The Human The Human ThoraxThorax

The Thoracic WallThe Thoracic Wall

Lectured by Bien Eli Nillos, Lectured by Bien Eli Nillos, MDMD

Thorax a.k.a ChestThorax a.k.a Chest

Region of the body Region of the body between the neck between the neck and the abdomenand the abdomen

Flattened in front Flattened in front and behind but and behind but rounded at the rounded at the sidessides

Framework of the ChestFramework of the Chest Behind – vertebral Behind – vertebral

columncolumn Either sides – ribs Either sides – ribs

and intercostal and intercostal spacesspaces

Front – sternum and Front – sternum and costal cartilagescostal cartilages

Superior – thoracic Superior – thoracic inletinlet

Inferiorly - Inferiorly - diaphragmdiaphragm

Cavity of the ThoraxCavity of the Thorax

Examination of the Anterior Examination of the Anterior SurfaceSurface

Suprasternal Notch – superior margin Suprasternal Notch – superior margin of the manubrium sterni, easily felt of the manubrium sterni, easily felt between the prominent medial ends of between the prominent medial ends of the clavicles in the midline. It lies the clavicles in the midline. It lies opposite the lower border of the body opposite the lower border of the body of the Second Thoracic Vertebraeof the Second Thoracic Vertebrae

Sternal Angle – the angle made Sternal Angle – the angle made between the manubrium and body of between the manubrium and body of the sternum. At this level, the second the sternum. At this level, the second costal cartilage joins the lateral margin costal cartilage joins the lateral margin of the sternum. It lies opposite the of the sternum. It lies opposite the intervetebral disc between the fourth intervetebral disc between the fourth and fifth thoracic vertebrae. and fifth thoracic vertebrae.

Xiphisternal joint – joint between the Xiphisternal joint – joint between the xiphoid process of the sternum and xiphoid process of the sternum and the body of the sternum. It lies the body of the sternum. It lies opposite the body of the ninth opposite the body of the ninth vertebra.vertebra.

Subcostal angle – situated inferior Subcostal angle – situated inferior end of the sternum, between the end of the sternum, between the sternal attachments of the seventh sternal attachments of the seventh costal cartilages.costal cartilages.

Costal Margin – lower boundary of Costal Margin – lower boundary of the thorax and is formed by the the thorax and is formed by the cartilages of the 7cartilages of the 7thth, 8, 8thth and 10 and 10thth ribs ribs and the ends of the 11and the ends of the 11thth and 12 and 12thth cartilages. cartilages.

The lowest part of the costal margin The lowest part of the costal margin is formed by the 10is formed by the 10thth rib and lies at rib and lies at the level of the 3the level of the 3rdrd lumbar vertebra. lumbar vertebra.

Clavicle – easily palpated. It articulates at Clavicle – easily palpated. It articulates at its lateral extremity with the acromion its lateral extremity with the acromion process of the scapula. process of the scapula.

Ribs – first rib lies deep to the clavicle. Ribs – first rib lies deep to the clavicle. Lateral surfaces of the remaining ribs can Lateral surfaces of the remaining ribs can be felt by pressing the fingers upward into be felt by pressing the fingers upward into the axilla and drawing them downward the axilla and drawing them downward over the lateral surface of the chest wall. over the lateral surface of the chest wall.

The 12The 12thth rib may be difficult to palpate. rib may be difficult to palpate.

Nipple – it usually lies in the 4Nipple – it usually lies in the 4thth intercostal space about 4 inches intercostal space about 4 inches from the midline. from the midline.

Apex Beat – is due to the apex of the Apex Beat – is due to the apex of the heart being thrust forward against the heart being thrust forward against the thoracic wall as the heart pumpsthoracic wall as the heart pumps

It can be felt by placing the flat of the It can be felt by placing the flat of the hand on the chest wall over the heart.hand on the chest wall over the heart.

It is normally found in the 5It is normally found in the 5thth Left Left Intercostal space 9 cms from the Intercostal space 9 cms from the midline. midline.

