AEMCA Practice Exam

From which part of the spinal cord does motor response enter?

1. Dorsal horn

2. Lateral horn

3. Anatomical horn

4. Anterior horn

The correct answer is: Anterior horn

The anterior horn of the spinal cord is where motor neurons are located, and it is responsible for sending motor responses to the muscles of the body. These lower motor neurons reside in the anterior horn and extend their axons out through the ventral roots of the spinal cord to innervate skeletal muscles, facilitating voluntary movement. In contrast, the dorsal horn primarily processes sensory information, receiving input from the body's sensory receptors. While the lateral horn is found in certain regions of the spinal cord and contains autonomic neurons, it is not directly responsible for motor responses. The term "anatomical horn" is not a standard term in spinal cord anatomy, which further distinguishes the anterior horn as the correct choice for this question regarding motor response entry. Understanding the structure and function of these areas reinforces why the anterior horn is pivotal in initiating motor responses in the body.