Thorax Anatomy-Thoracic wall(Snell's Clinical Anatomy By Regions 10th Edition) Flashcards
What is the terminology of the Thorax or chest?
Thorax is a Greek for breast plate or chest.
Define the thorax
The Chest or thorax is the region of the body between the neck and the abdomen.
Discuss the shape of the thoracic wall
(1)In front and behind-flattened (2)At the sides-rounded
What structures cover the thoracic wall?
(1)The exterior of the thoracic wall-skin and muscles of the shoulder girdle. (2)The inner surface of the thoracic wall-Parietal pleura.
What are the divisions of thoracic wall ?
(1)The thoracic cage (2)The thoracic cavity
Define the thoracic cage
The skeletal framework of the thoracic walls
Mention the boundaries of the thoracic cage
I)Posteriorly-Thoracic part of vertebral column II)Laterally on either side-(1)Ribs (2)Intercostal spaces III)Anteriorly-(1)Sternum (2)Costal cartilages IV)Superiorly-Neck-superiorly the thorax communicates with the neck V)Inferiorly-Diaphragm-Inferiorly,the thorax is separated from the abdomen by the diaphragm.
What is the shape of the thoracic cage?
The thoracic skeleton forms an osseocartilaginous,cage like unit
What are the components of the thoracic cage?
The thoracic cage is a component of the axial skeleton and is formed by the:- (1)Sternum (2)Ribs (3)Costal cartilages (4)Thoracic vertebrae
What are the functions of the thoracic cage?
(1)The thoracic cage surrounds and protects the: 1.heart 2.lungs 3.adnexia (2)It covers all or part of certain upper abdominal organs,e.g: 1.liver 2.stomach 3.spleen 4.kidneys (3)It provides attachment for the muscles of the: 1.thorax 2.upper extremity 3.abdomen 4.neck
Discuss thoracic cage distortion
The shape of the thorax can be distorted by congenital anomalies of the vertebral column or by the ribs. Destructive disease of the vertebral column that produces lateral flexion or scoliosis results in marked distortion of the thoracic cage.
Discuss traumatic injury to thorax
Traumatic Injury to the thorax is common, especially as a result of automobile accidents.
Discuss the classification of the thoracic cavity?
The thoracic cavity can be divided into:
I)Mediastinum: a median portion
II)Lungs:Laterally placed
III)Pleura:location-laterally placed
Types:(1)Visceral pleura-covers the lungs
(2)Parietal pleura-the visceral pleura passes from each lung at its root(i.e,where the main air passages and
blood vessels enter)to the inner surface of the chest wall,where it is called the parietal pleura.
(3)Pleural cavities:Definition-Two membranous sac
Location-1.One on each side of the thorax
2.Between the lungs and thoracic walls.
IV)Pleural membrane:Features-(1)Thin
(2)Serous
Function-(1)Covers each lung
(2)Passes from each lung at its root(i.e.,where the main air passages and blood vessels enter)
(3)Continues onto the inner surface of the thoracic wall
Where is the mediastinum in relation to the thoracic cavity?
A median portion
Where is the lungs in relation to the thoracic cavity?
Laterally placed
Where is the pleura in relation to the thoracic cavity?
Laterally located
What are the types of pleura in relation to the thoracic cavity?
I)Visceral pleura-covers the lungs II)Parietal pleura-The visceral pleura passes from each lung at its root (i.e,where the main air passages and blood vessels enter)to the inner surface of the chest wall,where it is called the parietal pleura. III)Pleural cavities-Df:Two membranous sacs Location:(1)One on each side of the thorax (2)Between the lungs and thoracic walls
What is the terminology of the sternum,the manubrium and the xiphoid process?
I)The Sternum:Stern is Greek for “breast “;breast bone. II)The manubrium:Manubri_is Latin for handle III)The xiphoid process:Xiph-is Greek for sword
What is the location of the sternum?
Lies in the middle of the anterior chest wall
What is the shape of the sternum?
Elongate,flat bone
Enumerate the parts of the sternum?
(1)The manubrium (2)The body (3)The xiphoid process
Define the manubrium?
Is the upper part of the sternum
What is the location of the manubrium?
It lies opposite the 3rd and 4th thoracic vertebrae
Enumerate the structures at the upper part of the sternum?
(1)Left brachiocephalic vein (2)Brachiocephalic artery (3)Left common carotid artery (4)Left subclavian artery
Enumerate the structures the manubrium articulates with?
(1)Body of the sternum-at the manubriosternal joint (2)Clavicle (3)On each side:1.1st costal cartilage 2.upper part of the 2nd costal cartilage
Discuss the landmarks of the manubrium?
(I)Suprasternal(jugular)notch .location:1)on the superior border of the sternum 2)It lies opposite the lower border of the body of T2 .features:1)easily palpable-easily felt between the prominent medial ends of the clavicles in the midline. 2)concave notch (II)Clavicular notch .location:1)at each suprapleural corner of the manubrium 2)on each side of the jugular notch .shape:is an ovoid articular surface .function:each holds the sternal end of clavicle
Discuss the suprasternal(jugular)notch
.location:1)on the superior border of the sternum 2)It lies opposite the lower border of the body of T2 .features:1)easily palpable-easily felt between the prominent medial ends of the clavicles in the midline. 2)concave notch
What is the location of the suprasternal notch
1)on the superior border of the sternum 2)It lies opposite the lower border of the body of T2
What are the features of the suprasternal notch?
1)easily palpable-easily felt between the prominent medial ends of the clavicles in the midline. 2)concave notch
Discuss the clavicular notch
.location:1)at each suprapleural corner of the manubrium 2)on each side of the jugular notch .shape:is an ovoid articular surface .function:each holds the sternal end of clavicle
What is the location of the clavicular notch?
1)at each suprapleural corner of the manubrium 2)on each side of the jugular notch
What is the shape of the clavicular notch?
