Final answer:
When inserting a needle at the patella, you would sequentially pass through the skin, subcutaneous tissue, patellar ligament, and finally the patella itself, which serves to protect the quadriceps tendon and increase muscle leverage.
Step-by-step explanation:
If you were to insert a needle through the skin at the patella, the structures you would hit, in order, would be the skin, subcutaneous tissue, the patellar ligament, and then the patella itself before reaching the underlying structures like the femur. The patella is the largest sesamoid bone and is incorporated into the tendon of the quadriceps femoris muscle.
It is important as it protects the muscle tendon from friction against the distal femur by creating a smoother surface for the tendon to slide over when the knee joint is in motion. Additionally, the patella increases the leverage of the quadriceps femoris muscle, which is essential for leg extension at the knee joint.