Axillary Folds – Axillary Folds – ANTERIOR FOLD - lower border of the ANTERIOR FOLD - lower border of the

pectoralis major musclespectoralis major muscles POSTERIOR FOLD – tendon of the POSTERIOR FOLD – tendon of the

latissimus dorsi musclelatissimus dorsi muscle

Examination of the Examination of the Posterior SurfacePosterior Surface

Spinous process of the thoracic Spinous process of the thoracic vertebrae – palpated in the midline vertebrae – palpated in the midline posteriorly. The first spinous process to posteriorly. The first spinous process to be felt is that of the 7be felt is that of the 7thth cervical vertebra cervical vertebra (C7), a.k.a. (C7), a.k.a. vertebra prominensvertebra prominens

The cervical spines of 1-6 are covered by a The cervical spines of 1-6 are covered by a large ligament, the large ligament, the ligamentum nuchaeligamentum nuchae. .

Scapula – located on the upper part of Scapula – located on the upper part of the posterior surface of the thorax, flat the posterior surface of the thorax, flat and triangular in shape.and triangular in shape.

Superior angle – lies opposite the spine Superior angle – lies opposite the spine of the 2of the 2ndnd thoracic vertebra (T2) thoracic vertebra (T2)

Inferior angle – lies on the level with the Inferior angle – lies on the level with the spine of T7spine of T7

Spinous process of the scapula – the root Spinous process of the scapula – the root of the spine lies on a level with the of the spine lies on a level with the spine of T3 spine of T3

Lines of OrientationLines of Orientation

Bones of the ThoraxBones of the Thorax

Rib – 12 pairs, “true”, “false” and Rib – 12 pairs, “true”, “false” and “floating”“floating” Head – postero-medial end of the ribHead – postero-medial end of the rib Neck – constricted region lateral to the headNeck – constricted region lateral to the head Tubercle – a projection located postero-inferior Tubercle – a projection located postero-inferior

and lateral to the neck of the riband lateral to the neck of the rib Body – shaftBody – shaft Angle – marked angulation located lateral to Angle – marked angulation located lateral to

tubercletubercle Costal groove – inner surface of the inferior Costal groove – inner surface of the inferior

borderborder

Sternum – broad, flat bone at the Sternum – broad, flat bone at the anterior of the chestanterior of the chest Manubrium – superior part of the Manubrium – superior part of the

sternumsternum Sternal angle – junction between the Sternal angle – junction between the

manubrium and body of sternummanubrium and body of sternum Body – middle part of the sternumBody – middle part of the sternum Xiphoid Process – inferior part of the Xiphoid Process – inferior part of the

sternumsternum

Clavicle – “S” shaped situated Clavicle – “S” shaped situated between the scapula and the between the scapula and the sternumsternum Sternal end – thickened proximal end of Sternal end – thickened proximal end of

the claviclethe clavicle Acromial end – the flattened lateral end Acromial end – the flattened lateral end

of the clavicleof the clavicle

Scapula – bone of the shoulder, very hard Scapula – bone of the shoulder, very hard to fracture and articulates with only one to fracture and articulates with only one bone: the clavicle. bone: the clavicle. Superior border – superior edge of the Superior border – superior edge of the

scapulascapula Medial border – border which runs from the Medial border – border which runs from the

superior angle to inferior anglesuperior angle to inferior angle Superior angle – angle formed by the union Superior angle – angle formed by the union

of the superior and medial bordersof the superior and medial borders Lateral border – runs inferiormedially from Lateral border – runs inferiormedially from

the infraglenoid tubercle to the inferior the infraglenoid tubercle to the inferior angleangle

Inferior angle – angle formed by the Inferior angle – angle formed by the union of the medial and lateral bordersunion of the medial and lateral borders

Glenoid cavity – articular surface Glenoid cavity – articular surface located at the junction of the superior located at the junction of the superior and lateral borders of the scapulaand lateral borders of the scapula

Supraglenoid tubercle – projection Supraglenoid tubercle – projection located superior to the glenoid cavitylocated superior to the glenoid cavity

Infraglenoid tubercle – projection Infraglenoid tubercle – projection located inferior to the glenoid cavitylocated inferior to the glenoid cavity

Spine – a heavy ridge that runs from Spine – a heavy ridge that runs from medial border of the scapula to the medial border of the scapula to the acromion processacromion process

Scapular notch – notch on the superior Scapular notch – notch on the superior border located medial to the attachment border located medial to the attachment of the coracoid processof the coracoid process

Coracoid process – beak-like process Coracoid process – beak-like process projects anteriorly from the lateral end of projects anteriorly from the lateral end of the superior borderthe superior border

