Thoracic Wall Anatomy PDF

Chest Wall anatomy keywords 1. Skeletal Structures The bony thorax provides protection for the heart and lungs, and serves as an attachment point for the thoracic muscles. Sternum (Breastbone) Manubrium – Upper part; articulates with the clavicles and first two ribs. o jugul...

Chest Wall anatomy keywords 1. Skeletal Structures The bony thorax provides protection for the heart and lungs, and serves as an attachment point for the thoracic muscles. Sternum (Breastbone) Manubrium – Upper part; articulates with the clavicles and first two ribs. o jugular notch - or the suprasternal notch Body – Central portion; connects to ribs 2-7 via costal cartilage. Xiphoid Process – Small, lower projection; an important landmark for CPR. Clavicle (Collarbone) Connects the sternum to the scapula. Fractures are common, especially in falls. Ribs True Ribs (1-7): Directly attached to the sternum from each side. False Ribs (8-10): Indirectly attached to the sternum via cartilage from each side. Floating Ribs (11-12): No anterior attachment; vulnerable to fractures. Thoracic Spine Vertebrae (T1-T12) Have attachment points for rib connection. Provide support for the thoracic cavity. 2. Muscles of the Chest Wall Chest muscles are involved in breathing, movement, and protection. Pectoral Muscles Pectoralis Major – Responsible for arm adduction, flexion, and medial rotation. Pectoralis Minor – Stabilizes the scapula. Intercostal Muscles (Between the Ribs) External Intercostals – Aid in inspiration (elevate ribs). Internal Intercostals – Aid in forced expiration (depress ribs). Innermost Intercostals – Assist internal intercostals in expiration. Diaphragm Primary muscle of respiration.  Innervated by the phrenic nerve (C3-C5) – "C3, 4, 5 keeps the diaphragm alive!" Contraction → Inspiration (flattens downward). Relaxation → Expiration (moves upward). Accessory Muscles of Respiration (Used in deep or forceful breathing) Serratus Anterior – Protracts the scapula; aids in forced breathing. Scalene Muscles – Elevate the first two ribs during inspiration. Sternocleidomastoid – Raises the sternum in deep breathing. 3. Thoracic Cavity & Spaces The thoracic cavity houses the lungs, heart, major vessels, and lymphatic structures. Pleura & Pleural Cavity Visceral Pleura – Covers the lungs. Parietal Pleura – Lines the chest wall. Pleural Cavity – Space between pleural layers containing pleural fluid (reduces friction). Pleural Effusion – Excess fluid in the pleural cavity. 4. Nerves of the Thorax Phrenic Nerve (C3-C5) – Controls the diaphragm. Vagus Nerve (CN X = cranial nerve 10) – Parasympathetic control of heart, lungs, digestive tract. Intercostal Nerves (T1-T11) – Sensory & motor supply to chest wall. Sympathetic Trunk – Fight-or-flight response. 5. Lymphatic System Thoracic Duct – Drains lymph from most of the body into the left subclavian vein. Right Lymphatic Duct – Drains the right upper body. Hilar Lymph Nodes – Drain the lungs. Mediastinal Lymph Nodes – Drain the thoracic organs. 6. Breast Location & Relations Anterior to Pectoralis Major & Minor Extends from Ribs 2-6 Lies between the Sternum and Midaxillary Line Structural Components - Mammary Gland, Nipple, Areola (Pigmented Area) Lymphatic Drainage (Breast Cancer Spread) - Axillary Lymph Nodes (Most Important – 75%)