THORAX

THORACIC CAGE

Conical, osseo-cartilagenous elastic cavity

On cross section • Reniform- adult • Rounded- new born

Thoracic inlet

Viscera : trachea,

oesophagus, lung apex

Vessels : BCA on rt side,

Lt CCA, Lt SCA, Rt & Lt ITA, Rt & Lt sup ICA, Rt & Lt BCV, Rt & Lt first post ICV, Inf. thyroid vein

Nerves : prhenic, vagus,

sympathetic trunk

Muscles : sternohyoid,

sternothyroid, Longus coli

Thoracic Outlet

Diaphragmatic Hernias –

1. Morgagnian hernia

2. Bockdalek’s hernia : Costo-vertebral

trigone –a bockdalek’s triangle –

• Usually absorbed on the left side

3. Hiatal Hernia – through the dilated

oesophageal hiatus

It consists of two types

- Sliding

- Rolling

INTERCOSTAL SPACE

VERTEBRAL COLUMN

Abnormal Curvatures of Vertebral Column

crooked or curved back Dowager('s) hump

THE MEDIASTINUM

THE PLEURA AND LUNGS

Recesses of pleura

Costomediastinal recesses

Costodiaphragmatic recesses

Nerve supply-

Parietal pleurae : sensitive to pain,temperature & touch and supplied by

:

– Intercostals nerve - Costal pleura & Peripheral part of diaphragmatic pleura

– Phrenic nerve - Mediastinal pleura & Central part of diaphragmatic pleura

Visceral pleura : Insensitive to touch & pain, Sensitive to stretch and

supplied by autonomic nerves

– Sympathetic - T2-T5

– Parasympathetic - vagus nerve

Blood supplies:

Artery - intercostals, internal thoracic & musculo-phrenic arteries

Vein - azyges & internal thoracic veins

Applied Anatomy of pleura :

Paracentesis thoracis : Aspiration of any fluid from pleural cavity

Done in 8th ICS in mid axillary line

Pleurisy - inflammation of pleura –> pleural rub - heard by with

stethoscope doing inspiration & expiration

Pneumothorax - presence of air in pleural cavity

Haemothorax - presence of blood in pleural cavity

Empyema - presence of pus in pleural cavity

THE LUNGS

Essential organ of respiration

Porous, highly elastic & spongy in

texture

Colour

• Newborm - Rosy pink

• Adult – Dark slaty grey

Weight

• RL- 700 gms

• LL- 600 gms

Features

Apex

Base

Surfaces :

• Costal

• medial (vertebral &

mediastinal)

Borders :

• Anterior

• posterior

• Inferior

Root : T5,T6,T7

RIGHT LUNG

LEFT LUNG

Tracheo-bronchial tree

Trachea – membrano-cartilagenous

tube • Length : 10-11 cm • Breadth : 1.5(F) -2(M) cm (1.2)- adults 3 mm – new born (up to 3rd year -> 1mm/year upto 12th year ) • Carina

Bronchopulmonary Segments

Arterial supply of lungs Bronchial arteries- supply nutrition to bronchial tree till respiratory

bronchiole

• Right lung- one, from 3rd posterior Inter-costal artery

• Left lung- two, from descending aorta

Pulmonary arteries- carries deoxygenated blood to lungs from heart

Venous drainage of lungs Bronchial vein- do not drain all blood supplied by bronchial arteries

• Two on each side

Pulmonary vein- carries oxygenated blood from lung to heart

• Two on each side

Nerve Supply :

Parasympathetic-- vagus

– Motor to bronchial muscles bronchospasm

– Secretomotor to mucous glands

– Sensory : stretch & cough reflex

Sympathetic – T2 - T5

– Inhibitory to smooth muscles & glands

Both form pulmonary plexus in lung roots distributed along

blood vessels & bronchi

Types of Cells Lining The Alveoli

Type 1 pneumocytes :

– Simple squamous cells

– 97% of alveolar surface

– Gaseous exchange takes place through type 1 cells

Type 2 pneumocytes :

– Large secretory cells surfactant

– Has proliferative power & replace damaged type 1 cells

– Neonatal RDS is due to deficiency of surfactant secretion

Alveolar macrophages:

