What is Medulla Oblongata and its Function in the Body?

The brain makes only 2% of the body weight and uses more than 20% of the body’s energy.⁽¹⁾ The medulla oblongata is the lowest part of the brain and the lowest part of the brainstem and connects the brain to the spinal cord. It looks like a rounded bulge and is located in front of the cerebellum that is a part of the brain.

There is a hole in the skull through which the spinal cord passes, this is known as the foramen magnum. The medulla oblongata is located at the same level or slightly above.

It is made up of both types of matter i.e. the white matter and the grey matter and is formed about 20 weeks into gestation from the end of the neural tube in the embryo.

Despite being small in size, the medulla oblongata has some essential roles to play. It relays information between the spinal cord and the brain and also regulates cardiovascular and respiratory function. The body’s 12 cranial nerves originate in this region.⁽²⁾

The communication between the brain and the spinal cord is through columns of nerve fibers that run through the medulla, which are known as spinal tracts. These tracts are ascending and descending. The ascending tracts send information towards the brain and the descending tracts take information to the spinal cords.

A specific spinal tract may carry specific information. Such as the lateral spinothalamic tract carry information related to pain and temperature.

Damage to the medulla oblongata may affect the ability to relay a specific message between the body and brain.

The information carried by different spinal tract include:

• Pain and sensation
• Proprioception
• Fine touch
• Perception of vibration
• Crude touch
• Balance
• Muscle tone
• Eye function
• Conscious control of muscles
• Perception of pressure

The motor neurons cross from the left side of the brain to the right side of the spinal cord through the medulla. If there is a problem in the left side of the medulla the motor function of the right side of the body would be affected.⁽²⁾ Similarly, a problem with the right side of the medulla would affect the left side of the body.

Damage to the medulla oblongata would affect the way the brain and spinal cord transmit information to each other. This may lead to the following signs and symptoms:

• Breathing problems
• Vomiting
• Tongue dysfunction
• Loss of muscle control
• Problems swallowing
• Uncontrollable hiccups
• Loss of sensation of limbs, torso, and face
• Balance problems
• Loss of sneeze, gag, and cough reflexes

Stroke or sudden head injury can lead to damage to the medulla, which can leads to various problems.

1. Parkinson’s Disease

   Parkinson’s disease affects the brain and nervous system and lead to the following symptoms:

   • Slow movements
   • Tremors
   • Trouble balancing
   • Limb and torso stiffness

   The symptom of Parkinson’s disease are due to the degradation of neurons that produce dopamine that is a neurotransmitter.

   The degeneration of the brain starts in the medulla oblongata before spreading to the other parts of the brain.⁽³⁾

   People who have Parkinson’s disease are seen to frequently have cardiovascular dysfunctions.

   A study was conducted in 2017 on 52 people with Parkinson’s disease. It established a link between Parkinson’s and atypical characteristics of the medulla.⁽⁴⁾

2. Wallenberg Syndrome

   Wallenberg syndrome, also known as lateral medullary syndrome results from a stroke near the medulla. It includes the following symptoms:

   • Vomiting
   • Nausea
   • Dizziness
   • Uncontrollable hiccups
   • Balance problem
   • Loss of pain and temperature sensation
   • Swallowing difficulties
   • One-sided numbness

3. Dejerine Syndrome

   Dejerine syndrome is a rare condition that affects only 1 percent of people who have stroke affecting the back of the brain.⁽⁵⁾ The symptoms include:

   • Tongue weakness on the same side of the brain damage
   • Weakness of the arm and leg on the opposite side of the brain damage
   • Paralysis of the opposite side of the brain damage
   • Loss of sensation of the opposite side of the brain damage

4. Bilateral Medial Medullary Syndrome

   The bilateral medial medullary syndrome is also a rare condition that is known to affect only a fraction of 1 percent of people with stroke.⁽⁶⁾ The symptoms of this condition include:

   • Respiratory failure
   • Tongue dysfunction
   • Paralysis of all the four limbs

5. Reinhold Syndrome

   Reinhold syndrome is a hemimedullary syndrome and is completely rare. It is researched that only 10 people in the medical literature have developed this condition and the symptoms include:

   • Paralysis
   • Nausea
   • Vomiting
   • Difficulty in speaking
   • Horner’s syndrome
   • Loss of sensation of one side of the face
   • Loss of muscle control
   • Sensory loss of one side

   The Medulla oblongata is located at the base of the brain and regulates respiratory and cardiovascular functions. Damage to it can lead to the loss of sensation, respiratory failure, and paralysis.