Tibia Anatomy

Tibia Overview

• The tibia is the main bone of the lower leg, forming the shin, and is the second largest bone in the body.
• It is a key weight-bearing structure that expands at its proximal and distal ends and articulates at the knee and ankle joints respectively.

Proximal Tibia

• The proximal tibia is widened by medial and lateral condyles, which aid in weight-bearing.
• The condyles form a flat surface known as the tibial plateau.
• The condyles articulate with the femoral condyles to form the key articulation of the knee joint.
• Located between the condyles is the intercondylar eminence, which projects upwards on either side as medial and lateral intercondylar tubercles.
• The intercondylar tubercles are the main site of attachment for ligaments and menisci of the knee joint.
• The intercondylar tubercles of the tibia articulate with the intercondylar fossa of the femur.

Shaft of Tibia

• The shaft of the tibia is prism-shaped with three borders and three surfaces: anterior, posterior, and lateral.
• The anterior border of the shaft of the tibia is palpable subcutaneously down the anterior surface of the leg as a shin.
• The proximal aspect of the anterior border is marked by the tibial tuberosity, which is the attachment site for the patella ligament.
• The posterior surface of the shaft of the tibia is marked by the soleal line, which is the site of origin for part of the soleus muscle.
• The soleal line extends inferomedially and eventually blends with the medial border of the tibia.
• There is usually a nutrient artery proximal to the soleal line.
• The lateral border (interosseous border) of the shaft of the tibia gives attachment to the interosseous membrane that binds the tibia and fibula together.

Distal End of Tibia

• The distal end of the tibia widens to assist with weight-bearing.
• The medial malleolus is a bony projection continuing inferiorly on the medial aspect of the tibia and articulates with the tarsal bones to form part of the ankle joint.
• On the posterior surface of the tibia, there is a groove through which the tendon of the tibialis posterior passes.
• Laterally is the fibular notch, where the fibula is bound to the tibia forming the tibiofibular joint.