The middle pharyngeal constrictor is a fan-shaped

muscle Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contra ...

located in the

neck The neck is the part of the body in many vertebrates that connects the head to the torso. It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body. Addition ...

. It is one of three pharyngeal constrictor muscles. It is smaller than the

inferior pharyngeal constrictor muscle The inferior pharyngeal constrictor muscle is a skeletal muscle of the neck. It is the thickest of the three outer pharyngeal muscles. It arises from the sides of the cricoid cartilage and the thyroid cartilage. It is supplied by the vagus nerve ...

. The middle pharyngeal constrictor originates from the

greater cornu The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verteb ...

and lesser cornu of the

hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

, and the stylohyoid ligament. It inserts onto the pharyngeal raphe. It is innervated by a branch of the

vagus nerve The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...

through the pharyngeal plexus. It acts to propel a bolus downwards along the pharynx towards the esophagus, facilitating swallowing.

Structure

The middle pharyngeal constrictor is a sheet-like, fan-shaped muscle. The muscle's fibers diverge from their origin: the more inferior fibres descend deep to the

; the middle portion of fibres pass transversely; the more superior fibers ascend and overlap the

superior pharyngeal constrictor muscle The superior pharyngeal constrictor muscle is a quadrilateral muscle of the pharynx. It is the uppermost and thinnest of the three pharyngeal constrictors. The muscle is divided into four parts according to its four distincts origins: a pterygop ...

Origin

Two parts of the middle pharyngeal constrictor muscle are distinguished according to its sites of origin: * Ceratopharyngeal part - arises (the entire superior margin of) the

of the

. * Chondropharyngeal part - arises from the lesser cornu of the

, and (the inferior portion of) the stylohyoid ligament. The chondropharyngeal part represents the muscle's anterior origin.

Insertion

The muscle inserts (posteriorly) into the pharyngeal raphe, blending with its contralateral partner at the midline.

Innervation

Similarly to the superior and

s, it is innervated by a branch of the

through the pharyngeal plexus.

Actions/movements

The contraction of the muscle constricts the middle portion of the

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

Function

The muscle contracts during swallowing: as soon as the bolus of food is received in the pharynx, the elevator muscles relax, the pharynx descends, and the constrictors contract upon the bolus, and convey it downward towards the

esophagus The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), c ...

. They also have respiratory mechanical effects.

Additional images

Image:Gray186.png, Hyoid bone. Anterior surface. Enlarged. Image:Gray385.png, Muscles of the neck. Lateral view. Image:Slide12mmm.JPG, Middle pharyngeal constrictor muscle Image:Slide4iiii.JPG, Middle pharyngeal constrictor muscle Image:Slide1kuku.JPG, Deep dissection of larynx, pharynx and tongue seen from behind Image:Slide2kuku.JPG, Deep dissection of larynx, pharynx and tongue seen from behind Image:Slide3kuku.JPG, Deep dissection of larynx, pharynx and tongue seen from behind

References

External links

* () {{Authority control Muscles of the head and neck Pharynx