ISSN:
0362-2525
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Serial transverse paraffin sections of intrafusal muscle fibers of spindles from the extensor pollicis and the extensor digitorum communis of ducks show that only one type of intrafusal muscle fiber exists, based on the mid-equatorial nucleation pattern, diameter, and length. Although the overall range in fiber diameter at the mid-equatorial region is between 4.2-20.0 μm, the average caliber is 10.4 ± 3.18 μm (S.D.) for spindles of the extensor pollicis and 9.3 ± 2.11 μm (S.D.) for spindles of the extensor digitorum communis muscles. The range in spindle length for the extensor pollicis is 290-2,090 μm, average 1,120 ± 569 μm (S.D.), and for the extensor digitorum communis 1,160-2,500 μm, average 1,745 ± 367 μm (S.D.). Therange in number of fibers per spindle for the extensor pollicis muscle is 5-12, average 8.2, and for the extensor digitorum muscle it is 1-11. In the extensor digitorum communis, there appear to be two groups, based on fiber number. Spindles of one group have a range of 5-11 fibers per spindle with an average of 7.2, whereas the second group has a range of 1-4 with an average of 2.7 fibers per spindle. The second group of spindles constitutes 52.5% of the 40 spindles studied, and of these 7.5% were monofibril spindles, 15.0% difibril, 17.5% trifibril, 12.5% quadrifibril spindles.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jmor.1051910304
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