Problem 29 - Anatomy and Physiology of Animals

Question

The tibia ________. a. has an expanded distal end called the lateral malleolus b. is not a weight-bearing bone C. is firmly anchored to the fibula by an interosseous membrane d. can be palpated (felt) under the skin only at its proximal and distal ends

Step-by-Step Solution

Answer

The correct answer is c: the tibia is firmly anchored to the fibula by an interosseous membrane.

Step 1: Understanding the Question

We need to identify which statement accurately describes the tibia, a bone located in the lower leg.

Step 2: Option Analysis for Statement a

Statement a claims that the tibia has an expanded distal end called the lateral malleolus. This is incorrect because the lateral malleolus is a feature of the fibula, not the tibia.

Step 3: Option Analysis for Statement b

Statement b states that the tibia is not a weight-bearing bone. This is incorrect because the tibia is a major weight-bearing bone in the lower leg.

Step 4: Option Analysis for Statement c

Statement c mentions that the tibia is firmly anchored to the fibula by an interosseous membrane. This is true; the interosseous membrane connects these two bones along the length of the lower leg.

Step 5: Option Analysis for Statement d

Statement d suggests that the tibia can be palpated (felt) under the skin only at its proximal and distal ends. This is incorrect since the shaft of the tibia is also palpable throughout its length.

Step 6: Conclusion

The correct statement is option c, which accurately describes the relationship between the tibia and fibula.

Key Concepts

lower leg bones

The human leg is composed of two primary bones: the tibia and the fibula. These bones are located in the region below the knee and above the ankle. The tibia, often known as the shinbone, is larger and stronger compared to the fibula.
It plays a crucial role in bearing most of the body's weight. Locating beside the tibia, the fibula is slender and helps stabilize the lower leg.

• Tibia (shinbone): thick, strong, and weight-bearing.
• Fibula: slender, assists in lower leg stability.

These bones work harmoniously, allowing movements and providing support for physical activities.

interosseous membrane

The interosseous membrane is a fibrous sheet that connects the tibia and fibula along their lengths. Acting like a strong ligament, it maintains the correct spacing between these two bones.
This membrane is essential for leg stability and supports the whole lower leg's structural integrity. Additionally, it serves as an attachment point for muscles in the lower leg, allowing for efficient locomotion.

• Stabilization: Keeps tibia and fibula in position.
• Muscle Attachment: Provides a site for muscles to attach.

This membrane adds to the functional capacity of the leg during everyday activities.

fibula

The fibula is the slender bone located on the outer side of the lower leg. Despite not being a primary weight-bearing bone, it plays an essential role in stabilizing the leg and ankle.
It runs parallel to the tibia and assists in balancing the body by working with the tibia and attached muscles.
The fibula's distal end forms the lateral malleolus, an important feature that forms part of the ankle joint.

• Position: Parallel to tibia, on outer leg side.
• Key Features: Lateral malleolus, contributes to ankle structure.

Overall, the fibula contributes to both balance and flexibility.

weight-bearing bone

In the lower leg, the tibia is the primary weight-bearing bone. Unlike the fibula, it bears the majority of the body's weight. This bone is robust and suited for such a crucial load-bearing role.
The tibia supports the leg during activities like walking, running, and jumping. Because of its strength and size, it provides a sturdy platform for the body's weight.

• Tibia Role: Main bone that bears weight.
• Activity Support: Vital in movements and load transfer.

The tibia's ability to withstand the body’s mass makes it essential for mobility and balance.