Problem 72 - Objective Biology for NEET

Question

The bone present on ventral midline of thorax is (a) Vertebral column (b) Ribs (c) Scapula (d) Sternum

Step-by-Step Solution

Answer

The bone present on the ventral midline of the thorax is the sternum.

Step 1: Define Terms

First, it's necessary to define each of the provided options to understand what each bone is and where it's located. The vertebral column is a series of small bones, called vertebrae, that forms the backbone and protects the spinal cord. Ribs are a set of long curved bones enclosing the chest cavity and forming the structure of the rib cage. The scapula, also known as the shoulder blade, is the bone that connects the humerus bone (bone of the upper arm or forelimb) with the clavicle bone (collar bone). The sternum, or breastbone, is a long, narrow flat plate that forms the center of the front of the rib cage and is connected to the ribs with cartilage.

Step 2: Determine the Correct Answer

Having defined each bone, the next step is to match these definitions with the location mentioned in the question, i.e., the ventral midline of the thorax. From the definitions, it can be deduced that the sternum is the bone that is found on the ventral midline of the thorax, which is the front center of the chest.

Step 3: Validate Your Answer

Upon analyzing the position and function of each bone, it is confirmed that the bone found on the ventral midline of the thorax is indeed the sternum. This is the bone that connects to the ribs via cartilage, forming the front part of the rib cage, and is located in the centerline of the body.

Key Concepts

Vertebral Column

The vertebral column, often referred to as the backbone or spinal column, is a vital structure that runs along the middle of the back. It is composed of a series of individual bones called vertebrae. Each vertebra is separated by intervertebral discs which act as cushions, providing flexibility and absorbing shocks.
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Here are some key functions and components of the vertebral column:

• It provides the main structural support for the body.
• Protects the spinal cord, which is a critical component of the central nervous system.
• Allows a range of movements through its flexibility, such as bending and twisting.

The vertebral column is segmented into different regions: cervical, thoracic, lumbar, sacrum, and coccyx. Each of these sections has a specific number of vertebrae and serves unique functions, such as supporting the head or providing a strong attachment point for muscles.

Ribs

The ribs are an essential component of the human skeletal system and play a major role in protecting the vital organs within the thoracic cavity, such as the heart and lungs. Humans typically have 12 pairs of ribs that enclose the chest and contribute to the rib cage structure.
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Here are important aspects of ribs:

• The ribs are semi-flexible and connected to the vertebral column at the back.
• They are curved and act as a shield for internal organs.
• Most of the ribs are connected to the sternum at the front through costal cartilages, allowing the rib cage to expand during breathing.

There are three types of ribs based on their attachment:

• True ribs, which are directly attached to the sternum.
• False ribs, which are indirectly attached to the sternum via cartilage.
• Floating ribs, which do not attach to the sternum at all.

Scapula

The scapula, or shoulder blade, is a flat bone located on the upper back and is an integral part of the shoulder girdle. It plays a crucial role in connecting the arm to the trunk and providing attachment for several muscles.
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Consider the following points about the scapula:

• It works with the clavicle to facilitate arm movements by forming the shoulder joint.
• The scapula is triangular in shape and provides a large surface area for muscle attachment.
• It has several important parts, including the glenoid cavity, which articulates with the humerus, and the acromion, which connects with the clavicle.

This bone enables a wide range of shoulder movements such as lifting and rotating the arms. Proper functioning of the scapula is essential for tasks that require arm and shoulder mobility.

Sternum

The sternum, known as the breastbone, is a long, flat bone located at the center front of the rib cage. It serves as a vital component for connecting the ribs through cartilage and forming the anterior section of the thoracic cavity.
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Here's why the sternum is important:

• It supports and protects major internal organs such as the heart and lungs.
• The sternum is divided into three parts: the manubrium, the body, and the xiphoid process, each with specific roles.
• Its position and connections allow flexibility, contributing to the respiratory function by allowing rib cage expansion during inhalation.
• Being central in the thoracic area, it provides a stable base for the attachment of several muscles.

The location of the sternum as the ventral midline of the thorax makes it a key reference point in medical examinations and procedures.