Thoracic Wall Anatomy

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Questions and Answers

What is the primary function of the thoracic wall?

To move air into and out of the lungs (correct)

To protect the spine

To support the shoulder girdle

To facilitate blood circulation

What is the name of the partition that separates the pleural cavities?

Diaphragm

Mediastinum (correct)

Visceral pleura

Parietal pleura

What is the main function of the mediastinum?

To protect the heart

To support the shoulder girdle

To facilitate breathing

To act as a conduit for structures passing through the thorax (correct)

What is the name of the muscle that plays a crucial role in inspiration?

Diaphragm Signup and view all the answers

What is the name of the cavity that surrounds the heart?

Pericardial cavity Signup and view all the answers

What is the purpose of the thoracic wall?

To provide protection to vital organs and facilitate breathing Signup and view all the answers

What is the name of the soft tissue that lines the thoracic wall?

Parietal pleura Signup and view all the answers

What is the function of the thoracoabdominal pump?

To pump blood and lymph through the body Signup and view all the answers

What is the name of the muscle that assists in the lifting of heavy weights?

Postvertebral muscle Signup and view all the answers

What is the name of the cavity that surrounds the lungs?

Pleural cavity Signup and view all the answers

Which part of the sternum articulates with the 1st costal cartilage and the upper part of the 2nd costal cartilage on each side?

Manubrium Signup and view all the answers

What is the function of the three layers of flat muscles in the lateral thoracic wall?

To provide support for the intercostal spaces Signup and view all the answers

How many thoracic vertebrae make up the posterior part of the thoracic wall?

12 Signup and view all the answers

What is the term for the notch in the midline of the superior surface of the manubrium?

Jugular notch Signup and view all the answers

What type of ribs are the 8th, 9th, and 10th ribs?

False ribs Signup and view all the answers

What is the term for the joint between the manubrium and the body of the sternum?

Manubriosternal joint Signup and view all the answers

What is the function of the ribs in the lateral thoracic wall?

To provide support for the intercostal spaces Signup and view all the answers

What is the term for the joint between the body of the sternum and the xiphoid process?

Xiphisternal joint Signup and view all the answers

What is the level of the sternal angle?

Opposite the 4th and 5th thoracic vertebrae Signup and view all the answers

What is the type of the 11th and 12th ribs?

Floating ribs Signup and view all the answers

What is the characteristic of the inferior border of a typical rib?

It is sharp and thin Signup and view all the answers

What is the function of the tubercle on a typical rib?

It has a facet for articulation with the transverse process of the corresponding vertebra Signup and view all the answers

What is the characteristic of the shaft of a typical rib?

It is thin and flattened, and twisted on its long axis Signup and view all the answers

What is the unique feature of the 1st rib?

It is the shortest and most sharply curved of the seven true ribs Signup and view all the answers

What is the attachment of the anterior scalene muscle?

To the 1st rib Signup and view all the answers

What is the characteristic of the vertebral body of a typical thoracic vertebra?

It is heart-shaped and roughly equal in dimensions Signup and view all the answers

What is the characteristic of the vertebral foramen of a typical thoracic vertebra?

It is circular and large Signup and view all the answers

What is the characteristic of the laminae of a typical thoracic vertebra?

They are broad and overlap with those of the vertebra below Signup and view all the answers

What is the direction of the grooves on the superior surface of the 1st rib?

Transverse Signup and view all the answers

Study Notes

Thoracic Wall (Skeletal Elements and Muscles)

The thoracic wall consists of skeletal elements (bones) and muscles.
The thoracic wall is covered on the outside by skin and muscles attaching the shoulder girdle to the trunk.

Skeletal Elements

The thoracic wall consists of:
- 12 thoracic vertebrae and their intervening intervertebral discs (posteriorly)
- 12 pairs of ribs (laterally)
- Sternum (anteriorly)

Sternum

The sternum is a flat bone divided into three parts:
- Manubrium of sternum
- Body of sternum
- Xiphoid process
The manubrium sterni articulates with the body of the sternum at the manubriosternal joint and with the clavicles and the 1st and 2nd costal cartilages.
The body of the sternum articulates with the xiphoid process at the xiphisternal joint and with the 2nd to 7th costal cartilages.
The xiphoid process is a thin plate of cartilage that becomes ossified at its proximal end during adult life.

Ribs

There are 12 pairs of ribs, divided into three categories:
- True ribs (1st - 7th)
- False ribs (8th, 9th, 10th)
- Floating ribs (11th and 12th)
A typical rib has a:
- Head
- Neck
- Tubercle
- Shaft
- Angle
The 1st rib is atypical, being close to the brachial plexus and the main vessels, and is small, flattened, and sharply curved.

Thoracic Vertebrae

A typical thoracic vertebra has a:
- Heart-shaped vertebral body
- Long spinous process
- Vertebral foramen (generally circular)
- Broad and overlapping laminae

Thoracic Cavity

The thoracic cavity is subdivided into three major compartments:
- Left and right pleural cavities, each surrounding a lung
- Mediastinum (a thick, flexible soft tissue partition)
The mediastinum contains the heart, esophagus, trachea, major nerves, and major systemic blood vessels.

Functions

The thoracic wall provides the machinery necessary for effective movement of air into and out of the lungs.
The thoracic wall protects vital organs.
The mediastinum acts as a conduit for structures that pass through the thorax from one body region to another.
The thoracic wall and diaphragm act as a muscle of inspiration, abdominal straining, weight-lifting, and thoracoabdominal pump (for blood and lymph).

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Description

This quiz covers the skeletal and muscular elements of the thoracic wall, including the thoracic cage, vertebral column, ribs, and diaphragm. Learn about the structure and function of the thoracic wall and its attachments.