Final answer:
The 'winging' of the scapula in the motorcycle accident scenario suggests damage to the long thoracic nerve. A hemisection of the thoracic spinal cord would result in Brown-Séquard syndrome, causing loss of proprioception and light touch on the same side as the injury, and loss of pain and temperature sensation below the injury on the opposite side.
Step-by-step explanation:
The motorcycle accident described involves a situation where the patient has landed on the right lateral side of the rib cage, resulting in a winging scapula. The scapula winging is a sign of damage to the long thoracic nerve, which innervates the serratus anterior muscle. This muscle is responsible for holding the scapula against the thoracic wall, and its paralysis would cause the medial border of the scapula to protrude posteriorly, known as a winged scapula.
Concerning the second scenario, that of a spinal cord hemisection, this type of injury to the thoracic region would likely result in a sensory deficit pattern known as Brown-Séquard syndrome. This would mean that the side of the body that has lost motor function (the right leg, in this case) would also experience loss of proprioception and light touch sensation due to damage to the dorsal columns on the same side as the injury. However, the patient would experience loss of pain and temperature sensation on the opposite side of the body, below the level of the injury, due to the crossing fibers of the spinothalamic tract.