Diaphragm and Posterior Abdominal Wall PDF

Diaphragm and posterior abdominal wall Gastrointestinal tract Dr Sara Sulaiman [email protected] Learning outcomes By the end of this lecture, you should be able to: Describe the anatomy and openings of the diaphragm Describe the muscles of the posterior abdominal wall Describe the anatomy o...

Diaphragm and posterior abdominal wall Gastrointestinal tract Dr Sara Sulaiman [email protected] Learning outcomes By the end of this lecture, you should be able to: Describe the anatomy and openings of the diaphragm Describe the muscles of the posterior abdominal wall Describe the anatomy of the main abdominal aorta and inferior vena cava Outline the lymphatics of the posterior abdominal wall Outline the sympathetic nervous structures within the abdomen Describe the lumbar plexus and its branches Identify the aorta and inferior vena cava on radiological imaging Recommended reading Abrahams, Peter H. et al. McMinn & Abrahams’ Clinical Atlas of Human Anatomy. Seventh edition. Maryland Heights, Missouri: Elsevier Mosby, 2013. PrintDrake, Richard L. Gray’s Anatomy For Students. 4th. ed. Philadelphia: Elsevier, Inc., 2020. Print. Moore, Keith L., Arthur F. Dalley, and A. M. R. Agur. Essential Clinical Anatomy. 4th ed. Philadelphia, Pa.; London: Lippincott Williams & Wilkins, 2011. Print. Netter, Frank H. (Frank Henry). Atlas of Human Anatomy. 5th ed. Philadelphia, Pa.; London: Saunders, 2010. Print. Smith, C., Dilley, A., Mitchell, B. and Drake, R.L., 2017. Gray’s Surface Anatomy and Ultrasound: Gray’s Surface Anatomy and Ultrasound E-Book. Elsevier Health Sciences. Spratt, J., Salkowski, L.R., Loukas, M., Turmezei, T., Weir, J. and Abrahams, P.H., 2020. Weir & Abrahams' Imaging Atlas of Human Anatomy. Elsevier Health Sciences.  Diaphragm Median arcuate ligament Double dome: right higher than left Central tendon Innervation: Medial arcuate ligament Motor: the phrenic nerve (C3-5) Sensory: central-phrenic nerve; Lateral arcuate peripheral-intercostal nerves. ligament Blood supply: Superior (from the thoracic aorta) and inferior phrenic (from the abdominal aorta) arteries Musculophrenic and pericardiophrenic arteries (from internal thoracic a) Consists of a central tendinous part surrounded by muscle fibres. Lumbar part: anchored to the Quadratus L2 vertebral column by right and left lumborum L3 crura L4 Sternal part: attaches to the xiphoid Aorta process Left crus Costal part: attaches to the internal Psoas major surface of the lower 6 costal Right crus Pain from the cartilages diaphragm is referred Inferior view Imaging Right dome is higher than left What do you notice? Look at the big picture Where are the gas bubbles? Where is the apex of the heart? Case courtesy of Bahman Rasuli, Radiopaedia.org, rID: 97617 What do you notice? Case courtesy of Henry Knipe, Case courtesy of Mostafa El-Feky, Radiopaedia.org, rID: 31783 Radiopaedia.org, rID: 94922 Left diaphragmatic hemiparalysis Structures passing through the diaphragm At the level of T12: Aorta Superior epigastric Thoracic duct artery Azygos vein (sometimes) Oesophagus with the At the level of T10 vagal trunks IVC Oesophagus Right phrenic nerve Anterior and posterior vagal trunks Left phrenic Oesophageal branches nerve At the level of T8 IVC Right phrenic nerve Hemi-azygos vein Other openings: Left phrenic pierces the Splanchnic nerves diaphragm through the muscular part Thoracic Greater lesser, and least duct Quadratus splanchnic nerves pass through Sympathetic chain lumborum the crura Hemi-azygos pass through the left crus Sympathetic chains pass posterior to the medial arcuate ligament Psoas major I8, 10 Eggs, At, 12 Posterior abdominal wall Bony framework Five lumbar Quadratus vertebrae lumborum Sacrum Pelvic bones Ribs (11-12) L1 Muscles L2 Psoas Psoas major and L3 L4 minor minor Iliacs L5 Part of iliopsoas-flexes the trunk/LL Psoas major Quadratus lumborum Iliac fossa Depresses and stabilises rib 12 Iliacs Part of iliopsoas-flexes the trunk/LL Iliopsoas inserting into the lesser trochanter of the femur  Inferior phrenic artery Celiac trunk Aorta Superior mesenteric artery Begins at T12 and Middle bifurcates at L4 as the suprarenal artery common iliac arteries Anterior branches Lumbar arteries Celiac trunk (T12/Upper Renal artery border of L1) Superior mesenteric (L1) Inferior mesenteric Gonadal artery Inferior mesenteric (L3) artery (ovarian/testicular) Paired branches Median sacral artery Inferior phrenic (T12) Middle adrenal (L1) Right common iliac Renal (L1/L2) artery Gonadal (L2) Lumbar arteries Imaging Vessels of the abdomen Abdominal aortogram. 