A Restricted Hyoid Movement Can Effect Infant Feeding

Introduction

The hyoid bone is a horseshoe-shaped bone located in the neck, just below the chin and above the larynx (voice box). It is unique in that it is not directly connected to any other bones in the body. Instead, it is suspended in place by a complex network of muscles and ligaments.

The hyoid bone plays an important role in the mechanics of infant feeding. It provides support and stability for the base of the tongue and the muscles involved in swallowing and feeding. During feeding, the hyoid bone moves upward and forward, helping to create the pressure necessary to compress the nipple or bottle and extract milk. It also helps to protect the airway by keeping the larynx closed during swallowing.

Proper positioning and stability of the hyoid bone are essential for effective and safe feeding in infants. Infants with low muscle tone or weakness in the muscles that support the hyoid bone may have difficulty maintaining proper positioning and stability of the hyoid bone during feeding. This can lead to issues such as poor latch, difficulty creating and maintaining suction, decreased milk transfer, and increased risk of aspiration (inhaling milk or formula into the lungs). 

Muscles that attach to and effect the movement of the hyoid, and ultimately feed, are the mylohyoid, the digastric, the geniohyoid, the stylohyoid, the genioglossus, the stylohyoid, the hyoglossus, the omohyoid, the sternohyoid, and the middle constrictor of the pharynx. Apart from the middle constrictor of the pharynx, they are divided into the suprahyoid (above) and infrahyoid (below) muscles. The tightness and or weakness of these muscles can affect infant feeding in both groups as well as individually.

Suprahyoid Muscles

The suprahyoid muscles are a group of four muscles located above the hyoid bone in the neck. These muscles are the digastric, mylohyoid, geniohyoid, stylohyoid, and genioglossus muscles. They tend to affect an infant’s breast and/or bottle feeding when weak or uncoordinated.

The suprahyoid muscles play an important role in the movement of the hyoid bone and tongue during swallowing and speaking. These muscles help to elevate the hyoid bone and tongue, which is important for the coordination of the tongue and pharynx during feeding.

If the suprahyoid muscles become weak or are not functioning properly, they may limit the upward movement of the hyoid bone and tongue during swallowing, which can interfere with the coordination of the tongue and pharynx during feeding. This can result in difficulty with latching onto the breast or bottle, maintaining a strong suck, and coordinating the swallowing and breathing reflexes.

Infrahyoid Muscles

The infrahyoid muscles are a group of four muscles located in the neck, below the hyoid bone. These muscles are the hyoglossus, sternohyoid, omohyoid, thyrohyoid, and sternothyroid muscles. They tend to affect an infant’s breast and/or bottle feeding when tight or restricted.

The infrahyoid muscles play an important role in the movement of the hyoid bone, which is a small bone in the neck that supports the tongue and is involved in swallowing and breathing. These muscles help to stabilize the hyoid bone during swallowing and speaking and also play a role in depressing the hyoid bone and larynx during swallowing.

If the infrahyoid muscles become tight or shortened, they may limit the upward movement of the hyoid bone during swallowing, which can interfere with the coordination of the tongue and pharynx during feeding. This can result in difficulty with latching onto the breast or bottle, maintaining a strong suck, and coordinating the swallowing and breathing reflexes.

Middle Constrictor of The Pharynx

The middle constrictor muscle of the pharynx is a circular muscle that is located in the middle part of the pharynx, which is the muscular tube that connects the mouth to the esophagus. It is not directly involved in the mechanics of infant feeding.

However, the middle constrictor muscle can indirectly affect infant feeding by contributing to the closure and coordination of the upper esophageal sphincter (UES), which is the muscular ring that separates the pharynx from the esophagus. During infant feeding, the UES must relax to allow food or liquid to pass from the pharynx into the esophagus. If the UES does not relax or coordinate properly, this can lead to feeding difficulties such as aspiration (inhaling food or liquid into the lungs) or choking.

The middle constrictor muscle, along with other muscles of the pharynx, helps to close the UES and coordinate its relaxation during swallowing. If an infant has weakness or dysfunction in their middle constrictor muscle, this may affect the ability of the UES to relax and coordinate properly during feeding. This can lead to issues such as difficulty swallowing, coughing or choking during feeds, and an increased risk of aspiration or choking.

Digastric Muscle

The digastric muscle is a paired suprahyoid muscle located in the neck, which has two bellies connected by a tendon that runs through a loop of bone known as the hyoid bone. The muscle is involved in a number of movements related to swallowing, speech, and facial expression.

During infant breastfeeding, the digastric muscle helps to control the position and movement of the tongue and jaw. Specifically, it plays a role in the coordinated movement of the tongue and jaw that is necessary to create and maintain a proper latch onto the nipple or bottle.

