**Question:** Standard site for primary bone graft - a) Pelvis, b) Greater trochanter, c) Medial malleolus, d) Lateral malleolus, e) Fibula

**Core Concept:** The standard sites for primary bone grafting refer to the preferred locations for obtaining autologous bone grafts, which involve using a portion of the patient's own bone tissue. These sites are commonly used due to their rich blood supply, which ensures survival and integration of the graft into the recipient site.

**Why the Correct Answer is Right:** The correct answer is **c) Medial malleolus** because it is a reliable source of bone graft and provides adequate bone mass for filling defects or augmenting existing bone. The medial malleolus is the triangular bony prominence on the inside of the ankle joint. It has a rich blood supply, making it an ideal site for bone grafting.

**Why Each Wrong Option is Incorrect:**

A) Pelvis (a) Pelvis refers to the pelvic bones, which are not specific enough for a single answer and may not always yield sufficient bone mass.

B) Greater trochanter (b) The greater trochanter is part of the hip bone, making it unsuitable for an ankle graft.

D) Lateral malleolus (d) The lateral malleolus is located on the outside of the ankle joint, which has a poorer blood supply compared to the medial malleolus.

E) Fibula (e) The fibula is a tibial bone and is not a standard site for primary bone grafting as it lacks the rich blood supply of the medial malleolus.

**Clinical Pearl:** The choice of bone graft site depends on the specific clinical scenario and the surgeon's preference. However, for an ankle graft, the medial malleolus is the preferred site due to its rich blood supply and suitability for bone grafting.