Muscles about the mouth

Elevating the upper lip (smiling) muscle #1:

The LLSAN (Levator labii superioris alaeque nasalis) is a facial muscle that elevates the upper lip and dilates the nostrils, playing a crucial role in facial expressions.

Adjacent Structures:

Laterally: Zygomaticus minor muscle and the levator labii superioris muscle.
Medially: Nasalis muscle.
Deeply along the nose: Alar cartilage forming the nostril’s structure, and maxillary bone
Superficially: Angular artery

Question:

What are the anatomical borders of the Levator Labii Superioris Alaeque Nasi (LLSAN) muscle?

Elevating the upper lip (smiling) muscle #2:

The levator labii superioris (LLS) is a crucial facial muscle involved in elevating and inverting the upper lip, essential for various facial expressions, notably smiling.

Adjacent Structures:

Laterally: Zygomaticus minor muscle.
Medially: Levator labii superioris alaeque nasi muscle.
Deeply: Levator anguli oris muscle (LAO)
Notable Landmark: Crosses above the infraorbital foramen.

Question:

What are the anatomical borders of the levator labii superioris (LLS) muscle?

Elevating the upper lip (smiling) muscle #3

The Levator Anguli Oris (LAO) is a key facial muscle primarily involved in the elevation of the angle of the lips, contributing to the expression of smiling.

Adjacent Structures:

Deep and lateral to the levator labii superioris.
Deep to LAO is the maxillary bone.

Question:

What Which of the following best describes the anatomical relationship of the Levator Anguli Oris (LAO)?

The Zygomaticus Minor is a facial muscle involved in elevating the upper lip, contributing to various facial expressions such as smiling and smugness.

Adjacent Structures:

Just deep and inferior to the Orbicularis Oculi muscle
Medial to Zygomaticus Major
Superficial and lateral to the LAO and LLS

Question:

Which of the following best describes the anatomical position of the Zygomaticus Minor muscle?

Elevating the upper lip (smiling) muscle #5:

The Zygomaticus Major muscle is pivotal in facial expression, especially smiling, as it pulls the corner of the mouth upward.

Anatomical Position:

Superficially: Runs diagonally on top of the buccinator and masseter muscles.
Vascular Relations: Between the buccinator and Zygomaticus Major muscles, the facial artery and vein travel together.
Medially to this muscle is the Zygomaticus Minor

Question:

What are the correct anatomical relationships of the Zygomaticus Major muscle?

Elevating the upper lip (smiling) muscle #6:

The Risorius is a facial muscle primarily involved in stretching the lips horizontally, contributing to expressions such as smiling.

Anatomical Position and Adjacent Structures:

Superior to the Buccinator muscle, separated by buccopharyngeal fascia.
Vascular Relationship: The facial artery runs between the Risorius and the buccinator, giving off the superior labial artery.
Connectivity: May connect inferiorly to the upper fibers of the platysma muscle; contributes to the formation of the modiolus at the corner of the lips.

Question:

Which of the following best describes the anatomical relationship of the Risorius muscle?

Depressing and everting the lower lip (frowning) muscle #1:

The mentalis muscle, located on the mandible, plays a key role in the mobility and expressiveness of the lower lip and chin. Elevates and protrudes the lower lip, contributing to expressions of sadness, dislike, or uncertainty.

Adjacent Structures:

Superior Coverage: The superior and lateral parts are covered by the depressor labii inferioris muscle.
Skin relationship: Connect directly to the subcutaneous tissue and is palpable just under the skin.

Note that this muscle has anatomical variation, with both bellies occasionally being joined or entirely separate. There is also a lot of variation in the thickness of this muscle, with about 1/10 individuals having a mentalis that is thin enough to be difficult to identify under ultrasound. If you frequently perform ultrasound of the chin, you will quickly become accustomed to the wide spectrum of variation seen in this muscle.

Question:

Considering the anatomical context of the mentalis muscle, which of the following muscles covers the superior-lateral part of the mentalis muscle?

Depressing and everting the lower lip (frowning) muscle #2:

The Depressor Labii Inferioris (DLI) is a facial muscle primarily involved in the downward and medial movement of the lower lip, integral for expressing emotions such as sadness, doubt, and melancholy.

Key Anatomical Relationships:

Location: Deep to the depressor anguli oris muscle on its superior margin.
Overlap: Its superior medial part covers some of the mentalis muscle.The depressor anguli oris covers its lateral margin.

Question:

Which statement best describes the anatomical relationship of the Depressor Labii Inferioris (DLI) muscle?

Depressing and everting the lower lip (frowning) muscle #3:

The Depressor Anguli Oris (DAO) is a crucial facial muscle in the buccolabial group, primarily responsible for depressing the corner of the mouth. Pulls the corners of the mouth downwards and outwards, demonstrating emotions such as sadness or anger.

Anatomical Position:

Superficially: Most superficial muscle in the buccolabial group.
Inferior Relationship: Runs superficial to the depressor labii inferioris muscle.
Connection: Inferiorly connected to the platysma muscle.
Insertion Point: Connects at the modiolus at the corner of the lips.

Question:

Which muscle is the Depressor Anguli Oris (DAO) most closely related to in terms of anatomical position and function?

Muscle involved in closing the lips (pouting):

The orbicularis oris is a complex, multifunctional muscle encircling the mouth. It is a superficial muscle encircling the lips and crossing well beyond the vermillion border. It inserts at the modiolus at the lateral aspect of the lips. It plays a pivotal role in various facial expressions and oral functions.

Key Functions:

Closure of the mouth during chewing, preventing food from becoming lodged between the teeth.
Facilitation of facial expressions such as pouting, puckering, and twisting of the lips.
Contribution to the articulation of sounds like “p,” “b,” “f,” and “v.”
Assisting in activities like whistling and playing wind instruments.

Question:

What do you think?

Muscle compressing the cheek:

The buccinator muscle plays a crucial role in mastication and facial expressions, maintaining cheek tension, and preventing buccal mucosal injury. This helps to keep our cheeks tight against our teeth and prevents them from bulging outward when we chew or speak. The buccinator’s role in mastication and its unique contribution to playing wind instruments, earning it the nickname “trumpet muscle.”

This is a deep muscle in the face. The parotid duct that carries saliva from the parotid gland also runs superfical over this muscle and goes through the buccinator muscle near the third upper molar tooth entering the mouth.Adjacent Structures:

Below the Buccinator: oral mucosa
Above the Buccinator: Buccal fat pad, Zygomaticus major, Zygomaticus minor, risorius, levator anguli oris, levator labaii superioris, and depressor anguli oris muscles.
Vascular: Facial artery and vein, travel above this muscle

Question:

Which of the following structures is partially deep to the buccinator muscle?

The modiolus is a dense, fibromuscular structure located at the angles of the mouth. It serves as a convergence point for multiple peri-oral facial muscles.

Contributing Muscles:

There is some anatomical debate about what muscles contribute to this structure. Classically the following 9 muscles are regarded to converge on the structure:

Levator anguli oris, levator labii superioris, zygomaticus major, Orbicularis oris, risorius, platysma, buccinator, depressor labii inferioris, depressor anguli oris

Question:

Which of the following muscles does NOT contribute to the formation of the modiolus at the angles of the mouth?