Division of Anatomy and Embryology, Department of Basic Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Ph.D. student of Comparative Anatomy and Embryology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Ann Anat. 2022 Jan;239:151842. doi: 10.1016/j.aanat.2021.151842. Epub 2021 Oct 19.
The detailed morphology and topography of the sympathetic cardiac nerves (SCNs) and ganglia with their surrounding structures in Syrian hamsters were examined to document the general topography and morphology and variations and to discuss the comparative anatomy between the SCNs and ganglia in Syrian hamsters and other rodents, as well as their comparative morphology and macroscopic evolutionary changes among rodents, rabbits, domestic animals (cats, dogs, sheep, goats, oxen, pigs and horses), primates, and humans.
The composition of the cervical and thoracic parts of the sympathetic trunks and ganglia was bilaterally microdissected in twenty-eight sides of 14 adult male and female Syrian hamsters under a stereomicroscope.
The general morphology of the SCNs and related ganglia in Syrian hamsters was obtained and noted as follows: (1) the absence of the vago-sympathetic trunk, (2) the absence of the middle cervical ganglion (MG), (3) constant presence of the cervicothoracic ganglion (CT) comprising generally from the caudal cervical ganglion and 1-2 thoracic ganglia and locating over the lateral surface of the longus colli muscle ventral to the heads of the first two ribs and communicating to the eight cervical and first two thoracic spinal nerves (C8-T2) in addition to the vertebral nerve, (4) extensive coverage of the lateral surface of the CT by branches of the subclavian artery, (5) the cranial and caudal limbs of the ansa subclavia (AS) joining the CT to the caudal end of the cervical sympathetic trunk, (6) the presence of an independent thoracic ganglion from the 2nd or 3rd to the 13th and connecting by single interganglionic branches, and communicating to each thoracic spinal nerve, (7) close relationship between the caudal portion of the thoracic sympathetic trunk and the psoas minor muscle, (8) the primary cardiac nerves (CNs) arising from the CT, and (9) the absence of CNs originating generally from the cervical sympathetic trunk, AS, MG, or independent thoracic ganglia or their interganglionic branches. Individual variations of the SCNs and ganglia in Syrian hamsters were noted, including the absence of the ansa subclavia on 5/28 sides (17.86%), the presence of the intermediate ganglia (IG) placed on the C7 on 3/28 sides (10.71%) or the C8 on 3/28 sides (10.71%), and no CNs arising from the IG as well as the presence of the double thoracic sympathetic trunk on 5/28 sides (17.86%). The anatomical characteristics of the SCNs and related ganglia were also exhibited sex and laterality differences.
From a comparative anatomy viewpoint, the general morphology of the SCNs and related ganglia in Syrian hamsters was very similar to that in rats but was considerably different from that in guinea pigs, especially concerning the MG, cranial position and composition of the CT. The general morphology of the SCNs and related ganglia in Syrian hamsters and other laboratory rodents resembled that of rabbits but was essentially different from that in rabbits with respect to the cranial position and composition of the CT. The general morphology of the SCNs and ganglia exhibited significant morphological differences and similarities among laboratory rodents, rabbits, domestic animals, primates, and humans. The main differences include the relationship between the cervical parts of the vagus nerve and sympathetic trunk, the presence of the MG, the position and composition of the CT, the origins and frequencies of the cardiac nerves, and the primary sympathetic contributor. From macroscopic evolutionary change, the expansion of the range of the SCNs origin has occurred from laboratory rodents, rabbits, domestic animals, and primates to humans.
本研究旨在详细描述叙利亚仓鼠心脏交感神经（SCN）及其周围结构的形态和分布，记录其一般形态和分布特征、变异情况，并讨论其与其他啮齿动物（如大鼠）、兔类、家畜（猫、狗、羊、牛、猪、马）、灵长类和人类的 SCN 及其神经节之间的比较解剖学，以及它们在啮齿动物、兔类、家畜、灵长类和人类中的比较形态和宏观进化变化。
在 14 只成年雄性和雌性叙利亚仓鼠的 28 侧标本中，在体视显微镜下双侧显微解剖颈胸交感干和神经节的组成部分。
获得并记录了叙利亚仓鼠 SCN 及其相关神经节的一般形态特征如下：（1）缺乏迷走交感干；（2）缺乏颈中神经节（MG）；（3）恒定存在颈胸神经节（CT），通常由颈胸神经节和 1-2 个胸神经节组成，位于头 2 肋头外侧的胸长肌腹侧，与第 8 颈神经（C8）和第 2 胸神经（T2）及椎动脉沟通；（4）锁骨下动脉分支广泛覆盖 CT 的外侧表面；（5）颈胸交感干和 CT 与 CT 至颈交感干尾端的颅侧和尾侧支的ansa subclavia（AS）；（6）存在第 2 或第 3 到第 13 个独立的胸神经节，通过单节间支连接，并与每一个胸神经节沟通；（7）胸交感干尾端与腰小肌密切相关；（8）发自 CT 的初级心神经（CN）；（9）发自颈交感干、AS、MG 或独立胸神经节或其节间支的 CN 一般不存在。在叙利亚仓鼠中还观察到 SCN 和神经节的个体变异，包括 5/28 侧（17.86%）无ansa subclavia，3/28 侧（10.71%）或 C7 或 3/28 侧（10.71%）有中间神经节（IG），IG 没有发出 CN，也有 5/28 侧（17.86%）有双胸交感干。SCN 和相关神经节的解剖学特征也表现出性别和侧位差异。
从比较解剖学的角度来看，叙利亚仓鼠 SCN 和相关神经节的一般形态与大鼠非常相似，但与豚鼠有很大的不同，尤其是 MG、CT 的颅侧位置和组成。叙利亚仓鼠 SCN 和相关神经节的一般形态与实验室啮齿动物的兔类相似，但与兔类的 CT 的颅侧位置和组成有很大的不同。实验室啮齿动物、兔类、家畜、灵长类和人类的 SCN 和神经节的一般形态存在显著的形态学差异和相似性。主要差异包括迷走神经颈段与交感干的关系、MG 的存在、CT 的位置和组成、心神经的起源和频率以及主要的交感神经贡献。从宏观进化变化来看，SCN 起源范围的扩大发生在实验室啮齿动物、兔类、家畜和灵长类到人类。
