كتاب الحيض
3  
The Book of Menstruation
(3)
Chapter: It is permissible for a menstruating woman to wash her husband’s head, and comb his hair; her leftovers are pure (tahir); and regarding reclining in her lap and reciting Qur’an
(3)
باب جَوَازِ غَسلِ الْحَائِضِ رَأْسَ زَوْجِهَا وَتَرْجِيلِهِ وَطَهَارَةِ سُؤْرِهَا وَالاِتِّكَاءِ فِي حِجْرِهَا وَقِرَاءَةِ الْقُرْآنِ فِيهِ
Sahih Muslim 297 d

'Urwa reported it from 'A'isha that she observed:

The Messenger of Allah (ﷺ) inclined his head towards me (from the mosque) while I was in my apartment and I combed it in a state of menstruation.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا أَبُو خَيْثَمَةَ، عَنْ هِشَامٍ، أَخْبَرَنَا عُرْوَةُ، عَنْ عَائِشَةَ، أَنَّهَا قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُدْنِي إِلَىَّ رَأْسَهُ وَأَنَا فِي حُجْرَتِي فَأُرَجِّلُ رَأْسَهُ وَأَنَا حَائِضٌ ‏.‏
Reference : Sahih Muslim 297d
In-book reference : Book 3, Hadith 9
USC-MSA web (English) reference : Book 3, Hadith 585
  (deprecated numbering scheme)