What is in the lacrimal fossa?
Lacrimal fossa consists of maxilliary bone (MB, yellow) and lacrimal bone (LB, green) and these 2 bones connect at anterior lacrimal crest (MB-LB). In this case the location of the anterior insertion of the uncinate process (UP) is anterior to the posterior lacrimal crest (PLC) and posterior to the maxillary bone.
Where is the lacrimal located?
orbitThe lacrimal gland is located within the orbit above the lateral end of the eye. It continually releases fluid which cleanses and protects the eye's surface as it lubricates and moistens it. These lacrimal secretions are commonly known as tears.
What organ is located in the lacrimal fossa?
The lacrimal gland is a bilobed, tear-shaped gland with the primary function of secreting the aqueous portion of the tear film, thereby maintaining the ocular surface. It is primarily located in the anterior, superotemporal orbit within the lacrimal fossa of the frontal bone.
How is lacrimal fossa formed?
Anterior to the posterior lacrimal crest is a longitudinally positioned groove called the lacrimal groove (or lacrimal sulcus). The inner margin of this sulcus unites with the frontal process of the maxilla and in this way forms the lacrimal fossa.
Is lacrimal fossa the same as lacrimal bone?
Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation.
What is a fossa in anatomy?
Fossa - A shallow depression in the bone surface. Here it may receive another articulating bone or act to support brain structures. Examples include trochlear fossa, posterior, middle, and anterior cranial fossa.
Does the lacrimal fossa contains tear gland?
Structure. The lacrimal gland is an almond-shaped structure, about 2 cm in length. It is located in the anterior, superotemporal aspect of the orbit, within the lacrimal fossa of the frontal bone.
Where is the lacrimal gland located quizlet?
The lacrimal gland is located in the superior and lateral aspects of the orbit of the eye. The lacrimal gland secretes lacrimal fluid, which contains mucus, antibodies, and lysozyme. Two tiny openings on the medial margin of each eyelid.
What cavity are the lacrimal ducts located?
nasal cavityThe lacrimal duct system transmits tears from the surface of the eye to the nasal cavity. Tears enter the duct system at the lacrimal punctae and conduct through canaliculi within the eyelids. The canaliculi drain into the lacrimal sac.
Where is the lacrimal gland located quizlet?
The lacrimal gland is located in the superior and lateral aspects of the orbit of the eye. The lacrimal gland secretes lacrimal fluid, which contains mucus, antibodies, and lysozyme. Two tiny openings on the medial margin of each eyelid.
Where is the lacrimal sac in the eye?
The lacrimal, or tear, sac lies in a hollow at the inner corner of the eye in the front part of the nasal wall of the orbit; under normal conditions, tears run along the margins of the eyelids toward…
What is a lacrimal?
Listen to pronunciation. (LA-krih-mul ...) A gland that secretes tears. The lacrimal glands are found in the upper, outer part of each eye socket.
What cavity are the lacrimal ducts located?
nasal cavityThe lacrimal duct system transmits tears from the surface of the eye to the nasal cavity. Tears enter the duct system at the lacrimal punctae and conduct through canaliculi within the eyelids. The canaliculi drain into the lacrimal sac.
What is the medial surface of the lacrimal bone?
Medial surface. The medial surface of the lacrimal bone faces the nasal cavity, which is why it is also called the nasal surface. There is notable longitudinal furrow on this surface, which corresponds to the posterior lacrimal crest of the orbital surface.
What is the function of the lacrimal bone?
After this article, it will be clear that the function of the lacrimal bone is to support parts of the lacrimal apparatus, especially the lacrimal sac and lacrimal canaculi, while at the same time, it participates in forming of the medial wall of the orbit. Key facts.
What is the lacrimal groove?
Anterior to the posterior lacrimal crest is a longitudinally positioned groove called the la crimal groove (or lacrimal sulcus). The inner margin of this sulcus unites with the frontal process of the maxilla and in this way forms the lacrimal fossa. The upper part of the lacrimal fossa houses the lacrimal sac, whereas the lower part contains ...
What is the most fragile facial bone?
It was mentioned before that the lacrimal bone is the most fragile facial bone. Fractures of this bone often causes obstruction of the nasolacrimal duct. This increases pressure in the duct, and can cause injury to its walls. Increased pressure within the duct presents with watery and irritated eyes because the tears cannot drain normally.
