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.

Outlines

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🦴 Hyoid Muscles Overview

This paragraph provides an anatomical overview of the hyoid muscles, which are divided into two main groups: the suprahyoid and infrahyoid muscles. The suprahyoid muscles, located above the hyoid bone, include the digastric with its anterior and posterior bellies, the mylohyoid which forms the floor of the mouth, the stylohyoid attached to the temporal bone's styloid process, and the geniohyoid running front to back. These muscles work together to elevate the hyoid bone. The digastric's anterior belly also plays a role in depressing the mandible, making it an antagonist to the masseter and temporalis muscles, which are involved in mastication and mandible elevation. The infrahyoid muscles, situated below the hyoid bone, consist of the omohyoid with superior and inferior bellies, the sternohyoid connecting the sternum to the hyoid, the sternothyroid, and the thyrohyoid. Although the sternothyroid is not directly attached to the hyoid, it is connected to the thyrohyoid, making it part of the infrahyoid group. All these muscles work synergistically to depress the hyoid bone and are antagonistic to the suprahyoid muscles.

Keywords

💡Hyoid Muscles

Hyoid muscles are a group of muscles located in the neck that are involved in the movement of the tongue and the floor of the mouth. In the video, the hyoid muscles are divided into two main groups: suprahyoid and infrahyoid, which are crucial for understanding the mechanics of swallowing and speech. The suprahyoid muscles elevate the hyoid bone, while the infrahyoid muscles depress it.

💡Suprahyoid Group

The suprahyoid group refers to the muscles that are situated above the hyoid bone. These muscles are responsible for elevating the hyoid bone, which is essential for various oral functions. The script mentions several muscles in this group, including the digastric, mylohyoid, stylohyoid, and geniohyoid, each with specific roles in movement and support.

💡Digastric Muscle

The digastric muscle is part of the suprahyoid group and has two bellies, anterior and posterior, which are connected by a central tendon. It plays a dual role in both elevating the hyoid bone and depressing the mandible. This muscle's dual function is highlighted in the script as an example of how muscles can have antagonistic actions.

💡Mylohyoid Muscle

The mylohyoid muscle is a flat muscle that extends from the mandible to the hyoid bone, forming the floor of the mouth. It is involved in elevating the hyoid bone and plays a significant role in the oral cavity's structure, as mentioned in the script.

💡Stylohyoid Muscle

The stylohyoid muscle connects the hyoid bone to the styloid process of the temporal bone. It is part of the suprahyoid group and assists in the elevation of the hyoid bone. Its connection to the temporal bone is a key anatomical feature discussed in the script.

💡Geniohyoideus Muscle

The geniohyoid muscle runs from the mental symphysis (chin area) to the hyoid bone and is involved in the elevation of the hyoid bone. Its role in the suprahyoid group is to facilitate the upward movement of the hyoid, which is essential for speech and swallowing.

💡Infrahyoid Muscles

Infrahyoid muscles are those located below the hyoid bone and are responsible for depressing it. The script lists the omohyoid, sternohyoid, sternothyroid, and thyrohyoid muscles as part of this group, each contributing to the downward movement of the hyoid bone.

💡Omohyoid Muscle

The omohyoid muscle has two bellies, superior and inferior, and is named for its connection to the shoulder ('omo' means shoulder in Greek). It is part of the infrahyoid group and plays a role in depressing the hyoid bone, as described in the script.

💡Sternothyroid Muscle

The sternothyroid muscle is part of the infrahyoid group and connects the sternum to the thyroid cartilage. Although it is not directly attached to the hyoid bone, it is connected to the thyrohyoid muscle, which in turn is connected to the hyoid bone, making it an important muscle for depressing the hyoid.

💡Synergists

In the context of the script, synergists refer to muscles that work together to achieve a common action, such as the elevation or depression of the hyoid bone. The suprahyoid and infrahyoid muscles are described as synergistic groups because they work in unison to perform their respective functions.

💡Antagonists

Antagonists are muscles that have opposite actions to each other. In the script, the suprahyoid and infrahyoid muscles are antagonists because one group elevates the hyoid bone while the other depresses it. The anterior belly of the digastric is also an antagonist to the masseter and temporalis muscles, as it depresses the mandible while the latter elevates it.

Highlights

There are two groups of hyoid muscles: super and infrahyoid.

Super hyoid muscles are located above the hyoid bone.

Infrahyoid muscles are situated below the hyoid bone.

The suprahyoid group includes the digastric, mylohyoid, stylohyoid, and geniohyoid muscles.

The digastric muscle has anterior and posterior bellies.

Mylohyoid muscle contributes to the floor of the mouth.

Stylohyoid muscle is connected to the styloid process of the temporal bone.

Geniohyoideus muscle extends from the chin to the hyoid bone.

Sprahyoid muscles work synergistically to elevate the hyoid bone.

Anterior belly of the digastric can also depress the mandible.

Digastric's anterior belly is an antagonist to the masseter and temporalis muscles.

Infrahyoid muscles include omohyoid, sternohyoid, sternothyroid, and thyrohyoid.

Omohyoid has a superior and an inferior belly.

Sternohyoid muscle connects the sternum to the hyoid.

Sternohyoid muscle is indirectly connected to the hyoid through the thyrohyoid.

Infrahyoid muscles work synergistically to depress the hyoid bone.

Infrahyoid muscles are antagonists to the suprahyoid muscles.

Transcripts

so there are two groups of hyoid muscles

there are the super hyoid muscles above

the hyoid bone and the infrahyoid

muscles which are below the hyoid bone

in the suprahyoid group there's the

digastric which has anterior and a

posterior belly um the mylohyoid which

is going side to side and it's making up

the floor of the mouth the stylohyoid

connected to the styloid process of the

temporal bone and the geno hyoid which

is going front to back so all of these

muscles will elevate the hyoid because

they're above the hyoid so they are

synergists to each other but also the

anterior belly of the digastric can work

to depress the mandible so because it

depresses the mandible

it's an antagonist to the masseter and

the temporalis which you might remember

are the muscles of mastication which

elevate the mandible

moving on to the infrahyoid muscles

there's the omohyoid omo means shoulder

and the omohyoid has a superior belly

and an inferior belly the sternohyoid

from sternum to hyoid then the sterno

thyroid because this little butterfly

shaped guy in the neck is the thyroid

gland so it's not directly connected to

the hyoid and then the Cyro hyoid and

the sternothyroid and thyrohyoid are

sort of connected to each other so even

though the sternothyroid isn't directly

connected to the hyoid bone it's

connected to the thyrohyoid which is

connected to the hyoid bone making it

therefore that's why it's one of the

infrahyoid muscles even though it's not

connected directly so all of these

muscles um will depress the hyoid bone

so they're all synergists to each other

but they are antagonists to the

suprahyoid bone which elevates the hyoid

so that wraps it up for the hyoid group

have a good day and have fun studying