🥇 MÚSCULOS MASTICATORIOS. Fácil, Rápidos y Sencillos

Anatomy of the Masticatory Muscles

Introduction to Masticatory Muscles

• The video focuses on the anatomy of the masticatory muscles, specifically four major muscles: masseter, temporalis, medial pterygoid, and lateral pterygoid.

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Masseter Muscle

• The masseter muscle is located superficially in the lateral region of the face and is covered by the masseteric aponeurosis.

• Beneath this layer lies adipose tissue from the parotid gland and buccal fat pads that contribute to facial roundness, especially in newborns.

• The muscle originates at the zygomatic arch and inserts into the external face of the ascending ramus of the mandible; it is innervated by a branch of V3 (the inferior maxillary nerve).

• Its primary function is to elevate or close the lower jaw during chewing; it has three portions: superficial, intermediate, and deep.

Temporalis Muscle

• The temporalis muscle originates from various bones including frontal, parietal, temporal, and sphenoid bones within the temporal fossa. It has both superficial and deep portions.

• This muscle inserts into the coronoid process of the mandible and also receives innervation from a branch of V3 (the inferior maxillary nerve), known as the temporal nerve.

• Its function complements that of the masseter by assisting in elevating and closing the mouth when clenching molars together.

Lateral Pterygoid Muscle

• Located deep to temporalis, this muscle consists of two heads: an upper head originating from greater wing crest of sphenoid bone and a lower head from lateral pterygoid plate.

Understanding the Pterygoid Muscles

Lateral Pterygoid Muscle

• The lateral pterygoid muscle inserts into the articular capsule, articular cartilage, and a pit called the Pterygoid fossa of the lower jaw. Understanding its insertion points is crucial for comprehending its function.

• Innervated by the lower maxillary nerve (third branch of the trigeminal nerve), this muscle helps in opening the mouth by moving the condyle forward during contraction.

• Unlike other muscles like temporalis and masseter that close the mouth, lateral pterygoid works synergistically with anterior digastric muscle to facilitate mouth opening and ensure proper jaw alignment during closure.

• The muscle has two portions originating from different anatomical landmarks: one from the greater crest of sphenoid and another from the external face of the lateral pterygoid plate, both inserting into the joint capsule.

• A deep view shows how these portions are positioned relative to each other as they connect to the temporomandibular joint capsule.

Medial Pterygoid Muscle

• The medial pterygoid muscle, also known as internal pterygoid, consists of superficial and deep portions that embrace part of the lateral pterygoid muscle.

• The deep portion originates from the internal face of lateral pterygoid lamina and palatine bone's pyramidal process; whereas, superficial portion also arises from this pyramidal process but is located deeper than upper jaw structures.

• Both portions insert into an area called pterygoid tuberosity on the internal face of ascending branch of lower jaw. This positioning is critical for their functional role in mastication.