  The nematic ordering in semiflexible polymers with contour length $L$
exceeding their persistence length $\ell_p$ is described by a confinement of
the polymers in a cylinder of radius $r_{eff}$ much larger than the radius
$r_\rho$, expected from the respective concentration of the solution. Large
scale Molecular Dynamics simulations combined with Density Functional Theory
are used to locate the Isotropic-Nematic ($I-N$)-transition and to validate
this cylindrical confinement. Anomalous fluctuations, due to chain deflections
from neighboring chains in the nematic phase are proposed. Considering
deflections as collective excitations in the nematically ordered phase of
semiflexible polymers elucidates the origins of shortcomings in the description
of the $I-N$ transition by existing theories.
