THE THORAX THORACIC WALL BREAST
THE THORAX THORACIC WALL • BREAST •
THE THORAX THORACIC WALL
THE THORAX THE THORAX - BONES & JOINTS The part of the body between the neck and abdomen. The thoracic cage (rib cage), with the horizontal bars formed by ribs and costal car;lages , is also supported by the ver>cal sternum (breastbone) and thoracic vertebrae The thoracic skeleton includes: • 12 pairs of ribs and associated costal car>lages, • 12 thoracic vertebrae and the intervertebral (IV) discs interposed between them, • and the sternum .
THE RIBS THE THORAX - BONES & JOINTS Ribs are curved, flat bones that form most of the thoracic cage There are three types of ribs that can be classified as typical or atypical: • true (vertebrosternal) ribs (1st–7th ribs) • false (vertebrochondral) ribs (8th, 9th, and usually 10 th ribs) • floa;ng (vertebral, free) ribs (11th, 12th, and some>mes 10th ribs)
THE RIBS THE THORAX - BONES & JOINTS There are three types of ribs that can be classified as typical or atypical: • true (vertebrosternal) ribs (1st–7th ribs): they aWach directly to the sternum through their own costal car>lages. • false (vertebrochondral) ribs (8th, 9th, and usually 10th ribs): their car>lages are connected to the car>lage of the rib above them; thus their connec>on with the sternum is indirect. • floa;ng (vertebral, free) ribs (11th, 12th, and some;mes 10th ribs): the rudimentary car>lages of these ribs do not connect even indirectly with the sternum; instead they end in the posterior abdominal musculature.
THE RIBS THE THORAX - BONES & JOINTS Typical ribs (3rd–9th) have the following components: • Head • Neck • Tubercle • Body Typical ribs (3rd–9th) have the following components: • Head : has two facets, one for ar>cula>on with the numerically corresponding vertebra and one facet for the vertebra superior to it. • Neck : connects the head of the rib with the body at the level of the tubercle. • Tubercle : ar>culates with the corresponding transverse process of the vertebra, • Body (sha[): thin, flat, and curved.
THE RIBS THE THORAX - BONES & JOINTS ATYPICAL RIBS (1st, 2nd, and 10th–12th) are dissimilar: • the 1st rib is the broadest (i.e., its body is widest and nearly horizontal), shortest, and most sharply curved • the 1st rib has a single facet on its head for ar>cula>on with the T1 vertebra only • the 1st rib has two transversely directed grooves crossing its superior surface for the subclavian vessels • the 1st rib has the grooves separated by a scalene tubercle and ridge, to which the anterior scalene muscle is aWached.
THE RIBS THE THORAX - BONES & JOINTS Atypical ribs (1st, 2nd, and 10th–12th) are dissimilar: • the 2nd rib is has a thinner, less curved body • has two facets for ar>cula>on with the bodies of the T1 and T2 vertebrae Atypical ribs (1st, 2nd, and 10th–12th) are dissimilar: • The 10th–12th ribs, like the 1st rib, have only one facet on their heads and ar;culate with a single vertebra . Atypical ribs (1st, 2nd, and 10th–12th) are dissimilar: • The 11th and 12th ribs are short and have no neck or tubercle .
THE COSTAL CARTILAGES THE THORAX - BONES & JOINTS Costal car;lages prolong the ribs anteriorly and contribute to the elas>city of the thoracic wall, providing a flexible aWachment for their anterior ends (>ps). Intercostal spaces separate the ribs and their costal car>lages from one another
THE THORACIC VERTEBRAE THE THORAX - BONES & JOINTS Characteris>c features of thoracic vertebrae include: • Bilateral costal facets (demifacets) on the vertebral bodies, usually occurring in inferior and superior pairs, for ar>cula>on with the heads of ribs. • Costal facets on the transverse processes for ar>cula>on with the tubercles of ribs, except for the inferior two or three thoracic vertebrae. • Long, inferiorly slan>ng spinous processes .
THE THORACIC VERTEBRAE THE THORAX - BONES & JOINTS Superior and inferior costal facets occur as bilaterally paired, planar surfaces on the superior and inferior posterolateral margins of the bodies of typical thoracic vertebrae (T2–T9). Atypical thoracic vertebrae: • The superior costal facets of vertebra T1 are not demifacets because there are no demifacets on the C7 vertebra above, and rib 1 ar;culates only with vertebra T1 . T1 has a typical inferior costal facet. • T10 has only one bilateral pair of (whole) costal facets , located partly on its body and partly on its pedicle. • T11 and T12 also have only a single pair of (whole) costal facets , located on their pedicles.
