clinical anatomy of lungs

Clinical Anatomy of lungs

Dr. Ashish kumar

Dept. of Chest & T.B, Santosh university

Points

1. Basic anatomy

2. Surface anatomy

3. Blood circulations

4. Innervations

5. Lymphatic

Respiratory System starts at the nares

Major Functions

Upper respiratory system:1. Air conditioning (warming)2. Defense against pathogens3. Gas Transport

Lower respiratory system:1. Speech & other

respiratory sounds2. Gas exchange (ventilation)3. Maintenance of

homeostasis, e.g. pH

Respiratory Muscles

Diaphragm: depresses on contraction inhalation

External intercostals: elevate ribs inhalation

Internal intercostals: depress ribs active exhalation

(Accessory muscles - serratus anterior, scalenes, pectoralisminor, sternocleidomastoid, internal and external obliques, transverse abdominus, rectus abdominus)

Upper Respiratory System

1. Nose

2. Nasal Cavity

3. Paranasal sinuses

4. Pharynx

Upper Respiratory System

1) Nose External and internal nares =

Nostrils Nose Hairs = vibrissae Alar cartilages on the nose Paranasal Sinuses

Upper Respiratory System

• 2) Nasal Cavity

• Nasal Conchae:

– Superior, middle and inferior

– Other name: “Turbinate bones” because they create

Upper Respiratory System

3)Paranasal Sinuses

• Named after their bones

– Frontal

– Ethmoid

– Sphenoid

– Maxillary

Upper Respiratory System

4) Pharynx

Shared passageway for respiratory and digestive systemsNasopharynx - part above uvula and posterior to internal

naresOropharynx – portion visible in mirror when mouth is wide

openfauces = the openinguvula - posterior edge of soft palate

Laryngopharynx – between the hyoid bone & the esophagus

Larynx (voice box)

The larynx consists of threearticulating cartilages,

1. Thyroid2. cricoid3. Arytenoid

Lungs

Light, soft, spongy

Conical in shape, apex, base, costal surface, medial surface, hilus. Note various impressions

Right lung

Three lobes; superior, middle and inferior

Oblique and horizontal fissure

Left Lung

Two lobes; superior and inferior also Lingula and Cardiac notch, oblique fissure

Right Lung

Left Lung

Right Lung

Lung Fissures:

Oblique fissure (Right & Left):

It starts at the 3rd thoracic spine while the arms are elevated, descends downwards, laterally & anteriorly along the medial border of the scapula touching the inferior angle of the scapula) cutting the midaxillary line in the 5th rib & ending at the 6th costal cartilage 3 inches from the midline.

In cadaver it arise at the 2nd thoracic spine.

The transverse fissure (Right):

It arises at the 4th costal cartilage, runs horizontally to meet the oblique fissure in the midaxillary line in the 5th rib.

Fissures & Lobes of the Lungs

Fissures & Lobes of the Right Lung

Right Upper Lobe

Right Middle Lobe

Right Lower lobe

Left Lung

Fissures of the Left Lung

Left Upper Lobe

Left Lower Lobe

Airways

Trachea, primary bronchi, secondary bronchi, tertiary bronchi out to 25 generations

All comprised of hyaline cartilage

Trachea

Begins where larynx ends (about C6)

10 cm long, half in neck, half in mediastinum

20 U-Shaped rings of hyaline cartilage – keeps lumen intact but not as brittle as bone

Lined with epithelium and cilia which work to keep foreign bodies/irritants away from lungs

From Bronchi to Lungs: The Bronchial Tree

1 bronchi (enter lungs at hilus, complete cartilage rings)

2 bronchi (from now on cartilage plates)

3 bronchi

Bronchioles

Terminal bronchioles

Respiratory bronchioles

Alveolar ducts

Alveolar sacs

Conducting portion

Respiratory portion

Airways

Primary Brochi One to each lung – continuation of trachea Right bronchus is wider and shorter 2.5 cm as opposed to

