Question

Which of the following nerves is the pretrematic branch associated with the first pharyngeal (mandibular) arch?

• A. Facial nerve
• B. Recurrent laryngeal nerve
• C. External laryngeal nerve
• D. Chorda tympani

Hint:

Pretrematic nerve = branch of the next arch nerve supplying the previous archFor the first arch, the pretrematic branch is chorda tympani (from facial nerve).

Answer 1

The Correct Option is D

Step 1: Understanding Pharyngeal Arch Innervation.
Each pharyngeal arch is associated with a specific cranial nerveThe first pharyngeal (mandibular) arch is primarily supplied by the trigeminal nerve (mandibular division, V3)However, special branches called pretre­matic and posttrematic nerves are also related to the arches
Step 2: Concept of Pretrematic Nerve.
A pretrematic nerve is a branch from the nerve of the succeeding arch that supplies the preceding archIn relation to the first arch, the pretrematic branch comes from the second arch nerve, which is the facial nerve (cranial nerve VII)
Step 3: Identification of the Specific Branch.
The chorda tympani is a branch of the facial nerveIt joins the lingual nerve (branch of mandibular nerve) and carries taste fibers from the anterior two-thirds of the tongueIt is considered the pretrematic branch associated with the first pharyngeal arch
Step 4: Evaluation of Options.
(A) Facial nerve: It is the nerve of the second arch but not specifically the pretrematic branch
(B) Recurrent laryngeal nerve: Associated with the sixth pharyngeal arch
(C) External laryngeal nerve: Branch of superior laryngeal nerve related to the fourth arch
(D) Chorda tympani: CorrectIt is the pretrematic branch from the second arch nerve to the first arch
Step 5: Conclusion.
Therefore, the pretrematic branch associated with the first pharyngeal arch is chorda tympani