Need Certificate chain (on the incoming interface) from Nginx

Hi,

I am using a setup wherein a chain certificate(Root CA Cert-> Intermediate CA Cert -> Client Cert) is being sent to the Nginx. I need to configure Nginx in such a way that it forwards the entire certificate chain to the middleware. Right now, it is just sending the leaf certificate i.e. client certificate. I found the following options from the Nginx's documentation (http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_client_certificate)
1- $ssl_client_escaped_cert
2- $ssl_client_cert

None of the above returns the full certificate chain. Is anyone aware if there is such an option available ?