Final answer:
Firstly, establish and maintain an open airway for the unconscious athlete with a suspected cervical spine injury. Proceed with emergency protocols without moving the athlete, as movement could worsen injuries.
Step-by-step explanation:
When providing a primary emergency care to an unconscious athlete with a suspected cervical spine injury, the first action that should be taken is to establish and maintain an open airway. This is critical as securing the airway is a top priority in emergency situations to ensure that the athlete can breathe. Once an open airway is ensured, further steps should include calling for emergency medical help, keeping the person very still, and preventing the head and neck from moving by placing heavy towels on both sides of the neck or holding the head and neck securely. Applying a rigid cervical collar or assessing heart rate via the carotid pulse are also important, but after the airway has been secured.
Additional care like treating the athlete for shock by elevating the lower extremity and applying a rigid cervical collar should only be done if trained to do so, and if it doesn't compromise the spine's stability. Remember, it's crucial not to move the injured person as this may lead to permanent paralysis or other serious complications. Basic first aid such as stopping any bleeding should be performed without moving the head or neck.