Is an ovoid articular surface
What is the function of the clavicular notch?
Each holds the sternal end of a clavicle
Define the body of the sternum?
Is the relatively long,middle part of the sternum
What are the joints of the body of the sternum?
(I)Above-Manubriosternal joint (sternal angle or angle of Louis) (2)Below-xiphisternal joint (3)On each side-The body of the sternum articulates with the 2nd to 7th costal cartilages on each side.
Define the manubriosternal joint
The body of the sternum articulates above with the manubrium at the manubriosternal joint (or manubriosternal angle or sternal angle or angle of Louis)
How to identify the sternal angle?
The sternal angle can be recognised by the presence of a transverse ridge on the anterior aspect of the sternum.
What is the location of the manubriosternal joint?
Between the manubrium and the body of the sternum
What is the type of the manubriosternal joint?
Is a cartilaginous joint
Discuss the movement of the manubriosternal joint
A small amount of angular movement is possible here.
What is the anatomical importance of the manubriosternal joint (sternal angle or angle of Louis)?
The manubriosternal joint (sternal angle or angle of Louis)is an important landmark for thoracic anatomy because it marks(i.e,structures at the level of manubriosternal joint or also called sternal angle or angle of Louis)the following:- (1)The manubriosternal joint (symphyseal joint). (2)The attachment points of the 2nd costal cartilages of the 2nd ribs(thus these attach to both manubrium and body). (3)A horizontal line that typically projects posteriorly onto T4 intervertebral disc(or in another words,the lower border of T4 or the intervertebral disc between T4 and and T5). (4)The plane of separation (i.e.,transition point)between the superior and inferior medistina. (5)Arch of the aorta (6)Tracheal bifurcation (7)Union of the azygos vein and superior vena cava(SVC). (8)The thoracic duct crosses to the midline. (9)Pulmonary trunk (10)Ligamentum arteriosum (11)Nerves:1.cardiac plexus 2.left recurrent laryngeal nerve
What are the other names for manubriosternal joint?
1)Manubriosternal angle 2)Sternal angle 3)Angle of Louis
What is the clinical importance of the manubriosternal joint?
Counting the ribs:- (1)The position of the sternal angle can easily be felt and is often seen as a transverse ridge. (2)The finger moved to the right or to the left will pass directly onto the 2nd costal cartilage and then the 2nd rib. (3)All ribs may be counted from this point. (4)Occasionally in a very muscular male,large pectoral muscles may obscure the ribs and intercostal spaces.In this case it may be easier to count up from the 12th rib.
Discuss the xiphisternal joint
.definition:Is the joint between the xiphoid process of the sternum and the body of the sternum. .Formation:The body of the sternum articulates below with the xiphoid process at the xiphisternal joint. .Location(vertebral level):(1)The xiphisternal joint lies opposite the body of T9. (2)Between the xiphoid process and the body of the sternum. (3)The xiphoid process usually fuses with the body of of the sternum during middle age.
Define the xiphisternal joint
Is the joint between the xiphoid process of the sternum and the body of the sternum.
Discuss the formation of the xiphisternal joint
The body of the sternum articulates below with the xiphoid process at the xiphisternal joint.
Discuss the location of the xiphisternal joint?
(1)The xiphisternal joint lies opposite the body of T9. (2)Between the xiphoid process and the body of sternum. (3)The xiphoid process usually fuses with the body of the sternum during middle age.
What are the structures the body of the sternum articulates with on each side?
The body of the sternum articulates with the 2nd to 7th costal cartilages on each side.
Discuss the xiphoid process
.Features:1.small 2.pointed(at its inferior end) 3.Thin plate-It is a thin plate of cartilage that becomes ossified at its proximal end during adult life. 4.It is highly variable in size,shape and degree of ossification .Location:It is the most inferior part of the sternum. .Joint:1.No ribs or costal cartilages attach to the xiphoid process. 2.However,the 7th costal cartilage may have a shared attachment with the xiphoid process and the body.
What are the features of the xiphoid process?
1.small 2.pointed(at its inferior end) 3.Thin plate-It is a thin plate of cartilage that becomes ossified at its proximal end during adult life. 4.It is highly variable in size,shape and degree of ossification
What is the location of the xiphoid process?
It is the most inferior part of the sternum.
Discuss the joint of the xiphoid process
1.No ribs or costal cartilages attach to the xiphoid process. 2.However,the 7th costal cartilage may have a shared attachment with the xiphoid process and the body.
What are the features of the sternum?
(1)Subcutaneous (2)Readily palpable along its entire length
Discuss the structure of the sternum
(1)Like the ribs,it consists largely of highly vascular cancellous bone enclosed by a thin shell of compact bone. (2)It possesses red haematopoitic marrow throughout life.
Discuss sternum and marrow biopsy
.Indication:For aspiration of red marrow .Technique:(1)Because of its morphology and shallow depth in the chest,the sternum can be punctured readily in a needle biopsy procedure(sternal puncture)for aspiration of red marrow. (2)Under a local anaesthetic(LA),a wide bore needle is inserted into the marrow cavity through the anterior surface of the bone.
What is the indication of the marrow biopsy?
For aspiration of red marrow
What is the technique used for marrow biopsy?
(1)Because of its morphology and shallow depth in the chest,the sternum can be punctured readily in a needle biopsy procedure(sternal puncture)for aspiration of red marrow (2)Under a local anaesthetic(LA),a wide bore needle is inserted into the marrow cavity through the anterior surface of the bone.
Discuss sternotomy
The sternum may also be split in surgery to allow the surgeon to gain access to the:- 1.heart 2.great vessels 3.thymus
Discuss sternum fracture
The sternum Is a resilient structure that Is held In position by relatively pliable costal cartilages and bendable ribs. For these reasons, fracture of the sternum is not common; however, It does occur tn high-speed motor vehicle accidents. Remember that the heart lies posterior to the sternum and may be severely contused by the sternum on impact.
