"inward citations" is a slightly unusual term and I think they are probably referring to forward and backward citations here.

Here are some definitions in English:
the number of citations in subsequent patents (forward citations)
the number of existing patents cited in the application (backward citations)
http://www.dime-eu.org/files/active/0/SC-session4A-Cremers-L...

Take US 4,980,355, “Compositions for protecting plants against disease,” as an example, which has 16 FamPat family members. A search in MicroPatent, a service without family-based citation search features, revealed that individually, US 4,980,335 had cited 4 documents (backward citations), and has subsequently appeared as a cited document by 8 additional patent references (forward citations), for 12 total citations.
http://www.intellogist.com/wiki/Report:QPAT/Viewing_Results/...

The following links show the terminology used in the esp@cenet database
Caractéristiques
- accès à plus de 60 millions de documents brevet du monde
entier
- données datant de 1836 à aujourd’hui
- informations relatives à la situation juridique (cf. p. 17)
- informations relatives aux familles de brevets (cf. p. 17)
- documents citants et documents cités.
http://documents.epo.org/projects/babylon/eponet.nsf/0/7265b...$file/products_services_fr.pdf
Features
- access to more than 60 million patent
documents from all over the world
- data from 1836 to today
- legal status information (see page 17)
- patent family information (see page 17)
- forward and backward citations.
http://documents.epo.org/projects/babylon/eponet.nsf/0/7265b...$file/products_services_en.pdf

--------------------------------------------------
Note added at 51 mins (2010-06-11 09:42:04 GMT)
--------------------------------------------------

To view the esp@cenet links, you need to click on the appropriate pdf link in the "attachments" column.