thoracic cage inlet and outlet landmarks of the anterior chest wall muscles of the thoracic wall sternum joints ribs intercostal spaces diaphragm

Transcription

1 Thoracic Wall

2 Lecture Objectives Describe the shape and outline of the thoracic cage including inlet and outlet. Describe the anatomical landmarks of the anterior chest wall. List various structures making the thoracic wall. Make a list of muscles of the thoracic wall including their nerve and blood supply and their actions. List various parts of the thoracic vertebrae and name its characteristic features. Describe the sternum with its joints. Classify ribs, name their various parts and compare them with each other. Define intercostal spaces and discuss their various components including intercostal muscles. Describe the diaphragm, its origin, insertion, function, nerve and blood supply. Study openings in the diaphragm and structures that pass through.

3 Bony cage flattened from front to back Sternum (breastbone) Ribs 1 7 are true ribs (vertebrosternal) 8 10 are false ribs (vertebrochondral) are floating Costal cartilages Bodies of the thoracic vertebrae Thoracic Cage

4 Skeleton of Thoracic Wall

5 Thoracic Cage: Functions Enclose and protect the organs in the thoracic and abdominal cavities Provide support for the bones of the upper limbs Play a role in breathing

6 Manubrium 1st & 2nd ribs Clavicular notch (sternoclavicular joint) Sternal angle T3 T4 Body Costal cartilages of 2 7 ribs Xiphoid Ossifies by 40 CPR position Abdominal mm. T9 Sternum

7 Sternum

8 Ribs Increase in length from ribs 1 7, thereafter decreasing Head and tubercle articulate with facets Body with costal groove containing nerve & blood vessels Intercostal spaces contain intercostal muscles

9 Ribs Typical ribs Long & twisted Rounded superior edge Grooved inferior edge (costal groove) Head (2 facets 2 9, 1 facet 1, 10 12), neck, tubercle, shaft & angle

10 Ribs Atypical ribs 1 st rib Widest, shortest, most curved true rib Articulate with T1 Surface marking 11 th and 12 th No neck No tubercle Floating

11 Thoracic Wall: Joints Cartilaginous Joints Joints of sternum Manubriosternal joint (2 ) Xiphisternal joint Costochondral joints 1st sternocostal joint Synovial Joints (plane joints) Joints between ribs and thoracic vertebrae 2nd 7th sternocostal joints 6th 10th interchondral joints

12 Joints of the Heads of Ribs 2 9 ribs 2 synovial joints With the corresponding vertebra and one above Intra articular ligament Between head and IVD 1, ribs 1 synovial joint with the corresponding vertebra

13 Costotransverse Joint Joints of the tubercles (1 10 ribs) With the transverse process of the corresponding vertebra

14 Thoracic Wall: Joints

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16 Thoracic Apertures

17 Superior Thoracic Aperture Between thoracic cavity and the root of the neck Boundaries.. Orientation.. Content Trachea Esophagus Nerves & BVs Lungs & pleurae Suprapleural membrane Close the sides of the opening above the parietal pleurae

18 Superior Thoracic Aperture

19 Inferior Thoracic Aperture

20 Intercostal Spaces Between successive ribs Contain the intercostal mm. External, internal, and innermost intercostal mm. Neurovascular bundle run superficial to the innermost intercostal m. Arranged from superior to inferior as vein, artery, and nerve

21 Intercostal Muscles Nerve supply: intercostal nerves Three layers External intercostal Orientation Anterior (external) intercostal membrane Helps in inspiration Internal intercostal Orientation Posterior (internal) intercostal membrane Helps in expiration Innermost intercostal Cross more than one intercostal spaces Attached to the endothoracic fascia internally Attached to parietal pleura Divided into three parts Works with the internal intercostal

22 Accessory Muscles of Respiration Transversus thoracis Help in expiration Pectoralis major, pectoralis minor, serratus anterior, scalene mm. May help in inspiration

23 Accessory Muscles of Respiration Levator costarum Between the transverse processes and the ribs Nerve supply: posterior rami of thoracic spinal nerves Help in inspiration Serratus posterior superior m. Deep to rhomboids Nerve supply: 1 4 intercostal nerves Help in inspiration Serratus posterior inferior m. Deep to latissmus dorsi Nerve supply: last 4 intercostal nerves Help in expiration

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25 Diaphragm Physical barrier between thoracic and abdominal cavities Functions Inspiration Abdominal pressure Abdominothoracic pump Dome like shape Peripheral muscular Reach up to the 5 th rib Central tendon At level of xiphisternal joint

26 Origin of the diaphragm Sternal posterior surface of xiphoid process Costal the lower six ribs and their costal cartilages Vertebral Right crus bodies of L1 L3 Left crus bodies of L1 L2 Arcuate ligaments Medial L2 (body) to L1 (transverse process) Lateral L1 (transverse process) to 12 th rib Median connects crura anterior to aorta

27 Openings in the Diaphragm Aortic opening T12 Between crura Content Aorta, thoracic duct, & azygos vein Esophageal opening T10 In right crus Content Esophagus, vagi, BVs & lymphatic vessels Caval opening T8 Content IVC, branches of right phrenic nerve

28 Openings in the Diaphragm Other structures pass the diaphragm Splanchnic nerves through crura Sympathetic trunk medial arcuate lig. Subcostal nerve lateral arcuate lig. Superior epigastric vessels between sternal & costal origins

29 Diaphragm: Innervation Motor Phrenic nerves (C3 C5) Sensory Centrally phrenic nerves Peripherally intercostal nerves (T7 T12)

30 Diaphragm: Blood Supply

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32 Arteries of Thoracic Wall Posterior intercostal aa. 1 2 superior intercostal costocervical trunk 2 nd part of supclavian 3 12 descending thoracic aorta Anterior intercostal aa. 1 6 internal thoracic 1 st part of subclavian 7 12 musculophrenic internal thoracic

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34 Veins of Thoracic Wall Posterior intercostal veins Drain into azygos and hemiazygos veins Anterior intercostal veins Follow the corresponding aa. (internal intercostal and musculophrenic vv.)

35 Nerves of Thoracic Wall Anterior rami of thoracic spinal nerves 1 11 intercostal nerves 1 6 end within the intercostal spaces 7 9 pass anterior deep to the costal cartilage to reach the abdominal wall continue anteriorly to the abdominal wall 12 subcostal nerve In the abdominal wall

36 Branches of the Intercostal Nerves Rami communicants Collateral branch Lateral cutaneous branch 1 st part of the brachial plexus Intercostobrachial nerve (2nd) Referral pain in coronary artery disease Anterior cutaneous branch Muscular branches Pleural sensory branches Peritoneal sensory branches (6 11)

37 Surface Anatomy