Film preparations and histological sections of human trigeminal nerve impre
gnated with silver nitrate and treated according to Falck-Hillarp revealed
a rich innervation within the intraneural blood vessels. Highly diverse and
complex neural interconnections were noted in the arterioles and venules o
f the trigeminal ganglion capsule as well as in the epineurium and external
layers of the perineurium of the trigeminal nerve branches. Neural plexuse
s were detected on the vessel walls within these layers. Sensory innervatio
n of the neural blood vessels was mainly relegated to polyvalent tissue-vas
cular receptors with adrenergic neural plexuses encountered on the walls of
the intraneural vessels.