Anatomy clinical correlates: Spinal cord pathways

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A 56-year-old man presented to the emergency department for evaluation of chest pain radiating to the back. He was diagnosed with a type A aortic dissection and proceeded to the operating room for emergent open repair. Following the procedure, the patient is brought to the post-operative care unit for further monitoring. During the patient’s postoperative assessment, he reports thoracic back pain and an inability to move the bilateral lower extremities. The patient's temperature is 98.6.0 °C (37 C °F), pulse is 30/min, respirations are 24/min, blood pressure is 195/95 mmHg, and O2 saturation is 97% on room air.  Pinprick testing demonstrates bilateral loss of pain sensation below the xiphoid process. The patient has preserved proprioception, vibratory sense, fine touch, and two-point discrimination. Which of the following best describes the underlying etiology of this patient’s clinical presentation? 

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The spinal cord is made up of millions of neurons, whose axons and cell bodies are constantly transmitting information between our brain and the rest of our body.

In doing so, the spinal cord acts as an amazing information highway, allowing our brain and body to work together to interact with the world around us!

But what happens when this information highway is disrupted or damaged? Well, injury to the spinal cord leads to a variety of classic clinical conditions with predictable deficits which we will explore in this video, so let’s get to it!

Okay, before we move on to spinal cord injuries, let’s freshen up our knowledge of the spinal cord itself. Zooming in on a cross-section of the spinal cord, it’s made up of both grey and white matter.

Grey matter is found in the centre of the spinal cord and has two dorsal or posterior horns that contain sensory neuron cell bodies, and two ventral or anterior horns that contain motor neuron cell bodies.

Surrounding the grey matter is white matter, which consists of the axons of various neurons. They are organized into tracts that carry information to and from the brain.

There are four main sensory pathways ascending the spinal column. First, there’s the spinothalamic tract which is divided into two parts.

The lateral tract carries sensory information for pain and temperature, while the anterior tract carries information for crude touch and pressure.

Next, there are two dorsal column tracts: the fasciculus gracilis which carries sensory information from the lower trunk and legs, and the fasciculus cuneatus which carries sensory information from the upper trunk and arms.

These tracts both carry sensations such as two point discrimination, vibration, fine touch and proprioception. Then, there’ s the spinocerebellar tract which has an anterior and posterior part.

These are ascending pathways from the spinal cord to the cerebellum, and carry proprioceptive information from the body.

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