Question

activity 17 : quiz
module : nervous
topic : structures / type : combination

what structure is highlighted?

a. olfactory tract
b. masseter m.
c. olfactory bulb
d. axillary n. with spinal nerve roots
e. olfactory nn. (cn i)

Explanation:

Identify anatomical landmarks

The image shows a sagittal section of the human head, focusing on the nasal cavity and the anterior cranial fossa. We can observe the nasal septum/cavity, the cribriform plate of the ethmoid bone, and the olfactory structures lying directly above it.

Analyze the highlighted structure

A specific structure is highlighted in bright green.

• The small, fan-like nerve fibers passing through the cribriform plate from the nasal mucosa are the olfactory nerves (CN I).
• These fibers synapse in an expanded oval structure resting on the cribriform plate, which is the olfactory bulb.
• The highlighted green structure extends posteriorly from the olfactory bulb toward the brain. This bundle of projection fibers is the olfactory tract.

Match with options

Let's evaluate the given choices:

• A. Olfactory tract: This matches the highlighted green band extending posteriorly from the olfactory bulb.
• B. Masseter m.: This is a muscle of mastication located in the jaw, not in the anterior cranial fossa.
• C. Olfactory bulb: This is the slightly expanded anterior end where the olfactory nerves synapse, located anterior to the highlighted green tract.
• D. Axillary n. with spinal nerve roots: This is a nerve of the upper limb, completely unrelated to head anatomy.
• E. Olfactory nn. (CN I): These are the small, vertical nerve filaments descending into the nasal cavity, anterior to the highlighted tract.

Therefore, the highlighted structure is the olfactory tract.

Answer:

• (A) Olfactory tract (Correct answer)
• (B) Masseter m.
• (C) Olfactory bulb
• (D) Axillary n. with spinal nerve roots
• (E) Olfactory nn. (CN I)