Intercostal Nerves & Diaphragm PDF

Intercostal nerves & Diaphragm Department of human Anatomy and Embryology Faculty of Medicine Mansoura National University, Egypt  Intended Learning Outcomes (ILOs) 1. Identify the components of the Thoracic Wall. 2. Name the boundaries and structures p...

Intercostal nerves & Diaphragm Department of human Anatomy and Embryology Faculty of Medicine Mansoura National University, Egypt  Intended Learning Outcomes (ILOs) 1. Identify the components of the Thoracic Wall. 2. Name the boundaries and structures passing through the thoracic inlet. 3. Name the boundaries and structures passing through the thoracic outlet. 4. Recognize the origin, insertion, nerve supply, extent, direction of fibers and action of intercostal muscles. 5. Mention the mechanism of respiration. 6. Identify the origin, features and branches of intercostal nerves 7. Recognize the origin, branches and termination of intercostal arteries 8. Recognize the origin, tributaries and termination of intercostal veins  Agenda 1. What are the components of the Thoracic Wall. 2. What are the boundaries and structures passing through the thoracic inlet? 3. What are the boundaries and structures passing through the thoracic outlet? 4. What is the origin, insertion, nerve supply, extent, direction of fibers and action of intercostal muscles? 5. What is the mechanism of respiration? 6. What is the origin, features and branches of intercostal nerves? 7. What is the origin, branches and termination of intercostal arteries? 8. What is the origin, tributaries and termination of intercostal veins?  Intercostal Nerves Definition: they are the ventral rami of the thoracic spinal nerves. Number: 11 nerves on each side. (The 12th is called Subcostal nerve) Types: 1. Typical: supply only the thoracic wall. They are the 3rd – 6th nerves. 2. Atypical: supply parts outside the thoracic wall. They are the 1st, 2nd, 7th – 11th The 1st joins the brachial plexus and supplies the upper limb The 2nd has a lateral cutaneous branch called intercostobrachial, which supplies the skin of the axilla 7th-11th (thoraco-abdominal) & 12th (subcostal): Supply the Anterior Abdominal wall Source: https://www.google.com.eg/url?sa=i&url=https%3A%2F%2Fwww.jaypeedigital.com%2FeReader%2Fchapter%2F9788184484618%2Fch17&psig=AOvVaw1 v9JQbexC RX2SnrHppnO9n&ust=1729564445166000&source=images&cd=vfe&opi=89978449&ved=0CBcQjhxqFwoTCOiuoum3nokDFQAAAAAdAAAAABAR  Intercostal Nerves Typical intercostal nerves Number: they are the 3rd – 6th intercostal nerves. Course and relations: At the posterior part of the intercostal space: it passes between the parietal pleura and posterior intercostal membrane. At the angle of the rib: it passes between the internal intercostal and innermost intercostal muscles. It passes in the intercostal groove below the intercostal vessels (VAN from above downwards). At the costo-chondral junction: passes between the internal intercostal muscle and the parietal pleura. Passes in front of the Sternocostalis muscle and internal thoracic artery. 1 cm lateral to the sternum: it pierces the internal intercostal muscle, anterior intercostal membrane and pectoralis major to become anterior cutaneous nerve.  Intercostal Nerves Branches: 1) Communicating branches to the sympathetic chain: they are: Preganglionic branch: myelinated (white ramus). Postganglionic branch: non-myelinated (gray ramus) 2) Muscular branches: to the intercostal muscles. 3) Pleural Branch: To the parietal pleura 4) Collateral branch: runs on the upper border of the rib below to supply the intercostal muscles. 