Infants with weakness or dysfunction in their digastric muscle may have difficulty maintaining a proper latch, creating and maintaining suction, and effectively transferring milk. This can lead to feeding difficulties such as poor weight gain, slow or inefficient feeding, and increased risk of nipple damage or infection.

Geniohyoid Muscle

The geniohyoid muscle is a narrow, triangular suprahyoid muscle that extends from the mandible (lower jaw) to the hyoid bone in the neck. It is one of the suprahyoid muscles, which are a group of muscles that are located above the hyoid bone and are involved in swallowing and speech.

The geniohyoid muscle plays an important role in elevating and stabilizing the hyoid bone during swallowing. When an individual swallows, the geniohyoid muscle contracts to pull the hyoid bone upward and forward, which helps to create space in the pharynx and facilitate the movement of milk down the throat.

In addition to its role in swallowing, the geniohyoid muscle also helps to support the floor of the mouth and is involved in tongue movements during speech and other oral activities.

If an infant has weakness or dysfunction in their geniohyoid muscle, they may have difficulty coordinating the complex movements required for successful breastfeeding. This can lead to issues such as poor latch, decreased milk transfer, and inadequate weight gain. Healthcare providers may evaluate an individual’s geniohyoid muscle function as part of a comprehensive assessment of their swallowing and speech abilities.

Mylohyoid Muscle

The mylohyoid muscle is a suprahyoid muscle that plays an important role in swallowing and feeding, particularly in infants. It is a thin, flat muscle that forms the floor of the mouth and is located in the anterior (front) part of the tongue.

During feeding and swallowing, the mylohyoid muscle contracts to lift the tongue and push food or milk backward toward the pharynx. This action helps to create the pressure necessary to propel food through the oral cavity and into the esophagus.

In infants, the mylohyoid muscle is particularly important because it is one of the primary muscles responsible for initiating the sucking and swallowing reflexes that are necessary for successful breastfeeding. When an infant latches onto the breast or a bottle, the mylohyoid muscle contracts to lift the tongue and create negative pressure that draws milk into the mouth.

If an infant has difficulty controlling their mylohyoid muscle, they may have difficulty initiating the sucking and swallowing reflexes, leading to issues with feeding and weight gain. Therefore, healthcare providers often assess an infant’s ability to control their mylohyoid muscle as part of a routine evaluation of their feeding skills.

Stylohyoid Muscle

The stylohyoid muscle is a slender suprahyoid muscle that extends from the styloid process of the temporal bone (a small, pointed bone in the skull) to the hyoid bone in the neck. It is one of the muscles that make up the suprahyoid group of muscles.

The stylohyoid muscle plays an important role in elevating and supporting the hyoid bone during swallowing. When an infant swallows, the stylohyoid muscle contracts to pull the hyoid bone upward and backward, which can help to support the tongue and create negative pressure in the oral cavity, allowing milk to be drawn out of the breast.

If an infant has weakness or dysfunction in their stylohyoid muscle, they may experience difficulty with swallowing. They may also experience pain or discomfort in the neck or ear area, as the stylohyoid muscle is closely associated with these structures. In some cases, weakness or dysfunction of the stylohyoid muscle may be related to underlying medical conditions or injuries, and further evaluation by a healthcare provider may be necessary to determine the cause of these symptoms.

Genioglossus Muscle

The genioglossus muscle is a suprahyoid muscle that runs from the inner surface of the mandible (lower jaw) to the tongue. It is an important muscle involved in many oral functions, including speech, swallowing, and feeding.

During infant feeding, the genioglossus muscle plays a critical role in the proper positioning and movement of the tongue. It helps to move the tongue forward and downward, which can help to create a seal around the nipple or bottle and facilitate the extraction of milk. The genioglossus muscle also helps to control the shape and movement of the tongue during swallowing, which is necessary for efficient milk transfer.

If an infant has weakness or dysfunction in their genioglossus muscle, they may have difficulty controlling the shape and movement of their tongue during feeding. This can lead to issues such as poor latch, difficulty extracting milk from the breast or bottle, and inadequate weight gain. In some cases, infants with genioglossus muscle weakness may also experience issues with speech or other oral functions.

Hyoglossus Muscle

The hyoglossus muscle is an infrahyoid muscle with a flat, fan-shaped muscle located in the floor of the mouth that runs from the hyoid bone to the side of the tongue. It is one of the muscles involved in tongue movement and stabilization.

During infant feeding, the hyoglossus muscle helps to control the position and movement of the tongue, which is important for creating a seal around the nipple or bottle and extracting milk. It also helps to stabilize the tongue during feeding and prevent it from retracting too far back into the throat.

