MUSCLES OF MASTICATION

MUSCLES OF MASTICATION

Mastication is the process of chewing food in the mouth. The muscles of mastication are a group of muscles responsible for this process.

Muscles of Mastication:

• Masseter muscle
• Temporalis muscle
• Medial pterygoid muscle
• Lateral pterygoid muscle

Attachments of Muscles of Mastication:

• Masseter muscle: originates from zygomatic arch and inserts into mandibular ramus and angle.
• Temporalis muscle: originates from temporal fossa and inserts into mandibular coronoid process.
• Medial pterygoid muscle: originates from sphenoid bone and inserts into mandibular angle and ramus.
• Lateral pterygoid muscle: originates from sphenoid bone and inserts into mandibular condyle.

Nerve Supply to Muscles of Mastication:

• Masseter nerve: branches of trigeminal nerve.
• Deep temporal nerves: branches of trigeminal nerve.
• Medial pterygoid plate nerve: branches of mandibular division of trigeminal nerve.
• Lateral pterygoid nerve: branches of mandibular division of trigeminal nerve.

Actions of Muscles of Mastication:

• Masseter muscle: elevates mandible.
• Temporalis muscle: elevates mandible.
• Medial pterygoid muscle: elevates mandible.
• Lateral pterygoid muscle: protrudes mandible and rotates it.

Sequence of Mastication:

1. Relaxation of muscles of mastication.
2. Closure of jaw due to contraction of muscles of mastication.
3. Chewing of food due to coordination of muscles of mastication.
4. Swallowing of food due to contraction of muscles of pharynx and esophagus.

Applied Anatomy:

• Temporomandibular joint is a synovial joint that connects mandible to temporal bone.
• Muscle of mastication are responsible for the movement of jaw.
• Temporal bone has a groove for the passage of mandibular nerve.
• Sphenoid bone has a pit for the passage of lateral pterygoid muscle.