AIIMS 2005 Biology Human Skeletal System MCQ Question

To address the question regarding the incorrectly labeled bones of the left human hindlimb, we need to understand the anatomy of the hindlimb and the specific bones involved. The key bones are the femur, tibia, fibula, tarsals, and phalanges, each playing a significant role in locomotion and movement.

Explanation of the Correct Answer: C) Fibula and Phalanges

In the context of human anatomy, the fibula is the smaller bone located on the lateral side of the tibia in the lower leg. It does not bear weight but provides stability to the ankle and supports muscles of the lower leg.

The phalanges are the bones of the toes. Each toe consists of three phalanges (proximal, middle, and distal) except for the big toe, which has only two (proximal and distal).

If the diagram incorrectly labels the fibula as a phalanx or vice versa, it represents a fundamental mistake because:

1. Location and Function: The fibula is part of the leg structure, while phalanges are part of the toe structure. Confusing these two would lead to misunderstandings about their roles in movement—where the fibula supports the leg and the phalanges facilitate toe movement.

2. Anatomical Structure: In a correctly labeled diagram, we should clearly distinguish the fibula from the phalanges due to their distinct functions and locations in the skeletal system.

Clarification of Other Options

A) Tibia and Tarsals

• The tibia is the larger bone of the lower leg and supports the majority of the body's weight, while the tarsals are a group of seven bones in the foot that help form the ankle and contribute to foot structure. These bones are correctly labeled in their respective positions, so this option is incorrect.

B) Femur and Fibula

• The femur is the thigh bone, the longest bone in the human body, which supports the upper leg. The fibula, as mentioned earlier, is located below the femur in the lower leg. These two bones are distinct and cannot be confused in a correctly labeled diagram, making this option incorrect.

D) Tarsals and Femur

• The tarsals are located in the foot, while the femur is in the thigh. The anatomical locations of these bones are vastly different, and thus they cannot be mistaken for one another. This option is also incorrect.

Summary

To summarize, the correct answer to the question is C) Fibula and Phalanges because these two bones are not only located in different regions of the hindlimb but also serve different functions essential for movement and support. Mislabeling these would indicate a misunderstanding of human skeletal anatomy.

Understanding the human skeleton's anatomy is crucial for fields related to biology and health sciences, especially since it affects locomotion and movement dynamics. Thus, clear knowledge of each bone's position and function is essential for any further studies in zoology or human biology.