The functional anatomy of the ciliary muscle in four avian species.

摘要: The functional anatomy of avian ciliary muscles has been difficult to describe, due the muscle's inaccessible location inside eye. muscle chicken (Gallas gallus domesticus), pigeon (Columbia livia), kestrel (Falco sparverius), and hooded merganser (Margus cucullatus) (four species with differing accommodative needs) was examined histologically in both relaxed contracted states. all four can be divided into three main fibre groups based on insertion origin: anterior, posterior internal. anterior group originates at sclera under scleral ossicles inserts inner lamellae cornea. During accommodation these fibres pull cornea posteriorly, changing curvature posteriorly onto baseplate body. acts body, pulling it forward change lens during accommodation. internal extends from body thus a role corneal lenticular Species differences do exist, as seen subgroups determined by orientation between states percentage within groups. In general, majority chickens, pigeons, kestrels are group, suggesting an emphasis accommodation; merganser, groups, indicating that is predominant form