What is the Lumbar Plexus?

The lumbar plexus is a nerve plexus, an area which a group of spinal nerves intersect, which innervates muscles in the lower body. This cluster of nerves is part of the larger lumbosacral plexus, which includes the lumbar plexus, sacral plexus, and pudendal plexus. Understanding the location and function of the nerves in the lumbar plexus is important to medical practitioners in a number of fields.

This nerve plexus includes the first four lumbar nerves, which innervate muscles in the calves, knees, groin, thighs, abdomen, and lower back. Patients who develop neurological problems in these areas may be examined by a neurologist who will determine where the source of the problems is; it may be in the spine, the lumbar plexus, or along the body of the nerve. Assessment of patients after accidents, spinal surgery, and spinal injuries also usually includes a detailed series of checks which are designed to determine whether any neurological problems have emerged, including an assessment of the nerves involved in the lumbosacral plexus.

The psoas muscle houses the bundle of nerves in the lumbar plexus. The nerves can be buried quite deep, especially in heavier patients who may have deposits of fat over the psoas muscle which can make it difficult to identify and isolate. For surgery involving this area of the body, the patient may be placed on his or her stomach to allow the surgeon to access the area easily and safely.

Anesthesiologists may utilize the lumbar plexus or lumbosacral plexus as a convenient location for a nerve block. Doing blocks in this area can be tricky, but highly useful, and the ability to perform such a block is a skill which an anesthesiologist is often expected to have. Nerve blocks can be used to create regional anesthesia for surgery, allowing a patient to undergo surgery without the risk of general anesthesia, and regional nerve blocks can also be used for pain management.

Some complications of a lumbosacral nerve block can include infection, hematomas, adverse reactions to anesthesia, accidental puncture of a vein, nerve injuries, and hemodynamic instability. The risk of these complications can be greatly reduced by using an experienced, competent, and meticulous anesthesiologist who will take his or her time during the critical stages of placing the nerve block. The nerve block may also be contraindicated for some patients, with the anesthesiologist determining the most appropriate anesthetic for a given patient and case.