The muscles involved in the movement of the lower jaw and tongue play crucial roles in chewing, swallowing, and speaking.
Masseter Muscle:
Known as the "powerhouse of chewing."
Primary function: Elevates the mandible to close the mouth.
Location: Lateral surface of the face.
Functionality: Capable of exerting significant force to bite through tough foods, critical for breaking down food types from plants to meat.
Temporalis Muscle:
Assists the masseter muscle in closing the jaw.
Function: Retracts the mandible.
Location: Positioned on the side of the head.
Interaction: Feel contraction when chewing by placing fingers on the temple.
Medial Pterygoid Muscle:
Supports jaw closure by working with the masseter.
Function: Elevates the mandible and assists in grinding food.
Location: Inside of the jaw (deep within the oral cavity).
Lateral Pterygoid Muscle:
Functions in the protrusion of the mandible.
Allows for side-to-side movements during chewing and food manipulation.
Location: Also positioned inside the jaw, deep within the oral cavity.
The combination of masseter, temporalis, medial pterygoid, and lateral pterygoid muscles enables effective chewing.
This intricate interplay optimizes digestion and nutrient extraction, showcasing adaptation to dietary needs.
All muscles of mastication are located within the cheek and originate from skull processes, allowing for increased leverage during chewing.
The tongue is a versatile muscle essential for tasting, chewing, swallowing, and speaking.
It comprises extrinsic and intrinsic muscles that contribute to its unique movements.
Genioglossus Muscle:
Origin: Genial tubercles of the mandible.
Function: Allows the tongue to move downward and forward; essential for speech and swallowing.
Styloglossus Muscle:
Origin: Styloid process of the temporal bone.
Function: Moves the tongue up and back; aids in chewing and articulation.
Palatoglossus Muscle:
Origin: Soft palate.
Function: Elevates the back of the tongue; important in the swallowing process.
Hyoglossus Muscle:
Origin: Hyoid bone.
Function: Moves the tongue downward and flattens it; aids in precise movements for speech and chewing.
Origin: Entirely within the tongue, providing intricate shape changes.
Function: Enable skilled movements such as rolling and flattening the tongue, crucial for phonetics in human language.
The combined actions of extrinsic and intrinsic muscles allow complex tongue movements necessary for effective speech and swallowing.
The remarkable adaptability of the tongue facilitates various functions, enhancing the sensory experience of eating.
During general anesthesia, body homeostatic controls are paused, affecting muscles critical for breathing and tongue movement.
The relaxed state of the tongue can block airways; hence, endotracheal intubation is performed to maintain an open airway.
After surgery, breathing functions gradually restore, and patients often experience a sore throat.
Deglutition: The act of swallowing, moving food or liquid from the mouth to the stomach.
Styloid Process: A bony projection on the temporal bone that serves as the origin for the styloglossus muscle.
Protrusion: The action of pushing or extending a body part outward, such as the tongue.