Accessory medial pterygoid muscle

Area of Science:

• Anatomy
• Human Morphology
• Skeletal Muscle Anatomy

Background:

• The medial pterygoid muscle is a key masticatory muscle.
• Accessory muscles of mastication are rare and poorly understood.
• Variations in pterygoid muscle anatomy can affect jaw biomechanics.

Purpose of the Study:

• To describe a previously unrecognized accessory medial pterygoid muscle.
• To investigate the anatomical characteristics and innervation of this accessory muscle.
• To hypothesize the functional significance of the accessory medial pterygoid muscle in mastication.

Main Methods:

• Systematic dissection of cadaveric specimens.
• Detailed anatomical description of the accessory muscle's origin, insertion, and path.
• Histological examination to confirm muscle type.
• Analysis of innervation via the mandibular nerve.

Main Results:

• A uniform accessory medial pterygoid muscle was identified in all specimens studied.
• The muscle originates from the superior pterygoid plate and inserts onto the medial pterygoid muscle.
• Independent innervation from the mandibular nerve was observed.
• Histology confirmed it as striated muscle.

Conclusions:

• The accessory medial pterygoid muscle is a consistent anatomical finding.
• Its unique innervation and insertion suggest a role in fine-tuning jaw movements, potentially related to Bennett movement.
• Variations in this muscle's size may explain observed variations in Bennett movement and dental occlusion.