Acromion – broad flat process located at Acromion – broad flat process located at the lateral end of the spinethe lateral end of the spine

Supraspinatus Fossa – depression located Supraspinatus Fossa – depression located superior to the spine of the scapula superior to the spine of the scapula (versus Infraspinatus fossa)(versus Infraspinatus fossa)

Muscles of the ThoraxMuscles of the Thorax

Pectoralis MajorPectoralis Major

Origin – medial ½ of the clavicle, manubrium, Origin – medial ½ of the clavicle, manubrium, body of sternum, costal cartilages of ribs 2-6body of sternum, costal cartilages of ribs 2-6

Insertion – crest of the tubercle of the Insertion – crest of the tubercle of the humerushumerus

Action – flexes and adducts the arm, medially Action – flexes and adducts the arm, medially rotates the armsrotates the arms

Blood supply – pectoral branch of the Blood supply – pectoral branch of the thoracoacromial trunkthoracoacromial trunk

Innervation – medial and lateral pectoral Innervation – medial and lateral pectoral nervesnerves

Pectoralis MinorPectoralis Minor

Origin – ribs 3,4 and 5Origin – ribs 3,4 and 5 Insertion – coracoid process of the Insertion – coracoid process of the

scapulascapula Action – draws the scapula forward, Action – draws the scapula forward,

medialward and downwardmedialward and downward Blood supply – pectoral branch of Blood supply – pectoral branch of

the thoracoacromial trunkthe thoracoacromial trunk Innervation – medial pectoral nerveInnervation – medial pectoral nerve

DiaphragmDiaphragm

Origin: xiphoid process, costal Origin: xiphoid process, costal margin, lateral and medial arcuate margin, lateral and medial arcuate ligaments, vertebral bodies of L1-L3ligaments, vertebral bodies of L1-L3

Insertion: central tendonInsertion: central tendon Action: pushes the abdominal organs Action: pushes the abdominal organs

inferiorlyinferiorly Blood supply: musculophrenic, Blood supply: musculophrenic,

superior phrenic, inferior phrenicsuperior phrenic, inferior phrenic Innervation: phrenic nerve (C3-C5)Innervation: phrenic nerve (C3-C5)

External IntercostalsExternal Intercostals

Origin: lower border of a rib within Origin: lower border of a rib within an intercostal spacean intercostal space

Insertion: upper border of rib below, Insertion: upper border of rib below, coursing downward and mediallycoursing downward and medially

Action: keeps intercostal space from Action: keeps intercostal space from blowing out or sucking inblowing out or sucking in

Blood supply: intercostal arteryBlood supply: intercostal artery Innervation: intercostal nervesInnervation: intercostal nerves

Internal IntercostalsInternal Intercostals

Origin: upper border of a ribOrigin: upper border of a rib Insertion: lower border of rib above, Insertion: lower border of rib above,

coursing upward and mediallycoursing upward and medially

Levatores CostarumLevatores Costarum

Origin: transverse process of C7-T11Origin: transverse process of C7-T11 Insertion: rib below its origin, medial Insertion: rib below its origin, medial

to the angleto the angle Action: elevates the ribAction: elevates the rib Blood supply: deep cervical artery, Blood supply: deep cervical artery,

intercostal arteriesintercostal arteries Innervation: dorsal primary rami of Innervation: dorsal primary rami of

spinal nerves C7-T11spinal nerves C7-T11

SubcostalisSubcostalis

Origin: angle of ribsOrigin: angle of ribs Insertion: angle of a rib 2-3 ribs Insertion: angle of a rib 2-3 ribs

above originabove origin Action: compresses the intercostal Action: compresses the intercostal

spacespace Blood supply: intercostal arteryBlood supply: intercostal artery Innervation: intercostal nervesInnervation: intercostal nerves

Transversus ThoracisTransversus Thoracis

Origin: posterior surface of the Origin: posterior surface of the sternumsternum

Insertion: inner surface of costal Insertion: inner surface of costal cartilages 2-6cartilages 2-6

Action: compresses the thorax for Action: compresses the thorax for forced expirationforced expiration

Blood supply: internal thoracic arteryBlood supply: internal thoracic artery Innervation: intercostal nerves 2-6Innervation: intercostal nerves 2-6