The tibia is expanded at the lower end and offers a bearing surface to which bone?

Appeared in: BSF Staff Nurse - 2015

Explanation

The lower (distal) end of the tibia is expanded to form the tibial plafond, which serves as the primary weight-bearing surface of the ankle.
This surface directly articulates with the superior trochlear surface of the talus bone.
This articulation, known as the tibiotalar joint, is the main component of the ankle joint responsible for transferring the body's weight from the leg to the foot.

Option A: The calcaneus (heel bone) is located inferior to the talus and does not directly articulate with the tibia's weight-bearing surface.
Option B: The femur articulates with the upper (proximal) end of the tibia to form the knee joint, not with the lower (distal) end at the ankle.
Option D: The fibula runs parallel to the tibia and forms the lateral malleolus. It articulates with the side of the talus to provide stability but is not the primary weight-bearing surface the tibia rests on.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the lower limb and ankle joint as background academic context rather than a clinical decision trigger.
Understanding this anatomy is crucial for assessing ankle injuries. The tibiotalar joint is the most frequently injured joint in the body, and nurses are often the first to assess these injuries.
A key nursing assessment for ankle injuries is checking the ability to bear weight, which directly tests the integrity of the tibiotalar joint.
What if? If a patient has a severe ankle fracture involving displacement of the talus from under the tibia (a fracture-dislocation), it is a surgical emergency. The nursing priority shifts from simple RICE (Rest, Ice, Compression, Elevation) to immediate immobilization, neurovascular checks, and preparing the patient for urgent surgical intervention to prevent long-term damage like avascular necrosis of the talus.

How to Approach the Question

First, identify the key terms in the question: 'tibia', 'lower end', and 'bearing surface'. This directs you to the anatomy of the ankle.
Visualize or recall the bones of the lower leg and foot. The tibia is the large shin bone, and its lower end forms the ankle.
Consider the function 'bearing surface'. This means you are looking for the bone that the tibia sits on to transfer weight.
Evaluate the options: The Femur is at the knee (eliminate). The Calcaneus is the heel bone, below the ankle joint's main articulation (eliminate). The Fibula is lateral and for stability, not primary weight-bearing (eliminate).
This leaves the Talus, which fits the description as the bone situated directly under the tibia to receive the body's weight.

Concept Tested & Keywords

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E6 Anatomy BDChaurasia V2 10e Part 1 pp. 55-57, 48-50

Practise the full BSF Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.