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Eyelid
An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyelid features a row of eyelashes along the eyelid margin, which serve to heighten the protection of the eye from dust and foreign debris, as well as from perspiration. "Palpebral" (and "blepharal") means relating to the eyelids. Its key function is to regularly spread the tears and other secretions on the eye surface to keep it moist, since the cornea must be continuously moist. They keep the eyes from drying out when asleep. Moreover, the blink reflex protects the eye from foreign bodies. The appearance of the human upper eyelid often varies between different populations. The prevalence of an epicanthic fold covering the inner corner of the eye account for the majority of East Asian and Southeast Asian populations, and is also found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levator Palpebrae Superioris Muscle
The levator palpebrae superioris ( la, elevating muscle of upper eyelid) is the muscle in the orbit that elevates the upper eyelid. Structure The levator palpebrae superioris originates from inferior surface of the lesser wing of the sphenoid bone, just above the optic foramen. It broadens and decreases in thickness (becomes thinner) and becomes the levator aponeurosis. This portion inserts on the skin of the upper eyelid, as well as the superior tarsal plate. It is a skeletal muscle. The superior tarsal muscle, a smooth muscle, is attached to the levator palpebrae superioris, and inserts on the superior tarsal plate as well. Blood supply The levator palebrae superioris receives its blood supply from branches of the ophthalmic artery, specifically, muscular branches and the supraorbital artery. Blood is drained into the superior ophthalmic vein. Nerve supply The levator palpebrae superioris receives motor innervation from the superior division of the oculomotor nerve. The smoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Artery
The lacrimal artery is an artery of the orbit. It is a branch of the ophthalmic artery. It accompanies the lacrimal nerve along the upper border of the lateral rectus muscle, travelling forward to reach the lacrimal gland. It supplies the lacrimal gland, two rectus muscles of the eye, the eyelids, and the conjunctiva. Structure Origin The lacrimal artery is normally a branch of the ophthalmic artery and represents one of its largest branches. It's origin occurs near the optic canal. It usually branches off the ophthalmic artery just after the ophthalmic artery's entery into the orbit. It can rarely arise before the ophthalmic artery enters the optic canal. Course and relations The lacrimal artery accompanies the lacrimal nerve along the upper border of the lateral rectus muscle. It travels anterior-ward to supply the lacrimal gland. Branches and distribution The lacrimal artery supplies the lacrimal gland, the eyelids and conjunctiva, and the superior rectus muscle a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epicanthic Fold
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the possession of "partial epicanthic folds" or "slight epicanthic folds" is noted in the relevant literature.Lang, Berel (ed.) (2000) ''Race and Racism in Theory and Practice'', Rowman & Littlefield, p. 10 Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. Etymology ''Epicanthus'' means 'above the canthus', with epi-canthus being the Latinized form of the Ancient Greek : 'corner of the eye'. Classification Variation in the shape of the epicanthic fold has led to four types being recognised: * ''Epicanthus supraciliaris'' runs from the brow, curving downwards towards the lachrymal sac. * ''Epicanthus palpebralis'' begins above the upper tarsus and extends to the inferior orbital rim. * ''Epicanthus tarsalis'' originates at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Septum
In anatomy, the orbital septum (palpebral fascia) is a membranous sheet that acts as the anterior (frontal) boundary of the orbit. It extends from the orbital rims to the eyelids. It forms the fibrous portion of the eyelids. Structure In the upper eyelid, the orbital septum blends with the tendon of the levator palpebrae superioris, and in the lower eyelid with the tarsal plate. When the eyes are closed, the whole orbital opening is covered by the septum and tarsi. Medially it is thin, and, becoming separated from the medial palpebral ligament, attaches to the lacrimal bone at its posterior crest. The medial ligament and its much weaker lateral counterpart, attached to the septum and orbit, keep the lids stable as the eye moves. The septum is perforated by the vessels and nerves which pass from the orbital cavity to the face and scalp. Clinical significance Orbital septum supports the orbital contents located posterior to it, especially orbital fat. The septum can be weakene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palpation
Palpation is the process of using one's hands to check the body, especially while perceiving/diagnosing a disease or illness. Usually performed by a health care practitioner, it is the process of feeling an object in or on the body to determine its size, shape, firmness, or location (for example, a veterinarian can feel the stomach of a pregnant animal to ensure good health and successful delivery). Palpation is an important part of the physical examination; the sense of touch is just as important in this examination as the sense of sight is. Physicians develop great skill in palpating problems below the surface of the body, becoming able to detect things that untrained persons would not. Mastery of anatomy and much practice are required to achieve a high level of skill. The concept of being able to detect or notice subtle tactile signs and to recognize their significance or implications is called appreciating them (just as in general vocabulary one can speak of appreciating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbicularis Oculi Muscle
