Emergency Medical Technician (EMT) Intermediate Practice Exam

What is the complex network of spinal nerves that controls the lower extremities called?

1. Brachial plexus

2. Cervical plexus

3. Lumbosacral plexus

4. Thoracic plexus

The correct answer is: Lumbosacral plexus

The complex network of spinal nerves that controls the lower extremities is known as the lumbosacral plexus. This structure is formed by the ventral rami of the lumbar and sacral spinal nerves, specifically from L1 to S4. Its primary function is to provide motor and sensory innervation to the lower limbs, including the hips, thighs, legs, and feet. The lumbosacral plexus not only facilitates movement through various muscles by relaying motor nerve signals but also enables sensation in the lower extremities, allowing for proprioception and the ability to feel touch, temperature, and pain. Key nerves that derive from this plexus include the femoral nerve, sciatic nerve, and tibial nerve, which are crucial for voluntary movement and sensory feedback from the lower limbs. Understanding the specific contributions of the lumbosacral plexus is essential for EMTs and other healthcare providers, as injuries to this plexus can lead to significant mobility and sensory deficits in the patient.