Insomnia is a sleep disorder, in which people have trouble falling or staying asleep. It can be an acute or chronic disorder. Insomnia can cause other problems such as anxiety, inattention, or depression. It can be treated by lifestyle changes, medication, or therapy.

Narcolepsy is a disorder that leads to extreme daytime sleepiness and/or muscle weakness. It causes people to fall asleep suddenly, even in the middle of tasks. There is no cure, but it can be managed by medicine, lifestyle changes, or therapy.

Sleep apnea is a disorder in which you stop breathing at night while asleep. Often, those suffering from the disorder are not aware they wake up at night to breathe. It creates a poor quality of sleep, which leads to daytime sleepiness.

Hydrocephalus occurs when there is a disruption in the circulation of cerebral spinal fluid or CSF. This can cause swelling of the head and may be treated by shunting some of the excess CSF out of the cranial cavity. Temporomandibular joint (TMJ) disorder affects the jaw and is caused by a misalignment of joints. Hemorrhagic fever is caused by an infectious agent, like the Ebola virus. Uncontrollable cell growth is also known as cancer. 

Epilepsy is also known as a seizure disorder and is a disorder of the nervous system. A seizure is a short term change in normal brain activity. There are two types of seizures: generalized, which affects both sides of the brain, and focal, which affects one area of the brain. Ebola is caused by a virus that causes hemorrhagic fever. Cerebral edema is classified by swelling of the brain, which can cause irreversible damage and death in severe cases. Elephantiasis is a symptom classified by excessive swelling of a certain part of the body.

Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a progressive disease that attacks the nerve cells that control voluntary movement. It is not known what causes ALS and there is currently no treatment. The US has a registry that tracks who gets ALS in an attempt to understand the disease. 

Autism Spectrum Disorder (ASD) has a wide range of signs or symptoms. These can vary from mild to severe, depending on the individual. There is no single cause for autism and there is no cure. Treatment includes management of behaviors, therapy, interventional services. 

Meningitis is an illness that features fevers, headaches, and stiff necks. This is a serious illness that can be fatal if not treated promptly. It typically begins showing symptoms 3-7 days after exposure. If the infection is bacterial in origin, it can be treated effectively with antibiotics. If it is viral, the treatment is supportive in nature.  

Botulism is caused by a toxin released by the Clostridium botulinum bacteria. The bacteria lives in the intestinal tract and releases the toxin. The toxin leads to double vision, slurred speech, and flaccid muscle paralysis. It can lead to death if not treated as botulism can cause the respiratory system to shut down. This is the same toxin that individuals often elect to inject into their face for cosmetic purposes.

The tibial nerve is a branch of the sciatic nerve. It passes through the popliteal fossa and gives off branches to the gastrocnemius, popliteus, soleus, and plantaris muscles. It also gives off a branch that will become the sural nerve. The nerve also supplies the tibialis posterior, the flexor digitorium longus, and the flexor hallucis longus muscles.

Since the tibial nerve is a branch of the sciatic nerve, it too is derived from spinal nerves L4-S3. Damage to the tibial nerve would result in clawed toes, a shuffling gait, loss of plantar flexion, impaired inversion of the foot (due to damage to tibialis posterior), and the heel would be grounded.