ISSN:
0362-2525
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The original innominate bone consisted of ischiopubis only. From this developed a dorsally-directed ilium, upon which the dorsal limb muscles, originally arising from fascia, settled, and which thrust dorsalward between roots of the limb plexus, thus dividing the nerves into prozonal (dorsal and ventral) and metazonal (dorsal and ventral) groups. The primitive muscles of the tetrapod hip and thigh comprised a dorsal mass, soon divisible into sheets, innervated by both prozonal and metazonal dorsal nerves, and a similar ventral mass comparably innervated. The original two elements thus became four basic elements, and probably in early mammals or mammal-like reptiles all dually innervated muscles split into singly innervated units. With this four-group basis as the chief criterion, but considering other factors as well, it is possible to homologize the muscles of urodeles (ventral components only), lacertilians, mammals, and birds in entirely satisfactory manner, except for doubt in several instances in which specialization has secondarily obscured the precise relationships. In different mammals there is shown a tendency toward a final fusion of certain unrelated muscle units (biceps plus gluteus longus, human type of biceps, adductor magnus, and tensor fasciae femoris with gluteus maximus).
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jmor.1050620203
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