Remember that the Lords of the various Limbs of the Panchaanga whenever happen to be Guru or Shukra then that limb is strong. Even otherwise if the Lord of any limb happen to have Sambandha with either of the two or both then also, it is said to protect that particular aspect of life.

RishiRahul and vivek.

Karana:
Karana means to do or to act. This is the Prithvi tatwa (solid or Earth element). This shows the actions required for manifesting a desire.
Karana is half a Tithi hence also called the child of the Tithi and is measured in the span of 6 degrees.  
There are 11 karans in all of which 7 are char (movable) and the rest four are Sthira (fixed) Karans.
The chara Karanas are so called because they repeat cyclically. They are:
1.Bava
2.Baalava
3.kaulava
4.Taitila
5.Gara (Some name it as Garija)
6.Vanija
7.Vishtthi  

The rulers of these Karanas are in the order of the weekday lords.

The First Karana (Bava) starts from the second half of  Shukla Paksha Prathami (second half of the first Tithi in the waxing phase of Chandra), followed by Baalava in the first half of Shukla Paksha Dwiteeya and so on till First half of  Krishna Paksha Chaturdashi (First half of  trhe fourteenth Tithi in the Waning phase of Chandra) which if you count properly you will get to Vistthi.

The Sthira Karanas are:
1.Shakuni, lorded by the Lord of the first Bhaava – the Lagna Lord.
2.Chatuspada, Lorded by the lord of the fourth Bhaava.
3.Naaga, lorded by the lord of the seventh Bhaava.
4.Kistughna, lorded by the lord of the tenth Bhaava of the Horoscope.

The first of the Sthira Karana Shakuni lords the second half of Krishna Paksha Chaturdashi.
Followed by Chatuspada in the First half of Amaavasya (First half of New Moon).
Followed by Naaga in the second half of  Amaavasya.
Followed by Kistughna in the first half of  Shukla Paksha Prathami.

After this the Chara Karanas repeat in the cyclical order starting from Bava Karana.
The Chara Karanas repeat eight times in the full Soli-lunar month.

RishiRahul and vivek.

The Graha Ruling the limb of Karana is Budha, Budha is the primary Kaaraka of the Tenth Bhaava (Karma Bhaava). This gives us a lead as to the use of the Karana.
The lord ruling the birth karana plays a very important role in the Karma Yoga of the Native.

In the example chart given in this lesson the child was born in taitila karan lorded by Budha.

RishiRahul and vivek.

Vishtthi karana is also called Bhadra and is considered inauspicious. Birth during Bhadra is said to cause a flaw (dosha).
Vishtthi Karana repeats eight times in a month.
Chandra placed in Kark, Simha, Kumbha or meena and Vishtthi Karana coinciding is not good.
Bhadra falling in the first half of a Tithi at night is auspicious.
For example First half of Pournima (full moon day) is Vishtthi Karana. Birth during night at this time is auspicious.
bhadra falling in the second half of a Tithi at Day is auspicious.
For example Shukla Paksha Chaturthi second half is Bhadra, if this falls in day time then the birth is auspicious.

Usually birth in Vishtthi Karana requires remedies to overcome the Dosha.

RishiRahul and vivek.

Dear Vivekji Rahulji

    What about the application part of the karanas. Visti karana is a bad karana is bad for child birth(also known as bhadra karana). What about the other karanas. How is the concept applied in charts.

regards