The tibia is the key bone the the lower leg, creating what is much more commonly recognized as the shin.

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It broadens at that is proximal and also distal ends; articulating at the knee and ankle joints respectively. The tibia is the 2nd largest bone in the body and also it is a an essential weight-bearing structure.

In this article, us shall look in ~ anatomy the the tibia – the bony landmarks, articulations and clinical correlations.


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Fig 1 – synopsis of the tibia in the human being skeleton


Proximal

The proximal tibia is widened by the medial and also lateral condyles, which aid in weight-bearing. The condyles kind a level surface, recognized as the tibial plateau. This structure articulates with the femoral condyles to type the crucial articulation of the knee joint.

Located between the condyles is a region called the intercondylar eminence – this projects upwards on either side together the medial and lateral intercondylar tubercles. This area is the key site the attachment because that the ligaments and the menisci that the knee joint. The intercondylar tubercles that the tibia articulate through the intercondylar fossa of the femur.


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Fig 2 – The tibial plateau. The tibial condyles articulate with the femoral condyles to type the knee joint.


Shaft

The column of the tibia is prism-shaped, with three borders and also three surfaces; anterior, posterior and lateral. Because that brevity, only the anatomically and also clinically essential borders/surfaces are discussed here.

Anterior border – palpable subcutaneously under the anterior surface ar of the leg as the shin. The proximal element of the anterior border is marked by the tibial tuberosity; the attachment website for the patella ligament.Posterior surface – marked by a ridge of bone known as soleal line. This line is the website of beginning for part of the soleus muscle, and also extends inferomedially, eventually blending through the medial border of the tibia. There is typically a nutrient artery proximal to the soleal line.Lateral border – additionally known as the interosseous border. It gives attachment to the interosseous membrane that binds the tibia and the fibula together.
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Fig 3 – Bony landmarks of the tibial shaft.


Clinical relevance – Intraosseous Access

Intraosseous access is a type of vascular access used in the emergency setting. It enables the administration of fluids, blood products and medications directly into the bone marrow.

IO accessibility is generally used in one emergency when intravenous accessibility is no obtainable. There are two main sites in the tibia that are perfect for IO access:

Anteromedial surface, 2-3cm below the tibial tuberosityProximal come the medial malleolus

Complications that IO access include osteomyelitis, iatrogenic fracture and also compartment syndrome. IO infusions have to be discontinued once IV access has to be achieved.


Distal

The distal end of the tibia widens to help with weight-bearing.

The medial malleolus is a bony projection continuing inferiorly on the medial aspect of the tibia. The articulates with the tarsal skeleton to type part of the fishing eye joint. On the posterior surface of the tibia, there is a groove through which the tendon that tibialis posterior passes.

Laterally is the fibular notch, whereby the fibula is bound to the tibia – forming the distal tibiofibular joint.


Clinical Relevance: Fractures of the Tibia

Fractures that the tibia are reasonably common. There space two key types:

High energy trauma – occurs mainly in the younger population.Low energy trauma or insufficiency fractures – occurs predominantly in the elderly.

Fractures most generally occur at the obelisk of the tibia, and are typically associated with fibula fractures. Fractures of the proximal tibia are well-known as tibial plateau fractures; the condyles may be broken and also injury to the menisci and also ligaments that the knee is not uncommon. This fractures room classified using the Schatzker classification, and if very displaced will likely required operative management.

It is essential to monitor patients for indications of compartment syndrome in the pre-and post-operative phases.

At the ankle, the medial malleolus have the right to be fractured. This is resulted in by the ankle being twisted inwards (over-inversion) – the talus the the foot is forced against the medial malleolus, resulting in a spiral fracture. This hardly ever happens in isolation and typically the lateral malleolus is also fractured; potentially producing an turbulent fracture that requires operative management.

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Fig 4 – Fracture of the medial malleolus (black arrow) in a child, through the whiting arrowhead marking a normal expansion plate. This is a Salter Harris type III fracture.