What is the smallest bone in the skull?
Lacrimal bone. The lacrimal bone is a paired facial bone that makes up the most anterior part of the medial wall of the orbit. It is the size and shape of a fingernail and thus the smallest bone of the skull. “Lacrima” is latin for “tear”, so the name of the bone corresponds with its relation to the nearby lacrimal structures.
What is the posterior lacrimal crest?
Posterior to the posterior lacrimal crest is a smooth surface that participates in forming the medial wall of the orbit. The part of this smooth surface that is immediately behind the posterior lacrimal crest is the place of origin of the orbicularis oculi muscle . This portion of the lateral surface also extends in the shape ...
Which bone articulates with the frontal process of the maxilla?
The anterior border of the lacrimal bone articulates with the frontal process of the maxilla, whereas the posterior border articulates with the orbital lamina of the ethmoid bone. The superior border articulates with the frontal bone, while the inferior border has complex relations since it is divided into two parts by the inferior edge ...
Where are the lacrimal glands located?
They are positioned in the upper lateral area of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Swelling of the lacrimal glands is called dacryoadenitis.
What is the lacrimal gland?
Lacrimal gland is an important part of the lacrimal part (the lacrimal system) that plays an essential role in maintaining ...
Why does my lacrimal gland swell?
Lacrimal Gland swelling might be acute or chronic. Acute swelling is triggered by a bacterial or viral infection such as mumps, Epstein-Barr infection, gonococcus and staphylococcus. Chronic swelling might be due to non-infectious inflammatory conditions such as thyroid eye condition, sarcoidosis and orbital pseudotumor.
How to detect lacrimal gland swelling?
To detect Lacrimal Gland swelling, your doctor will conduct an assessment of the eyes and covers. Special diagnostic tests such as CT scan may be performed to recognize the cause of the inflammation. In specific cases, a biopsy may also be done to dismiss the existence of a lacrimal gland tumour.
What are the symptoms of a swollen lacrimal gland?
Symptoms of Lacrimal Gland inflammation include: Discomfort in the area of the tear ducts. Dry eyes. Excessive discharge or tearing. Inflammation of the external portion of the upper lid. Inflammation and redness of the external part of the upper cover. Inflammation of lymph nodes in front of the ear.
How many excretory ducts are there in the orbital part of the eye?
The orbital part consists of great interlobular ducts that unite to form 3-5 main excretory ducts, signing up with 5– 7 ducts in the palpebral portion prior to the secreted fluid might enter upon the surface area of the eye. Tears secreted collect in the fornix conjunctiva of the upper cover, and pass over the eye surface to the lacrimal puncta, little holes found at the inner corner of the eyelids. These pass the tears through the lacrimal canaliculi on to the lacrimal sac, in turn to the nasolacrimal duct, which discards them out into the nose.
Which nerve supplies the sensory part of the lacrimal gland?
Nerve supply. The lacrimal nerve, derived from the ophthalmic nerve, provides the sensory part of the lacrimal gland. The higher petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland. The higher petrosal nerve passes through alongside branches of the V1 and V2 divisions ...
Where is the lacrimal fossa located?
This gland is about the size of an almond, and sits within the lacrimal fossa, located in the superior and outer edge of the orbital roof. The gland is divided into two sections anatomically. These are the small palpebral portion that lies closer to the eye, and the orbital portion that forms around four ducts. These ducts then combine with the 6 ducts of the palpebral portion, and are secreted onto the surface of the eye. The lacrimal gland is composed of cells that produce proteins and electrolytes, and cause water to follow by osmosis.
What is the lacrimal sac?
Lacrimal sac. This is the upper dilated end of the nasolacrimal duct. It connects to the lacrimal canaliculi, which function to drain the tears from the eyes surface to the nasal cavity via the nasolacrimal duct. The cells that line these canaliculi are stratified columnar epithelium, with goblet cells.
How many meibum glands are there in the eye?
Lipids (meibum) are secreted by these specialized sebaceous glands and they form a part of the tear film. There are approximately 50 glands on the upper eyelid, and 25 on the lower lid. These are squeezed from the glands upon blinking, and they have numerous functions including closing the eyelid airtight and also preventing tear spillage onto the cheek, by maintaining the tears between the oiled edge of the eyelid and the eyeball.
