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Raja Gnanadev,1 Joe Iwanaga,2 Marios Loukas,3 and R. Shane Tubbs4
Corresponding author.

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The hyoid contributes to numerous biomechanical processes including swallowing. Additionally, the hyoid bone has been studied because that over a century in an effort to catalog and categorize many observed biometric differences. This has led come the hyoid gift a significant structure associated in forensic pathology. In this paper, we discuss a an extremely unusual recognize of an adult woman hyoid bone.


Introduction

The hyoid bone is a unique structure in the human being body for plenty of reasons. The larynx is very cartilaginous area, other than for the sole local bony structure—the hyoid bone. Famously, the hyoid bone is the just bone in people that does not articulate with any other bone, but only has muscular, ligamentous, and cartilaginous attachments. Provided this peculiarity, it has been explained as “free floating” <1>.

Given that the vast variety of muscles is attached to the hyoid, it is no surprise that the hyoid bone contributes come actions such as mastication and also swallowing. Additionally, sport in morphometric data between the sexes have been fine studied and have had actually a solid contribution come forensic medication for decades <2-3>.

Herein, we report an unusual variation the the hyoid bone and briefly evaluation morphometric studies on hyoid bone anatomy.


Case presentation

During the regime dissection that the head and also neck of an adult woman Caucasian new frozen cadaver, an unexplained morphology that the hyoid bone to be observed. The sternohyoid and also omohyoid muscles space attached to the reduced border of the hyoid body as usual. The hyoid bone was resected from the anterior neck and also the soft tissues on the bone to be removed. The elevation of the human body of the hyoid bone climate was discovered to be bigger than normal and measured 15.9 mm (Figure 1). However, the higher cornu and lesser cornu were found to be regular in size and orientation. The worse edge the the human body of the bone was drawn out and also presented v an inexplicable edge in ~ the website of attachments of the omohyoid and sternohyoid muscles. No ahead scars or proof of trauma was discovered in this specimen in the an ar dissection. Additionally, no other anatomical variations to be noted. 


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Figure 1
Measurement the the different hyoid bone.

Discussion

The hyoid bone is situated inferior to the mandible, and also superior come the thyroid cartilage in ~ the level of the third cervical vertebra in the midline. Laryngeal muscles connect on the premium body, worse body, and also laterally along the each of the horns. Embryologically, the cartilage that the 2nd pharyngeal (hyoid) arch creates the lesser horn and also that of the 3rd pharyngeal arch offers rise come the greater horn. The ventral next of the 2nd and 3rd pharyngeal arches fuses to type the body of the hyoid bone during the 4th week the gestation.

This report focuses on the inferior part of the hyoid body whereby the omohyoid and sternohyoid muscles attach. An elongated human body (15.9 mm) follow me this worse edge was listed in the specimen.

Many researchers have investigated the sex dimorphism observed about the hyoid bone and the variation appears to be consistent across many measurements. This variations include angles that measurement indigenous the body to the greater and also lesser tubercles, size of the horns, and also thickness of the body, amongst many others <1-3>. Through cataloging this variations, forensic pathologists have actually been maybe to use hyoid bone morphology with relatively great accuracy to make determinations related to identifying the deceased <3>. Provided the definition of being able to do this, a relatively complicated categorization system has actually been emerged for various recognized shapes of the hyoid. Remarkably, it has been listed that 60% of hyoid skeleton still execute not fit right into one that these frequently described categories <4>.

Unfortunately, there are couple of studies that have actually analyzed the distance from the exceptional border come the inferior border that the body. A find of the literature has actually yielded simply two studies, be separated by over a century, v metrics ~ above this dimension of the hyoid. In 1909, Parsons analyzed the hyoid bone indigenous 108 adult cadavers from male adult (53), female adults (28), and also children (27). His results proved an average elevation of 1.2 centimeter for males (range: 1.0-1.6 cm), and 1.0 cm for females (range: 0.9-1.2 cm) <5>. In 2012, a team of Japanese researchers analyzed 600 hyoid bones (310 males, 290 females) using three-dimensional computed tomography (CT) imaging. Their data very closely matched that of the 1909 study showing a mean elevation of 9.4 mm in males (range: 6.3-16.0 mm), and 7.8 mm in females (range: 3.0-8.8 mm) <6>. However, the precise morphology of the hyoid bone in these instances was no reported.

Finally, there room reported instances of ossification that the muscle that affix to the hyoid bone, e.g., traumatic and also genetic myositis ossificans <7>. A evaluation of the literature yielded a single case report on traumatic myositis ossificans in the remarkable belly that the omohyoid. In this case, the ossification to be unilateral, palpable on physical examination, and plainly visible ~ above radiographs <8>.

Anatomical sports such as the one described herein, can result in dorn level surgical treatment as the typically positioned and also sized hyoid bone is offered by operated doctor to calculation the C3 vertebral level <9-12>. Furthermore, together the anterior neck is often palpated throughout physical examination, bony variants such as the one explained here can lead to misdiagnosis or in ~ least, unnecessary testing.


Conclusions

The hyoid bone has actually both plenty of unique anatomical features and also clinical relationship in forensic pathology. Therefore, reports of hyoid bone sports are necessary to anatomists and also clinicians alike.

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Notes

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