Читать книгу Essentials of Veterinary Ophthalmology - Kirk N. Gelatt - Страница 25

The eyelids develop from surface ectoderm, which gives rise to the epidermis, cilia, and conjunctival epithelium. Neural crest mesenchyme gives rise to deeper structures, including the dermis and tarsus. The eyelid muscles (i.e., orbicularis and levator) are derived from craniofacial condensations of mesoderm called somitomeres. The upper eyelid develops from the frontonasal process; the lower eyelid develops from the maxillary process. The lid folds grow together and elongate to cover the developing eye. The upper and lower lids fuse on day 32 of gestation in the dog. Separation occurs two weeks postnatally.