I had to do a bit of research on this one. 

Trichorrhexis nodosa is a disorder of the hair shaft.  The hair is very fragile and breaks, leaving short, stubbly broken ens and patches of partial baldness.  It may affect small patches of the scalp or the entire head.

Apparently there are 2 different forms of Trichnorrhexis nodosa, one that is inherited, the other that is not.  The inherited form usually includes tooth and nail deformities as well.

The acquired form of trichorrhexis nodosa comes ini two types: one where the hair shaft breaks close to the scalp, the other where the hair breaks further out.  Cornrows, braiding,tight headwear, straightening and harsh brushing will compound this disorder.

Cream rinses, protein conditioners and gentle handling of the hair is recommended.  Limiting the frequency of shampooing is also suggested.