Muscles of Facial Expression

Summary

This video script delves into the intricate workings of facial muscles, focusing on those involved in expression and mastication. It introduces the orbicularis oculi and oris, responsible for eye closure and lip pressing, respectively. The levator labii superioris elevates the upper lip, while the zygomaticus minor and major are key to smiling. The risorius and triangularis muscles contribute to lateral lip movement and frowning. The depressor labii inferioris and mentalis manipulate the lower lip, with the mentalis protruding it outward. The buccinator aids in cheek movement during chewing. The masseter and temporalis muscles are highlighted as essential for jaw movement, with the masseter elevating the mandible during jaw closure, and the temporalis working in synergy to achieve the same.

Takeaways

• 😉 The orbicularis oculi is a circular muscle around the eye that closes the eye.
• 😋 The orbicularis oris surrounds the mouth and is responsible for pressing the lips together.
• 📌 The levator labii superioris is named for its function of elevating the upper lip.
• 😄 The zygomaticus minor and major muscles pull the mouth upward, contributing to the smile.
• 😁 The risorius muscle is connected to the corner of the mouth and pulls the lips laterally, as if stretching them back towards the ears.
• 😞 The triangularis muscle is triangularly shaped and pulls the corner of the mouth downward, indicating a frown.
• 😐 The depressor labii inferioris pulls the lower lip downward, creating a frowning expression.
• 😡 The mentalis is a paired muscle on the chin that protrudes the lower lip, as seen in pouting.
• 🍽 The buccinator muscle moves and compresses the cheeks during chewing.
• 🦷 The masseter is a muscle of mastication with its origin on the zygomatic arch and insertion on the jaw, responsible for elevating the mandible when closing the jaw.
• ⏫ The temporalis muscle has its origin on the skull and insertion on the coronoid process of the mandible, working in synergy with the masseter to elevate the mandible.

Q & A

What does 'masticate' mean in the context of the video?

In the context of the video, 'masticate' refers to the act of chewing.

What is the primary function of the orbicularis oculi muscle?

The orbicularis oculi muscle is responsible for closing the eye.

What is the role of the orbicularis oris muscle?

The orbicularis oris muscle is involved in pressing the lips together.

What does the levator labii superioris muscle do?

The levator labii superioris muscle elevates the upper lip.

Which muscles are associated with smiling and why?

The zygomaticus minor and zygomaticus major are associated with smiling because they pull the mouth upward at an angle.

What is the function of the risorius muscle?

The risorius muscle is responsible for pulling the corner of the mouth laterally, as if pulling the lips straight back towards the ears.

How does the triangularis muscle contribute to facial expressions?

The triangularis muscle is a frown muscle that pulls the corner of the mouth downward.

What is the depressor labii inferioris muscle and its function?

The depressor labii inferioris muscle pulls the lower lip downward.

What is the role of the mentalis muscle on the chin?

The mentalis muscle is responsible for protruding the lower lip, as seen in a pouting expression.

What is the buccinator muscle and its function during chewing?

The buccinator muscle moves and compresses the cheeks while chewing.

Which muscle is the first one mentioned in the script that moves a joint and what is its function?

The masseter is the first muscle mentioned that moves a joint; it is responsible for elevating the mandible during jaw closure.

What is the temporalis muscle and how does it work in conjunction with the masseter?

The temporalis muscle has its insertion on the coronoid process of the mandible and its origin on the skull. It works as a synergist with the masseter by elevating the mandible.