Honors Anatomy & Physiology Unit 4: Thorax & Abdominopelvis

1. Honors Anatomy & Physiology Unit 4: Thorax & Abdominopelvis Lecture 1: External Structures of Thorax & Abdomen

2. Thorax Sternum Pectoral Mammary Abdomen Umbilicus Pelvis Pubis Relevant Regions

3. Quadrants: Regions: ABDOMINOPELVIC REGIONS Left Hypochondriac Right Hypochondriac Epigastric Upper Left Upper Right Right Lumbar Umbilical Left Lumbar Lower Right Lower Left Right Iliac Hypogastric Left Iliac

4. Serratus Posterior Superior Thorax - Muscles Spinalis Longissimus • Posterior (Found superficial to ribs) • Posture • Erector Spinae Muscle Group • Spinalis, Longissimus, Iliocostalis • Respiration • Serratus Posterior Superior • Serratus Posterior Inferior Iliocostalis Action: Extend Vertebral Column Inn: Dorsal ramiof spinal nerves Serratus Posterior Inferior Action: Increase thoracic cavity Inn: Ventral rami of Thoracic spinal (Intercostal) nerves

5. Thorax Muscles • Anterior (Found between or deep to ribs) • Respiration • External Intercostal mm. • Vertebrae – 2/3 around • “Hands-in-pocket” fiber direction • Internal Intercostal mm. • Sternum – 2/3 around • “Cross-Your-Heart” fiber direction • Innermost Intercostal mm. • Deep & Lateral group • “Cross-Your-Heart” also • TransversusThoracis mm. • Deep to sternum • Reminder: Scalenes (forced respiration) External Intercostal Internal Intercostal Innermost Intercostal Transversus Thoracis Anterior Intercostal a. Intercostal v. Intercostal n. Diaphragm

6. External and Internal intercostals For Inspiration For Expiration

7. External Intercostal Internal Intercostal Innermost Intercostal

8. Anterior Intercostal a. Intercostal v. Intercostal n. Innermost Intercostal Transversus Thoracis Transversus Thoracis Internal Intercostal Innermost Intercostal Diaphragm

10. Thorax Muscles - DIAPHRAGM • Diaphragm • A: Pulls central tendon downwards to increase thoracic cavity for inspiration • Inn: Phrenic nerve (from cervical plexus) • Seals the Inferior Thoracic Aperture • Pierced by: • Esophagus • Inferior Vena Cava

11. Diaphragm: Primary muscle for respiration

12. Anatomy and Physiology of the Thorax • Physiology of Respiration • Changing pressure assists: • Venous return to heart • Pumping blood to systemic circulation • Inhalation • Diaphragm contracts and flattens • Intercostals contract expanding ribcage • Thorax volume increases • Less internal pressure than atmospheric • Air enters lungs • Exhalation • Musculature relaxes • Diaphragm & intercostals return to normal • Greater internal pressure than atmospheric • Air exits lungs

14. Thorax – Vessels & Nerves **Veins, Arteries & Nerves all run between Internal Intercostal mm. & Innermost Intercostal mm.** • Arteries • Anterior Intercostalaa. • branches of the Internal Thoracic a. • Run parallel to sternum • Branch of the Subclavianaa. • Posterior Intercostalaa. • branches of the Thoracic Aorta • Veins • Intercostal vv. • Dump into the azygous system of veins • Nerves • Intercostal nerves • They are the ventral rami of thoracic spinal nerves • Sympathetic Trunk • is seen on the posterior thoracic cavity wall along side the vertebral bodies Ramicommunicans

15. Figure 19.17

16. Veins of the Thorax • Azygous System of Veins • Lt. Side: Hemiazygous v. • Dumps into the Azygous v. • Rt. Side: Azygous v. • Dumps into the Superior Vena Cava • Other Veins (Great Vessels) • L. Subclavian v. • L. Internal Jugular v. • R. Subclavian v. • R. Internal Jugular v. • Inferior Vena Cava Drain the Intercostal vv. L. Brachiocephalic v. Superior Vena Cava R. Brachiocephalic v. Rt. Atrium

17. Figure 19.27

19. Veins of the Thorax • Azygos vein • Hemiazygos vein • Accessory hemiazygos vein Figure 19.21b

20. Abdomen - Landmarks • Bony Landmarks: • Costal arches • Iliac Crest • Anterior Superior Iliac Spine • Pubic Bone • Non-Bony Landmarks: • Umbilicus • Linea Alba • Tendinous Inscriptions

21. 6 5 3 4 2 1

22. Abdomen – Muscles (Assist in Expiration) • Rectus Abdominis m. • O: Pubic symphysis • I: Xiphoid process & 5-7 costal cartilages • A: Antagonistic to Erector spinae (flex lumbar region) • External Oblique m. (hands-in-pocket fiber direction) • O: ribs 5-7 • I: aponeurosis at linea alba, iliac crest & pubic bone as the ANTERIOR RECTUS SHEATH • A: Compress Abdominal contents, Flex & rotate trunk • Internal Oblique m. (Cross-your-heart fiber direction) • A: Compress Abdominal contents; Flex & Rotate Trunk • Transversus Abdominis m. (Deepest; horizontal fibers) • A: Compress Abdominal contents

24. Six Pack Ab’s

25. Rectus Sheaths

27. Inguinal Region • External Oblique m. Aponeurosis • Attaches at Anterior Superior Iliac Spine & Pubic Bone (This straight line of tissue = Inguinal Ligament) • Descent of Testes • Testes are pulled out of abdomen into the scrotum • 3 layers of muscle are pulled into scrotum also: • Tranversalis fascia = Internal Spermatic Fascia • Internal Oblique m. = Cremaster muscle • External Oblique Aponeurosis = External Spermatic Fascia • Structures within the Sperrmatic Cord: • Vas Deferens • Testicular vein, artery & nerve • Deep Opening in the abdomen = Deep Inguinal Ring • Superficial Opening in abdomen = Superficial Inguinal Ring Spermatic Cord

28. Descent of Testes

29. 2 degrees cooler down south

30. Hernias • What is it? • A section of the small intestine pushes through abdominal wall into the scrotum • How can you get it? • More prominent in men • Congenital • Defect at birth makes penetration of small intestine more prone. • Pressure • Lifting and Forceful abdominal contractions can force the small intestine through the weak deep and superficial inguinal rings,

31. Hernia Examples

32. Transversus Thoracis 5 Innermost Intercostal External Intercostal 1 3 6 4 2 Internal Intercostal Anterior Intercostal a. Intercostal v. Intercostal n. Diaphragm

34. Azygos System of Veins

35. Thorax – Vessels & Nerves **Veins, Arteries & Nerves all run between Internal Intercostal mm. & Innermost Intercostal mm.** • Arteries (CG P. 149) • Anterior Intercostal aa. • branches of the Internal Thoracic a. • Run parallel to sternum • Branch of the Subclavian aa. • Posterior Intercostal aa. • branches of the Thoracic Aorta • Veins (CG P. 155) • Intercostal vv. • Dump into the azygous system of veins • Nerves • Intercostal nerves • They are the ventral rami of thoracic spinal nerves • Sympathetic Trunk • is seen on the posterior thoracic cavity wall along side the vertebral bodies