体侧线是压力感受器官，俗称鱼腥线。几乎所有的鱼、在水中生活的两栖动物如蝾螈或是爪蟾，还有很多水生的爬行动物，如鳄鱼等，都有体侧线。这种细小的感受器官成百上千的排列在身体侧边。在鱼类身体侧面大于正中，人们可以看见一条清晰的点状线，故名。体侧线感受水流和压力波。

体侧线的组成有两种，一是劳伦氏壶腹（Ampullae of Lorenzini），二是神经丘（Neuromasts）。后者是众多的感受细胞，它们的感觉毛在胶质状的壶腹帽（Cupula）中。水流造成壶腹帽的偏移，产生神经冲动。

The lateral line is a system of sense organs found in aquatic vertebrates used to detect movement and vibration in the surrounding water. The sensory ability is achieved via modified epithelial cells, known as hair cells, which respond to displacement caused by motion and transduce these signals into electrical impulses via excitatory synapses. Lateral lines serve an important role in schooling behavior, predation, and orientation. For example, fish can use their lateral line system to follow the vortices produced by fleeing prey. They are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail. In some species, the receptive organs of the lateral line have been modified to function as electroreceptors, which are organs used to detect electrical impulses, and as such these systems remain closely linked. Most amphibian larvae and some fully aquatic adult amphibians possess mechanosensitive systems comparable to the lateral line.