Final answer:
The anterior thoracic muscle responsible for protracting and depressing the scapula is the serratus anterior.
Step-by-step explanation:
The anterior thoracic muscle that is responsible for protracting and depressing the scapula is known as the serratus anterior. The serratus anterior lies on the surface of the ribcage and extends around the thorax to insert on the medial border of the scapula. It is a crucial muscle for movements such as pushing and punching because it holds the scapula against the thoracic wall and allows its motion. The serratus anterior allows for the forward movement of the arms and shoulders, permitting a wide range of actions that are essential in athletic endeavors and everyday tasks. The anterior thoracic muscle that protracts and depresses the scapula is the Serratus anterior.
Located on the anterior thorax, the serratus anterior muscle originates on the surface of the upper eight or nine ribs and inserts on the medial border of the scapula. When the serratus anterior muscle contracts, it pulls the scapula forward and downward, allowing for protraction and depression of the scapula.