Astanga Hrudaya
दीर्घाच्छिद्राङ्गुलि महत्पाणिपादं प्रतिष्ठितम्। गूढवंशं बृहत्पृष्ठं, निगूढाः सन्धयो दृढाः॥११३॥
the fingers should be long and separate. The hands and feet should be big; the back should have the vertebral column concealed and big, the joints should be deep and firm.
english translation