Understanding Pins and Needles (Parathesia)

Introduction

• Common experience: feeling of "pins and needles" when a limb "falls asleep."
• Scientific term: Parathesia.
• Often linked with paralysis; individuals with paralysis may experience parathesia.

Types of Parathesia

1. Transient Parathesia

   • Short-lasting, caused by awkward posture or pressure on nerves.
   • Often results from temporary physical conditions like sitting cross-legged.

2. Chronic Parathesia

   • Long-lasting, usually due to nerve damage or infection (e.g., Lyme disease).

Focus on Transient Parathesia

• Occurs due to pressure on nerves or blood supply.
• Common scenario: sitting cross-legged, putting pressure on the back of the thigh.

Anatomy Involved

• Hamstrings: biceps femoris, semitendinosus, semimembranosus.
• The Sciatic Nerve: splits into the common peroneal nerve and tibial nerve.
  • Common Peroneal Nerve: wraps around fibula, affects side/front of lower leg.
  • Tibial Nerve: stretches to the bottom of the foot.

Cause of Symptoms

• Pressure on the sciatic nerve leads to a "traffic jam" of nerve signals.
• Pressure can also limit blood supply, affecting nerve function.
• Results in numbness and tingling due to nerve signal shutdown.

Relief and Recovery

• Removing pressure allows nerve to "reboot."
• As blood supply and nerve function restore, rapid signal transmission occurs.
• This causes the sensation of pins and needles as nerve signals return.
  • Feels like standing on tacks (painful and dramatic sensations).

Long-Term Considerations

• Extended pressure can cause lasting damage.
• Individuals like wheelchair users may be vulnerable to prolonged pressure.

Conclusion

• Pins and needles are essentially the nerves "rebooting."
• Normal condition if transient, but prolonged pressure should be avoided to prevent damage.