THE STERNUM THE THORAX - BONES & JOINTS The sternum is the flat, elongated bone that forms the middle of the anterior part of the thoracic cage. The sternum consists of three parts : • manubrium , • body , and • xiphoid process
THE STERNUM THE THORAX - BONES & JOINTS The easily palpated concave center of the superior border of the manubrium is the jugular notch (suprasternal notch). The jugular notch lies at the level of the inferior border of the body of T2 vertebra and the space between the 1st and 2nd thoracic spinous processes . The manubrium and body of the sternum lie in slightly different planes superior and inferior to their junc>on, the manubriosternal joint ; hence, their junc>on forms a projec>ng sternal angle (of Louis). Inferolateral to the clavicular notch, the costal car>lage of the 1st rib is >ghtly aWached to the lateral border of the manubrium – - the synchondrosis of the first rib
THE STERNUM THE THORAX - BONES & JOINTS The body of the sternum , is longer, narrower, and thinner than the manubrium, and is located at the level of the T5–T9 vertebrae The xiphoid process , the smallest and most variable part of the sternum, is thin and elongated. Its inferior end lies at the level of T10 vertebra .
THE STERNUM THE THORAX - BONES & JOINTS The xiphisternal joint is a midline marker for the superior limit of the liver, the central tendon of the diaphragm, and the inferior border of the heart.
JOINTS OF THORACIC WALL THE THORAX - BONES & JOINTS • Intervertebral (of vertebrae T1–T12) • Costovertebral (joints of head of rib) • Costochondral • Interchondral • Sternocostal • Sternoclavicular • Manubriosternal • Xiphisternal
JOINTS OF THORACIC WALL THE THORAX - BONES & JOINTS
JOINTS OF THORACIC WALL THE THORAX - BONES & JOINTS
THE THORAX - BONES & JOINTS THE THORACIC APERTURES
THE THORAX - BONES & JOINTS THE THORACIC APERTURES While the thoracic cage provides a complete wall peripherally, it is open superiorly and inferiorly . The much smaller superior opening (aperture) is a passageway that allows communica>on with the neck and upper limbs. The larger inferior opening provides the ring-like origin of the diaphragm, which completely occludes the opening.
THE THORAX - BONES & JOINTS THE THORACIC APERTURES The SUPERIOR THORACIC APERTURE is bounded: • Posteriorly, by vertebra T1, the body of which protrudes anteriorly into the opening. • Laterally, by the 1st pair of ribs and their costal car>lages. • Anteriorly, by the superior border of the manubrium.
THE THORAX - BONES & JOINTS THE THORACIC APERTURES THE THORACIC INLET Space-occupying tumours in this loca>on may compress adjacent structures, leading to the clinical condi>on called thoracic outlet syndrome .
THE THORAX - BONES & JOINTS THE THORACIC APERTURES Inferiorly the cavity of the thorax is separated from the abdominal contents by a fibromuscular sheet called the diaphragm . The floor of the thoracic cavity (thoracic diaphragm) is deeply invaginated inferiorly (i.e., is pushed upward) by viscera of the abdominal cavity.
THE THORAX - BONES & JOINTS THE THORACIC APERTURES The INFERIOR THORACIC APERTURE is bounded as follows: • Posteriorly, by the 12th thoracic vertebra, the body of which protrudes anteriorly into the opening. • Posterolaterally, by the 11th and 12th pairs of ribs. • Anterolaterally, by the joined costal car>lages of ribs 7–10, forming the costal margins. • Anteriorly, by the xiphisternal joint.
THE MUSCLES OF THE THORAX MUSCLES OF THORACIC WALL
THE MUSCLES OF THE THORAX THE THORAX MUSCLES OF THE PECTORAL REGION: • Pectoralis major • Lateral and medial pectoral nerves • Subclavius • Nerve to subclavius • Pectoralis minor • Medial pectoral nerve The pectoralis major muscle is the largest and most superficial of the pectoral region muscles. The subclavius and pectoralis minor muscles underlie pectoralis major: • subclavius is small and passes laterally from the anterior and medial part of rib I to the inferior surface of the clavicle; • pectoralis minor passes from the anterior surfaces of ribs III to V to the coracoid process of the scapula.
THE MUSCLES OF THE THORAX THE THORAX The muscles of the pectoral region form the anterior wall of the axilla , a region between the upper limb and the neck through which all major structures pass. Nerves, vessels, and lympha>cs that pass between the pectoral region and the axilla pass through the clavipectoral fascia between subclavius and pectoralis minor or pass under the inferior margins of pectoralis major and minor.
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