– Phagocytosed the bacteria & other debris

– Heart failure cells (engulf extra-vasated r.b.c. in congestive heart failure & produce brick- red sputum)

APPLIED ANATOMY

Foreign body aspiration- apical segment(6) of right lower lobe

(Mendelson’ syndrome)

Posterior seg. of right upper lobe– frequently the site of tuberculosis

Anterior seg. of upper lobe– tends to be cancerous

Troracic outlet syndrome (TOS)– a tumour affecting upper lobe may

compress neuro-vascular structure around apex and manifested by:

• Venous engorgement & edema of face &UL on affected side

• Dimnished pulsation at wtist (subclavian artery)

• Paralysis of hemidiaphram (phrenic nerve)

• Hoarseness of voice (recurrent laryngeal nerve)

PERICARDIUM

(N = 50ml, Maxm = 300 ml)

(Inter-visceral space)

(Parieto-visceral space)

A cul-de-sac

PERICARDIUM

Arterial supply :

• Fibrous & parietal layer, by branches of internal thoracic artery &

descending thoracic aorta

• Visceral layer, by coronary arteries

Venous drainage :

• Fibrous & parietal layer drain into azygos & internal thoracic veins

• Visceral layer drains into coronary sinus

Nerve supply

• Fibrous & parietal layer by phrenic nerve

• Visceral layer by vagus & sympathetic nerve via coronary plexus

HEART

Measurement :

• Apex to Base= 12 cm

• A-P dia. = 6 cm

• Widest tran. dia. = 8-9 cm

• Weight

Adult male (280-340 gms)

Adult female (230-280 gms)

Features :

• Apex

• Base

• Borders- right, inferior, left

• Surfaces- sternocostal, diaphragmatic, left

Surfaces of the Heart Ortner ‘ s Syndrome

RIGHT ATRIUM

LEFT ATRIUM

RIGHT VENTRICLE LEFT VENTRICLE

Anterior aortic sinus Left posterior aortic sinus

Musculature - RV : LV = 1 : 3

On cross section – RV= similunar, LV= circular

Papillary muscles –

RV = 3 anterior, posterior & septal (smaller)

LV = 2 anterior & posterior

Aortic cusp-

1 Anterior : right cusp anterior aortic sinus right coronary artery

2 Posterior :

• left cusp left posterior aortic sinus left coronary artery

• Posterior cusp

Pulmonary cusp-

2 anterior - anterior semilunar cusp

- right semilunar cusp

1 posterior - left semilunar cusp

Conducting System of Heart

SA Node : Keith & Flack (1907) AV Node : Tawara (1906)

Internodal tract (INT) of James

anterior - INT of Bachman

middle - INT of Wenckebach

posterior – INT of Thorel

BLOOD SUPPLY OF HEART

Right dominant coronary artery

Left dominant coronary artery

Stimulation of parasympathetic system:

• decreases heart rate;

• reduces force of contraction;

• constricts the coronary arteries

Stimulation of sympathetic system:

• increases heart rate;

• increases the force of contraction

Surface marking of heart valve

AZYGOS VENOUS SYSTEM

Right Superior IC vein

THORACIC DUCT

OESOPHAGUS

Narrowest part of GIT except appendix

25 cm length, 2 cm breadth

Begins in neck as continuous of pharynx

at lower border of cricoid cartilage,

opposite C6 vertebra

4 Constriction:

• At its commencement – C6, 6 inch from

incisor

• Crossed by arch of aorta – T4, 9”

• Crossed by left bronchus – T6, 11”

• At oesopgageal opening of diaphragm –

T10, 16”

Blood supply of oesophagus :

• Upper third- by inferior thyroid artery

• Middle third- branches from descending thoracic aorta

• Lower third- branches from Left gastric artery

Lymph drainage :

• Upper 1/3rd deep cervical node

• Middle 1/3rd superior & posterior mediastinal nodes

• Lower 1/3rd nodes along left gastric blood vessels & celiac nodes

Nerve supply :

• Sympathetic from T5-T9

• Parasympathetic from both vagus & recurrent laryngeal nerve