What is the function of the zygomatic branches of the facial nerve?
Zygomatic branches of facial nerve (lateral-left view) The function of the lacrimal apparatus is to produce tears, channel them to the surface of the eye where they maintain moisture, and flush debris and waste material from the ocular surface. The control of tears is under a multitude of inputs and sensory responses.
Where are the canaliculi located?
These are small channels that lie in each eyelid, and commence at the puncta lacrimalia; small openings where the tears are drained from the surface of the eye. These canaliculi are divided into the superior duct and the inferior duct that drain into the lacrimal sac. They are lined with stratified squamous epithelium.
Which nerve leaves the skull via the foramen lacerum?
Lacrimal artery (lateral-left view) The facial nerve leaves the skull via the foramen lacerum by hitching a ride with the greater petrosal nerve, eventually reaching the eye by merging with the lacrimal and zygomatic divisions of the ophthalmic division of the trigeminal nerve.
Which part of the eye is the flexible region that connects the tarsal and bulbar parts?
The palpebral part lines the internal surface of the eyelids themselves. The bulbar section covers the eyeball. The fornix section is the flexible region that connects the tarsal and bulbar parts, and allows the eye to move with freedom. Bulbar conjunctiva (cranial view)
Where is the lacrimal puncta located?
The lacrimal puncta are the openings of the lacrimal canaliculi which are located on the lacrimal papilla at the medial end of the upper and lower eyelids. From the lacrimal canaliculi, lacrimal fluid drains medially into the lacrimal sac, the dilated upper aspect of the nasolacrimal duct.
What are the two parts of the lacrimal gland?
The lacrimal gland consists of two connecting parts: the larger orbital part and the smaller palpebral part . The gland together with its associated drainage system of ducts form the lacrimal apparatus . This article will discuss the anatomy and function of the lacrimal gland. Key facts about the lacrimal gland. Structure.
How many excretory ducts are there in the lacrimal gland?
The lacrimal gland contains about 12 main excretory ducts. Ducts from the orbital part of the gland accompany those of the palpebral part by piercing through the levator palpebrae superioris aponeurosis to empty into the conjunctival sac. These ducts open along the lateral aspect of the superior fornix of the conjunctiva. In addition to the lacrimal gland, several accessory lacrimal glands (glands of Krause and Wolfring) are usually present in the palpebral conjunctiva. Although these glands are considerably smaller, they are structurally similar to the main lacrimal gland. The accessory glands account for about 10% of the total lacrimal secretion. Compared to the upper eyelid, the lower eyelid has fewer accessory lacrimal glands.
How are the lobes of the levator palpebrae superioris split?
The gland is split into two contiguous parts (lobes) by the lateral aponeurotic fibers of the levator palpebrae superioris muscle into an orbital part and a palpebral part. This division is only partial due to a posterior wall of parenchyma between the lobes.
What is the main supply of blood to the lacrimal gland?
Blood supply. The main arterial supply of the lacrimal gland is by the lacrimal artery, which is a branch of the ophthalmic artery (from the internal carotid artery ). The gland is also sometimes supplied by the infraorbital artery which is a branch of the maxillary artery (from the external carotid artery ).
What is the name of the fluid that is secreted by the eye?
It secretes lacrimal fluid (tear fluid), a watery fluid isotonic to plasma, onto the surface of the eyeball. This fluid forms the aqueous portion of a multilayered tear film that lubricates, protects and provides nutrients to the conjunctiva and cornea. The lacrimal fluid ultimately drains through a series of ducts into the nasal cavity.
Which fibers are responsible for the flow of blood through the lacrimal gland?
The sympathetic fibers, subsequently, without synapsing in the ganglion, travel along the same path as the parasympathetic fibers supplying the lacrimal gland. Sympathetic innervation regulates blood flow through the lacrimal gland and glandular secretions.
What are the two surfaces of the lacrimal?
The lacrimal has two surfaces: the nasal surface, which faces the nose, and the orbital surface, which faces the eye socket. It is similar in size to a fingernail and this rectangular-shaped bone is near the frontal bone, the maxilla, the ethmoid, and the inferior nasal concha. The orbital surface of the lacrimal is parted by a ridge called ...
What is the lacrimal crest?
