Henry Gray (18251861). Anatomy of the Human Body. 1918.
of the facia bulbi, which he has named the suspensory ligament of the eye. It is slung like a hammock below the eyeball, being expanded in the center, and narrow at its extremities which are attached to the zygomatic and lacrimal bones respectively.1
The Orbital Fascia forms the periosteum of the orbit. It is loosely connected to the bones and can be readily separated from them. Behind, it is united with the dura mater by processes which pass through the optic foramen and superior orbital fissure, and with the sheath of the optic nerve. In front, it is connected with the periosteum at the margin of the orbit, and sends off a process which assists in forming the orbital septum. From it two processes are given off; one to enclose the lacrimal gland, the other to hold the pulley of the Obliquus superior in position.
The Eyebrows (supercilia) are two arched eminences of integument, which surmount the upper circumference of the orbits, and support numerous short, thick hairs, directed obliquely on the surface. The eyebrows consist of thickened integument, connected beneath with the Orbicularis oculi, Corrugator, and Frontalis muscles.
The Eyelids (palpebræ) are two thin, movable folds, placed in front of the eye, protecting it from injury by their closure. The upper eyelid is the larger, and the more movable of the two, and is furnished with an elevator muscle, the Levator palpebræ superioris. When the eyelids are open, an elliptical space, the palpebral fissure (rima palpebrarum), is left between their margins, the angles of which correspond to the junctions of the upper and lower eyelids, and are called the palpebral commissures or canthi.
The lateral palpebral commissure (commissura palpebrarum lateralis; external canthus) is more acute than the medial, and the eyelids here lie in close contact with the bulb of the eye: but the medial palpebral commissure (commissura palpebrarum medialis; internal canthus) is prolonged for a short distance toward the nose, and the two eyelids are separated by a triangular space, the lacus lacrimalis(Fig. 892). At the basal angles of the lacus lacrimalis, on the margin of each eyelid, is a small conical elevation, the lacrimal papilla, the apex of which is pierced by a small orifice, the punctum lacrimale, the commencement of the lacrimal duct.
The eyelashes (cilia) are attached to the free edges of the eyelids; they are short, thick, curved hairs, arranged in a double or triple row: those of the upper eyelid, more numerous and longer than those of the lower, curve upward; those of the lower eyelid curve downward, so that they do not interlace in closing the lids. Near the attachment of the eyelashes are the openings of a number of glands, the ciliary glands, arranged in several rows close to the free margin of the lid; they are regarded as enlarged and modified sudoriferous glands.
Structure of the Eyelids.The eyelids are composed of the following structures taken in their order from without inward: integument, areolar tissue, fibers of the Orbicularis oculi, tarsus, orbital septum, tarsal glands and conjunctiva. The upper eyelid has, in addition, the aponeurosis of the Levator palpebræ superioris (Fig. 893).
The integument is extremely thin, and continuous at the margins of the eyelids with the conjunctiva.
The subcutaneous areolar tissue is very lax and delicate, and seldom contains any fat.
The palpebral fibers of the Orbicularis oculi are thin, pale in color, and possess an involuntary action.
The tarsi (tarsal plates) (Fig. 894) are two thin, elongated plates of dense connective tissue, about 2.5 cm. in length; one is placed in each eyelid, and contributes to its form and support. The superior tarsus (tarsus superior; superior tarsal plate), the larger, is of a semilunar form, about 10 mm. in breadth at the center, and gradually narrowing toward its extremities. To the anterior surface of this plate the aponeurosis of the Levator palpebræ superioris is attached. The inferior tarsus (tarsus inferior; inferior tarsal plate), the smaller, is thin, elliptical in form, and
Note 1. Wilson, J. G., American Journal of Anatomy, 1911, xi. [back]