Thoracic Cage Anatomy PDF

Thoracic Cage BY Ala’a Shurrab The thoracic cage is an Osseo cartilaginous which is composed of : Anteriorly : sternum and costal cartilages Posteriorly : vertebral column On either side : ribs  Function of Thorax Cage 1- Protection of Thoracic organ and Abdominal organ e.g.,...

Thoracic Cage BY Ala’a Shurrab The thoracic cage is an Osseo cartilaginous which is composed of : Anteriorly : sternum and costal cartilages Posteriorly : vertebral column On either side : ribs  Function of Thorax Cage 1- Protection of Thoracic organ and Abdominal organ e.g., Heart , lungs , vessels, Liver ,spleen. 2- Respiration  Sternum It has Three parts Manubrium Body Xiphoid process The sternal angle (angle of Louis) it formed by the articulation of the manubrium with the body of the sternum It is at the level of the second costal cartilage Q. What is function of sternal angle ? A. Counting of the ribs N.B : Sternum is one of sites to take Bone marrow biopsy Sternum Bone marrow biopsy  Ribs 12 Pairs True ribs 1st to 7th ribs Attach to thoracic vertebrae and sternum False ribs 8th ,9th ,10th ribs are attached anteriorly to each other and to the 7th rib Floating ribs 11th ,12th ribs Have no attachment in the front * Each typical rib consists of 3 parts: I) Anterior or sternal end:  Cup-shaped and articulates with costal cartilage. II) Shaft: formed of ❖ Two borders: upper rounded and lower sharp. ❖ Two surfaces: outer convex and inner concave. ❖ A costal groove: present in the lower part of the inner surface and contains intercostal vein, artery and nerve. ❖ The angle: divides the shaft into anterior 3/4 (flat from side to side) and posterior 1/4 (cylinder). III) Posterior or vertebral end: formed of head, neck and tubercle: 1. Head: has 2 facets separated by a crest. The superior facet articulates with inferior demifacet on the side of the body of the vertebra above it. The inferior facet articulates with the superior demifacet on the side of the body of the corresponding vertebra. The crest articulates with the intervertebral disc. 2. Neck: constricted part following the head. 3. Tubercle: formed of 2 parts : A rough lateral non-articular part. A smooth medial part, which articulates with the facet on the transverse process of the corresponding vertebra. Typical Rib should has these landmarks Head Neck Tubercle Angle Shaft or body Subcostal Groove , contains A-Intercostal Vein B-Intercostal Artery C-Intercostal Nerve  Subcostal Groove : contains; Intercostal vein Intercostal artery and Intercostal nerve VAN The needle should be inserted above the superior border of the rib VAN Joints of the Thoracic Wall I. Joints of the Sternum A. Manubriosternal joint Secondary cartilaginous joint between the manubrium and the body of the sternum. A small amount of angular movement is possible during respiration. B. Xiphisternal joint Secondary cartilaginous joint between the xiphoid proces s and the body of the sternum. Xiphisternal joint  Joints related to the rib: B) Joints of the posterior end: (Plane Synovial joint) 1. Costo-vertebral joints ▪ Between head of a typical rib and the corresponding vertebra and the vertebra above and their intervertebral disc. ▪ The head of 1st, 10th , 11th and 12th ribs carries only one facet to articulate with the body of the corresponding vertebra only. 1.Costo- transverse joint: ▪ The smooth articular part of the tubercle of the rib articulates with the articular facet on the transverse process of the corresponding vertebra. ▪ The 11th and 12th ribs carry no tubercles and therefore have no costo-transverse joints. III- Joints of the Costal Cartilages A.Sternocostal Joint Plane Synovial joint Between sternum and costal cartilage of true ribs The 1st costal cartilages articulate with the manubrium, by primary cartilaginous joints with no movement B. Chostochondral Joint primary Cartilaginous joints. Between ribs and costal cartilage. No movement is possible. C. Interchondral joints Between 6-9 costal cartilages. Plane synovial Joint Costochondral joints Sternochondral joints Chest wall abnormalities 1- Pectus excavatum (sunken or funnel chest) It is a congenital deformity in which several ribs and the sternum grow abnormally, producing a concave, or caved-in, appearance in the anterior chest wall. 2- Rectus carinatum (pigeon chest) is a deformity of the chest characterized by a protrusion of the sternum and ribs.  Flail Chest ✓ It is s a life-threatening medical condition that occurs when a segment of the rib cage breaks due to trauma. ✓ In this case ; multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall moves independently ✓ Two of the symptoms of flail chest are chest pain and shortness of breath. Chest X ray Posterior anterior view