Final answer:
The digastric muscle is responsible for elevating the hyoid bone and depressing the mandible during swallowing. The geniohyoid muscle also assists with these actions while moving the hyoid bone anteriorly.
Step-by-step explanation:
The muscle that acts to both elevate the hyoid bone and depress the mandible is the digastric muscle. This muscle has two parts, an anterior and a posterior belly, helping in the swallowing process and the depression of the mandible.
The geniohyoid muscle also plays a role as it contributes to depressing the mandible while also elevating and pulling the hyoid bone anteriorly. Suprahyoid muscles are primarily responsible for raising the hyoid bone and thus aiding in deglutition, or swallowing. Among these, mylohyoid muscle is noteworthy as it lifts the hyoid bone and assists in pressing the tongue against the roof of the mouth.
The muscle that acts to elevate the hyoid bone and depress the mandible is the digastric muscle. The digastric muscle has two bellies, the anterior belly and the posterior belly. When one swallows, both bellies of the digastric muscle work together to elevate the hyoid bone and larynx. Additionally, the digastric muscle depresses the mandible or lower jaw.