Eyelid anatomy

Knowledge of the relationship between structure and function in the human eyelid is essential to understand its anatomic complexity ( 1 The eyelids also contribute to the lacrimal pump and their blinking action helps eliminate tears from the lacrimal lake. The eyelids play an essential role in protecting the ocular surface by means of eye protective mechanisms. These are normal physiologic responses that maintain the precorneal tear film and ensure ocular surface defense. Important eye protective mechanisms provided by the eyelids that act to protect the ocular surface from drying and exposure include tear production, eyelid closure, blink frequency and adequacy, and stabilization of the precorneal tear film by reduction of evaporative tear loss. This chapter briefly reviews embryology, growth, and development of the eyelids to provide a better understanding of eyelid anatomy. The anatomy and function of the layers of the eyelid are discussed including skin and eyelid margin, orbicularis muscle, septum, orbital fat, retractor muscles, tarsus, and conjunctiva. Other important components of the adnexal structures will also be discussed; the surrounding lacrimal drainage system; and the vascular, lymphatic, and nervous supply to the orbit and eyelids. The eyelids are derived from an “inductive interaction” between mesodermal and ectodermal tissues. Development of the five brachial or pharyngeal arches occurs in the first few weeks of gestation. At about 5 weeks, a sheet of im...

The anatomy of the lid is best approached initially by reviewing a sagittal cross section of the eyelid. The exact number of tissue layers and the relationship between the many layers are modified significantly by the level of the lid examined. The orbital septum represents the anatomic boundary between the lid tissue and the orbital tissue, but an assessment of eyelid function and preparation for lid surgery requires knowledge of these postseptal structures. The upper and lower lids may be considered analogous structures, with differences mainly in the lid retractor arrangement. [ The upper eyelid skin crease (superior palpebral sulcus) is approximately 8-11 mm superior to the eyelid margin and is formed by the attachment of the superficial insertion of levator aponeurotic fibers (8-9 mm in men and 9-11 mm in women). The inferior eyelid fold (inferior palpebral sulcus), which is seen more frequently in children, runs from 3 mm inferior to the medial lower lid margin to 5 mm inferior to the lateral lid margin. The nasojugal fold runs inferiorly and laterally from the inner canthal region along the depression of separation of the orbicularis oculi and the levator labii superioris, forming the tear trough. The malar fold runs inferiorly and medially from the outer canthus toward the inferior aspect of the nasojugal fold. The open eye presents the palpebral fissure, a fusiform space between the lid margins that is 28-30 mm in length and about 9 mm in maximal height. The natur...

Figure 26.1 Eyelid anatomy. Each eyelid consists of an anterior lamella of skin and orbicularis muscle and a posterior lamella of tarsus and conjunctiva. The orbital septum forms the anterior border of the orbital fat. (Reprinted from Neligan, P.C., Buck, D.W. [Eds.], 2013. Core Procedures in Plastic Surgery. Elsevier, 1–22.) 2. • 3. • ▪ ▪ ▪ • ▪ ▪ ▪ 4. • ▪ ▪ ○ ○ ▪ • Figure 26.4 Fascial muscles of the orbital region. Note that the preseptal and pretarsal orbicularis muscles fuse with the medial and lateral canthal tendons. (Reprinted from Neligan, P.C., Buck, D.W. [Eds.], 2013. Core Procedures in Plastic Surgery. Elsevier, 1–22.) 7. • • ▪ 8. • ▪ ○ ○ ▪ • ▪ ▪ ▪ ▪ • ▪ ▪ ▪ 9. • • ▪ 10. • • • Figure 26.5 The orbicularis muscle fascia attaches to the skeleton along the orbital rim by the lateral orbital thickening (LOT) in continuity with the orbicularis retaining ligament (ORL). (Adapted from Ghavami, A., Pessa, J.E., Janis, J., etal., 2008. The orbicularis retaining ligament of the medial orbit: closing the circle. Plast. Reconstr. Surg. 121 [3], 994–1001.) 11. • • 12. • • 13. • ▪ ▪ ○ ▪ • ▪ Figure 26.6 The lateral canthal tendon inserts securely into the thickened periosteum overlying Whitnall’s tubercle. The tarsal strap is a distinct anatomic structure that suspends the tarsus medial and inferior to the lateral canthal tendon to the lateral orbital wall, approximately 4 to 5mm from the orbital rim. (Reprinted from Neligan, P.C., Buck, D.W. [Eds.], 2013. Core Procedures in Pla...

Previous 1 of 7 Eyelids Your eyes are your windows to the world — but they need to be shielded from the elements to keep you seeing clearly. Upper and lower eyelids protect the front of the eyeballs by blocking foreign objects and bright light. The eyelids also involuntarily open and close (blink) every few seconds when you're awake. • Riordan-Eva P, et al. Anatomy and embryology of the eye. In: Vaughan & Asbury's General Ophthalmology. 18th ed. McGraw-Hill Education; 2017. https://www.accessmedicine.com. Accessed March 2, 2022. • Yanoff M, et al., eds. Optics of the human eye. In: Ophthalmology. 5th ed. Elsevier; 2019. https://www.clinicalkey.com. Accessed March 2, 2022. • Standring S, et al. Development of the eye. In: Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. Elsevier; 2021. https://wwwclinicalkey.com. Accessed March 2, 2022.