In dacrocystorhinostomy (DCR) lacrimal sacs are directly opened into:
**Core Concept**
Dacryocystorhinostomy (DCR) is a surgical procedure aimed at relieving nasolacrimal duct obstruction by establishing a new pathway for tear drainage from the lacrimal sac to the nasal cavity. This procedure involves the creation of a new ostium (opening) between the lacrimal sac and the nasal cavity.
**Why the Correct Answer is Right**
During a DCR procedure, the lacrimal sac is directly opened into the nasal cavity to bypass the obstructed nasolacrimal duct. This is achieved by creating a new opening between the lacrimal sac and the nasal cavity, allowing tears to drain directly into the nasal cavity. The nasal mucosa is then brought in contact with the lacrimal sac to form a new ostium, ensuring proper tear drainage.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the lacrimal sac is not opened into the conjunctiva during a DCR procedure. The conjunctiva is a thin membrane covering the white part of the eye and the inside of the eyelids, and it is not a suitable location for the new ostium.
**Option B:** This option is incorrect because the lacrimal sac is not opened into the skin during a DCR procedure. The skin is not a suitable location for the new ostium, as it would not allow for proper tear drainage into the nasal cavity.
**Option D:** This option is incorrect because the lacrimal sac is not opened into the canaliculi during a DCR procedure. The canaliculi are small tubes that collect tears from the eye and channel them into the lacrimal sac.
**Clinical Pearl / High-Yield Fact**
It's essential to note that a DCR procedure is indicated in cases of nasolacrimal duct obstruction, which can be caused by various factors such as trauma, tumors, or congenital anomalies. The procedure is usually performed under general anesthesia or local anesthesia with sedation.
**Correct Answer:** C. The nasal cavity.