Thoracic Wall

THORACIC CAGE : 

THORACIC CAGE Dr. Richard S. Hannah Emeritus Professor of Anatomy University of Calgary Professor of Anatomy American University of Antigua

Thoracic Cage : 

Thoracic Cage The thoracic cage is formed by the vertebral column behind, the ribs and intercostal spaces on either side and the sternum and costal cartilages in front. Above, it communicates through the 'thoracic inlet' with the root of the neck; below, it is separated from the abdominal cavity by the diaphragm

Thoracic Cage : 

Thoracic Cage The greater part of the thoracic cage is formed by the twelve pairs of ribs. The first seven are connected anteriorly by way of their costal cartilages to the sternum, the cartilages of the 8th, 9th and 10th articulate each with the cartilage of the rib above ('false ribs') and the last two ribs are free anteriorly ('floating ribs').

Thoracic Cage : 

Thoracic Cage The greater part of the thoracic cage is formed by the twelve pairs of ribs. The first seven ate connected anteriorly by way of their costal cartilages to the sternum, the cartilages of the 8th, 9th and 10th articulate each with the cartilage of the rib above ('false ribs') and the last two ribs are free anteriorly ('floating ribs').

Thoracic Vertebra : 

Thoracic Vertebra 39. Given a thoracic vertebra (or appropriate model), identify its parts.

Thoracic Vertebra : 

Thoracic Vertebra

OBJECTIVE : 

OBJECTIVE 40. In an appropriate dissection or a skeleton, identify or locate specific ribs and intercostal spaces, chondral cartilages, vertebrocostal and costo- and sternochondral joints and parts of the sternum.

Thoracic Cage : 

Thoracic Cage Each typical rib has a head bearing two articular facets, for articulation with the numerically corresponding vertebra and the vertebra above,

Thoracic Cage : 

Thoracic Cage A stout neck, which gives attachment to the costotransverse ligaments

Thoracic Cage : 

Thoracic Cage A tubercle with a rough non-articular portion and a smooth facet, for articulation with the transverse process of the corresponding vertebra.

Thoracic Cage : 

Thoracic Cage a long shaft flattened from side to side and divided into two parts by the 'angle' of the rib. The angle demarcates the lateral limit of attachment of the erector spinae muscle.

Vertebrocostal Joints : 

Vertebrocostal Joints

The Costal Cartilages : 

The Costal Cartilages These bars of hyaline cartilage serve to connect the upper seven ribs directly to the side of the sternum and the 8th, 9th and 10th ribs to the cartilage immediately above. The cartilages of the 11th and 12th ribs merely join the tapered extremities of these ribs and end in the abdominal musculature.

The Costal Cartilages : 

The Costal Cartilages Clinical features: The cartilage adds considerable resilience to the thoracic cage and protects the sternum and ribs from more frequent fracture. In old age (and sometimes also in young adults) the costal cartilages undergo progressive ossification; they then become radioopaque and may give rise to some confusion when examining a chest radiograph of an elderly patient.

STERNUM : 

STERNUM The manubrium is roughly triangular in outline and provides articulation for the clavicles and for the first and upper part of the 2nd costal cartilages on either side.

STERNUM : 

STERNUM Body of the Sternum This is composed of four parts or 'sternebrae' which fuse between puberty and 25 years of age. Its lateral border is notched to receive part of the 2nd and the 3rd to the 7th costal cartilage.

STERNUM : 

STERNUM The Xiphoid Process is the smallest part of the sternum and usually remains cartilaginous well into adult life.

Abnormalities : 

Abnormalities 32. Describe the more common variations in rib numbers, and the locations of supernumerary ribs and the structures which they may compress.

Thoracic Cage : 

Thoracic Cage A cervical rib occurs in 0.5 per cent of subjects and is bilateral in half of these. It is attached to the transverse process of the 7th cervical vertebra.