Discuss the development of the sternum
1st /postnatally (A)The adult sternum consists of three parts: manubrium, body, and xiphoid process. (B)The three main parts were named after the resemblance of the sternum to the short sword favored by Roman troops and gladiators-thus, the manubrium(= handle), the body (in older terminol- ogy =gladiolus =small sword), and the xiphoid process (=sword point) 2nd/Prenatally-It consists of six main parts: (A)The first and last parts-remain distinguishable as the manubrium and xiphoid process, respectively. (B)The middle four parts (sterne- brae)-fuse to form the body.
Discuss the development of the sternum postnatally
(A)The adult sternum consists of three parts: manubrium, body, and xiphoid process. (B)The three main parts were named after the resemblance of the sternum to the short sword favored by Roman troops and gladiators-thus, the manubrium(= handle), the body (in older terminol- ogy =gladiolus =small sword), and the xiphoid process (=sword point)
Discuss the development of the sternum prenatally
It consists of six main parts: (A)The first and last parts-remain distinguishable as the manubrium and xiphoid process, respectively. (B)The middle four parts (sterne- brae)-fuse to form the body.
What is the terminology of the ribs?
Cost-is Latin for ribs
What are the general features of the ribs?
Mnemonic:EFAF (1)Elongate (2)Flattened (3)Arched bone (4)Forming a large part of the thoracic wall
Discuss the structure of the ribs
The ribs consist largely of a highly vascular cancellous bone enclosed by a thin shell of compact bone.
What is the number of the ribs
Normally,both males and females have 12 pairs of ribs
Discuss the ends of the ribs
I)Head or posterior(dorsal,vertebral)end of each rib: -Has two facets for articulation with the numerically corresponding vertebral body and that of the vertebra immediately above. -Articulates with one or two thoracic vertebrae. II)The anterior(ventral;sternal)ends: -Have variable relations that allow the ribs to be categorised as 1.True ribs 2.False ribs 3.Floating ribs -The anterior end of each rib is attached to the corresponding costal cartilage. -Is flat and has a depression for the costal cartilage
Discuss the classification of the ribs
I)True ribs(pairs 1 to 7)-are connected directly to the sternum via individual costal cartilages
II)False ribs(pairs 8 to 10)-are connected to the sternum via individual costal cartilages that join together and attach collectively
to the 7th costal cartilages.
III)Floating ribs(pairs 11 to 12)-do not attach to the sternum
Define the true ribs
Are connected directly to the sternum via individual costal cartilages
What are the true ribs
Pairs 1 to 7
Define the false ribs
Are connected to the sternum via individual costal cartilages that join together and attach collectively to the 7th costal cartilages.
What are the false ribs?
Pairs 8 to 10
Define the floating ribs
Do not attach to the sternum
What are the floating ribs?
Pairs 11 to 12
What are the features of the typical ribs?
(1)All the ribs share a common structural floor plan (2)Long (3)Twisted (4)Flat bone
Enumerate the parts of the typical rib
(1)Borders (2)Ends (3)Head or posterior(dorsal;vertebral)end of each rib (4)Neck (5)Tubercle (6)Body(shaft) (7)Costal groove (8)Angle
Discuss the borders of the typical ribs
I)Superior border:(1)Rounded (2)Smooth II)Inferior border:Thin
What are the features of the superior border of the typical ribs?
(1)Rounded (2)Smooth
What is the feature of the inferior border of the typical ribs?
Thin
Discuss the ends of the typical ribs
I)Head or posterior(dorsal,vertebral)end of each rib: -Has two facets for articulation with the numerically corresponding vertebral body and that of the vertebra immediately above. -Articulates with one or two thoracic vertebrae. II)The anterior(ventral;sternal)ends: -Have variable relations that allow the ribs to be categorised as 1.True ribs 2.False ribs 3.Floating ribs -The anterior end of each rib is attached to the corresponding costal cartilage. -Is flat and has a depression for the costal cartilage.
Discuss the head or posterior(dorsal;vertebral)end of each typical rib
-Has two facets for articulation with the numerically corresponding vertebral body and that of the vertebra immediately above. -Articulates with one or two thoracic vertebrae.
Discuss the anterior (ventral;sternal)end of typical ribs
The anterior(ventral;sternal)ends: -Have variable relations that allow the ribs to be categorised as: 1.True ribs 2.False ribs 3.Floating ribs -The anterior end of each rib is attached to the corresponding costal cartilage. -Is flat and has a depression for the costal cartilage
Discuss the neck of the typical ribs
.Location:Situated between the head and the tubercle .Features:(1)Flattened (2)Slightly constricted portion
What is the location of the neck of the typical ribs?
Situated between the head and the tubercle
What are the features of the neck of the typical ribs?
(1)Flattened (2)Slightly constricted
Discuss the tubercle of the typical ribs
.Definition:Is a prominence .Location:(1)On the outer posterior surface of the rib (2)At the junction of the neck with the body .Feature:It has a facet for articulation with the transverse process of the numerically corresponding vertebra
Define the tubercle of the typical ribs
Is a prominence
What is the location of the tubercle of the typical ribs?
(1)On the outer surface of the rib (2)At the junction of the neck with the body
What are the features of the tubercle of the typical ribs?
It has a facet for articulation with the transverse process of the numerically corresponding vertebra
Discuss the body(shaft)of the typical ribs
.Location:Extends from the tubercle to the anterior(sternal)end .Features:(1)Long (2)Thin (3)Flattened (4)Twisted part(on its long axis)
What is the location of the body(shaft)of the typical ribs?
Extends from the tubercle to the anterior(sternal)end
What are the features of the body(shaft)of the typical ribs?
