E2: THE THORACIC WALL

• The thorax (or chest)

  is the region of the body between the neck and the abdomen.
• Thoracic cage


  The framework of the walls of the thorax, which is referred to as the thoracic cage.
• mediastinum


  The cavity of the thorax can be divided into a median partition,called the _______ and the laterally placed pleurae and lungs.
• visceral pleura


  The lungs are covered by a thin membrane called the ________, which passes from each lung at its root (i.e., where the main air passages and blood vessels enter)
• parietal pleura


  to the inner surface of the chest wall, where it is called the
• pleural cavities


  In this manner, two membranous sacs called the ___________ are formed, one on each side of the thorax, between the lungs and the thoracic walls.
• thoracic wall


  is covered on the outside by skin and by muscles attaching the shoulder girdle to the trunk. It is lined with parietal pleura. is formed posteriorly by the thoracic part of the vertebral column
• sternum


  lies in the midline of the anterior chest wall.
• -manubrium sterni-body of the sternum-xiphoid process

  sternum is a flat bone that can be divided into three parts:
• manubrium


  is the upper part of the sternum.
• body of the sternum


  articulates above with the manubrium at the manubriosternal joint
• xiphoid process


  articulates above with the manubrium at the manubriosternal joint and below with the __________ at the xiphisternal joint.
• sternal angle (angle of Louis)


  formed by the articulation of the manubrium with the body of the sternum
• transverse ridge


  lies at the level of the 2nd costal cartilage, the point from which all costal cartilages and ribs are counted.
• sternal angle


  lies opposite the intervertebral disc between the 4th and 5th thoracic vertebrae.
• xiphisternal joint


  lies opposite the body of the ninth thoracic vertebra.
• Sternum and Marrow Biopsy


  Since the sternum possesses red hematopoietic marrow throughout life, it is a common site for marrow biopsy
• Ribs


  There are 12 pairs of ribs, all of which are attached posteriorly to the thoracic vertebrae
• -True ribs-False ribs-Floating ribs


  The ribs are divided into three categories:
• True ribs


  upper seven pairs are attached anteriorly to the sternum by their costal cartilages.
• False ribs


  The 8th, 9th, and 10th pairs of ribs are attached anteriorly to each other and to the 7th rib by means of their costal cartilages and small synovial joints.
• Floating ribs


  The 11th and 12th pairs have no anterior attachment.
• Typical Rib


  is a long, twisted, flat bone having a rounded, smooth superior border and a sharp, thin inferior border
• costal groove

  inferior border overhangs and forms the costal groove, which accommodates the intercostal vessels and nerve.
• -head-neck-tubercle-shaft-angle


  A rib has a ?
• head


  has two facets for articulation with the numerically corresponding vertebral body and that of the vertebra immediately above
• neck


  is a constricted portion situated between the head and the tubercle
• Tubercle


  is a prominence on the outer surface of the rib at the junction of the neck with the shaft.It has a facet for articulation with the transverse process of the numerically corresponding vertebra
• shaft


  is thin and flattened and twisted on its long axis.Its inferior border has the costal groove.
• angle


  is where the shaft of the rib bends sharply forward.
• Atypical Rib


  1st rib is important clinically because of its close relationship to the lower nerves of the brachial plexus and-main vessels to the arm, namely, the subclavian artery and vein
• Rib excision


  is commonly performed by thoracic surgeons wishing to gain entrance to the thoracic cavity.
• Costal Cartilages


  are bars of cartilage connecting the upper seven ribs to the lateral edge of the sternum and the 8th, 9th, and 10th ribs to the cartilage immediately above.
• -manubriosternal joint-xiphisternal joint

  Joints of the Chest WallWhat are the Joints of the Sternum
• manubriosternal joint


  is a cartilaginous joint between the manubrium and the body of the sternum
• xiphisternal joint

  is a cartilaginous joint between the xiphoid process (cartilage) and the body of the sternum.
• xiphoid process


  usually fuses with the body of the sternum during middle age.
• synovial joint


  Joints of the RibsWhat are the Joints of the Heads of the Ribs
• synovial joint


  The 1st rib and the three lowest ribs have a single synovial joint with their corresponding vertebral body
• tubercle of a rib

  Joints of the RibsWhat are the Joints of the Tubercles of the Ribs