Thoracic Cage : 

Thoracic Cage Pressure of such a rib on the lowest trunk of the brachial plexus arching over it may produce paraesthesiae

Thoracic Cage : 

Thoracic Cage Less commonly vascular changes, even gangrene, may be caused by pressure of the rib on the overlying subclavian artery.

Intercostal Spaces : 

Intercostal Spaces There are slight variations between the different intercostal spaces, but typically each space contains three muscles, comparable to those of the abdominal wall, and an associated neurovascular bundle. The muscles are: External Intercostal Internal Intercostal Innermost Intercostal

Intercostal Spaces : 

Intercostal Spaces External Intercostal The fibres of which pass downwards and forwards from the rib above to the rib below and reach from the vertebrae behind to the costo-chondral junction in front, where muscle is replaced by the anterior intercostal membrane

Intercostal Spaces : 

Intercostal Spaces Internal Intercostal Runs downwards and backwards from the sternum to the angles of the ribs where it becomes the posterior intercostal membrane.

Intercostal Spaces : 

Intercostal Spaces Innermost Intercostal Is only incompletely separated from the internal intercostal muscle by the neurovascular bundle. The fibres of this sheet cross more than one intercostal space and it may be incomplete.

Intercostal Spaces : 

Intercostal Spaces Innermost Intercostal Anteriorly it has a more distinct portion which is fan-like in shape, termed the transversus thoracis (or sterno-costalis), which spreads upwards from the posterior aspect of the lower sternum to insert onto the inner surfaces of the second to the sixth costal cartilages.

Intercostal Spaces : 

Intercostal Spaces

Intercostal Spaces : 

Intercostal Spaces The vessels comprise the: posterior intercostals anterior intercostals

Intercostal Spaces : 

Intercostal Spaces Posterior intercostal arteries of the lower nine spaces are branches of the thoracic aorta, while the first two are derived from the superior intercostal branch of the costo-cervical trunk, the only branch of the second part of the subclavian artery.

Intercostal Spaces : 

Intercostal Spaces Anterior intercostal arteries are branches of the internal thoracic artery (1st-6th space) or of its musculo-phrenic branch (7th-9th spaces). The lowest two spaces have only posterior arteries.

Intercostal Spaces : 

Intercostal Spaces

Venous Drainage : 

Venous Drainage

OBJECTIVE : 

OBJECTIVE Describe the innervation of the thoracic wall, and to indicate on a diagram of the thoracic wall dermatome levels, including the extent of segmental overlap.

Intercostal Spaces : 

Intercostal Spaces The intercostal nerves are the anterior primary rami of the thoracic nerves, each of which gives off a collateral muscular branch and lateral and anterior cutaneous branches for the innervation of the thoracic and abdominal walls

Slide 43: 

The following statements concerning structures in the intercostal space are correct except which? A. The anterior intercostal arteries of the upper six intercostal spaces are branches of the internal thoracic artery. B. The intercostal nerves travel forward in an intercostal space between the internal intercostal and innermost intercostal muscles. C. The intercostal blood vessels and nerves are positioned in the order of vein, nerve, and artery from superior to inferior in a subcostal groove. D. The lower five intercostal nerves supply sensory innervation to the skin of the lateral thoracic and anterior abdominal walls. E. The posterior intercostal veins drain backward into the azygos and hemiazygos veins.

Slide 44: 

The following statements concerning structures in the intercostal space are correct except which? A. The anterior intercostal arteries of the upper six intercostal spaces are branches of the internal thoracic artery. B. The intercostal nerves travel forward in an intercostal space between the internal intercostal and innermost intercostal muscles. C. The intercostal blood vessels and nerves are positioned in the order of vein, nerve, and artery from superior to inferior in a subcostal groove. D. The lower five intercostal nerves supply sensory innervation to the skin of the lateral thoracic and anterior abdominal walls. E. The posterior intercostal veins drain backward into the azygos and hemiazygos veins.