(1)Long (2)Thin (3)Flattened (4)Twisted part(on its long axis)
Discuss the costal groove
.Definition:Is the elongate depression .Location:Along the inferior aspect of the internal surface of the shaft of the rib. .Function:This holds the intercostal vessels and nerve
Define the costal groove of the typical ribs
Is the elongate depression
What is the location of the costal groove of the typical ribs?
Along the inferior aspect of the internal surface of the shaft of the rib.
What is the function of the costal groove of the typical ribs?
This holds the intercostal vessels and nerve
Discuss the angle of the typical ribs
.Definition:Is the point at which the body of the rib bends sharply and turns from a lateral to a more anteriorly directed orientation .Location:Usually slightly distal to the tubercle
Define the angle of the typical ribs
Is the point at which the body of the rib bends sharply and turns from a lateral to a more anteriorly directed orientation
What is the location of the angle of the typical ribs?
Usually slightly distal to the tubercle
Discuss the 1st rib
.Features:The 1st rib is small and flattened from above downward .Relations:I)The scalenus anterior muscle is attached to its:(1)Upper surface
(2)Inner border.
II)The subclavian vein anterior to the scalenus anterior,the subclavian
vein crosses the rib
III)The subclavian artery and the lower trunk of the brachial plexus
(1)The brachial plexus of nerves (C5 to 8 and Tl) and the
subclavian artery and vein are closely related to the upper
surface of the first rib and the clavicle as they enter the
upper limb.
(2)Posterior to the muscle attachment,the subclavian artery and
the lower trunk of the brachial plexus cross the rib and lie
in contact with the bone.
(3)At the level of the 1st rib,the lower cervical nerve roots
combine to form the 3 trunks of the brachial plexus.The
lowest trunk is formed by the union of C8 and T1,and this
trunk lies directly posterior to the artery and is in contact
with the superior surface of the 1st rib.
IV)Sibson’s fascia(suprapleural membrane):
(1)Attached to the inner margin of the 1st rib and C7.
(2)Covers the apex of the lung. .Clinical importance:The 1st rib is important clinically because its close
relationship to:
(1)The lower nerves of the brachial plexus
(2)The main vessels to the arm,namely,the
subclavian artery and vein.
What are the features of the 1st rib?
Is small and flattened from above downward
What are the relations of the the 1st rib?
I)The scalenus anterior muscle is attached to its:(1)Upper surface
(2)Inner border.
II)The subclavian vein anterior to the scalenus anterior,the subclavian vein crosses
the rib
III)The subclavian artery and the lower trunk of the brachial plexus
(1)The brachial plexus of nerves (C5 to 8 and Tl) and the
subclavian artery and vein are closely related to the upper
surface of the first rib and the clavicle as they enter the
upper limb.
(2)Posterior to the muscle attachment,the subclavian artery and
the lower trunk of the brachial plexus cross the rib and lie
in contact with the bone.
(3)At the level of the 1st rib,the lower cervical nerve roots
combine to form the 3 trunks of the brachial plexus.The
lowest trunk is formed by the union of C8 and T1,and this
trunk lies directly posterior to the artery and is in contact
with the superior surface of the 1st rib. IV)Sibson’s fascia(suprapleural membrane):
(1)Attached to the inner margin of the 1st rib and C7.
(2)Covers the apex of the lung.
What is the clinical importance of the 1st rib?
The 1st rib is important clinically because its close relationship to: (1)The lower nerves of the brachial plexus (2)The main vessels to the arm,namely,the subclavian artery and vein.
Discuss the cervical ribs
.Definition:It is usually a fibrous band that attaches to the 1st thoracic rib. .Location:A rib arising from the anterior tubercle of the transverse process of the seventh cervical vertebra .Incidence:Occurs in about 0.2-0.4%(or 0.5%)in humans .Aetiology:I)Cervical ribs occur as a result the elongation of the transverse process of the 7th cervical vertebra. II)Congenital cases-may present around the 3rd decade III)Trauma .Structure:I)Consist of an anomalous fibrous band -that often originates from C7 -may arc towards the sternum -rarely reaches the sternum II)It may have a free anterior end,may be connected to the 1st rib by a fibrous band. III)May articulates with the 1st rib .C/P:I)Bilateral in up to 70% II)Neurological symptoms -In most cases -It may cause pressure on the lower trunk of the brachial plexus,causing: (1)Pain down the medial side of the forearm and hand. (2) Wasting of the small muscles of the hand. III)Compression of the subclavian artery(absent radial pulse on clinical examination) -It can also exert pressure on the overlying subclavian artery and interfere with the circulation of the upper limb. -Positive Adsons test(lateral flexion of the neck towards the symptomatic side and traction of the symptomatic arm-leads to obliteration of the radial pulse). .Treatment:I)Indication When there is evidence of neurovascular compromise II)Method A transaxillary approach-is the traditional operative method for excision
Define the cervical rib
It is usually a fibrous band that attaches to the 1st thoracic rib.
What is the location of the cervical rib
A rib arising from the anterior tubercle of the transverse process of the seventh cervical vertebra(C7)
What is the incidence of the cervical rib
Occurs in about 0.2-0.4%(or 0.5%)in humans .
What is the aetiology of the cervical rib?
I)Cervical ribs occur as a result the elongation of the transverse process of the 7th cervical vertebra. II)Congenital cases-may present around the 3rd decade III)Trauma
What is the structure of the cervical rib?
I)Consist of an anomalous fibrous band -that often originates from C7 -may arc towards the sternum -rarely reaches the sternum II)It may have a free anterior end,may be connected to the 1st rib by a fibrous band. III)May articulates with the 1st rib
what is the treatment of the cervical rib?
Discuss the rib excision
To gain entrance to the thoracic cavity, thoracic surgeons commonly perform a rib excision. A longitudinal incision is made through the periosteum on the outer surface of the rib, and a segment of the rib is removed. A second longitudinal incision is then made through the bed of the rib, which is the inner covering of the periosteum. After the operation, the rib regenerates from the osteogenetic layer of the periosteum.
