Overview of Chaddock Reflex
In 1911, a man named Charles Gilbert Chaddock came up with a way to test a specific part of the brain known as the corticospinal tract (CST) through what would later be named the Chaddock reflex. This was a different approach to a method used by doctors called the Babinski reflex. Similarly, in 1906, Kisaku Yoshimura, from Japan, described a test also much like the Babinski sign.
The Chaddock reflex and the Babinski reflex are both simple tests that help doctors examine the health of the CST, a part of the brain that controls our motor (movement) functions. Both of these tests do not require much effort or special cooperation on the part of the patient, which makes them very useful, especially when dealing with patients who may not be able to fully participate in their examination.
Usually, doctors use the Babinski reflex as a standard part of examining a patient’s brain functions. But there are also other options like the Chaddock sign that can be useful in certain situations – for example, if a patient reacts strongly to the tickling sensation on the bottom of their feet (plantar stimulation) during the Babinski reflex.
Anatomy and Physiology of Chaddock Reflex
The Corticospinal Tract (CST) is like a communication highway from our brain to the muscles in our body. In this case, it’s the muscle control for our legs. This highway starts from a particular layer in the brain and travels down through the brain stem before reaching the spinal cord. Here, the majority of its ‘lanes’ cross over to the other side – this is why movement on the right side of our body is controlled by the left side of our brain, and vice versa.
When you stroke the outer part of the foot with a blunt object, this activates a specific nerve pathway, starting from the foot, up to the first sacral nerve root in the lower back (S1). This tells the muscles in the foot to contract and curl the toes downward. The CST’s role here is to constrain this response to just the S1 nerve root, preventing the reaction from spreading to other nerve roots.
However, if the CST isn’t functioning correctly due to illness or injury, the stroking stimulus can spread to other nerve roots in the lower spine. This causes an increased bending action of the lower extremity, as well as an upward movement of the big toe and a spread-out position of the other toes. This reaction is called a positive Chaddock reflex, and can be a sign that the CST isn’t working as it should.
Why do People Need Chaddock Reflex
The Babinski reflex is a normal response that doctors check for during a standard check-up of your brain and spinal cord. Yet, if touching the bottom of your foot causes you to pull away sharply, or if there’s a wound or infection on the outside of your foot, your doctor may use the Chaddock reflex as an alternative test. This helps the doctor evaluate the health of your central nervous system (your brain and spinal cord). If you’ve had a stroke or a spinal cord injury, this reflex might show up early on, which can alert the healthcare provider to these serious, potentially life-threatening conditions.
Equipment used for Chaddock Reflex
Typically, the Chaddock reflex, a type of physical examination, is done using a blunt tool. Using a sharp tool is not recommended as it could cause discomfort or harm to the skin. Often, the tool used could be the end of a small medical hammer known as a reflex hammer, a tongue depressor, which is a flat, thin piece of wood used by doctors, or the edge of a key. These are used to trigger this reflex.
Preparing for Chaddock Reflex
When a doctor needs to check the Chaddock reflex, it’s important that the patient is at ease and comfortable. The doctor will explain to the patient that the test may feel a bit uncomfortable. Some patients may feel a tickling sensation, but this is less common than with another test called the Babinski reflex, which requires a different type of foot stimulation. Before beginning, the doctor will make sure there are no wounds or sores on the top side of the patient’s foot.
How is Chaddock Reflex performed
The Chaddock reflex is a response that doctors can provoke to test nerve functioning. They stimulate, or lightly touch, the outer side of your foot, moving from just below the bump on the outside of your ankle (known as the external malleolus) towards the front and side of your foot.
This reflex, along with another called the Babinski reflex, causes your big toe to bend and your other toes to spread out in a fan-like way if there are issues with your central nervous system. This is one of the ways doctors can check for any problems related to the nerves in your body.
What Else Should I Know About Chaddock Reflex?
The Babinski and Chaddock reflex tests are used to examine the health of your brain and spinal cord. Both tests are performed by stimulating your foot and observing your body’s reflexes. One of the key things doctors look for is the big toe moving upwards and the other toes spreading apart – we call this a “positive reflex.”
If instead, your toes point downwards, it can indicate the communication from your brain to your spinal cord (CST) is functioning correctly. Remember though, no reaction isn’t something to worry about and doesn’t mean anything clinically significant.
Interestingly in babies less than two years, a “positive reflex” during this test is considered normal due to their still-developing nervous system.
However, in the case of comatose patients, if the upward movement of the big toe and fanning of the other toes occurs, along with the upward movement of the foot and bending in the knee and hip, it conveys serious CST dysfunction and must be distinguished from a withdrawal response.
The Chaddock reflex test is said to have an advantage over the Babinski reflex test, in that it reduces a withdrawal reaction because of the stimulation on the underside of the foot. This is important because any slight issue along the CST can cause abnormalities in these reflexes. Hence, this test proves to be a good way to determine the system’s health.
There are other ways to perform these tests as well, all involving different methods of stimulating the foot:
– Gordon sign: Squeezing the calf muscle
– Oppenheim sign: Putting pressure on the inner side of your shin bone
– Stransky sign: Pulling away and then releasing your little toe
– Schaeffer sign: Squeezing the Achilles tendon
– Moniz sign: Putting pressure to bend the ankle downwards
– Gonda sign: Bending and then releasing the fourth toe
– Throckmorton reflex: Tapping over the joint of the big toe.
– Bing sign: Giving multiple tiny pinpricks on the top of your foot
– Cornell sign: Scratching along the inner side of the tendon on top of your foot
Overall, these tests offer a valuable insight into the functioning of your nervous system.