5 cm and branches from the trachea at a greater angle

Secondary bronchi – one to each lobe, three in right, two in left

Tertiary – one to each bronchopulmonary segment –approximately 10 per lung

All of the above are hyaline cartilage with no ability to change diameter

Bronchopulmonary Segments

Bronchopulmonary Segments

Bronchopulmonary Segments

Bronchioles

First level of airway surrounded by smooth muscle (not the cartilage ), therefore can change diameter as in brocho-constriction and broncho-dilation

Terminal

Respiratory

3-8 orders

alveoli

Bronchioles

Surface Anatomy

Borders of the lung:

The apex is about 2-3 cms (1 inch) above the medial 1/3 of the clavicle, then the anterior border of both lungs run downwards & medially meeting each other in the middle line behind the angle of Louis (sternalangle).

The anterior border of right lung continues running downwards till the 6th costochondral junction.

The anterior border of left lung continues running downwards till the 4th costal cartilage then curves laterally ½ inch forming the cardiac notch then descends downwards till the 6th costochondraljunction.

Borders of the lung:

The lower border of the lungs represented by a linestarting from 6th rib in the MCL, 8th rib in the MAL &10th rib in the scapular line.

Circulation of lungs

Two types

1. Bronchial circulation

2. Pulmonary circulation

Bronchial circulation

• The trachea (and esophagus), main-stem bronchi, and pulmonary vessels into the lung , as well as the visceral pleura in humans are supplied by the bronchial (systemic) circulation.

• The bronchial circulation has enormous growth potential. In long-standing inflammatory and proliferative diseases, such as bronchiectasis or carcinoma, bronchial blood flow may be greatlyincreased.

Pulmonary circulation

• In humans the pulmonary artery enters each lung at the hilum in a loose connective tissue sheath adjacent to the main bronchus.

• The pulmonary artery travels adjacent to and branches with each airway generation down to the level of the respiratory bronchiole.

• As blood enters the vast alveolar wall capillary network, its velocity slows, averaging approximately 1000 µm/sec (or 1 mm/sec),where gas exchange take place.

• Anatomically, the pulmonary blood vessels can be divided into two groups in

1. Extra-alveolar 2. Alveolar. Extra-alveolar

vessels lie in the loose-binding connective tissue (peribronchovascular sheaths, interlobular septa). Extra-alveolar vessels extend into the terminal respiratory units. Arteries as small as 100 µm in diameter have loose connective tissue sheaths. This is in contrast to the bronchioles, which are tightly embedded in the lung framework from the bronchioles (1 mm in diameter) onward.

Alveolar vessels lie within the alveolar walls and are embedded in the

parenchymal connective tissue

Innervation

Pleura via intercostal (thoracic) nerves.

Tracheobronchial tree motor pathway

Parasympathetic via CN X efferent function = broncho-constriction via smooth muscle, also to epithelial cells in trachea, afferent = responsible for cough reflex

Sympathetic from T1-T5 efferent = brocho-dilation

• Cholinergic, adrenergic, and peptidergic nerve Endings are present around tracheal glands and do not show patterns of slective innervation density between serous and mucous cells . Serous and mucous granule secretion is stimulated more by muscarinic than by adrenergic agents.

lymphatics

• Superficial plexuses- The superficial plexus is located n the surface of the lung just beneath the pulmonary pleura.

• Deep plexuses-accompanies the branches of the pulmonary vessels and ramifications of bronchi.

Right lung lymphatics

• Right upper lobe: • Upper 2/3rd-Right tracheobronchial nodes

• Lower l/3rd -Dorsolateral hilar nodes

• Right middle lobe: • Hilar nodes around middle lobe bronchus

• Right lower lobe: • Porsolateral part-Dorsolateral hilar nodes

• Ventromedial part- Ventromedial hilar and carinalnodes

Left lungs lymphatics

• Left upper lobe: • Apex-para-aortic node

• Other than apex-Anterior and posterior hilar nodes

• Left lower lobe • Dorsolateral part-Dorsolateral hilar nodes

• Ventromedial par^Ventromedial hilar and carinalnodes