Discuss rib contusion
Bruising of a rib, secondary to trauma, is the most common rib Injury. In this painful condition, a small hemorrhage occurs beneath the periosteum.
Discuss the rib fracture
.Incidence:I)In general-Common
Fractures of the rib are common chest injuries.
II)In children-Rare
In children the ribs are highly elastic,and fractures in
this age group are therefore rare.
III)In the young-More common
-Unfortunately,the pliable chest wall in the young can
be easily compressed so that the underlying lungs and
heart may be Injured.
-With increasing age,the rib cage becomes more rigid
owing to deposit of calcium in the costal cartilages,and
the ribs become brittle.The ribs then tend to break at
their weakest part ,their angles.
.Risk factor:The ribs prone to the fracture are those that are exposed or relatively
fixed.
.Sites:I)The 1st 4 ribs
(1)Anteriorly-The clavicle and pectoral muscles protect the 1st 4 ribs
(2)Posteriorly-The scapula and its associated muscles protect the 1st
4 ribs.
II)The ribs 5 through 10
Are the most commonly fractured ribs.
III)The 11th and 12th ribs
Floating and move with the force of impact
.C/P:I)Pneumothorax
Because the ribs is sandwiched between the skin externally and the
delicate pleura internally, not surprisingly, the jagged ends of a
fractured rib may penetrate the lungs and present as a pneumothorax.
II)Severe localised intercostal pain
-Is usually the most important symptom of a fractured rib
-The intercostal nerves above and below the rib innervate the
periosteum of each rib.
-To encourage the patient to breathe adequately, performing an
intercostal nerve block may be necessary to relieve the pain.
Discuss the costal cartilages
.Definition:Are bars of cartilage .Function:I)Connecting the: (1)Upper 7 ribs to the lateral edge of the sternum (2)8th,9th,and 10th ribs to the cartilage immediately above II)The cartilages of the 11th and 12th ribs end in the abdominal musculature III)The costal cartilages contribute significantly to the elasticity and mobility of the thoracic walls. .Clinical importance:In old age,the costal cartilages tend to lose some of their flexibility as the result of superficial calcification.
Define the costal cartilages
Are bars of cartilage
What are the functions of the costal cartilages?
I)Connecting the: (1)Upper 7 ribs to the lateral edge of the sternum (2)8th,9th,and 10th ribs to the cartilage immediately above II)The cartilages of the 11th and 12th ribs end in the abdominal musculature III)The costal cartilages contribute significantly to the elasticity and mobility of the thoracic walls.
What is the clinical importance of the costal cartilages?
In old age,the costal cartilages tend to lose some of their flexibility as the result of superficial calcification.
To what Costal cartilages the body of the sternum articulates with?
The body of the sternum articulates with the 2nd to 7th costal cartilages on each side.
Discuss thoracic cage distortion
The shape of the thorax can be distorted by:- I)Congenital anomalies of the vertebral column II)By the ribs III)Destructive disease of the vertebral column -produces lateral flexion or scoliosis -results in marked distortion of the thoracic cage
Discuss traumatic injury to thorax
Traumatic Injury to the thorax is common, especially as a result of automobile accidents.
Discuss flail chest
.Definition:A number of ribs may break,in which a section of the chest wall is disconnected from the rest of the thoracic wall. .Aetiology:Severe crush injuries .Site:I)If limited to one side the fractures may occur (1)Near the rib angle (2)Anteriorly near the costochondoral junction II)If the fractures occur on either side of the sternum The sternum may be flail .Mechanism:I)The stability of the chest wall is lost II)During inspiration-the flail segment is sucked in III)During expiration-the falil segment is driven out IV)This produces paradoxical and ineffective respiratory movements
Define flail chest
A number of ribs may break,in which a section of the chest wall is disconnected from the rest of the thoracic wall.
What the aetiology of the flail chest?
Severe crush injuries
What are the sites of the flail chest?
I)If limited to one side the fractures may occur (1)Near the rib angle (2)Anteriorly near the costochondoral junction II)If the fractures occur on either side of the sternum The sternum may be flail
What is the mechanism of the falil chest?
I)The stability of the chest wall is lost II)During inspiration-the flail segment is sucked in III)During expiration-the falil segment is driven out IV)This produces paradoxical and ineffective respiratory movements
Discuss traumatic injury to back of chest
The vertebral column forms the posterior midline wall of the chest. In severe posterior chest Injuries, the possibility of a vertebral fracture with associated Injury to the spinal cord should be considered. Remember also the presence of the scapula, which overlies the upper seven ribs. This bone is covered with muscles and is fractured only in cases of severe trauma.
Discuss traumatic injury to abdominal viscera and chest?
Recognising that the upper abdominal organs-namely, the liver, stomach, and spleen-may be injured by trauma to the rib cage is important. In fact, any injury to the chest below the level of the nipple line may involve abdominal organs as well as thoracic organs.
What is the feature that is only specific to the thoracic vertabrae?
Normally, only the thoracic vertebrae carry ribs, and these vertebrae have unique structures for that purpose.
What is the terminology of the facet?
Facet is Latin for little face
Define the costal facets
are small articular surfaces
What is the location of the costal facet?
I)At approximately the posterolateral aspect II)At the junction of the body and the pedicle
Discuss types of the costal facets of thoracic vertebrea
I)Typical thoracic vertebrae(2 to 8)
+Have 2 on each side:(1)Superior costal facet-Located superiorly.
(2)Inferior costal facet-Located inferiorly.
+These are the sites where the heads of the ribs articulate with the body (i.e.,
adjacent typical thoracic vertebrae,2 to 8,share the articulation of ribs).
+Thus,the head of an individual rib articulates with both the superior costal
facet of the numerically corresponding vertebral body and the inferior costal
facet of the vertebra immediately above.
