In the lower part of the head, you can distinguish, chin - the part of the head from the beginning of the lower jaw to the place of connection or attachment of the gill membranes; throat - the distance from the place of attachment or fusion of the gill membranes to the base of the pectoral fins. In addition, in the lower part of the head, a place of junction of the bones of the lower jaw, called symphysis, is distinguished.

Symphysis - the place where the bones of the right and left halves of the lower jaw join in fish.