The microscopic anatomy of the lower eyelid retractors
M. J. Hawes and R. K. Dortzbach
Twenty-two normal lower eyelids were studied microscopically to examine the
normal anatomy of the lower eyelid retractors. Eight lower eyelid specimens
from patients with involutional entropion and five from patients with
involutional ectropion were studied also. In the normal eyelids, the
inferior tarsal muscle consisted of scattered smooth-muscle fibers and did
not insert on the tarsus. The orbital septum fused with the
capsulopalpebral fascia 5 mm beneath the lower tarsal border to form a
single, complex fascial layer. In the involutional entropion and ectropion
cases, the fused capsulopalpebral fascia-orbital septum complex was
attached to the tarsus in all specimens. The first identifiable
smooth-muscle strands of the inferior tarsal muscle averaged 3.9 mm from
the lower tarsal border in entropion cases, 4.5 mm in ectropion cases, and
2.5 mm in the normal eyelids.
