Pleural

Definition

Of or relating to the pleuron—the lateral wall of an arthropod body segment, located between the dorsal tergum and the ventral sternum. In insects, the pleural region includes the pleural sclerites (episternum, epimeron, pleural wing process) that form the articulation site for the coxa and, in winged segments, provide the fulcrum for wing movement. The term distinguishes lateral body-wall structures from tergal (dorsal) and sternal (ventral) components.

Etymology

From Greek pleura, 'side' or 'rib'.

Example

In a grasshopper's thorax, the pleural apophyses—internal ridges of the pleural sclerites—brace against the exoskeleton to provide leverage for the powerful hind leg muscles.

Synonyms

• pleurite (noun, specific sclerite)

Related Terms

• pleuron
• Tergum
• sternum
• episternum
• epimeron
• pleural wing process
• pleurosternal
• pleurotergal

Usage Notes

Not to be confused with the vertebrate anatomical term 'pleural' (pertaining to the pleural membranes surrounding lungs). In arthropod morphology, 'pleural' is strictly positional and sclerite-based. Some authors restrict 'pleurite' to discrete sclerites and use 'pleural' more broadly for the entire lateral region. The plural 'pleura' is sometimes used for the pleuron of multiple segments, but 'pleurons' or 'pleura' (treated as plural of pleuron) creates ambiguity; specialists usually specify 'pleural sclerites' or 'pleural regions' for clarity.