France and the United Kingdom agreed to support Poland and in August of 1939, German troops began to gather on the Polish border. By September 1st, Germany launched an invasion of Poland.
The brachial plexus is a network of nerves that originate in the neck region and branch off to form most of the other nerves that control movement and sensation in the upper limbs, including the shoulder, arm, forearm, and hand.
The sacral plexus is a network of nerve fibres that supplies the skin and muscles of the pelvis and lower limb. It is located on the surface of the posterior pelvic wall, anterior to the piriformis muscle.