Hyoid In Human Anatomy

In Human Anatomy, Hyoid is a U-shaped bone present in the ventral aspect of neck at the level of fourth cervical vertebra. It is a small bone placed between the root of tongue and the thyroid cartilage. Hyoid bone represents a link be- tween the head and neck. Although located in the neck, hyoid bone be- cause of its brachial origin belongs to the visceral skeleton(1). This bone is over stilohyoid ligament (ligamentum stylohyoideum) stilohyoid muscle (mus- culus stylohyoideus) and last digastric abdominal muscle (posterior venter musculi digastrici) related to the base of the skull, through geniohyoid muscle (musculus geniohyoideus) milohyoid mus- cle (musculus mylohyoideus) and anterior digas- tric muscle belly (venter anterior musculi digastrici)

So by suprahyoid muscle contraction comes to rise of hyoid bone, larynx and pharynx if the jaw is fixed, and if the muscle is fixed by infrahyoid comes to lowering of hyoid bone and retreat back the lower jaw, which allows you to open your mouth. The optimum position of the cranio-cervical structures is a prerequisite for performing various vital functions such as breathing or swallowing. Dysfunction of any structure in cranio-cervical region can lead to disorders, which can manifest itself in other structures of the cranio-cervical region. To what extent will a disorder manifested depends on a lot on the individual ability of individuals to adapt to the disturbance occurred

Stylohyoid ligament is attached to the lesser horn, the hyoid bone is suspended with long stylohyoid ligaments from the styloid process of the temporal bone of the outer skull base and maintains the position of the hyoid bone(4)(1). Anatomically the hyoid is composed of a body, two greater cornua and two lesser cornua. Each cornu is attached to the body by syn- chondrosis that calcifies with ageing. The tip of the cornu are directed postero-laterally. The important attachments of the hyoid are myelohyoid, omohyoid, thyorohyoid and stylohyoid(1).

Morphological variants of hyoid are well documented. Mainly the U-shaped and V-shaped hyoid is differentiated on the basis of the angle subtended between the cornu (extended). 25 degrees is the demarcating value according to a study on Croatian population(5). The hyoid bone is phylogenetically equivalent to the structure of a branchial arch. The upper part of the body, lesser horns, and stylohyoid ligament are derived from the 2nd branchial cartilages, and the lower part of the body and greater horns are derived from the third branchial cartilages