Variant Omohyoid Muscle: Report of Two Cases

International Journal of Research in Medical Sciences, 2020

Omohyoid muscle syndrome is a rare cause of a bulging lateral neck mass that occurs on swallowing that often a worrisome observation because of the concern of malignancy and cosmetic deformity. The first case has been documented on 1969. A 12 years old male came to Surgical Oncology Outpatient Clinic with chief complaint a protruding right lateral neck mass during swallowing. He noticed this complaint since three months prior. He had no previous history of medical illness. He had history of multiple chokehold trauma when playing with his friend 6 months ago. He had no symptoms besides the mass occurring on his right neck. The patient went through the cervical radiograph and neck ultrasonography examination. There were inconclusive results. The patient was informed that the implication of these findings was strictly cosmetic and did not pose any risk of long-term consequence. Corrective cosmetic surgery was recommended as an option if he was concerned about the cosmetic appearance an...

Yonsei Medical Journal, 2010

The omohyoid muscle is an infrahyoid muscle and consists of two bellies united by an intermediate tendon. This muscle is an important landmark in the neck because it divides the anterior and posterior cervical triangles into smaller triangles. 1 It passes behind the sternocleidomastoid muscle and lies superficial to the internal jugular vein, the brachial plexus, phrenic nerve, and transverse cervical artery and vein. Many studies reported variations in the omohyoid muscle and referred to the duplicated omohyoid muscle as a rare variation of the omohyoid muscle. The levator glandulae thyroideae muscle has been reported to occur infrequently and is described as an accessory muscle. This muscle has been reported by some

Journal of Case Reports, 2016

Variations in the infrahyoid muscle were identified as early as 19 th century. During regular dissection of cadaver in anatomy department in Kota an unilateral anomalous infrahyoid muscle was noted on right side with the absence of omohyoid muscle on same side. It was a flat, strap muscle 12 cm long and 2 cm wide. On one end it was attached to antero-lateral aspect of body of hyoid bone and on the other end to the clavicle. Its nerve supply was noted to be from the ansa cervicalis. Apart from this other infrahyoid muscles were normal. This muscle is best described as a cleidohyoid rather than the omohyoid. Hence in our case cleidohyoid appears to be variation of omohyoid muscle whereas some other workers have reported cleidohyoid as a variation of sternohyoid muscle. Surgeons and radiologists should be aware of such variations as it might interfere with the invasive techniques and knowledge of such variations should be kept in mind while interpreting MRI images of cervical region.

Anatomy & cell biology, 2017

The omohyoid muscle typically has an inferior belly originating from the superior border of the scapula, and then passes deep to the sternocleidomastoid muscle where its superior belly passes almost vertically upward next to the lateral border of sternohyoid to attach to the inferior border of the body of the hyoid bone lateral to the insertion of sternohyoid. Herein, we report an unusual variant of the omohyoid and sternohyoid muscles. As the omohyoid muscle is commonly used as a surgical landmark during neck dissections, knowledge of its variations such as the one described in the current report is important to surgeons.

Journal of Human Evolution, 1980

This study embodies a comparative study of the omohyoid muscles in six species of primates and in fetal and adult Homo. There are con-Received 29 January 1979 and siderable differences among the species in the origin of the muscle from accepted 18 November 1979 the scapula-clavicular complex, but little difference at its insertion to the hyoid bone. The origin in the gorilla is the most medial of all the species, on the superior border of the scapula very close to the superior angle. In the marmoset the muscle originates partly from the lateral one-third of the clavicle. The other species, including the adult Homo, have the origin of the muscle in between these two extreme positions. In the human fetus the origin is totally clavicular. An interesting concept is proposed in the light of recent advances in our knowledge of the immunological time scale for hominid evolution: Is the omohyoid muscle an indicator of the relative status of each species on such a time scale? Evidence to support such a theory is presented in this study. A cladogram shows the relationship of the above species.