II)The T1 vertebra
+Has a full costal facet(instead of a superior demifacet)for the head of the
1st rib.
+Plus an inferior demifacet for the superior half of the head of the 2nd rib.
(Think about these directional terms).
III)The T11 and T12 vertebrae
Each have full costal facets(located mainly on the pedicels)instead of
demifacet because the heads of ribs 11 and 12 articulate only with their own
individual vertebrae
Discuss the typical thoracic vertebrae(2 to 8) with regard to costal facets
+Have 2 on each side:(1)Superior costal facet-Located superiorly.
(2)Inferior costal facet-Located inferiorly.
+These are the sites where the heads of the ribs articulate with the body (i.e.,
adjacent typical thoracic vertebrae,2 to 8,share the articulation of ribs).
+Thus,the head of an individual rib articulates with both
(1) the superior costal facet of the numerically
corresponding vertebral body and
(2) the inferior costal facet of the vertebra immediately
above.
Discuss the T1 vertebrae with regard to costal facets
+Has a full costal facet(instead of a superior demifacet)for the head of the1st rib.
+Plus an inferior demifacet for the superior half of the head of the 2nd rib.
(Think about these directional terms).
What is the terminology of the demifacet?
Demi- is French for “half”
Discuss the demifacet
Because each of these facets carries half of the rib articulation, each is commonly termed a demifacet
Discuss the transverse costal facets
.Definition:are small articular surfaces on the transverse processes.
.Function:I)These are the sites where the tubercle of each rib articulates with the
transverse process.
II)Usually, these are not present on the Tll and Tl2 vertebrae because ribs
11 and 12 do not articulate with the transverse processes.
Define the transverse costal facets?
are small articular surfaces on the transverse processes.
What are the functions of the transverse costal facets?
I)These are the sites where the tubercle of each rib articulates with the transverse
process.
II)Usually, these are not present on the T11 and Tl2 vertebrae because ribs 11 and
12 do not articulate with the transverse processes.
Discuss the traumatic injury to back of chest
The vertebral column forms the posterior midline wall of the chest. In severe posterior chest Injuries, the possibility of a vertebral fracture with associated Injury to the spinal cord should be considered. Remember also the presence of the scapula, which overlies the upper seven ribs. This bone is covered with muscles and is fractured only in cases of severe trauma.
Discuss traumatic injury to abdominal viscera and chest
Recognising that the upper abdominal organs-namely, the liver, stomach, and spleen-may be injured by trauma to the rib cage is important. In fact, any injury to the chest below the level of the nipple line may involve abdominal organs as well as thoracic organs.
Discuss the joints of heads of ribs
I)The first rib and the 3 lowest ribs(i.e.,ribs 10,11,12)
have a single synovial joint with their corresponding vertebral body. II)For the second to ninth ribs
the head articulates by means of a synovial joint with the corresponding
vertebral body and that of the vertebra above it. III)Astrong intra-articular ligament
connects the head to the inter- vertebral disc.
Discuss the joints of the 1st and the 3 lowest ribs(i.e.,ribs 10,11,12)
I)have a single synovial joint with their corresponding vertebral body.
II)Astrong intra-articular ligament connects the head to the inter- vertebral disc.
Discuss the joints of the 2nd to 9th ribs
I)the head articulates by means of a synovial joint with the corresponding
vertebral body and that of the vertebra above it. II)Astrong intra-articular ligament connects the head to the inter- vertebral disc.
Discuss the joints of tubercles of ribs
I)The tubercle of a rib articulates by means of a synovial joint with the transverse
process of the corresponding vertebra.
II)This joint is absent on the 11th and 12th ribs.
Discuss the joints of ribs and costal cartilages
These joints are cartilaginous joints. No movement is possible here.
Discuss the joints of costal cartilages with sternum
I)The first costal cartilages articulate with the manubrium by cartilaginous joints
that do not permit movement.
II)The second to seventh costal cartilages articulate with the lateral border of the
sternum by synovial joints.
III)In addition, the 6th, 7th, 8th, 9th, and l0th costal cartilages articulate with one
another along their borders by small synovial joints.
IV)The cartilages of the 11th and 12th ribs do not articulate with the sternum and
are embedded in the abdominal musculature.
Write short notes on rib and costal cartilage movements
I)The first ribs and their costal cartilages are fixed to the manubrium and are
immobile. II)The raising and lowering of the ribs during respiration are accompanied by
movements in both the joints of the head and the tubercle, permitting the neck
of each rib to rotate around Its own axis.
Write short notes on thoracic openings
.Definition:Numerous gaps connect the thorax with other regions and/or separate
the bones of the thoracic cage from one another.
.Types:I)Relatively large apertures-occur at the upper and lower limits of the
thorax.
II)relatively narrow and elongate Intercostal spaces-separate adjacent ribs.
Define thoracic openings
Numerous gaps connect the thorax with other regions and/or separate the bones of the thoracic cage from one another.
What are the types of the thoracic openings?
I)Relatively large apertures-(1)Superior thoracic aperture or thoracic outlet
occur at the upper limits of the thorax.
(2)Inferior thoracic aperture or thoracic inlet.
occur at the lower limits of the thorax
II)Relatively narrow and elongate Intercostal spaces-separate adjacent ribs.
What are the types of the thoracic apertures?
(1)Superior thoracic aperture or thoracic outlet
occur at the upper limits of the thorax. (2)Inferior thoracic aperture or thoracic inlet.
occur at the lower limits of the thorax
Writes short notes on superior thoracic aperture or thoracic outlet
.Definition:The chest cavity communicates with the root of the neck through a
narrow opening called the superior aperture or thoracic outlet.
.Location:(1)The opening at the superior end of the rib cage through which
cervical structures enter the thorax.
