This document provides an overview of the anatomy of the thorax. It describes the structures that make up the thoracic cage including the sternum, ribs, and thoracic vertebrae. It discusses the divisions of the mediastinum and describes the anatomy of structures in the thorax including the lungs, heart, great vessels, diaphragm, and esophagus. Key details are provided about the lobes and fissures of the lungs, chambers and valves of the heart, arterial and venous supply of the heart, and lymphatic drainage of the lungs.
2. THORACIC CAGE - Apertures
1. Superior Thoracic Aperture (Inlet)
T1, First rib, Manubrium
2. Inferior Thoracic Aperture (Outlet)
T12, Rib 11, Rib 12,
Costal margin, Xiphoid process
3. THORACIC WALL
Bones
Sternum, 24 Ribs, 12 Thoracic vertebrae
Muscles
a. Intrinsic Muscles
Intercostals, Subcostals, Transverse
Thoracis
a. Extrinsic Muscles
Pectoralis Major & Minor,
Serratus anterior, Subclavius
4. Parts - Manubrium, Body, Xiphoid Process
Joints
Manubriosternal Joint (Secondary Cartilaginous)
Xiphisternal Joint (Primary Cartilaginous)
Sternoclavicular joint (Synovial Saddle)
Sternocostal joint 1st rib - (Primary Cartilaginous)
Sternocostal joints 2nd to 7th ribs (Synovial Plane)
Development
From 3 Sternabrae
STERNUM Basic Anatomy
5. STERNUM Vertebral Levels
T4/T5 Level
Demarcates sup & inf mediastinum
Bifurcation of trachea
Bifurcation of pulmonary trunk
Start & end of arch of aorta
Formation of SVC
Azygos vein joining SVC
Thoracic duct crossing
T2 Level
T9 Level
T5 to T8
T2 to T4
6. THORACIC VERTEBRAE - Classification
Classification
a. Typical
b. Atypical
Typical Thoracic Vertebrae
Parts Heart shaped body, Lamina,
pedicles, spinous process
Unique Costal facet on body, transverse
process
Atypical Thoracic Vertebrae
T1, T10, T11, T12 Only single facet on body
17. PLEURA - Pleural Recesses
The potential spaces, where the visceral and
parietal pleura are relatively distant (Expiration).
1. Costomediastinal Recess
Between costal pleura & mediastinal pleura.
Prominent in Left side.
2. Costodiaphragmatic Recess
Between costal pleura & diaphragmatic pleura.
19. LUNGS Lobes & Fissures
Lobes
Left 2 Lobes (Superior & Inferior)
Right 3 Lobes (Superior, Middle & Inferior)
Fissures
1. Oblique Fissure Runs superoposterly
From - Inferior border
To - Posterior border
2. Horizontal Fissure (R Only) Runs transversely
From - Sternum at 4th Rib
To - Oblique fissure
20. LUNGS - Hilum
Structures
Bronchus
Pulmonary artery
Two pulmonary veins
Bronchial arteries & veins
Pulmonary autonomic plexus
Lymphatics & LN
Dual blood supply (Pulmonary & Bronchial)
So that lung can survive in PE.
21. LUNGS Lymphatic Drainage
Lymphatic Plexus in Lung
Superficial lymphatic plexus beneath pleura
Deep lymphatic plexus around vessels
Lymph Drainage Pathway
1. Intrapulmonary LN (within lung)
2. Bronchopulmonary LN (at hilum)
3. Tracheobronchial LN (at bifurcation)
4. Paratracheal LN (beside trachea)
5. Mediastinal Lymph Trunks
6. Brachiocephalic veins
(Sometimes via Thoracic duct on L side)
22. LUNGS Bronchopulmonary Segments
Definition
A portion of lung Supplied by a specific
segmental bronchus, artery and vein.
Functionally separate divisions of each lobes
Structure
Wedge-shaped. Apex at hilum, base at surface.
