The tibia is the main bone of the lower leg, forming what is more commonly known as the shin.
It expands at its proximal and distal ends; articulating at the knee and ankle joints respectively. The tibia is the second largest bone in the body and it is a key weight-bearing structure.
In this article, we shall look at anatomy of the tibia – its bony landmarks, articulations and clinical correlations.
By Anatomography [CC-BY-SA-2.1-jp], via Wikimedia Commons
Fig 1 – Overview of the tibia in the human skeleton
Proximal
The proximal tibia is widened by the medial and lateral condyles, which aid in weight-bearing. The condyles form a flat surface, known as the tibial plateau. This structure articulates with the femoral condyles to form the key articulation of the knee joint.
Located between the condyles is a region called the intercondylar eminence – this projects upwards on either side as the medial and lateral intercondylar tubercles. This area is the main site of attachment for the ligaments and the menisci of the knee joint. The intercondylar tubercles of the tibia articulate with the intercondylar fossa of the femur.
By TeachMeSeries Ltd (2023)
Fig 2 – The tibial plateau. The tibial condyles articulate with the femoral condyles to form the knee joint.
Shaft
The shaft of the tibia is prism-shaped, with three borders and three surfaces; anterior, posterior and lateral. For brevity, only the anatomically and clinically important borders/surfaces are mentioned here.
- Anterior border – palpable subcutaneously down the anterior surface of the leg as the shin. The proximal aspect of the anterior border is marked by the tibial tuberosity; the attachment site for the patella ligament.
- Posterior surface – marked by a ridge of bone known as soleal line. This line is the site of origin for part of the soleus muscle, and extends inferomedially, eventually blending with the medial border of the tibia. There is usually a nutrient artery proximal to the soleal line.
- Lateral border – also known as the interosseous border. It gives attachment to the interosseous membrane that binds the tibia and the fibula together.
By TeachMeSeries Ltd (2023)
