Palatopharyngeus the missing palatal muscles: Anatomical and physiological review

Abstract

The first true anatomical descriptions of the normal anatomy of the palate and pharynx were published by Von Luschka in 1868, and then in 1935 anatomist James Whillis described pharyngeal sphincter. Later, in 1941 Michael Oldfield noted that the muscular elements of the soft palate have a sling-like function. Although there have been conflicting descriptions of the role of the palatopharyngeus, multiple function such as speech, swallowing, and respiration, it could role in all this function. Although, the palatopharyngeus muscle has many important functions, but it remains the missing muscle that we need to know more about it.

The palatopharyngeal muscle in otolaryngology practice: an anatomical-based surgical report

“…PPM has a fundamental role in velopharyngeal closure. In addition, it has a role in the production of both oral and nasal speech sounds [ 1 , 11 – 14 ].…”

“…Microscopic examination of PPM showed different muscle fibers in comparison with normal individuals. This change in the fibers’ properties and the disturbance of motor regulation might be important co-factors in abnormal upper airway collapse (allowing a retropalatal collapse) in patients with OSA [ 1 – 3 ].…”

“…Then, the muscle spreads radially (on the inner aspect of the pharyngeal wall) to be inserted into the pharyngeal raphe, the epiglottis, the pyriform fossa, and the thyroid cartilage. It was noticed that the most inferior portion of PPM passed antero-medially, and extended to the inner surface of the cricopharyngeal component of the inferior constrictor muscle to cover its inner surface [ 1 , 2 ]. Noticeably, there is no general agreement as regards the neural supply of PPM, and debates continue.…”

“…The muscle contributes to the soft palate’s movement, the pharynx’s shortening, and the hyo-laryngeal complex’s upward elevation movement. PPM is considered the key muscle in pharyngeal surgeries for obstructive sleep apnea (OSA); it has a role in the maintenance of patency of the upper airway (UA) by its activation in response to negative pressure (evident during nose breathing in the supine posture) [ 1 – 4 ].…”

Physiological Foundations

“…Horizontal fibres course from the velum to the lateral pharyngeal walls, while a second longer set (sometimes assigned as a separate muscle 'palatothyroideus') continue vertically and attach to the greater horns of the thyroid cartilage. The vertical compartment is in a position to act as an antagonist to the levator veli palatini while the transverse compartment may combine with fibres of the superior constrictor to form Passavant's ridge when contracted (Ezzat & El-Shenawy, 2015). Lowering the larynx for back vowels will tend to passively lower the velum via the palatothyroideus muscle fibres.…”