Slide 45: 

To pass a needle into the pleural space (cavity) in the midaxillary line, the following structures will have to be pierced except which? A. Internal intercostal muscle B. Levatores costarum C. External intercostal muscle D. Parietal pleura E. Innermost intercostal muscle

Slide 46: 

To pass a needle into the pleural space (cavity) in the midaxillary line, the following structures will have to be pierced except which? A. Internal intercostal muscle B. Levatores costarum C. External intercostal muscle D. Parietal pleura E. Innermost intercostal muscle

Slide 47: 

The following statements concerning the intercostal nerves are correct except which? A. They provide motor innervation to the peripheral parts of the diaphragm. B. They provide motor innervation to the intercostal muscles. C. They provide sensory innervation to the costal parietal pleura. D. They contain sympathetic fibers to innervate the vascular smooth muscle. E. The seventh to the eleventh intercostal nerves provide sensory innervation to the parietal peritoneum.

Slide 48: 

The following statements concerning the intercostal nerves are correct except which? A. They provide motor innervation to the peripheral parts of the diaphragm. B. They provide motor innervation to the intercostal muscles. C. They provide sensory innervation to the costal parietal pleura. D. They contain sympathetic fibers to innervate the vascular smooth muscle. E. The seventh to the eleventh intercostal nerves provide sensory innervation to the parietal peritoneum.

Breast : 

Breast Retromammary space permits some movement on pectoral fascia 15 - 20 lobules Suspensory ligaments

Breast : 

Breast 75% to Axilla Parasternal Abdominal

Breast : 

Breast Witch's Milk in the Newborn While the fetus is in the uterus, the maternal and placental hormones cross the placental barrier and cause proliferation of the duct epithelium and the surrounding connective tissue. This proliferation may cause swelling of the mammary glands in both sexes during the first week of life; in some cases a milky fluid, called witch's milk, may be expressed from the nipples. The condition is resolved spontaneously as the maternal hormone levels in the child fall.

Slide 52: 

A medical student inserting an intercostal drain for the first time forgets her anatomy and passes it at the lower border of the rib. The structure most likely to be damaged is the A. intercostal artery B. intercostal nerve C. intercostal vein D. internal intercostal muscle

Slide 53: 

A medical student inserting an intercostal drain for the first time forgets her anatomy and passes it at the lower border of the rib. The structure most likely to be damaged is the A. intercostal artery B. intercostal nerve C. intercostal vein D. internal intercostal muscle

Slide 54: 

A 23-year-old female college student is involved in an automobile accident. She sustains a blunt force injury to the chest, resulting in fracture of the left seventh rib. The patient is experiencing severe pain from this fracture. To relieve this pain, a resident administers a local anesthetic. Which of the following sites would be the most appropriate site for this injection? A. Seventh intercostal space immediately below the seventh rib in the midclavicular line B. Seventh intercostal space immediately below the seventh rib just lateral to the angle of the rib C. Seventh intercostal space immediately below the seventh rib just medial to the angle of the rib D. Sixth intercostal space immediately above the seventh rib in the midclavicular line E. Sixth intercostal space immediately above the seventh rib just lateral to the angle of the rib F. Sixth intercostal space immediately above the seventh rib just medial to the angle of the rib

Slide 55: 

A 23-year-old female college student is involved in an automobile accident. She sustains a blunt force injury to the chest, resulting in fracture of the left seventh rib. The patient is experiencing severe pain from this fracture. To relieve this pain, a resident administers a local anesthetic. Which of the following sites would be the most appropriate site for this injection? A. Seventh intercostal space immediately below the seventh rib in the midclavicular line B. Seventh intercostal space immediately below the seventh rib just lateral to the angle of the rib C. Seventh intercostal space immediately below the seventh rib just medial to the angle of the rib D. Sixth intercostal space immediately above the seventh rib in the midclavicular line E. Sixth intercostal space immediately above the seventh rib just lateral to the angle of the rib F. Sixth intercostal space immediately above the seventh rib just medial to the angle of the rib