(2)It marks the boundary between the neck & the superior mediastinum
.Reason of nomenclature:This is called thoracic outlet,especially clinically,because
important vessels and nerves emerge from the thorax
here to enter the neck and upper limbs.
.Direction:The outlet is obliquely directed
+Facing upward and forward, and
+Conveys the esophagus, trachea, and several vessels and nerves.
+Because of the angled tilt of the opening, the apices of the lungs
and pleurae project upward Into the neck.
.Boundaries:(I)Posteriorly:The body of the 1st thoracic vertebra(T1).
(II)Laterally(on both sides):The medial edges of the first ribs and their
costal cartilages.
(III)Anteriorly:The superior margin of the manubrium sterni
.Contents:Structures that pass through the thoracic inlet(The thoracic outlet
transmits structures that pass between the thorax: and the neck
(esophagus, trachea, blood vessels, etc.) and for the most part lie close to
the midline):
(I)Tubes:(1)Trachea
(2)Oesophagus
(II)Nerves:(1)Phrenic nerve
(2)Vagus nerve
(3)Recurrent laryngeal nerve
(4)Sympathetic trunks
(III)Arteries:(1)Common carotid arteries
(2)Brachiocephalic trunk
(3)Subclavian arteries
+Scalenus anterior has 2 parts,the subclavian artery
leaves the thorax by passing over the 1st rib and
between these 2 portions of the muscle.
+The subclavian artery lies posterior to scalenus
anterior,the vein lies in front.
+The subclavian artery passes anterior to the middle
scalene.
(IV)Veins:(1)Internal jugular veins
(2)Brachiocephalic veins
(3)Subclavian veins
+The subclavian vein is the most anterior structure and
is immediately anterior to scalenus anterior and its
attachment to the 1st rib.
(V)Lymphatic vessels and lymph nodes .SURGICAL IMPORTANCE: Thoracic outlet syndrome
What other names for superior thoracic aperture?
(1) Thoracic outlet.
(2) Root of the neck
Define superior thoracic aperture
The chest cavity communicates with the root of the neck through a narrow opening called the superior aperture or thoracic outlet.
What is the location of the superior thoracic aperture or thoracic outlet?
(1)The opening at the superior end of the rib cage through which cervical
structures enter the thorax.
(2)It marks the boundary between the neck & the superior mediastinum.
Why the superior thoracic aperture is called thoracic outlet?
This is called thoracic outlet,especially clinically,because important vessels and nerves emerge from the thorax here to enter the neck and upper limbs.
Write short notes on the direction of the superior thoracic aperture or thoracic outlet
The outlet is obliquely directed
+Facing upward and forward, and
+Conveys the esophagus, trachea, and several vessels and nerves.
+Because of the angled tilt of the opening, the apices of the lungs
and pleurae project upward into the neck.
What are the boundaries of the superior thoracic aperture or thoracic outlet?
(I)Posteriorly:The body of the 1st thoracic vertebra(T1).
(II)Laterally(on both sides):The medial edges of the first ribs and their
costal cartilages.
(III)Anteriorly:The superior margin of the manubrium sterni
What are the contents of the superior thoracic aperture or thoracic outlet?
Structures that pass through the thoracic inlet(The thoracic outlet transmits structures that pass between the thorax and the neck(esophagus, trachea, blood vessels, etc.) and for the most part lie close to the midline):
(I)Tubes:(1)Trachea
(2)Oesophagus
(II)Nerves:(1)Phrenic nerve
(2)Vagus nerve
(3)Recurrent laryngeal nerve
(4)Sympathetic trunks
(III)Arteries:(1)Common carotid arteries
(2)Brachiocephalic trunk
(3)Subclavian arteries
+Scalenus anterior has 2 parts,the subclavian artery
leaves the thorax by passing over the 1st rib and
between these 2 portions of the muscle.
+The subclavian artery lies posterior to scalenus
anterior,the vein lies in front.
+The subclavian artery passes anterior to the middle
scalene.
(IV)Veins:(1)Internal jugular veins
(2)Brachiocephalic veins
(3)Subclavian veins
+The subclavian vein is the most anterior structure and
is immediately anterior to scalenus anterior and its
attachment to the 1st rib.
(V)Lymphatic vessels and lymph nodes
What is the surgical importance of the superior thoracic aperture or thoracic outlet?
Thoracic outlet syndrome
Discuss thoracic outlet syndrome
.Definition:Obstruction of the thoracic outlet compressing the neurovascular
structures on the upper surface of the 1st rib.
.C/P:(I)Brachial plexus of nerves(C5 to 8 and T1) related symptoms
1)The brachial plexus of nerves (C5 to 8 and Tl) and the subclavian
artery and vein are closely related to the upper surface of the first rib
and the clavicle as they enter the upper limb.
2)Most of the symptoms are caused by pressure on the lower trunk of the
plexus,causing:
+Pain down the medial side of the forearm and hand.
+Wasting of small muscles of the hand.
(II)Blood vessels(subclavian vessels)related symptoms
Pressure on the blood vessels may compromise the circulation of the
upper limb.
Discuss the suprapleural membrane?
.Definition:A dense fascial layer closes the thoracic outlet on either side.
.Shape:Tent shaped
.Features:(1)Dense
(2)Fibrous sheet
(3)Thickening of endothoracic fascia
.Function:(1)It protects the underlying cervical pleura and
(2)Resists the changes in intrathoracic pressure occurring during
respiratory movements.
.Attachment:I)Laterally:to the medial border of the 1st rib and costal cartilage
II)Medially:to the fascia Investing the structures passing from the
thorax into the neck.
Discuss intercostal spaces
.Definition:Are the gaps between adjacent ribs.
.Layers of thoracic wall:
A needle passing through the entire depth of an intercostal space must penetrate
seven structural layers.These are most pronounced in the lateral aspect of the
thoracic wall. In superficial to deep sequence, the layers are the following:
1. Skin
2. Superficial fascia
3. Deep fascia
4. Intercostal muscles
+Depending on the specific location on the thoracic wall, an additional layer
of muscle, the serratus anterior, may cover the intercostal muscle layer.
