me-anat-41 pleura and medias tin um

8/3/2019 ME-Anat-41 Pleura and Medias Tin Um

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Objectives

Describe the subdivisions of pleura

Explain the pleural reflections and formationsand importance of pleural recesses

Describe the anatomical basis of pleural tap

Describe the nerve supply of pleura and explainthe cause of referred pain

List the sudivisions of the mediastinum

Describe the important structures in superiorand posterior mediastinum


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PLEURAE

Serous membrane, double layered Parietal layer lines the thoracic cavity

Visceral layer covers the external lungsurfaces

Pleural cavity is the space in between twolayers and contain pleural fluid.

FUNCTION

1. Produce lubricating fluid

2. Compartmentalize lungs and thoraciccavity


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Dissectionshowing costal

pleura & ribs


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Costal pleura liningposterior thoracic wall,vein, artery, nerve seenrunning in intercostalspace (costal groove)

Phrenicnerve +Pericardiophrenicvessels


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PARTS OF PARIETAL PLEURA

1. Cervical pleura lines the under surface of the

suprapleural membrane2. Costal pleura lines the inner surface of the rib cage

(nerve supply - intercostal nerves)

3. Diaphragmatic pleura covers the thoracic surface of thediaphragm (nerve supply phrenic nerve)

4. Mediastinal pleura covers the lateral surface ofmediastinum (nerve supply phrenic nerve)

PLEURAL RECESSES

1. Costodiaphragmatic recess

space between costal anddiaphragmatic pleurae

2. Costomediastinal recess space between costal andmediastinal pleurae


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CERVICAL

PLEURA


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PLEURAL REFLECTIONS1. Cervical pleura is represented by a curve line, convex upward,

from the stenoclavicular joint to the junction of medial andmiddle thirds of the clavicle

2. Anterior borders of both pleurae

pass behind thesternoclavicular joints, reach the midline at the sternal angle,and descend down to 4th costal cartilages

3. The right pleura continues descending until it reaches thexiphisternal joint

4. The left one deviate laterally to reach the left border of sterumto form the cardiac notch

5. Lower border of both pleurae a. cross 8th ribs at midclavicular line

b. cross 10th ribs at midaxillary linec. cross 12 ribs at the lateral border of erector spinae muscles.

The lower borders of lungs are two intercostal spaces highera. cross 6th ribs at midclavicular lineb. cross 8th ribs at midaxillary linec. cross 10 ribs at the lateral border of erector spinae muscles.


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Costo-diaphragmatic recess of pleuraCleft like potential space between lower limit of pleural sac81012 & lower limit of corresponding lung 6810in quiet respiration, separated by a capillary spacein Mid-axillary plane widest 5 Cms

Most Dependent part of pleural sac, if fluid appears it firstcollects in this recess [PLEURAL EFFUSION]


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THORACENTESIS

Midaxillary plane at oneor two intercostal spacebelow the fluid level

May be 6,7 or 8th space

Better not below 9thspace, it may injurespleen or liver


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Structures in

relation to

MEDIASTINAL

PLEURA


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Surface marking Rt. Lung & Pleura

6th.Rib.

10th.Rib

8th Rib

Mid Axillary line

.

4th.Rib


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10th.Rib.

12th.Rib.

T3

6th

.Rib


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SUB-DIVISIONS OF THORACIC

CAVITY

THORACIC MEDIASTINUM

is space between 2 pleural sacslimited above by thoracic inlet,below by the diaphragmand from sternum in front to12 thoracic vertebrae behind

SuperiorMediastinum

Imaginary horizontal plane fromSTERNAL ANGLE to LOWERBORDER of T-4divide mediastinum into

SUPERIOR & INFERIOR.

INFERIOR again divided intoANTERIOR,MIDDLE &POSTERIORby THE HEART & PERICARDIUM


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CONTENTS OF SUP.MEDIASTINUM(BEHINDMANUBRIUM STERNI)

SUPERFICIALSUPERIOR VENA CAVA,RIGHT BRACHIOCEPHALIC VEIN,LEFT BRACHIOCEPHALIC VEIN

INTERMEDIATE

ARCH OF AORTA & ITS 3LARGE BRANCHES-BRACHIOCEPHALIC TRUNK,LEFT COMMON CAROTID &LEFT SUBCLAVIAN ARTERIES

PHRENIC, VAGUS & CARDIACNERVES

DEEP

TRACHEA BEHIND ITOESOPHAGUS,

THORACIC DUCT,RECURRENT LARYNGEALNERVE (LEFT SIDE)


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THYMUS behind sternum

Superior Mediastinum Structures

Anterior thoracic wall


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Internal Thoracic (Branchof subclavian) gives offAnterior Intercostalarteries---

then Superior epigastric(Ant abdominal wall)

& Musculophrenic(diaphragm)

Posterior thoracic wall

Upper 2 spaces SupremeIntercostal artery givesoff Posterior intercostalarteries

Rest 9 spaces,Descending Aorta givesoff Posterior intercostalarteries


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Anterior intercostal vein drains into INTERNALTHORACIC VEINdrains intoBRACHIOCEPHALICVEIN

Posterior thoracic wall

Upper 2 spacesposteriorintercostal veins draininto SUPERIORINTERCOSTAL VEINdrain into

BRACHIOCEPHALICVEIN

Rest of the posterior intercostal veinRight Side drain into Azygos veinLeft side drain into Hemiazygos vein


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PosteriorMediastinum

Above: Imaginary

horizontal plane

Sternal angle to

Lower border T-4Below: The Diaphragm

In Front: Posteriorsurface of Heart &Pericardium

Behind: Lower 8thoracic vertebrae


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Structures inposterior

mediastinum

Posterior Mediastinum Structures


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Posterior Mediastinum Structures


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APPLIED ANATOMY

1. PainLung tissues and visceral pleura are devoid ofpain sensitive nerve endings. Pain may never beexperience in lung diseases e.g. Tuberculosis

2. Pleurisy = Pleuritis

Diseases involving the parietal pleura producesevere pain referred to the

shoulder, root of neck (mediastinal, diaphragmaticpleura, referred pain via PHRENIC nerve, C3C4)

oranterior abdominal wall (costal pleura referred painvia intercostal nerves)


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THANK YOU

me-anat-41 pleura and medias tin um

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