The orbicularis oculi is a muscle in the face that closes the eyelids. It arises from the nasal part of the frontal bone, from the frontal process of the maxilla in front of the lacrimal groove, and from the anterior surface and borders of a short fibrous band, the medial palpebral ligament. From this origin, the fibers are directed laterally, forming a broad and thin layer, which occupies the eyelids or palpebræ, surrounds the circumference of the orbit, and spreads over the temple, and downward on the cheek. Structure There are at least 3 clearly defined sections of the orbicularis muscle. However, it is not clear whether the lacrimal section is a separate section, or whether it is just an extension of the preseptal and pretarsal sections. Orbital orbicularis The orbital portion is thicker and of a reddish color; its fibers form a complete ellipse without interruption at the lateral palpebral commissure; the upper fibers of this portion blend with the frontalis and corrugator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tears
Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The different types of tears—basal, reflex, and emotional—vary significantly in composition. The functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. Tears also occur as a part of the body's natural pain response. Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress. Tears have symbolic significance among humans. Physiology Chemical composition Tears are made up of three layers: lipid, aqueous, and mucous. Tears are composed of water, salts, antibodies, and lysozymes (antibacterial enzymes); though composition varies among different tear types. The composition of tears caused by an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supratrochlear
The supratrochlear nerve is a branch of the frontal nerve, itself a branch of the ophthalmic nerve (CN V1) from the trigeminal nerve (CN V). It provides sensory innervation to the skin of the forehead and the upper eyelid. Structure The supratrochlear nerve is a branch of the frontal nerve, itself a branch of the ophthalmic nerve (CN V1) from the trigeminal nerve (CN V). It is smaller than the supraorbital nerve from the frontal nerve. It branches midway between the base and apex of the orbit. It passes above the trochlea of the superior oblique muscle. It then travels anteriorly above the levator palpebrae superioris muscle. It exits the orbit through the frontal notch in the superomedial margin of the orbit. It then ascends onto the forehead beneath the corrugator supercilii muscle and frontalis muscle. It then divides into sensory branches. The supratrochlear nerve travels with the supratrochlear artery, a branch of the ophthalmic artery. Function The supratrochlear ner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sebaceous Glands
A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number on the face and scalp, but also on all parts of the skin except the palms of the hands and soles of the feet. In the eyelids, meibomian glands, also called tarsal glands, are a type of sebaceous gland that secrete a special type of sebum into tears. Surrounding the female nipple, areolar glands are specialized sebaceous glands for lubricating the nipple. Fordyce spots are benign, visible, sebaceous glands found usually on the lips, gums and inner cheeks, and genitals. Structure Location Sebaceous glands are found throughout all areas of the skin, except the palms of the hands and soles of the feet. There are two types of sebaceous glands, those connected to hair follicles and those that exist independently. Sebaceous glands are found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infratrochlear
The infratrochlear nerve is a branch of the nasociliary nerve, itself a branch of the ophthalmic nerve. Structure The nasociliary nerve terminates by bifurcating into the infratrochlear and the anterior ethmoidal nerves. The infratrochlear nerve travels anteriorly in the orbit along the upper border of the medial rectus muscle and underneath the trochlea of the superior oblique muscle. It exits the orbit medially and divides into small sensory branches. Function The infratrochlear nerve provides sensory innervation to the skin of the eye lids, the conjunctiva, lacrimal sac, lacrimal caruncle and the side of the nose above the medial canthus. Etymology The infratrochlear nerve is named after a structure it passes under. ''Infratrochlear'' means "below the trochlea Trochlea (Latin for pulley) is a term in anatomy. It refers to a grooved structure reminiscent of a pulley's wheel. Related to joints Most commonly, trochleae bear the articular surface of saddle joint, saddle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigeminal Nerve
In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewing; it is the most complex of the cranial nerves. Its name ("trigeminal", ) derives from each of the two nerves (one on each side of the pons) having three major branches: the ophthalmic nerve (V), the maxillary nerve (V), and the mandibular nerve (V). The ophthalmic and maxillary nerves are purely sensory, whereas the mandibular nerve supplies motor as well as sensory (or "cutaneous") functions. Adding to the complexity of this nerve is that autonomic nerve fibers as well as special sensory fibers (taste) are contained within it. The motor division of the trigeminal nerve derives from the basal plate of the embryonic pons, and the sensory division originates in the cranial neural crest. Sensory information from the face and body is proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraorbital Nerve
The supraorbital nerve is one of two branches of the frontal nerve, itself a branch of the ophthalmic nerve. The other branch of the frontal nerve is the supratrochlear nerve. Structure The supraorbital nerve branches from the frontal nerve midway between the base and apex of the orbit. It travels anteriorly above the levator palpebrae superioris and exits the orbit through the supraorbital foramen (or notch) in the superior margin orbit. It exits the orbit lateral to the supratrochlear nerve. It then ascends onto the forehead beneath the corrugator supercilii and frontalis muscles and divides into a medial branch and lateral branch. Function The supraorbital nerve provides sensory innervation to the skin of the lateral forehead and upper eyelid, as well as the conjunctiva of the upper eyelid and mucosa of the frontal sinus The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
