S
saiyagirl
So, this is a questions I was subjected to on QBank today:
"A 65 year old man presents with a history of headache and difficulty walking. He felt well the previous night, but woke up with a severe headache and was unable to move his right leg. Clinical exam reveals no higher cortical function deficit. The optic dics are sharp, and the pupils are equal and reactive. The direct and consensual light reflexes are normal, and testing of the cranial nerves reveal no deficits. The right leg is hypotonic, and the man is unable to move it. Deep tendon reflexes are absent, and an extensor plantar reflex cannot be elicited. The most likely cause for ths problem is loss of blood flow in the....."
Answer: left anterior cerebral artery.
I got the question right (the other choices were basically right/left anterior/middle/posterior), mainly because i knew to look for a contralateral lesion in a place that would affect motor to the legs. But I am confused as to why doesn't he have UMN signs (Babinski, hyperreflexia)? Isn't this a UMN lesion?
The official explanation says: "The medial aspect of the cerebral hemispheres is supplied by the anterior cerebral arteries. The small portion of primary motor cortex located here sends fibers to spinal cord segments innervating the lower libs. Since the CST tracts cross over to the opposite side in the medulla oblongata, the left cerebral hemisphere controls the right side of the boyd. Hence, paralysis of the right left results from loss of blood flow to the portion of the left hemisphere supplied by the left anterior cerebral artery."
"A 65 year old man presents with a history of headache and difficulty walking. He felt well the previous night, but woke up with a severe headache and was unable to move his right leg. Clinical exam reveals no higher cortical function deficit. The optic dics are sharp, and the pupils are equal and reactive. The direct and consensual light reflexes are normal, and testing of the cranial nerves reveal no deficits. The right leg is hypotonic, and the man is unable to move it. Deep tendon reflexes are absent, and an extensor plantar reflex cannot be elicited. The most likely cause for ths problem is loss of blood flow in the....."
Answer: left anterior cerebral artery.
I got the question right (the other choices were basically right/left anterior/middle/posterior), mainly because i knew to look for a contralateral lesion in a place that would affect motor to the legs. But I am confused as to why doesn't he have UMN signs (Babinski, hyperreflexia)? Isn't this a UMN lesion?
The official explanation says: "The medial aspect of the cerebral hemispheres is supplied by the anterior cerebral arteries. The small portion of primary motor cortex located here sends fibers to spinal cord segments innervating the lower libs. Since the CST tracts cross over to the opposite side in the medulla oblongata, the left cerebral hemisphere controls the right side of the boyd. Hence, paralysis of the right left results from loss of blood flow to the portion of the left hemisphere supplied by the left anterior cerebral artery."
