Diverticulum

Definition

A blind outpouching or sac-like extension branching from a hollow organ or tubular structure, such as the gut, reproductive tract, or tracheal system. In arthropods, diverticula may be true (involving all tissue layers of the parent structure) or false (involving only some layers), and often serve functions including digestion, storage, gas exchange, or sperm transfer.

Etymology

Latin diverticulum, diminutive of devertere ('to turn aside')

Example

The crop of many insects, such as blow flies (Calliphoridae), gives rise to paired lateral diverticula that expand to store liquid food; in male spiders, the pedipalps contain complex diverticula of the sperm duct that form the spermathecae and embolus.

Related Terms

• caecum
• ampulla
• spermatheca
• tracheal gill
• gastric caeca
• Ejaculatory duct
• Reservoir

Usage Notes

Distinguish from 'diverticulosis' or 'diverticulitis' (clinical conditions in humans). In insect morphology, plural diverticula often refers specifically to gut extensions, while singular diverticulum may describe any tubular outpouching. The term is sometimes loosely applied to any blind-ending tubular structure, but precise usage reserves it for extensions of existing lumens.