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. 

The deep fibular nerve is also known as the deep peroneal nerve. The deep fibular nerve supplies branches to the tibialis anterior, extensor digitorum longus, peroneus tertius, and extensor hallicus longus. The common fibular nerve is derived from spinal nerves L2-L4 and branches off to the superficial and deep fibular nerves. Damage to the fibular nerve is often caused by traumatic injury to the lateral knee; this results in a foot drop which causes the affected person to walk with a high stepping gait. 

The sciatic nerve is a large nerve that runs through the buttocks and down the lower limb. The sciatic nerve innervates skin of the leg, and muscles in the posterior thigh, leg, and foot. The sciatic nerve is derived from spinal nerves L4-S3. Damage to the sciatic nerve would result in impaired hip extension and knee flexion. It would also lead to a loss of plantar/dorsiflexion and inversion and eversion of the foot.

The obturator nerve innervates skin of the medial aspect of the thigh. It is also responsible for the motor innervation of the adductor muscles of lower extremity (external adductor longus, adductor brevis, adductor magnus, and gracillis). The obturator nerve is derived from spinal nerves L2-L4. Damage to the obturator nerve would result in weakness in adduction and lateral swinging of the leg due to unopposed abductors.

The axillary nerve, which originates from the C5 and C6 spinal roots, provides motor innervation to the deltoid and teres minor muscles, both abductors of the shoulder. It also provides sensory input to the lower deltoid via  the superior lateral cutaneous nerve. Damage to this nerve is a possible complication during an axillary dissection. If a patient had sustained an injury to this area they would have difficulty abducting or raising the arm laterally. 

Hydrocephalus is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain. It can be caused by one of three mechanisms: impaired flow of CSF, decreased reabsorption, or excessive production. Hydrocephalus may cause increased intracranial pressure inside the skull. It is most common among infants and the elderly.

Brain herniations are a dangerous and potentially fatal. They occur when there is a very high pressure within the skull (via mass effect from hemorrhage, trauma, or tumors) that occurs when a part of the brain is pushed/squeezed across structures within the skull. There are three main types of herniation of brain tissue. Subfalcine, uncal transtentorial, and tonsillar herniations. The subfalcine herniation is also called the cingulated herniation, this occurs when the innermost part of the frontal lobe is scraped under a portion of the falx cerebri. The uncal transtentorial herniation involves the uncus (innermost part of the temporal lobe) moving the tentorium so far that is pushes against the brainstem. A tonsillar herniation is also called a “downward cerebellar herniation,” and occurs when the cerebellar tonsils are pushed downward through the foramen magnum.

The deep fibular (also called peronal) nerve traverses the posterior side of the lower leg. The deep fibular nerve supplies tibialis anterior, extensor digitorum longus, peroneus tertius, and extensor hallucis longus. After the ankle joint, a branch of the deep fibular nerve innervates digitorum brevis and extensor hallucis brevis. 

Damage to the deep fibular nerve (often via traumatic injury to the lateral knee) results in a foot drop. Foot drop inhibits the patient to clear toes off the ground during the swing stage of walking. 

Damage to nerve roots can cause weakness, paralysis, pain, and numbness to muscles and areas innervated by the affected nerve root. When nerves of the cervical region are involved, pain is usually the first symptom to develop. Pain typically will increase gradually before other symptoms of ridiculopathy present. Due to the way nerve roots exit the vertebrae, in the cervical region the nerve root affected usually correlates to the lower vertebrae. In this case there is a narrowing of the C3/C4 space and thus the C4 nerve is affected.