Lower Jaw in Mammals

The lower jaw in mammals is known as the mandible. It is a U-shaped bone that forms the lower part of the skull and supports the lower teeth. The mandible plays a crucial role in various functions such as chewing, speaking, and maintaining the structural integrity of the face.

Anatomy of the Mandible

The mandible is the largest and strongest bone in the human face. It consists of a horizontal body and two vertical branches called rami. The body of the mandible forms the central part of the lower jaw, while the rami extend upwards on both sides to articulate with the temporal bones of the skull.

The mandible has several important structures and landmarks, including:

1. Mandibular condyle: Located at the posterior end of each ramus, the mandibular condyle articulates with the temporal bone to form the temporomandibular joint (TMJ). This joint allows for the opening, closing, and side-to-side movement of the jaw.

2. Coronoid process: Situated anteriorly to the condyle, the coronoid process serves as an attachment site for the muscles involved in jaw movement.

3. Alveolar process: The alveolar process is the ridge-like region that contains the sockets for the lower teeth. It provides support and stability for the teeth.

4. Mental foramen: Located on the anterior surface of the mandible, the mental foramen allows for the passage of blood vessels and nerves that supply the chin and lower lip.

Function of the Mandible

The mandible plays a crucial role in various functions of the mammalian skull, including:

1. Mastication: The mandible moves in coordination with the muscles of mastication, allowing for the grinding and chewing of food.

2. Speech: The mandible, along with the tongue and other speech organs, forms the oral cavity necessary for speech production.

3. Facial structure: The mandible provides support and shape to the lower face, contributing to an individual's unique facial appearance.

4. Dental support: The alveolar process of the mandible houses the lower teeth, providing a stable foundation for biting and chewing.

Conclusion

In conclusion, the lower jaw in mammals is known as the mandible. It is a U-shaped bone that forms the lower part of the skull and supports the lower teeth. The mandible plays a crucial role in various functions such as chewing, speaking, and maintaining the structural integrity of the face.

It is an unpaired bone which is found in the skull. Dentary bone is found in the lower jaw in ancestral animals. Hence, the correct answer is option (C).