I\'d like to ask you a few questions based on your answers.
Q. Characteristic feature of dichorionic twin
1. Two placentae on USG (T)
2. Two fetuses of discordant gender (F: two fetuses of same gender do not always rule out dichorionic twin)
3. Visualization of the lambda sign on USG (F: absence of the sign does not always confirm monochorionicity)
Am I understanding your answer correctly?
Thank you in advance.
John
Posted by John N.
Dear Dr Paul,
I guess you will understand what I\'m confused with.
1. Two placentae on USG (T) Correct
YES. This is \"a feature without which the diagnosis is in question\" as you mentioned earlier.
2. Two fetuses of discordant gender (F: two fetuses of same gender do not always rule out dichorionic twin) T - You have not been asked about features which RULE OUT but about characteristic features - that is, features that \'RULE IN\' - take ther question at face value.
Before I asked you the original question, I thought so - RULE IN. After reading the answers, I thought I was a little bit wrong.
You taught me that it is \"a feature without which the diagnosis is in question\". DO WE THINK THE DIAGNOSIS OF DICHORIONIC TWIN IS IN QUESTION ONLY BECAUSE THE FETUSES SHOW SAME GENDER? (\"without the feature\")? This is why I wrote \"F: two fetuses of SAME gender do not always rule out dichorionic twin\" in the previous post.
And you also wrote that \"a characteristic feature of a condition is a feature which is almost always (one can never say always) present / associated with that condition and is a distinguishing feature of the condition\". YES, I AGREE WITH THIS COMMENT THOU. \'DISCORDANT GENDER\' ALMOST ALWAYS PRESENT / ASSOCIATED WITH DICHORIONIC TWIN.
Am I understanding your first comment wrongly?
And is my understanding of your second comment right?
3. Visualization of the lambda sign on USG (F: absence of the sign does not always confirm monochorionicity)
It is easy to get an answer T if I adopt your second comment: it is almost always present WITH the dichorionic twin (now I know that this is totally different from \'present IN\'-am I right?). Yet, I AM WONDERING WHETHER IT IS A FEATURE WITHOUT WHICH THE DIAGNOSIS IS IN QUESTION. Do we questionise the diagnosis only becasue there is no lambda sign?
Dr Paul, don\'t get me wrong. I always thank you for your guidance and help. Maybe I\'m so loyal to your comment that I try to digest every bit of it.
Please correct my understanding. I think this is more important to read one chapter of the book.
Thank you very much.
Best reagrds,
John
Posted by John N.
Dear Dr Paul,
I think I realise what was wrong with my understanding. Thank you very much for your analysis. I really appreciate it.
For the next few days, I will try to solve some questions and see how it goes. Hope you won\'t mind if I ask you once more if I happen to meet some other obstacles.
BTW, can you give me the answers for the original questions? I thought they were T and T.
Thank you always.
John
Posted by John N.
Dear Dr Paul,
Thanks for correction.
Will try harder.
