Risorius

Risorius is a facial muscle that is found in the human body. It is also known as the "laughing muscle" due to its role in facial expressions, particularly smiling and laughing.

Anatomy

The risorius muscle is a thin, broad muscle that is located in the face. It originates from the fascia over the parotid gland, which is a major salivary gland located in front of the ear. The muscle then runs horizontally across the cheek, inserting into the skin at the corner of the mouth.

The risorius is innervated by the facial nerve, which is the seventh cranial nerve. This nerve controls the muscles of facial expression, including the risorius.

Function

The primary function of the risorius muscle is to pull the corners of the mouth to the side, which is a movement involved in smiling and laughing. This muscle is also involved in other facial expressions that involve the mouth, such as grimacing.

In addition to its role in facial expressions, the risorius also assists in the opening of the mouth. This is because when the muscle contracts, it pulls the corners of the mouth outward, which can help to open the mouth wider.

Clinical significance

Damage to the risorius muscle or its nerve supply can result in facial paralysis, which can affect the ability to smile or make other facial expressions. This can occur as a result of conditions such as Bell's palsy or a stroke.

In some cases, the risorius muscle may be used in reconstructive surgery. For example, it can be used to reconstruct the mouth in patients who have had surgery for oral cancer.

See also

• Facial muscles
• Facial nerve
• Bell's palsy
• Stroke

References

Risorius Resources
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