Hyoid muscles

Summary

This script delves into the anatomy of the hyoid muscles, categorizing them into suprahyoid and infrahyoid groups. The suprahyoid muscles, including the digastric, mylohyoid, stylohyoid, and geniohyoid, are positioned above the hyoid bone and work in synergy to elevate it. The digastric's anterior belly also plays a role in mandibular depression, making it an antagonist to the masseter and temporalis muscles. The infrahyoid group, comprising the omohyoid, sternohyoid, sternothyroid, and thyrohyoid, is situated below the hyoid bone and functions collectively to depress it, opposing the action of the suprahyoid muscles. The script offers a clear explanation of these muscle groups' roles and interactions, essential for understanding facial and oral functions.

Takeaways

• 🦴 There are two main groups of hyoid muscles: the suprahyoid muscles above the hyoid bone and the infrahyoid muscles below it.
• 🔝 In the suprahyoid group, the digastric muscle has two bellies, anterior and posterior, and can both elevate the hyoid and depress the mandible.
• 🦷 The mylohyoid muscle contributes to the floor of the mouth and is involved in hyoid elevation.
• 🗝️ The stylohyoid muscle is connected to the styloid process of the temporal bone and assists in hyoid elevation.
• 🔁 The geniohyoid muscle runs from the chin (genial tubercle) to the hyoid bone and helps in elevating the hyoid.
• 🤔 The anterior belly of the digastric acts as an antagonist to the masseter and temporalis muscles, which are involved in mandibular elevation.
• 💪 The infrahyoid muscles work together to depress the hyoid bone, acting as synergists for each other.
• 🌐 The omohyoid muscle, named for its connection to the shoulder (omo), has superior and inferior bellies and is part of the infrahyoid group.
• 🔗 The sternohyoid connects the sternum to the hyoid bone and is involved in hyoid depression.
• 🦴 The sternothyroid muscle is connected to the thyroid gland and indirectly to the hyoid bone through the thyrohyoid muscle.
• 🔗 The thyrohyoid muscle connects the thyroid cartilage to the hyoid bone, integrating the sternothyroid into the infrahyoid muscle group.

Q & A

What are the two groups of hyoid muscles?

The two groups of hyoid muscles are the suprahyoid muscles, which are above the hyoid bone, and the infrahyoid muscles, which are below the hyoid bone.

What is the function of the suprahyoid muscles in relation to the hyoid bone?

The suprahyoid muscles elevate the hyoid bone because they are located above it, making them synergists to each other in this action.

Which muscle in the suprahyoid group has both an anterior and a posterior belly?

The digastric muscle in the suprahyoid group has both an anterior and a posterior belly.

What is the role of the mylohyoid muscle?

The mylohyoid muscle extends side to side and forms the floor of the mouth.

What is the connection of the stylohyoid muscle to the temporal bone?

The stylohyoid muscle is connected to the styloid process of the temporal bone.

What is the antagonistic relationship between the anterior belly of the digastric muscle and the masseter and temporalis muscles?

The anterior belly of the digastric muscle can depress the mandible, which makes it an antagonist to the masseter and temporalis muscles, as they elevate the mandible.

What does 'omo' in 'omohyoid' mean and what is its significance?

'Omo' in 'omohyoid' means shoulder, indicating the muscle's origin from the shoulder region.

How many bellies does the omohyoid muscle have?

The omohyoid muscle has two bellies, a superior belly and an inferior belly.

Which infrahyoid muscle is not directly connected to the hyoid bone but is still considered an infrahyoid muscle?

The sternothyroid muscle is not directly connected to the hyoid bone but is considered an infrahyoid muscle because it is connected to the thyrohyoid muscle, which is connected to the hyoid bone.

What is the general function of the infrahyoid muscles in relation to the hyoid bone?

The infrahyoid muscles depress the hyoid bone, making them synergists to each other in this action.

What is the antagonistic relationship between the infrahyoid and suprahyoid muscles in terms of the hyoid bone?

The infrahyoid muscles, which depress the hyoid bone, are antagonists to the suprahyoid muscles, which elevate the hyoid bone.