THE MANDIBLE

The mandible, commonly referred to as the lower jaw, is a crucial bone in the human face. It is recognized as the largest and strongest bone within the facial structure and plays a vital role in various functions such as chewing, speaking, and supporting facial shape. The mandible is the only movable bone in the skull, making it essential for a multitude of daily activities.

ANATOMY AND STRUCTURE

The mandible consists of two main parts: the body and the ramus. The body is the horizontal section that houses the teeth and is responsible for the chewing function, while the ramus is the vertical section that connects with the skull at the temporomandibular joint (TMJ), permitting movement.

Body of the Mandible

The body of the mandible can be further divided into two parts:

Base: The lower aspect of the body.
Alveolar Process: The upper part that contains the sockets for the teeth.

At the front of the mandible, there is a noticeable swelling on the anteroinferior surface known as the mental protuberance, with the mental tubercle being more pronounced laterally.

Mental Foramen

Roughly halfway between the upper border of the alveolar process and the lower border of the base lies the mental foramen, a significant anatomical feature through which a large branch of the mandibular nerve branches out to supply the teeth, as well as to provide sensation to the mucous membrane and skin of the lower lip and chin.

ADDITIONAL FEATURES

Other important features of the mandible include:

Oblique Line: A ridge running from the front of the ramus to the body of the mandible, usually traceable to the mental tubercle.
Mental Spine: A roughened projection on the inner surface of the mandible where muscles attach. It may appear bilateral or may be divided into upper and lower spines.
Sublingual Fovea: Concavities lateral to the mental spine that accommodate the anterior end of the sublingual salivary gland.
Digastric Fossa: A concave area where the anterior belly of the digastric muscle attaches.

The mylohyoid line runs from between the sublingual and digastric impressions, marking the attachment of the mylohyoid muscle that forms the mouth's floor. The mylohyoid line extends along the length of the alveolar process.

Ramus of the Mandible

The ramus is oriented perpendicular to the body and connects to the alveolar process and base. Notably, it includes:

Coronoid Process: The anterior, sharp point that serves as a muscle attachment site.
Condylar Process: The posterior part that articulates with the temporal bone to form the TMJ.

Below the condylar process is the neck, and at the junction of the head and neck is the pterygoid fovea, an attachment point for muscles.

Mandibular Apparatus

The mandibular foramen is located on the inner surface of the ramus and serves as the entry to the mandibular canal, which houses the nerves and blood vessels supplying the teeth. The mandibular lingula, a thin projection of bone, exists anterior to the mandibular foramen and serves as a landmark for nerve injection.

DEVELOPMENTAL CHANGES

The morphology of the mandible evolves significantly with age and is influenced by dental development. In infancy, the ramus forms an obtuse angle with the body of the mandible. As teeth emerge and the child begins chewing, the body grows, and the ramus becomes more vertical, thereby decreasing the obtuseness of this angle. This growth pattern is crucial for the proper function of the mandible throughout childhood and into adulthood.

Overall, the mandible is a complex structure with various anatomical features that not only serve essential functions but also present unique characteristics that may vary greatly between individuals and change over time.

Anatomy and Functions of the Mandible

Anatomy and Functions of the Mandible