. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 1054. THORAX. shortens, while the bars now decrease their perpendicular distance. Therefore it is per- fectly compatible for an intercostal fibre to separate the two ribs, between which it is at- tached, by its contracting ; and, if above a certain point (90° to the spine), to approxi- mate the same ribs by its further contraction. Fig. In deep inspiration it will be found that the ribs increase the breadth of their intercostal spaces (as was mentioned years ago by Ham- berger) ; and that by the contraction of an i
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 1054. THORAX. shortens, while the bars now decrease their perpendicular distance. Therefore it is per- fectly compatible for an intercostal fibre to separate the two ribs, between which it is at- tached, by its contracting ; and, if above a certain point (90° to the spine), to approxi- mate the same ribs by its further contraction. Fig. In deep inspiration it will be found that the ribs increase the breadth of their intercostal spaces (as was mentioned years ago by Ham- berger) ; and that by the contraction of an intercostal fibre. The bars (fig. 698.) in ro- tating, twice attain a minimum, and once a maximum, distance from each other; while the oblique tension in that revolution once attains its maximum, and once its minimum length. Of tensions at different parts of the bars or ribs. — Parallel tensions of equal power pro- duce the same effect, whether near the ful- crum or more distant from it ; an intercostal fibre near the vertebrae, has the same power as a fibre near the anterior extremity of the ribs. Let Fig. 696. represent ribs as before, with two parallel tensions at different distances from the bod}', E E, then t'+A-M— t' +am=t'+x'(—am)=t'+A o t + A N — t-\-a ?z=t+(A N — a n) = t + A O. Therefore the tension L T (fig. 69i.) acts with the same power as tensions p p', which is much nearer to the fulcra A B. Knowing now the effect of a single oblique tension, it is easy to consider an indefinite number of tensions, for they follow the same law of action. the tensions x acting on A c, /j/i Fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Todd, Robert Bentley, 1809-1860. London, Sherwood, Gilbert, and Piper
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