Complete transaction of the spinal cord at the C7 level produces all of the following effects except:
D i.e. Areflexia below level of lesion The diaphragm is innervated by two phrenic nerves that originate as branches of the cervical plexus in neck. This motor nerve to diaphragm arise from the anterior rami of cervical nerves C3, C4, C5Q, with major contribution coming from C4. So transection of spinal cord at C7 level is not going to stop respiration but due to involvement of thoracic intercostal muscles and abdominal muscles, there will be some weakness of respiratory effoQ. (i.e. limited respiratory effo) Complete Spinal Cord Injury Complete spinal cord transection (injury) is characterized by total absence of sensation and voluantry motor function caudal to the level of spinal cord injury in the absence of spinal shockQ Complete areflexia is found in spinal shockQ. Spinal shock occurs when the spinal cord fails temporarily following injury. Even pas of spinal cord with out structural damage do not function. It rarely lasts for more than 48 hours & during this period it is difficult to tell that lesion is complete or incomplete. Return of bulbocavernous reflex and anal wink (i.e. primitive reflexes) indicate, spinal shock has endedQ In the absence of sacral sparing (i.e. there is no sacral sensations) and with return of bulbocavernosus reflex (i.e. spinal shock is over which typically occurs with in 24 - 48 hours) the spinal cord injury is termed complete and there is viually no likelihood of functional spinal cord recovery. In other words return of bulbocavernosus reflex indicate that the spinal shock is over Q. And after spinal shock , intact sacral function may be the only sign of an at least paially functioning spinal cordQ. (i.e. incomplete neurological injury). In an acute setting any evidence of neurological functions. (sensory or motor) distal to the level of injury is significant and defines the lesion as being incomplete. Deep tendon reflexes above the level of complete spinal cord injury (i.e. biceps & brachioradialis) will be sparedQ; at the level of injury (triceps) will be absentQ and below the level of injury (quadriceps & tendoachilles) will be exaggeratedQ. Superficial reflexes above the level of injury are spared and at the level of injury and below the level of injury are absent.
Hypotension
Limited respiratory effo
Anaesthesia below the level of the lesion
Areflexia below the level of the lesion