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;
AREOLAR TISSUE, TENDONS, AND MUSCLES. 161
position of blood-vessels and nerves. The power of a muscle depends
upon the number of its contractile fibres. When contracted, it increases
in thickness ; its action, unless otherwise intluenced by associate parts
or by its tendon passing through loops of fascia or over a pnlley, is in
a direct line with the course of its fibres.
Faaclcull are the bundles of the fibres composing muscles. The
fibres which make up the fasciculi vary greatly in length in different
muscles. Tlie fasciculi Avhich form the bundles com})osing a muscle
run parallel with each other, never inter-
lacing, but extending from one terminal to
the other, except when interrupted by the
interposition of tendinous tissue, as in the
case of the digastric muscle.
The Perimysium (Fig. SO) is the sheath
of areolar tissue that invests the nniscles
and sends partitions inward between the
fasciculi, providing each with a special
sheath.
The Endomysium is the portion of the
above membrane partially surrounding the
fibres composing the fasciculi ; the latter
are not continuously invested with it. The
Transverse Section from the Steriio-
mastoid in man (50 times magni- chief uses of the perimysium and its parti-
fied) : o, perimysium ; 6, endomys- tions are to connect the fibres and fasciculi
ium f, fasciculi.
;
together, and to furnish spaces for the
accommodation of blood-vessels and nerves that supply the parts.
The fasciculi (Figs. 81 and 82) are prismatic in form, and the number
of fibres of which they are composed in different parts of the body
causes the variations in their thickness.
The texture of a muscle, whether coarse or fine, dc])ends upon this
circumstance. The length of a fasciculus
depends upon the length of the muscle, as YiG. 82.
well as upon the arrangement of the tendons
to which the extremities of the muscle are
attached. When the tendons are limited to
Fia. 81.
A, a small portion of Muscle, natural size
B, same magnified .5 diameters, of larger A few Muscular Fibres, being part of
and smaller fasciculi, seen in a trans- a small fasciculus (highly magni-
verse section. fied).
the ends or extremities of long -muscles, the fasciculi are of great length.
Vol. I.— 1
;
AREOLAR TISSUE, TENDONS, AND MUSCLES. 161
position of blood-vessels and nerves. The power of a muscle depends
upon the number of its contractile fibres. When contracted, it increases
in thickness ; its action, unless otherwise intluenced by associate parts
or by its tendon passing through loops of fascia or over a pnlley, is in
a direct line with the course of its fibres.
Faaclcull are the bundles of the fibres composing muscles. The
fibres which make up the fasciculi vary greatly in length in different
muscles. Tlie fasciculi Avhich form the bundles com})osing a muscle
run parallel with each other, never inter-
lacing, but extending from one terminal to
the other, except when interrupted by the
interposition of tendinous tissue, as in the
case of the digastric muscle.
The Perimysium (Fig. SO) is the sheath
of areolar tissue that invests the nniscles
and sends partitions inward between the
fasciculi, providing each with a special
sheath.
The Endomysium is the portion of the
above membrane partially surrounding the
fibres composing the fasciculi ; the latter
are not continuously invested with it. The
Transverse Section from the Steriio-
mastoid in man (50 times magni- chief uses of the perimysium and its parti-
fied) : o, perimysium ; 6, endomys- tions are to connect the fibres and fasciculi
ium f, fasciculi.
;
together, and to furnish spaces for the
accommodation of blood-vessels and nerves that supply the parts.
The fasciculi (Figs. 81 and 82) are prismatic in form, and the number
of fibres of which they are composed in different parts of the body
causes the variations in their thickness.
The texture of a muscle, whether coarse or fine, dc])ends upon this
circumstance. The length of a fasciculus
depends upon the length of the muscle, as YiG. 82.
well as upon the arrangement of the tendons
to which the extremities of the muscle are
attached. When the tendons are limited to
Fia. 81.
A, a small portion of Muscle, natural size
B, same magnified .5 diameters, of larger A few Muscular Fibres, being part of
and smaller fasciculi, seen in a trans- a small fasciculus (highly magni-
verse section. fied).
the ends or extremities of long -muscles, the fasciculi are of great length.
Vol. I.— 1