5) Lateral cutaneous branch: Arises at the angle of the rib. Pierces the internal intercostal, external intercostal and serratus anterior muscle. Divides into anterior and posterior branches. Supplies the skin of the lateral part of the thoracic wall. 6) Anterior cutaneous branch: Divides into medial and lateral branches. Supplies the skin of the front of the thoracic wall. https://www.google.com.eg/url?sa=i&url=https%3A%2F%2Fmobilephysiotherapyclinic.in%2Fintercostal-nerves%2F&psig=AOvVaw2mWKb6TnNi4lQCP- Aj2UYi&ust=1729564838038000&source=images&cd=vfe&opi=89978449&ved=0CBcQjhxqFwoTCPDOlKO5nokDFQAAAAAdAAAAABAE  Diaphragm Definition: it is the musculofibrous partition which separates the thoracic cavity from the abdominal cavity. Origin: Sternal: back of xiphoid process. Costal: inner surface of the lower 6 costal cartilages. Vertebral: 2 crura and 5 arcuate ligaments 2 crura: Right crus & Left crus 5 Arcuate ligaments: Median Arcuate ligament. 2 Medial Arcuate ligaments. 2 Lateral Arcuate ligaments. https://www.google.com.eg/url?sa=i&url=https%3A%2F%2Fwww.slides hare.net%2Fslideshow%2Fanatomy-of- diaphragm%2F227000633&psig=AOvVaw0NgdDgqb1x_oq9iWVyVxGy& ust=1729565560900000&source=images&cd=vfe&opi=89978449&ved= 0CBcQjhxqFwoTCID1q_u7nokDFQAAAAAdAAAAABAE Insertion: central tendon of diaphragm, which is U-shaped with its concavity directed backwards. It is formed of 3 lobes (leaflets). (central, the right copula & left copula) Nerve supply: phrenic nerve and lower 6 thoracic nerves. Actions: chief muscle of inspiration. https://en.wikipedia.org/wiki/Thoracic_diaphragm#/media/File:1113_The_Diaphragm.jpg https://www.google.com.eg/url?sa=i&url=https%3A%2F%2Fwww.amboss.com%2Fus%2Fknowledge%2Fthoracic-cavity&psig=AOvVaw1uRB- zc8yUV6Ec9Hrtk8Bi&ust=1729566168304000&source=images&cd=vfe&opi=89978449&ved=0CBcQjhxqFwoTCOCq36C-nokDFQAAAAAdAAAAABAw Relations: ❑ Upper surface: Right copula: right lung and pleura. Left copula: left lung and pleura. Central tendon: pericardium and heart. ❑ Lower surface: Right copula: right lobe of the liver, right kidney and right suprarenal gland. Left copula: left lobe of the liver, left kidney, left suprarenal gland, spleen and fundus of the stomach. Openings: Major openings Opening Level Structures passing - Abdominal aorta Aortic orifice - T12 - Vena azygos - Thoracic duct - Oesophagus Oesophageal https://www.google.com.eg/url?sa=i&url=https%3A%2F%2Fradiopaedia.org%2Fcases%2Fmajor-openings- - T10 - Vagi (gastric nerves) of-the-diaphragm-lateral-view&psig=AOvVaw0z5wSQc9pqI3Spjn3pNXh- &ust=1729566651864000&source=images&cd=vfe&opi=89978449&ved=0CBcQjhxqFwoTCMDTkoLAnokDFQ orifice AAAAAdAAAAABAE - Oesophageal vessels - IVC - Right phrenic nerve Vena caval orifice - T8 - Lymph vessels from the bare area of the liver Medical Points | Diaphragmatic openings The diaphragm has three openings: #Aortic_Hiatus - the most dorsal opening, contains the aorta, azygous vein and... | Instagram Minor openings: 1. Superior epigastric vessels: between the sterna and costal origin. 2. Musculophrenic vessels: through the costal origin. 3. Lower 5 intercostal vessels and nerves: through the costal origin 4. Subcostal nerve and vessels and quadratus lumborum: deep to the lateral arcuate ligament. 5. Sympathetic chain and psoas major muscle: deepto the meial arcuate ligament. 6. Splanchnic nerves: pierce the crura. 7. Inferior hemiazygos vein: pierces the left crus. 8. Left phrenic nerve: pierces the left lobe of central tendon.  Quiz What intercostal nerve supplies the axilla? A) The 1st B) The 2nd C) The 3rd D) The 7th E) The subcostal (the 12th) Answer: B