these two bones are connected at the ends of the discontinuity by a joint and separate in the middle allowing nerves and veins to pass between them. the medial of these two bones is large which is actually the shin and is called the greater tibia. the medial and lateral ulna are small and thick at the bottom to allow the joint between the shin and the foot to be smooth and its top is very thin not reaching the knee and is called the lesser tibia. the lateral ulna and the thin part of the shin in its front that is bare of flesh are called the dorsum of the shin and the two parts on its side at its bottom which are the ends of the shins are called the elbow and the wrist in resemblance to the wrist joint of the hand. for this reason the two shins are also called the ulnae.
وهذان العظمان يتصلان عند طرفي المنقطع بمفصل موثق وينفرجان عند الوسط فيدخل فيما بينهما عصب وعروق. والأنسي من هذين العظمين عظيم هو الساق بالحقيقة ويسمى القصبة الكبرى، والزند الأنسي والوحشي منهما صغير غليظ الأسفل ليجود معه مفصل الساق مع القدم، وأعلاه دقيق جدا لا يصل إلى الركبة، وتسمى القصبة الصغرى. والزند الوحشي، والموضع الدقيق من الساق في مقدمه العاري من اللحم يسمى ظهر الساق، والموضعان اللذان من جانبه في أسفله، وهما طرفا القصبتين يسميان الكوع والكرسوع تشبيها لهما بمفصل الرسغ من اليد، ولذلك أيضا تسمى القصبتان بالزندين.