Anatomy and Function of the Muscles of Mastication

Introduction

The muscles of mastication are essential for chewing and play a crucial role in the breakdown of food. These muscles are responsible for jaw movements and work in coordination with the temporomandibular joint.

Muscles Involved in Mastication

• Masseter Muscle – Provides powerful jaw closure
• Temporalis Muscle – Aids in elevation and retraction of the jaw
• Medial Pterygoid Muscle – Assists with jaw elevation
• Lateral Pterygoid Muscle – Crucial for jaw protrusion and lateral movements

Direction of Muscle Fibers

Each muscle has distinct fiber orientations that determine its function:

• Masseter: Fibers run obliquely to enhance forceful jaw closure.
• Temporalis: Fan-shaped fibers allow a range of movements.
• Medial Pterygoid: Vertically oriented fibers aid in elevation.
• Lateral Pterygoid: Horizontally directed fibers enable jaw protrusion.

Clinical Relevance

Disorders of mastication muscles, such as temporomandibular joint dysfunction (TMD), can cause pain and difficulty in chewing, necessitating medical or dental intervention.