spinous

Spinous is an adjective meaning having spines or spine-like projections. It derives from the Latin spinosus, from spina, spine or thorn, and is used in several biological and anatomical contexts to describe structures that are sharp, pointed, or thorny.

In human and vertebrate anatomy, spinous most often refers to the spinous process, a slender projection on the posterior aspect of a vertebra. The spinous process serves as an attachment point for muscles and ligaments and varies in size along the spine. It emerges from the junction of the vertebral arch components (the laminae) and extends posteriorly. The term helps distinguish this projection from other vertebral features such as the transverse processes and the articular processes. Clinical notes often address the integrity of spinous processes in trauma, or their involvement in conditions affecting the spine. Ligaments associated with spinous processes include the supraspinous and interspinous ligaments, which connect adjacent spinous processes along the vertebral column.

In botany, spinous describes plant parts that bear spines, prickles, or sharp projections. Spinose or spinulose leaves, stems, or fruits are equipped with such defenses, a common feature in many cacti, shrubs, and herbaceous species. The term is used in plant descriptions to convey the presence and arrangement of these sharp structures.

In zoological or paleontological contexts, spinous may describe organisms or body parts bearing spines or spiny projections, though more specific terms are often employed for particular structures (for example, spinous scales or dorsal spines in various taxa). The precise meaning of spinous is context-dependent, usually indicating a spiny or thorn-like characteristic.