**Core Concept:** Abductor of vocal cords refers to the muscles or structures that pull the vocal cords apart, increasing the vocal tract diameter and allowing for a higher pitch voice production. In humans, the main abductor of the vocal cords is the cricothyroid muscle.

**Why the Correct Answer is Right:** The cricothyroid muscle is a paired, triangular muscle located in the posterior aspect of the thyroid cartilage. It consists of two heads: the inferior pharyngeal constrictor muscle and the superior thyroid muscle. The cricothyroid muscle's primary function is to elevate the thyroid and cricoid cartilages, resulting in the abduction of the vocal cords. This action leads to increased vocal tract diameter, enabling higher pitch voice production.

**Why Each Wrong Option is Incorrect:**

A. **Superior thyroid artery**: This is a branch of the external carotid artery, providing blood supply to the thyroid gland and surrounding structures. It is not a muscle and does not play a role in vocal cord abduction.
B. **Inferior pharyngeal constrictor muscle**: Although part of the pharyngeal constrictor muscles, it is not specifically responsible for abducting the vocal cords, as its primary function is to constrict the pharynx.
C. **Thyroarytenoid muscle**: This muscle is a part of the intrinsic laryngeal muscles, responsible for lateral movement of the vocal cords (adduction and abduction). It is not the abductor of the vocal cords.
D. **Cricothyroid ligament**: A thin connective tissue structure connecting the thyroid cartilage to the cricoid cartilage, serving as a barrier to prevent injury and not directly involved in vocal cord movement.

**Clinical Pearl:** The correct abductor of the vocal cords is the **cricothyroid muscle**. Understanding the anatomy and function of the cricothyroid muscle is essential for understanding voice disorders and hoarseness, which can be caused by impaired vocal cord mobility due to muscle injury, inflammation, or tumors.