Anatomy clinical correlates: Vertebral canal

Our spinal cord is protected by a strong vertebral canal; however, it’s still vulnerable to a variety of clinical conditions. Being able to recognize and identify these clinical conditions can help us understand the functional deficits that coincide with those conditions, and ultimately allow us to treat them.

The spinal cord transmits information from both motor neuron branches and sensory neuron branches between the brain and the rest of the body.

One way we can test whether there is injury to the spinal cord and disruption of these neuronal pathways is eliciting the autonomic tendon reflexes, you know, when the doctor hits your knee with a tendon hammer you automatically kick him?

This occurs because when you hit the tendon with a tendon hammer, stretch receptors in the muscle tendon send afferent impulses to the spinal cord, through their cell bodies in the dorsal root ganglion, which synapse with alpha motor neurons in the anterior horn.

These alpha motor neurons then transmit an automatic efferent signal back to the muscle leading to a contraction in the muscle.

All you have to do is locate the muscle tendon, get the individual to fully relax the muscle, and strike the tendon with a tendon hammer. Testing tendon reflexes can give important information about a patient’s condition.

Eliciting testing tendon reflexes can tell us if there is damage to a particular nerve route, to an area of the spinal cord or brain, or the general state of a patient’s entire peripheral nervous system which can be affected in things such as diabetes and motor neuron disease.