It divides the lacrimal bone into two sections: the lacrimal sulcus and the orbial plate. The posterior lacrimal crest also creates a space for the lacrimal duct, a tube that allows tears to travel from the eyes to the nasal passages. The bone receives its name from that function; lacrimal is derived from the Latin word for tears.
What is the most fragile bone in the face?
The lacrimal bone is perhaps the most fragile bone of the face and one of the smallest bones in the body. Spanning between the middle of each eye socket, each lacrimal is thin and scalelike and serves as support for the eye. The pair of lacrimal bones are two of the fourteen facial bones.
Which bone forms the medial wall of the lacrimal sac?
For people of East Asian descent, the medial wall of the lacrimal sac is formed predominantly by the thicker maxillary bone rather than the lacrimal bone.[8] It is crucial to keep this in mind when forming the ostium during a dacryocystorhinostomy because the maxillary bone is thicker than the lacrimal bone.
How wide is the lacrimal sac?
The lacrimal sac fundus lies above the insertion, and the body lies below. The lacrimal sac is 12 to 15 mm long, 2 to 3 mm wide, 4 to 6 mm deep, and is predominantly in a collapsed position. [4]
How does the nasolacrimal duct form?
The nasolacrimal duct forms from a cord of ectodermal cells beginning at the seventh week of development. The surface ectodermal cord joins with a growing cord of epithelial cells extending from the nasal cavity. The cord bifurcates in the canthal area, forming early canaliculi. These projections reach the lid margins at 12 weeks.[6] By seven months' gestation, the papilla and punctual portions of the nasolacrimal duct system are fully formed and patent. The nasal lacrimal duct system canalizes along its extent simultaneously. The last portion to canalize, and the most frequent site of obstruction, is the opening to the inferior meatus of the nasal cavity. After birth, the size of the nasolacrimal duct system continues to increase relative to the surrounding facial structures. The most growth occurs in the first six months after birth. [7]
What is nasolacrimal duct obstruction?
Nasolacrimal duct obstruction is a common problem, especially in children. Up to 1 in 9 newborns have a congenital nasolacrimal duct obstruction.[9] It most often leads to excessive tearing and epiphora. Probing of the system and sometimes stenting are interventions that open the system and permit tears to flow normally.
What is the lower system of the lacrimal sac?
The lower system comprises the lacrimal sac and the lacrimal duct. The lacrimal sac is anterior to the orbital septum, nestled in its own fascia in the lacrimal fossa. The lacrimal crest of the maxillary bone forms the anterior border of the lacrimal fossa. The lacrimal crest of the small lacrimal bone forms the posterior border of the lacrimal fossa. The suture line joining the lacrimal and maxillary bones marks the medial border of the lacrimal fossa. [3]
Where do tears enter the lacrimal system?
The lacrimal duct system comprises upper and lower sections. Tears first enter the upper system at the lacrimal punctum. This visible structure contains a 0.2 to 0.3 mm opening at the mucocutaneous border on each of the upper and lower eyelids. The upper and lower lid punctae sit 5 mm and 6 mm, respectively, lateral to the medial canthal edge. The punctae typically oppose each other when the eyelids are closed. After entering the punctae, tears conduct through the canicular system. The 2 mm long vertical canaliculus extends perpendicular from the eyelid margin before widening to form the ampulla. At the ampulla, the canaliculus makes a 90-degree turn medially.[1] The canaliculi then continue 8 mm horizontally, following the arc of the eyelid. In 90% of individuals, the lower and upper canaliculi join proximal to the lacrimal sac, forming a single 3 to 5 mm long common canaliculus. For the remaining 10% of people, the canaliculi enter the lacrimal sac directly and independently. Just proximal to the lacrimal sac, the common canaliculus dilates to form the sinus of Maier. Tissue in-foldings form the valve of Rosenmuller, separating the common canaliculus from the lacrimal sac.[2] This separation prevents reflux through the lacrimal system.
Where do tears go in the eye?
The lacrimal duct system transmits tears from the surface of the eye to the nasal cavity. Tears enter the duct system at the lacrimal punctae and conduct through canaliculi within the eyelids. The canaliculi drain into the lacrimal sac. Tears continue down the intra-osseous lacrimal duct where they exit into the nasal cavity at the inferior meatus. Obstruction of the lacrimal duct system results in epiphora or excessive tearing. This condition is particularly common in children but is also common in adults.
