The nasolacrimal canal is a small tube-like structure that is located within the human anatomy. It is an important part of the eye and serves several important functions.
Structure
The nasolacrimal canal is a narrow, tube-like structure that begins at the lacrimal sac and ends at the nasal cavity. It is approximately 1.5 cm in length and is lined with a thin layer of mucous membrane. The walls of the nasolacrimal canal are made up of a thin layer of bone, which is covered by a layer of soft tissue.
It is divided into three sections: the infundibulum, the canaliculus, and the common canaliculus.
- The infundibulum is the uppermost part of the nasolacrimal canal and is located at the lacrimal sac.
- The canaliculus is the middle section of the nasolacrimal canal and is located between the infundibulum and the common canaliculus.
- The common canaliculus is the lowermost part of the nasolacrimal canal and is located at the nasal cavity.
Location
The nasolacrimal canal is located within the face and is situated between the eye and the nose. It runs from the lacrimal sac, which is located at the inner corner of the eye, to the nasal cavity. The nasolacrimal canal is located within the orbital bone, which is the bone that surrounds the eye.
Function
The primary function of the nasolacrimal canal is to drain tears from the eye. Tears are produced by the lacrimal gland and are released into the eye through small ducts called lacrimal ducts. The tears then flow through the nasolacrimal canal and into the nasal cavity, where they are absorbed by the mucous membranes.
The nasolacrimal canal also helps to maintain the normal moisture balance of the eye. Tears are produced constantly and are necessary for maintaining the health and function of the eye. Without the nasolacrimal canal, tears would not be able to drain from the eye properly, which could lead to dryness and other eye problems.
Clinical Significance
Problems with the nasolacrimal canal can lead to a number of clinical issues. One common problem is nasolacrimal duct obstruction, which is a blockage of the nasolacrimal canal. This can occur due to a variety of factors, including inflammation, infection, or injury.
Symptoms of nasolacrimal duct obstruction include watering of the eye, discharge from the eye, and eye pain. Treatment for nasolacrimal duct obstruction typically involves the use of medications to reduce inflammation and/or the insertion of a small tube called a nasolacrimal duct stent to help unblock the canal.
Another clinical issue related to the nasolacrimal canal is nasolacrimal duct stenosis, which is a narrowing of the nasolacrimal canal. This can also be caused by inflammation, infection, or injury and can lead to similar symptoms as nasolacrimal duct obstruction. Treatment for nasolacrimal duct stenosis may involve the use of medications or surgical procedures to widen the canal.
In rare cases, the nasolacrimal canal may be completely absent at birth (congenital absence). This can lead to problems with tear drainage and may require surgical intervention to create a new nasolacrimal canal or to connect the lacrimal ducts directly to the nasal cavity.
Another condition that may affect the nasolacrimal canal is dacryocystitis, which is an inflammation of the lacrimal sac. This condition is often caused by a blockage of the nasolacrimal canal, and can lead to symptoms such as swelling and redness around the inner corner of the eye, eye pain, and discharge from the eye. Treatment for dacryocystitis may involve the use of medications to reduce inflammation and/or the insertion of a nasolacrimal duct stent to unblock the canal. In severe cases, surgery may be necessary to repair or remove the affected portion of the nasolacrimal canal.
