Dorello canal transmitts
**Core Concept**
The Dorello canal is a small anatomical structure in the brainstem that plays a crucial role in the transmission of a specific cranial nerve. It is located near the brainstem and is involved in the passage of a particular cranial nerve root.
**Why the Correct Answer is Right**
The Dorello canal transmits the abducens nerve (CN VI) root. This nerve is responsible for the lateral rectus muscle, which is involved in the abduction of the eye. The abducens nerve root passes through the Dorello canal, which is a small canal located in the lateral wall of the pontine cistern, near the brainstem. This canal provides a passage for the abducens nerve root to exit the brainstem and travel to the orbit.
**Why Each Wrong Option is Incorrect**
**Option A:** The Dorello canal does not transmit the oculomotor nerve (CN III) root.
**Option B:** The trochlear nerve (CN IV) does not pass through the Dorello canal, but rather exits the brainstem dorsally.
**Option C:** The facial nerve (CN VII) does not pass through the Dorello canal, but rather exits the brainstem through the internal auditory meatus.
**Clinical Pearl / High-Yield Fact**
The Dorello canal is a small but important structure in the brainstem that can be compromised in various neurological conditions, such as aneurysms or tumors. Knowledge of the Dorello canal and its contents is essential for neurosurgeons and neurologists to diagnose and treat conditions affecting the brainstem.
**Correct Answer:** D. The abducens nerve (CN VI) root.