Department of Anatomy, Catholic Institution for Applied Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Yonsei Med J. 2010 Nov;51(6):984-6. doi: 10.3349/ymj.2010.51.6.984.
The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51- year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.
胸锁乳突肌的胚胎起源与其他颈部肌肉不同。已经报道了许多变异，如肌肉缺失、起源和插入部位的可变、多个肌腹等。然而，胸锁乳突肌的下腹肌腹变异很少见。尚未有报道称胸锁乳突肌变异与甲状腺舌骨肌同时出现。对一名 51 岁女性尸体的常规解剖发现了一个复发性胸锁乳突肌和甲状腺舌骨肌的出现。在这种情况下，两个胸锁乳突肌的下腹肌腹从肩胛的上缘起源。一个下腹肌腹通常与腱性交叉继续向上腹延伸。另一个下腹肌腹继续进入胸骨舌骨肌而没有腱性交叉。在这种情况下，甲状腺舌骨肌出现在左侧，从甲状腺的上缘附着到甲状软骨的下缘。这些变异对内镜诊断和手术中的临床医生很重要，因为医源性损伤会导致动脉和神经损伤。根据相关文献的描述，胸锁乳突肌和甲状腺舌骨肌的胚胎起源可能相似。
