Final answer:
Paresthesia can be caused by several factors including traumatic injury due to forceful needle contact with the bone, hemorrhage around the nerve, needle direction changes, or needle bending. The PNS's vulnerability to injury due to its lack of protection also contributes to paresthesia.
Step-by-step explanation:
Paresthesia can be caused by a variety of factors, including traumatic injury to a nerve, which may result from forceful contact of a needle to the bone during medical procedures. Other causes could include a hemorrhage around the nerve, the change of needle direction which could irritate or damage neural structures, or the bending of the needle which might lead to improper administration of medication or direct nerve damage. Additionally, the Peripheral Nervous System (PNS) lacks the protections of the Central Nervous System (CNS), making it more susceptible to injury from factors like diabetes, infectious diseases, or toxins. Symptoms of PNS disorders can include loss of feeling, tingling, burning sensations, or muscle weakness.