Final answer:
Spinal anesthesia uses the L3-L4 interspace as the landmark for injection.
Step-by-step explanation:
Spinal anesthesia is a regional anesthesia technique that involves injecting an anesthetic agent into the subarachnoid space to numb the spinal cord and surrounding nerves, resulting in loss of sensation and motor function in the lower half of the body. The landmark used for spinal anesthesia is called the 'L3-L4 interspace', which refers to the space between the third and fourth lumbar vertebrae.
When performing a spinal anesthesia procedure, a healthcare professional will typically identify the appropriate landmark by palpating the bony prominences along the spine and locating the L3 and L4 vertebrae. Once the landmark is identified, a small needle is inserted into the subarachnoid space to deliver the anesthesia.
It is important for the healthcare professional to accurately locate the L3-L4 interspace during spinal anesthesia to ensure the anesthesia is delivered to the correct area, resulting in effective pain relief and anesthesia for the patient.