Importance
Pathologies (Eg : Atelectasis, Bronchiectasis)
Bronchoscopy
Surgical Resection
23. TRACHOBRONCHIAL TREE
Trachea
From Cricoid (C6) to Angle of Louis (T4/T5)
Bronchi
Left (T6)
Right (T5) - Shorter, Wider & Less vertical
Angle of Carina - 600 (in adult), At T4/T5 (Mid Respiration)
Further Divisions
Main(1ry) Bronchi Lobar(2ry) bronchi Segmental(3ry)
bronchi Conducting bronchioles Terminal bronchioles
Respiratory bronchioles Alveolar ducts Alveoli
24. MEDIASTINUM - Divisions
Superior Mediastinum
Inferior Mediastinum
a. Anterior Mediastinum
b. Middle Mediastinum
c. Posterior Mediastinum
25. PERICARDIUM
Layers of Pericardium
Fibrous Pericardium
Serous Pericardium
a. Parietal layer
b. Visceral layer (Epicardium)
Attachments of Fibrous Pericardium
Adventitia of great vessels
Central tendon of diaphragm
Sternum Sternopericarial ligament
28. CHAMBERS OF HEART
Right Atrium
Inflow SVC, IVC, Coronary sinus
Outflow Tricuspid valve
Cavity - two compartments separated
by crista terminalis
Posterior Smooth (sinus venousus)
Anterior Rough (true atrium)
Pectinate muscles
Interatrial Septum Fossa Ovalis
29. CHAMBERS OF HEART
Right Ventricle
Inflow Tricuspid valve
Outflow Pulmonary Artery
(Infundibulum)
Cavity two compartments
Smooth part (near infundiculum)
Rough part trabecular carniae
a. Muscular Ridges
b. Muscular Bridges
c. Papillary Muscles
Moderator Band (Septomarginal trabeculae) - RBB
30. CHAMBERS OF HEART
Left Atrium
Inflow 4 Pulmonary veins
Outflow Mitral valve
Cavity Two compartments
Posterior Smooth (sinus venousus)
Anterior Rough (true atrium)
Pectinate muscles
31. CHAMBERS OF HEART
Left Ventricle
Inflow Mitral valve
Outflow Aorta
Cavity - two compartments
Smooth part (near aortic vestibule)
Rough part trabecular carniae
Thickest Myocardium
32. HEART Atrioventricular Valves
Tricuspid Valve
Anterior Cusp
Posterior Cusp
Septal Cusp
3 sets of Papillary muscles- connect to cusps via
cordi tendinae
Anterior Bulkiest
Posterior
Septal Often absent
Keep the valve closed during ventricular systole-
prevent regurgitation
33. HEART Atrioventricular Valves
Mitral Valve
Anterior Cusp
Posterior Cusp
2 sets of Papillary muscles connect to cusps
via cordi tendinae
Anterior - Bulkiest
Posterior
Keep the valve closed during ventricular systole-
prevent regurgitation
34. HEART - Semilunar Valves
Semilunar Valves
1. Aortic Valve
2. Pulmonary Valve
3 valve cusps blood fills in diastole valvular
closure
Aortic Valve
Coronary arteries arises from aortic sinuses.
Left CA Anterior coronary sinus
Right CA Posterior coronary sinus
35. HEART Arterial Supply
Two Coronary Arteries From Aortic sinuses
1. LCA Gives off LCx & LAD
2. RCA Gives off RMA & PIVA (70%)
Functional end arteries.
SA & AV node, Posterior 1/3 of IV septum
(by PIVA) supplied by RCA.
Clinical
Coronary Angiogram (SVD, DVD, TVD)
Cardiac Dominance (which CA gives off PIVA)
{In left dominance (30%) PIVA from LCA}
36. HEART Venous Drainage
Coronary Sinus
Receives 5 main tributaries Opens to RA
1. Great cardiac vein in Anterior IV groove
2. Middle cardiac vein in Posterior IV groove
3. Small cardiac vein with RMA
4. Posterior cardiac vein Posterior aspect of LV
5. Oblique cardiac vein Posterior aspect of LA
Other Veins
Anterior cardiac veins drain Anterior surface to RA
Venae cordis minimae drain myocardium to cavity
37. OESOPHAGUS Basic Anatomy
25 cm fibromuscular tube
From C6 to T11 (At T10 leaves thorax)
Cervical, Thoracic & Abdominal components
Blood Supply
Inferior thyroid, Thoracic aorta & Left Gastric
arteries
Lymph Drainage
Superior 1/3 Deep cervical LN
Middle 1/3 Mediastinal LN
Lower 1/3 Coeliac LN
39. THORACIC DUCT
Drain lymph from
1. Below the diaphragm
2. Left half above the diaphragm
From Cisterna Chyli Through aortic
opening of diaphragm on vertebral bodies
inclines to left at T5 drains to Left
Brachiocephalic vein
40. THORACIC SYMPATHETIC TRUNK
Runs lateral to vertebral bodies each side
Connecting sympathetic paravertebral ganglia
Behind Medial arcuate ligament become abdominal
sympathetic trunk
Paravertebral ganglia receives preganglionic nerves. They can,
1. Synapse in the paravertebral ganglia at the same level
2. Ascend in chain & synapse in higher paravertebral ganglia
3. Descend in chain & synapse in lower paravertebral ganglia
4. Travel without synapsing (Splanchnic nerves) to synapse in
prevertebral sympathetic ganglia.
41. THORACIC SPLANCHNIC NERVES
They are branches of sympathetic train that
carry preganglionic fibres to autonomic
plexuses.
They synapse in prevertebral ganglia
(coeliac, mesenteric, renal etc)
Lie medial to sympathetic trunk
3 Thoracic splanchnic nerves
1. Greater Splanchnic -T5-T9
2. Lesser Splanchnic - T10 & T11
3. Least Splanchnic -T12