Anatomy-Spinal Cord Lesions Flashcards
How does the sensory information transmitted by the sensory nerves shown below differ?
Blue: Posterior column transmits discriminative touch, vibration and conscious proprioception. Green: ALSTT transmits pain, temperature and light touch sensation.
What is the pathogenesis of fasciculations in lower motor neuron lesions?
The lower motor neurons are sick but not dead yet and cause muscle to randomly contract
Symptoms to remember for Horner’s syndrome.
Pseudoptosis, Redness, Enopthalmus, Miosis, Dryness
How do sympathetic fibers get from the spinal cord to their site of innervation in the head?
Preganglionic fibers come out T1-T4 -> Synapse in cervical ganglion -> Postganglionic fibers hop on blood vessels and travel to the organ they innervate.
There’s this guy that lives in your apartment complex that has to stop every few steps and look around to see where he is at. He has a wide gait and looks down as he walks. What region of his spinal cord may have a lesion on it? What clinical test would you do if you were examining him?
Posterior column. This region is responsible for conscious position sense. You would test him in clinic with the Rhomberg sign.
Your neighbor falls off his horse and injures his spinal cord. How will clinical signs of his injury progress from the initial accident?
First days: spinal shock (temporary cessation of neural activity below lesion) -> Days to weeks: Babinski sign -> Months: hyperactive DTRs, incontinence, ED.
A patient comes to see you 2 months after a car accident. He complains of muscle spasms, clumsiness and loss of coordination on the right lower extremity. Specifically he complains of inability to extend his right leg, muscle weakness in his right quadricep and loss of pain sensation in both quadriceps. Physical exam reveals loss of two point discrimination on the right side, loss of pain sensation on the left side and right sided + Babinski sign.
This patient has a spinal cord hemisection in the right L2,L3,L4 region (Brow-Sequard Syndrome). Lesion of the alpha motor neuron in the section accounts for ipsilateral paralysis of his quadriceps. Lesion of the lateral corticospinal tract accounts for ipsilateral muscle spasms and + Babinski. Lesion of the ALSTT accounts for loss contralateral pain sensation. Lesion of the AWC accounts for loss of bilateral pain sensation at the level of the lesion. Lesion of the posterior column accounts for ipsilateral clumsiness, ataxia and loss to two-point discrimination.
A 27 year old woman comes to see you complaining of decreased lower extremity coordination. Physical exam reveals an ataxic gait, loss of 2-pt tactile discrimination, + Babinski sign and + Romberg sign. History reveals that she is vegan. What is the most likely cause of her condition?
Vitamin B12 is needed for conversion of fatty acids into myelin and needs to be supplemented in a vegan diet. The long axons of fasciculus gracilis and the LCST will be affected first and present with these symptoms. Since the lower extremity neurons are longest they are often affected first.
A 27 year old woman comes to see you complaining of decreased lower extremity coordination. Physical exam reveals an ataxic gait, loss of 2-pt tactile discrimination, + and + Romberg sign. History reveals that she has had syphilis since high school. What is your diagnosis? What sensory signals might this patient present with?
Tabes dorsalis. This posterior column lesion is secondary to syphilis. Other symptoms may include loss of myotatic reflexes due to damage to the reflex arc and loss of pain sensation because of damage to zone of Lissauer.
A 30 year old man comes to see you in clinic. He complains of bilateral pain and temperature loss in his upper arms. Imaging of his spinal cord is shown below. What could cause this condition and how could it progress?
This is syringomyelia (a fluid-filled expansion of the central canal). This is associated with Chiari malformation, traum, tumors and meningitis. The cavity can expand and start hitting alpha motor neurons, the intermediolateral cell column and the posterior column.
A 38 year old man comes to see you after getting in a car accident. He has pain radiating down his leg initially and you think it’s because he herniated a disc during the accident. One day later he has spinal shock from his waist down. A few days later he develops a + Babinski sign and bilateral loss of pain and thermal sensation from the waist down. Physical exam reveals maintained two point discrimination. What is your diagnosis?
This patient has anterior spinal artery syndrome. This is often caused by blockade of a radicular artery that supplies the anterior spinal artery segments, killing the anterior 2/3 of the spinal cord that it supplies. This will cause damage to the LCST, ALSTT and alpha motor neurons.