If an infant has weakness or dysfunction in their hyoglossus muscle, they may have difficulty controlling the position and movement of their tongue during feeding. This can lead to issues such as poor latch, difficulty extracting milk from the breast or bottle, and inadequate weight gain. Infants with hyoglossus muscle weakness may also be at increased risk of developing feeding difficulties such as reflux or aspiration.

Sternohyoid Muscle

The sternohyoid muscle is an infrahyoid muscle with a long, thin muscle located in the front of the neck that runs from the sternum (breastbone) to the hyoid bone. It is not directly involved in the mechanics of infant feeding.

However, the sternohyoid muscle can indirectly affect infant feeding by contributing to the stability and positioning of the hyoid bone. The hyoid bone is a horseshoe-shaped bone in the neck that supports the base of the tongue and the muscles involved in swallowing and feeding. During infant feeding, the position of the hyoid bone can have a significant impact on the infant’s ability to create suction, compress the nipple or bottle, and extract milk.

If an infant has weakness or dysfunction in their sternohyoid muscle, this may affect the position and stability of the hyoid bone during feeding. This can lead to issues such as poor latch, difficulty creating and maintaining suction, and decreased milk transfer. Infants with sternohyoid muscle weakness may also be at increased risk of developing feeding difficulties such as reflux or aspiration.

Omohyoid Muscle

The omohyoid muscle is an infrahyoid muscle with a long, thin muscle that runs from the upper border of the scapula (shoulder blade) to the hyoid bone in the neck. It is not directly involved in the mechanics of infant feeding.

However, the omohyoid muscle can indirectly affect infant feeding by contributing to the stability and positioning of the hyoid bone. The hyoid bone is a horseshoe-shaped bone in the neck that supports the base of the tongue and the muscles involved in swallowing and feeding. During infant feeding, the position of the hyoid bone can have a significant impact on the infant’s ability to create suction, compress the nipple or bottle, and extract milk.

If an infant has weakness or dysfunction in their omohyoid muscle, this may affect the position and stability of the hyoid bone during feeding. This can lead to issues such as poor latch, difficulty creating and maintaining suction, and decreased milk transfer. Infants with omohyoid muscle weakness may also be at increased risk of developing feeding difficulties such as reflux or aspiration.

Thyrohyoid Muscle

The thyrohyoid muscle is an infrahyoid muscle that attaches to the thyroid cartilage and the hyoid bone. It is innervated by the first cervical nerve and helps to depress the hyoid bone during swallowing and speech.

During infant feeding, the thyrohyoid muscle can affect the positioning of the larynx and hyoid bone, which in turn can impact the effectiveness of the infant’s suckling and swallowing. If the thyrohyoid muscle is weak or dysfunctional, it may result in improper positioning of the hyoid bone and larynx, leading to difficulty with latching, suckling, and swallowing. Additionally, if the muscle is excessively tight or hypertonic, it may lead to a restriction in the movement of the hyoid bone, further impacting the infant’s feeding abilities. Therefore, the proper functioning of the thyrohyoid muscle is important for optimal feeding in infants.

Sternothyroid Muscle

The sternothyroid muscle is an infrahyoid muscle that attaches to the sternum and the thyroid cartilage. It is innervated by the ansa cervicalis, a nerve formed by branches of the cervical spinal nerves C1-C3. The sternothyroid muscle helps to depress the larynx and the hyoid bone during swallowing and speech.

During infant feeding, the proper functioning of the sternothyroid muscle is important for maintaining proper positioning of the larynx and hyoid bone, which can impact the infant’s suckling and swallowing abilities. If the sternothyroid muscle is weak or dysfunctional, it may result in improper positioning of the hyoid bone and larynx, leading to difficulty with latching, suckling, and swallowing. Additionally, if the muscle is excessively tight or hypertonic, it may lead to a restriction in the movement of the hyoid bone, further impacting the infant’s feeding abilities. Therefore, the proper functioning of the sternothyroid muscle is important for optimal feeding in infants.

In Conclusion

As you can see there are numerous muscles involved in the complex task of breast and bottle feeding. Tightness or weakness in one or more of these muscles caused by trauma, position, dysregulation, or medical condition can cause challenges with feeding. At Lunara our goal is to look for patterns and the root cause of your difficulty. This includes assessment of the hyoid muscles as well as many other muscles in your baby’s body. By determining the underlying reasons for feeding difficulty a simple directed intervention can be implemented. With a foundation in manual therapy and expertise in movement science Balanced Baby is a leader in the treatment of babies with feeding difficulties.