Surgical and radiologic anatomy, 2010

The presence of a unusual appearance of the stylohyoid and digastric muscles may lead to a confusion in some pathological cases, during the radiological examination and aesthetic facial surgery. These diVerences may cause pharyngeal pain and foreign body sensation in the throat. During the dissection, unusual insertions, origin, insertion, shape and bilaterality were investigated in 28 cadavers' heads. In a total of 56, the presence of unusual insertions which belong to the stylohyoid muscle were observed in 22 sides (39.3%), and atypical Wbers which belong to the digastric muscle were observed in 39 sides (69.6%). Bilaterality of the presence of atypical appearance was observed for stylohyoid and digastric muscles, in 10 (35.7%) and 19 (67.8%) specimens, respectively. In 12 heads (42.9%), atypical Wbers, the stylohyoid and the digastric coexisted. These Wbers which were shaped like a circular spiral were realized to have the shape of an arch or circle in front of the hyoid bone. The posterior bellies of the digastric muscle, the mylohyoid and the remaining suprahyoid muscles of both sides were normal. The unusual insertion of the stylohyoid muscles which cover the hyoid bone as a collar was not described in the classiW-cation of the previous studies. These Wbers may give an variant mobility to the hyoid and they occur depending on the diVerences in the stylohyoid chains. Although the styloid process was in normal size, unusual insertions of the stylohyoid muscle that cover the hyoid as a belt or collar may give symptoms similar to those of the stylohyoid syndrome.

The Permanente Journal

Introduction: Duplicate omohyoid muscles are uncommon anomalies and exceedingly rare causes of progressive clinical symptoms. The goals of this case report are to describe the clinical characteristics, cross-sectional imaging, intraoperative findings, and curative treatment of our patient, to develop a differential diagnosis for this condition, and to review the pertinent literature regarding this particular type of anomalous omohyoid muscle as one among many variations. Case Presentation: A 20 year-old man presented with progressive limited neck range of motion followed by dysphagia and then dyspnea caused by his duplicate omohyoid muscle. He underwent curative surgery in 2015 at our tertiary care center. Discussion: Although rare, a duplicate omohyoid muscle should be considered in the differential diagnosis of dysphagia and dyspnea with concurrent central neck deformity. We report the first case, to our knowledge, of an anomalous omohyoid that caused significant progressive clinical symptoms. Direct excision of the restrictive anomalous tissue proved curative.

During routine anatomical dissections two cases of unusually structured abductor digiti minimi muscle were discovered. In the first case, the variant muscle body was composed of three well-defined portions: lateral, intermediate and medial. The three portions fused in a common muscular body that attached to the ulnar side of the base of the fifth proximal phalanx. In the second case, the aberrant muscle was composed of two portions: lateral and medial. Distally, they fused in a common muscular body that distally inserted as in previous case. Because in each one of the cases a portion from the aberrant muscle crossed over the ulnar nerve and artery in the Guyon’s canal, both variant abductor digiti minimi muscles could be of clinical interest in differential diagnosis of ulnar nerve entrapment.

Journal of Morphological Sciences, 2016

Introduction: Digastric is a suprahyoid muscle and usually consists of two bellies. Its action consists in drawing the mental region downwards and backwards when opening the mouth, resulting in the depression of the mandible. Methods and Results: During a routine dissection of the cervical region, a muscle bundle arising from the intermediary tendon going towards the middle line was found. The supranumerary belly arised from the intermediary tendon so that some bundles inserted on the middle rafe and others continued towards the mento and inserted on the belly of mylohyoid muscle at the same side. These anatomic variations on the anterior belly of the digastric muscle could be significant during surgical procedures involving the submental region. Conclusion: Besides this surgical importance, we suggest that these supranumerary bellies have no direct action on the mandible, but on the floor of the mouth, due to its insertions on the mylohyoid muscle.

International Journal of Morphology, 2019

A routine dissection of the digastric muscle reflected that it originated by two muscle bellies namely. the anterior and posterior belly which are connected by an intermediate tendon (IT). These bellies originated from the mastoid process of the temporal bone and the digastric fossa of the mandible respectively. The digastric muscle serves as an important surgical landmark in surgical interventions involving the submental area however, accessory bellies may interfere with surgical intervention in this area. Therefore, this study aimed to document the occurrence of the anatomical variations in the anterior belly of the digastric muscle (ABDM) in a selected number of cadaveric samples. Ten bilateral adult cadaveric head and neck specimens (n = 20) were macro-dissected in order to document the morphology of the digastric muscle. The accessory bellies in the ABDM was observed in 60 % of the specimens. Unilateral and bilateral variations were observed in 20 % and 30 % of the specimens, respectively. These accessory bellies originated in the digastric fossa, ABDM, IT and hyoid bone, and inserted into the mylohyoid raphe, mylohyoid muscle and hyoid bone. In addition, an anomalous main ABDM was observed in 10 % of the specimens inserting through a transverse tendon into the hyoid bone. Variations in the digastric muscle are common especially the accessory bellies, therefore, a comprehensive understanding of these anatomical variations could be of clinical importance to the surgeons during head and neck radiological diagnosis and surgical interventions.