Types of pennate muscle Pennate muscle

figure 1 pennate muscle fiber arrangements: a, unipennate; b, bipennate; c, multipennate

in muscle tissue, 10-100 endomysium-sheathed muscle fibers organized perimysium-wrapped bundles known fascicles. each muscle composed of number of fascicles grouped sleeve of connective tissue, known epimysium. in pennate muscle, aponeuroses run along each side of muscle , attach tendon. fascicles attach aponeuroses , form angle (the pennation angle) load axis of muscle. if fascicles on same side of tendon, pennate muscle called unipennate (fig. 1a). examples of include muscles in hand. if there fascicles on both sides of central tendon, pennate muscle called bipennate (fig. 1b). rectus femoris, large muscle in quadriceps, typical. if central tendon branches within pennate muscle, muscle called multipennate (fig. 1c), seen in deltoid muscle in shoulder.