Note : I put the sheet's info within the slides to easily understand this lecture Done by : Zaid Al-Ghnaneem

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1 Note : I put the sheet's info within the slides to easily understand this lecture Done by : Zaid Al-Ghnaneem 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 laterally 1 7 are true ribs (vertebrosternal) 8 10 are false ribs (vertebrochondral) are floating Costal cartilages anteriorly Bodies of the thoracic vertebrae posteriorly Thoracic Cage Anteriorly Directly attached to sternum Indirectly attached to sternum No connection with sternum

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 Also attachment for muscles

6 sternum parts will ossifies to become one bone 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 join manubrium with body, second costal cartilage join sternum at this level site of attachment for abdominal muscles

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 these facets on body and transverse process of vertberae, we will disscus them

9 Typical ribs Long & twisted 2-10th ribs Ribs Rounded superior edge Grooved inferior edge (costal groove) Head for ribs from 2-9 has 2 facets because it will articulate with 2 sucessive vertebrae 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 have one facet on head so articulate only with body of vertebrae

11 Immovable (fibrous) joint Thoracic Wall: Joints Head with body of vertebrae Tubercle with transverse process 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 costal cartilage itself between them(costal cartilage and the next one) has cavity that allow movement and it is synovial joint

12 Joints of the Heads of Ribs so we will have 2 cavities 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 intervertebral disk so only one cavity

13 Costotransverse Joint remember 11th and 12th rib don't have tubercle Joints of the tubercles (1 10 ribs) With the transverse process of the corresponding vertebra

14 Thoracic Wall: Joints

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16 There is debate about inlets and outlets, some books consider the upper opening is inlet and the lower is outlet, other books the opposite,, so we will call them : Superior and inferior thoracic apertures Boundaries Posteriorly by body of 12th thoracic vertebrae Laterally by inferior margins of ribs and costal cartilages Anteriorly by xiphesternal joint Thoracic Apertures Boundaries anteriorly by suprasternal notch posteriorly by first thoracic vertebrae laterally by medial border of 1st rib Orientation is anterior inferior or forward downward

17 Superior Thoracic Aperture Previous slide 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 this membrane attached laterally with 1st rib, posteriorly, with transverse process of vertebrae, medially with deep fasica of the viscera

18 Superior Thoracic Aperture

19 Inferior Thoracic Aperture this is liver not lung because the section is at level of T12 and because of the dome within the center of thoracic cavity NOTE : periphery of thoracic cavity is more longer than center of thoracic cavity because of domes

20 Intercostal Spaces between internal and innermost 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 to push the blood within the veins becuase as we know the pressure within the vein is low 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 these are thicking of the aponeurosis of the muscles 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 most inferior most superior

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 remember.. part of rectus sheath

29 Diaphragm: Innervation Diaphragm is skeletal muscle so it needs somatic nerves Motor Phrenic nerves (C3 C5) Sensory Centrally phrenic nerves Peripherally intercostal nerves (T7 T12) sensory for diaphragm and other structers linked directly with diaphragm from superior and inferior, such as parietal layer of serous membrane these nerves are responsible for referred pain

30 Diaphragm: Blood Supply SUPERIOR INFERIOR

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32 اغلبھم من Thoracic aorta ما عدا الاول والثاني لانھ thoracic aorta ما بصلھم 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 Internal thoracic artery major branches at end of sternum to : superior epigastric and musculophrenic

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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 these nerves are exceptions,, the nerves in all the body once they exit the intervertebral foramen they divide to dorsal and ventral, most of nerves are ventral, they make plexuses except in thoracic region 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 remember..exit the diaphragm though lateral arcuate ligament

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 at the level of T2-23 at level of T4-T5