Quadratus lumborum's role in respiration

Classic kinesiology texts (Kendall, McCreary, & Provance, 1993; Norkin & Levangie, 1992, p.186; Rasch & Burke, 1978, Table 14-1) include quadratus lumborum on the list of accessory muscles of expiration. The authors point out that the quadratus lumborum's superior attachments, like those of the serratus posterior inferior, are on the ribs. They reason that contraction of these muscles depresses the ribs. Because rib depression is a feature of expiration, the authors reason that the muscles can assist with expiration.

However, Kendall points out (1993, pp.143,329) that quadratus lumborum shares attachments with the diaphragm. If quadratus lumborum can stabilize diaphragmatic attachments, and make the diaphragm's action more effective, is the muscle then part of a synergy for inspiration? Norkin and Levangie (1992, p.186) suggest that people use the quadratus lumborum to stabilize the diaphragm for functions that require eccentric diaphragmatic action. These functions include speaking and singing.

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References: Kendall, F.P., McCreary, E.K., & Provance, P.G. (1993). Muscles: Testing and function (4th ed.). Baltimore:Williams & Wilkins.

Norkin, C.C., & Levangie, P.K. (1992). Joint structure and function: A comprehensive analysis (2nd ed.). Philadelphia: F.A. Davis.

Rasch, P.J., & Burke, R.K. (1978). Kinesiology and applied anatomy (6th ed.). Philadelphia: Lea and Febiger.

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Last updated 10-31-01 Dave Thompson PT
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