1. Abdominal aorta 2. Accessory renal arteries 3. Coeliac trunk 4. Common iliac arteries 5. Common hepatic artery 6. Ileocolic artery 7. Jejunal branches of superior mesenteric artery 8. Left gastric artery 9. Left renal artery 10. Lumbar arteries 11. Right renal artery 12. Splenic artery 13. Superior mesenteric artery 14. Tip of pigtail catheter in abdominal aorta  Describe what you see Case courtesy of David Cuete, Radiopaedia.org, rID: 29248 Aortic aneurysm Abdominal aortic aneurysm is a dilation of the aorta and generally tends to occur in the infrarenal region. As the aorta expands, the wall gets thinner and the risk of rupture increases.  Inferior Hepatic veins IVC phrenic veins Formed by the joining of the common iliac veins at L5 and terminates at the right Right renal atrium of the heart. vein Crossed by: Right gonadal Right common iliac artery Right gonadal artery vein The root of the mesentery Right gonadal artery Lumbar veins The inferior and superior parts of the duodenum Head of the pancreas The bile duct The portal vein The liver Left common iliac vein Tributaries: Lumbar veins (3rd and 4th) Right gonadal vein Renal veins Right suprarenal vein Inferior phrenic veins Right common iliac Right common iliac artery vein Hepatic veins Collateral pathways Ascending lumbar veins connect the common iliac, iliolumbar, and lumbar veins with the azygos and hemi- azygos veins. Can function as a collateral pathway for blood return to the heart if the IVC is blocked  Celiac nodes Lymphatics Superior mesenteric As lymphatic vessels pass in the posterior nodes abdominal region, they continue to collect lymph from structures. Inferior Lateral aortic nodes mesenteric nodes Pre-aortic lymph nodes: arranged around the three major blood vessels Common iliac Celiac nodes: drain the foregut nodes Superior mesenteric nodes: drain the midgut Inferior mesenteric nodes: drain the hindgut Para-aortic/lumbar/lateral aortic lymph nodes: lateral side of the aorta and receive lymph from: The body wall, kidneys and suprarenal glands The gonads.  Lymphangiogram abdomen and pelvis early filling phase. 1. Ascending lumbar chains 2. Cisterna chyli 3. Common iliac nodes 4. Efferent inguinal lymphatics 5. External iliac nodes (early filling) 6. Inguinal nodes (early filling) 7. Lumbar crossover 9. Thoracic duct Lumbar plexus Subcostal nerve Formed by the anterior rami of Iliohypogastric L1-3 (L4) with contribution from nerve Genitofemoral T12. nerve Ilio-inguinal Lateral to psoas nerve Subcostal nerve (T12) Lateral cutaneous nerve of the thigh Ilio-hypogastric nerve (L1) Lumbosacral trunk Ilio-inguinal nerve (L1) Lateral cutaneous nerve of the thigh (L2-3) Femoral nerve (L2-4) Femoral nerve Medial to psoas Obturator Obturator nerve (L2-4) nerve Lumbosacral trunk (L4-5) Through psoas Genitofemoral nerve (L1-2) Innervation of the lumbar plexus  Already covered in Sacral plexus Lumbosacral trunk BMF module! Superior gluteal nerve Anterior rami of S1-4 and the Pudendal nerve lumbosacral trunk. Obturator Found anterior to the nerve piriformis muscle Main branches: Sciatic nerve (L4-S3) Pudendal nerve (S2-4) Superior (L4-S1) and inferior (L5- Inferior gluteal S2) gluteal nerves nerve Posterior cutaneous nerve of the thigh (S1-S3) Pelvic splanchnic nerves (S2-4) Sciatic nerve Preganglionic parasympathetic and visceral afferents  Autonomics Preganglionic/ Postganglionic/ Sympathetic Presynaptic Postsynaptic (SNS) Thoraco-lumbar Organs Target Sympathetic ganglia CNS PNS Preganglionic/ Parasympatheti Presynaptic c (PSNS) Cranio-sacral Cell bodies of neurons: Distinction between SNS and PSNS: Nucleus: if present in the Location of the pre-synaptic cell bodies CNS (nucleus) Parasympathetic Ganglion: if present in the Location of the post-synaptic cell bodies PNS ganglia (ganglia)  What do we already know? CN III, VII, Parasympathetic IX, X Preganglionic nucleus: Cranial Parasympathetic Sacral Postganglionic ganglia: Near/at the organs wall (except in the head) Thoracic region: vagus Abdominal region: Foregut: vagus Midgut: vagus Sacral S2- Hindgut: pelvic splanchnic S4  Vagus nerve Celiac plexus Superior Inferior Superior hypogastric plexus mesenteric mesenteric plexus plexus hypogastric nerve Pelvic splanchnic nerves Inferior hypogastric plexus What do we already know? Sympathetic Preganglionic nucleus: thoraco- lumbar regions (T1-L1/2) Postsynaptic ganglia: Para-vertebral: Sympathetic trunk Pre-vertebral: (Pre-aortic Sympatheti ganglion) Celiac T1-L2 Superior mesenteric (L3) c Inferior mesenteric Thoracic region: T1-4 Abdominal region: Foregut: Greater splanchnic T5- T9 Midgut: Lesser splanchnic T10- T11 Hindgut: Lumbar Splanchnic L1- L2  Greater splanchnic nerve Celiac Lesser splanchnic nerve ganglia Superior mesenteric ganglia Inferior mesenteric ganglia Lumbar splanchnic nerves Visceral afferents from the abdominal viscera Visceral afferents carry physiological sensations will accompany parasympathetic fibers. Visceral afferents carry pain sensation will accompany sympathetic fibers. For example: the stomach (foregut) receives innervation from the greater splanchnic nerves (T6-9), pain will accompany the greater splanchnic nerves to T6-9 spinal level. Thus, pain will be referred to T6-9 dermatomes. At the midpoint of the sigmoid colon, visceral afferents carrying pain sensation will accompany parasympathetic to S2-4. Case A 30-year-old female is admitted to the ER with severe right lower quadrant pain. The pain started in the early evening and was so vague that she thought it was indigestion. She took antacids and went back to sleep. Several hours later, she woke with severe pain in the right lower quadrant. Pain is better if she lies quietly in the fetal position. What clinical problems should you consider? Acute Appendicitis was diagnosed Where is the appendix located? Arises from the posteromedial wall of the cecum. The tenia coli merge at the base of the appendix. What is the surface markings of the appendix? One-third of the distance from the anterior superior iliac spine to the umbilicus  What is the appendix blood supply? The appendicular artery of the ileocolic artery, which comes off the superior mesenteric artery To which lymph nodes would lymph from the appendix drain? To superior mesenteric nodes Why did the patient feel vague and diffused pain? Visceral afferent fibres associated with pain receptors in the wall of the appendix would be accompany sympathetic fibres. As the appendix is a midgut structure, they will accompany the lesser splanchnic nerves to T10-T11dorsal root ganglia. Visceral pain sensations from the appendix will be perceived in/referred to the paraumbilical region and right upper quadrant (RUQ) and referred along the T10-T11 dermatomes.  Why did the pain change afterwards? Over time, the inflamed appendix may irritate the parietal peritoneum on the adjacent anterior abdominal wall. The parietal peritoneum lining the anterior abdominal wall receives sensory innervation from somatic afferent fibers in T11-12. Sensation from this irritated peritoneum presents sharp pain in the RLQ. Why was the patient more comfortable laying still in the foetal position? The inflamed appendix irritates the peritoneum around psoas major. Extending the thigh will result in discomfort/pain (which is called psoas sign)  The next slides are from the radiological section of NetAnatomy Do NOT forget the radiological anatomy and histology self- directed sessions!