MANDIBLE ANATOMY

OVERVIEW

• Represents the largest facial bone
• Functions as the supporting structure for the inferior dentition
• Comprises a curved horizontal segment (body) and two vertical projections (rami)
• The rami extend upward from the body at approximately right angles

BODY OF THE MANDIBLE

General Features

• Exhibits a horseshoe-shaped configuration
• Provides foundation for dental sockets
• Serves as attachment site for multiple muscles
• Contains channels for neurovascular structures

Subdivisions

• Consists of two main regions: the base and the alveolar portion

Base of the Mandible

• Constitutes the inferior segment of the mandibular body
• Provides muscular attachment points

External Surface Landmarks

• Mandibular Symphysis
  • Also termed mental symphysis
  • Represents the midline fusion line on the anterior mandible
• Mental Protuberance
  • Situated inferior to the mandibular symphysis
  • Constitutes the bony prominence of the chin
  • Features a central concavity bordered by mental tubercles
  • Mental tubercles demarcate the lateral margins of the chin
• Superior Mental Spines
  • Positioned near the inferior aspect of the mandibular symphysis
  • Serve as insertion points for the genioglossus muscles
• Inferior Mental Spines
  • Located inferior to the superior mental spines
  • Function as origin sites for the geniohyoid muscles
• Mental Foramen
  • Positioned beneath the second premolar tooth
  • Transmits the mental neurovascular bundle
• Oblique Line
  • Courses posterosuperiorly from the mental tubercles
  • Functions as a muscular attachment ridge

Internal Surface Landmarks

• Digastric Fossa
  • Located bilaterally on the internal mandibular surface adjacent to the midline
  • Provides attachment for the anterior digastric muscle belly
• Mylohyoid Line
  • Extends from the symphysis to the region of the last molar
  • Functions as a muscular attachment ridge
• Sublingual Fossa
  • Situated superior to the mylohyoid line
  • Accommodates the sublingual salivary gland
• Submandibular Fossa
  • Located inferior to the mylohyoid line
  • Accommodates the submandibular salivary gland

Alveolar Part of the Mandible

• General Features
  • Constitutes the superior portion of the mandibular body
  • Contains multiple dental sockets for tooth anchorage
• Alveolar Arch
  • Represents the curved segment of the mandible
  • Contains the dental alveoli
• Dental Alveoli
  • Represent cavities that receive individual teeth
  • Demonstrate variable dimensions corresponding to specific teeth
• Interalveolar Septa
  • Bony walls separating neighboring tooth sockets
• Interradicular Septa
  • Bony partitions between roots of multirooted teeth
• Alveolar Yokes
  • Bony elevations between adjacent teeth
• Retromolar Triangle
  • Triangular area posterior to the third molar
• Retromolar Fossa
  • Concavity posterior to the third molar

RAMUS OF THE MANDIBLE

General Features

• Exhibits a quadrilateral configuration
• Possesses two surfaces, four borders, and two processes
• Forms an angle at its junction with the mandibular body

Angle of the Mandible

• Represents the junction point between the horizontal body and vertical ramus

Lateral Surface

• Characterized by a flat contour with oblique ridges
• Provides attachment for the masseter muscle
• Masseteric Tuberosity
  • Roughened elevation on the lateral ramal surface
  • Serves as masseter muscle attachment

Medial Surface

• Contains the mandibular foramen for neurovascular transmission
• Pterygoid Tuberosity
  • Located on the medial ramal surface posterior to the mylohyoid groove
  • Provides insertion for the medial pterygoid muscle
• Mandibular Foramen (Inferior Alveolar Foramen)
  • Positioned on the medial ramal surface
  • Partially covered by the lingula
  • Transmits the inferior alveolar neurovascular bundle
• Lingula
  • Triangular projection anterior to the mandibular foramen
  • Provides attachment for the sphenomandibular ligament
• Mandibular Canal
  • Originates at the mandibular foramen
  • Descends obliquely through the ramus
  • Continues horizontally through the body beneath the dental alveoli
  • Contains the inferior alveolar neurovascular structures
• Mylohyoid Groove
  • Horizontal groove on the internal mandibular surface
  • Courses obliquely in an inferoanterior direction
  • Transmits the mylohyoid neurovascular bundle

Inferior Border

• Exhibits thick and straight characteristics
• Continuous with the inferior border of the mandibular body

Superior Border

• Mandibular Notch (Sigmoid Notch)
  • Deep concavity separating the coronoid and condylar processes
  • Transmits the masseteric neurovascular bundle

Coronoid Process

• Thin triangular projection
• Flattened in the mediolateral dimension
• Provides insertion for several muscles
• Temporal Crest
  • Ridge on the medial coronoid surface
  • Extends inferoanteriorly toward the last molar region
  • Serves as muscular attachment site

Condylar Process

• General Features
  • Thicker than the coronoid process
  • Comprises the condyle and supporting neck
  • Articulates with the temporal bone to form the temporomandibular joint
• Mandibular Condyle (Head of Mandible)
  • Rounded superior portion of the condylar process
  • Exhibits convex configuration
  • Articulates with the temporal bone and articular disc of the TMJ
• Neck of the Mandible
  • Constricted region inferior to the condyle
  • Supports the condylar head
  • Reinforced by descending ridges
• Pterygoid Fovea
  • Depression on the anterior surface of the condylar neck
  • Serves as attachment site for the lateral pterygoid muscle