analysis of gait selection of M. mephitis lead us to conclude that many features of the posture, locomotion and musculoskeletal design of the ankle extensor system of this species are primitive. The cat deviates from the primitive condition to some extent related to its more extreme specialization toward a jumping and sprinting way of life. Nevertheless, the domestic cat is a useful musculoskeletal model for studies concerned with the neural control of mammalian locomotion.