4THE THORACIC WALLThe thorax (or chest) is the region of the body between the neck and the abdomen. The thoracic cage : is formed by :the vertebral column behind,the ribs and intercostal spaces on either side,the sternum and costal cartilages in front
5Superiorly: the thorax communicates with the neck Inferiorly: it is separated from the abdomen by the diaphragmFunction of thoracic cage:Protect lungs & heart and give attachment for Mm.
6Structure of the Thoracic Wall 1- sternum.2- ribs & intercotal spaces3- vertebral column
112- The body of the sternum: articulates above with the manubrium at the manubriosternal jointand below with the xiphoid process at the xiphisternal jointNote: On each side it articulates with the second (lower part of 2nd rib )to the seventh costal cartilages .
13No ribs or costal cartilages are attached to it . 3- The xiphoid processNo ribs or costal cartilages are attached to it .angle of Louis) :) The sternal angleformed by the articulation of the manubrium with the body of the sternum.* The sternal angle is facing 2nd rib (ant.)* The sternal angle lies opposite the intervertebral disc between the fourth and fifth thoracic vertebrae .( Post.)* The xiphisternal joint lies opposite the body of the ninth(9th) thoracic vertebra .
15The Ribs :There are 12 pairs of ribs, all of which are attached posteriorly to the thoracic vertebrae .The ribs are divided into three types :True ribs :The 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 .Floating ribs :The 11th and 12th pairs have no anterior attachment
18The Intercostal Spaces : The spaces between the ribs(rib+rib) contain three muscles of respiration: the external intercostal.the internal intercostal.the innermost intercostal muscle.__lies internally by parietal pleuraThe intercostal nerves and blood vessels VAN run betweenthe internal intercostal.(middle)& the innermost intercostal muscle(internal)
19Increase in anteroposterior dimension by true ribs
23The Openings of the Thorax Chest cavity Upper part (open with thoracic outlet)The chest cavity communicates with the root of the neck through an opening called the thoracic outlet.(important for B.V.)Opening is bounded by:Posteriorly: by the first thoracic vertebra,T1Laterally:1st ribanteriorly :by the superior border of the manubrium sterni
24Lower part (closed by diaphragm) The thoracic cavity communicates with the abdomen through a large opening which is closed by diaphragm.Opening is bounded by:posteriorly :by the 12th thoracic vertebre T12laterally :by the curving costal marginanteriorly :by the xiphisternal joint.
26The Diaphragm :The diaphragm is a thin muscular and tendinous septum LIKE DOME SHAPED(peripheral muscular part & and a centrally placed tendon ) that separates the chest cavity above from the abdominal cavity below .function of The Diaphragm : respiration
28The Thoracic CavityThe thoracic cavity is bounded by the chest wall and below by the diaphragmThe chest cavity can be divided into a median partition, called the mediastinum, and the laterally placed pleurae and lungs.Middle-mediastenium :(heart,trachea,esophagus,big vesseles)laterally( pleura , lungs(
29Mediastinum The mediastinum is divided into: superior and inferior mediastina by an imaginary plane passing from the sternal angle anteriorly to the lower border of the body of the fourth thoracic vertebra posteriorlyThe inferior mediastinum is subdivided into the middle mediastinum,the anterior mediastinum,the posterior mediastinum
30Subdivision of mediastinum as seen on cross section. anterior mediastinum (1)middle mediastinum (2)posterior mediastinum (3)
31Subdivision of mediastinum as seen on sagittal section superior mediastinum (1)anterior mediastinum (2)medial mediastinum (3)posterior mediastinum (4)
34Nose Nasal cavity is divided by nasal septum. The lateral wall has three bony projections the chonchae.The nose is separated from the mouth by the palate, the anterior part is bony, posterior part is fleshy.
35Larynx Is the voice box, below pharynx? It is formed of nine cartilages, the largest are thyroid, cricoid, and the leaf like which cover the laryngeal opening, the epiglottisThe vocal cords are ligaments covered by mucous membrane.The lower part of larynx and upper part of trachea.
36Pharynx Is muscular passage 13 cm in length? It is divided into : Nasopharynx , Oropharynx LaryngopharynxAuditory tube opens into naso pharynx.Tonsil is a cluster of lymphoid tissue.Pharyngeal tonsil is located high in nasopharynx called adenoidsThe palatine tonsils located in oropharynx, lingual tonsil at base of the tongue.
37The Trachea The trachea is a mobile cartilaginous and membranous tube. In adults the trachea is about 4 in. (11.25 cm) long and 1 in. (2.5 cm) in diameterIt is continuation of the larynx at the lower border of the cricoid cartilage.The end of trachea is called the carina by dividing into right and left principal (main) bronchi at the level of the sternal angle.
45The Pleurae It placed lateral to mediastenium Each pleura has two parts:parietal pleura (inner surface of chest)Visceral pleura (inner surface of lung).In between 2 pleura – pleural space which contain pleural fluidNerve Supply of the Pleura :The parietal pleura is sensitive to pain, temperature, touch, and pressure and is supplied by the intercostal Nn. & Phrenic N.The visceral pleura covering the lungs is sensitive to stretch but is insensitive to common sensations such as pain and touch. It receives an autonomic nerve supply from the pulmonary plexus.
46The Lungs it’s apex: toward thoracic outlet Base: diaphragm The right lung is slightly larger than the left and is divided by the oblique and horizontal fissures into three lobes: the upper, middle, and lower lobes ;The left lung is divided by a similar oblique fissure into two lobes: the upper and lower lobes . There is no horizontal fissure in the left lung.
47The lungs fill the pleural cavities and are divided into lobes. The left lung has 2 lobes and the right lung has 3 lobes.The bulk of the lung surface is against the ribs
50The Heart Surfaces of the Heart: The heart has three surfaces: * sternocostal (anterior)* diaphragmatic (inferior)* base (posterior).Chambers of the Heart:The heart is divided by vertical septa into four chambers: the right and left atria and the right and left ventricles
52The wall of the heart Outer layer epicardium Middle layer myocardium Deep layer endocardium
53Major arteries of systemic circulation AortaIt is the largest artery in the body.It start as the ascending aorta, then continue as aortic arch, curve downward as descending aorta, ends in the diaphragmatic opening by becoming abdominal aorta.Brachicephalic, lt common carotid, lt subclavian arterie
54Brachiocephalic artery divides in to RT common carotid, RT subclavian arteries behind rt sternoclavicular joint.Common carotid artery divides into:External, and internal carotid arteries at level of thyroid cartilage C4External carotid artery is the artery to the neck, supply face tongue, thyroid.Internal carotid artery supplies the brain.Subclavian artery gives vertebral artery to the brain.Continue as axillary artery in axilla, then brachial artery in the arm, divide into radial and ulnar arteries at elbow joint.