The applications of wireless sensor network (WSN) exhibits a significant rise in recent days since it is enveloped with various advantageous benefits. In the medical field, the emergence of WSN has created marvelous changes in monitoring the health conditions of the patients and so it is attracted by doctors and physicians. WSN assists in providing health care services without any delay and so it plays predominant role in saving the life of human. The data of different persons, time, places and networks have been linked with certain devices, which are collectively known as Internet of Things (IOT); it is regarded as the essential requirement of people in recent days. In the health care monitoring system, IOT plays a magnificent role, which has produced the real time monitoring of patient's condition. However the medical data transmission is accomplished quickly with high security by the routing and key management. When the data from the digital record system (cloud) is accessed by the patients or doctors, the medical data is transferred quickly through WSN by performing routing. The Probabilistic Neural Network (PNN) is utilized, which authenticates the shortest path to reach the destination and its performance is identified by comparing it with the Dynamic Source Routing (DSR) protocol and Energy aware and Stable Routing (ESR) protocol. While performing routing, the secured transmission is achieved by key management, for which the Diffie Hellman key exchange is utilized, which performs encryption and decryption to secure the medical data. This enables the quick and secured transmission of data from source to destination with improved throughput and delivery ratio.