+Three intercostal muscles fill the intercostal spaces
+The three intercostal muscles all act as muscles of respiration.
+From superficial to deep, these are:1)the external intercostal
2)the internal intercostal, and
3)the innermost intercostal muscles.
+The intercostal nerves and blood vessels(the neurovascular bundle), as in
abdominal wall, run between the intermediate(middle)and deepest
deepest(innermost)layers of muscles.They are arranged in the following
order from above downward: intercostal vein, intercostal artery, and
intercostal nerve (i.e., VAN).
5. Endothoracic fascia
+The innermost intercostal muscle is lined internally by the endothoracic
fascia, which is lined internally by a highly variable extrapleural fatty layer
and then the parietal pleura.
6. Extrapleural fatty layer
7. Parietal pleura
Discuss layers of thoracic wall
.Layers of thoracic wall:
A needle passing through the entire depth of an intercostal space must penetrate
seven structural layers.These are most pronounced in the lateral aspect of the
thoracic wall. In superficial to deep sequence, the layers are the following:
1. Skin
2. Superficial fascia
3. Deep fascia
4. Intercostal muscles
+Depending on the specific location on the thoracic wall, an additional layer
of muscle, the serratus anterior, may cover the intercostal muscle layer.
+Three intercostal muscles fill the intercostal spaces
+The three intercostal muscles all act as muscles of respiration.
+From superficial to deep, these are:1)the external intercostal
2)the internal intercostal, and
3)the innermost intercostal muscles.
+The intercostal nerves and blood vessels(the neurovascular bundle), as in
abdominal wall, run between the intermediate(middle)and deepest
deepest(innermost)layers of muscles.They are arranged in the following
order from above downward: intercostal vein, intercostal artery, and
intercostal nerve (i.e., VAN).
5. Endothoracic fascia
.Definition:A thin layer of loose connective tissue.
.Function:(1)Separates the parietal pleura from the thoracic wall.
(2)The innermost intercostal muscle is lined internally by the
endothoracic fascia, which is lined internally by a highly variable
extrapleural fatty layer and then the parietal pleura.
6. Extrapleural fatty layer
7. Parietal pleura.
Discuss the shape of the diaphragm
I)As seen from in front-It is dome shaped
+The diaphragm curves into Rt and Lt domes(cupulae).
+The arching domes of the diaphragm can reach the level of the fifth rib (the right dome can reach a higher level).
+Th Rt dome:(1)The arching dome reaches as high as the upper border of the
5th rib.
(2)Lies at a higher level because of the large size of the Rt lobe
of the liver.
+The Lt dome:The arching may reach the lower border of the 5th rib.
+The domes support the Rt and Lt lungs
II)When seen from the side-The diaphragm has the appearance of an inverted J
with the:-
(1)Long limb-Extending up from the vertebral column
(2)Short limb-Extending forward to the xiphoid process
Discuss the attachment of the diaphragm
It consists of :-
1st/Origin:Peripheral muscular part
-Which arises from the margins of the thorax.
-The origin of the diaphragm can be divided into 3 parts:
(I)Sternal part:arising from the posterior surface of the xiphoid process.
(II)Costal part:arising from the deep surfaces of the lower six ribs and their
costal cartilages.
(III)Vertebral part:(a)2 crura-arising by vertebral column
1)The Rt crus:arises from the sides and front of the
bodies of the first or upper 3 lumbar
vertebrae and the intervertebral discs.
2)The Lt crus:arises from the sides and front of the
bodies of the first or upper 2 lumbar
vertebrae and the intervertebral discs.
(b)5 arcuate ligaments-arising from the arcuate ligaments
lateral to the crura(i.e.,lateral to the
crura the diaphragm arises from the:)
1)The medial arcuate ligament(2 ligaments)
+extends from the sides of the body the 2nd lumbar
vertebra to the tip of the transverse process of the
1st lumbar vertebra.
+bridges over psoas major muscle.
2)The lateral arcuate ligaments(2 ligaments)
+extends from the tip of the transverse process of the
1st lumbar vertebra to the lower border of the
12th rib.
+bridges over quadratus lumborum
3)The median arcuate ligament(1 ligament)
+which crosses over the anterior surface of the aorta
+connects the medial borders of the two crura
2nd/Insertion:a central tendon
-Definition:A centrally placed tendon
-Location:The central tendon lies at the level of the xiphosternal joint
-Shape:Is shaped like three leaves
-Function:I)Insertion point:The diaphragm inserts into a central tendon
II)Heart support:(1)The central tendon supports the heart
(2)The superior surface of the tendon is partially
fused with the inferior surface of the fibrous
pericardium.
III)Oesophageal sphincter:(1)Some of the muscle fibres of the Rt crus
pass up to the Lt and surround the
oesophageal orifice in a sling like loop.
(2)These fibres appear to act as a sphincter
and possibly assist in the prevention of
regurgitation of the stomach contents into
the thoracic part of the oesophagus.
Discuss the shape of the diaphragm as seen from in front
It is dome shaped.
+The diaphragm curves into Rt and Lt domes(cupulae).
+The arching domes of the diaphragm can reach the level of the fifth rib (the right
dome can reach a higher level).
+The Rt dome:(1)The arching dome reaches as high as the upper border of the 5th
rib.
(2)Lies at a higher level because of the large size of the Rt lobe of
the liver.
+The Lt dome:The arching dome may reach the lower border of the 5th rib.
+The domes support the Rt and Lt lungs
Discuss the shape of the diaphragm when seen from the side
The diaphragm has the appearance of an inverted J with the:-
(1) The long limb:Extending UP from the vertebral column.
(2) The short limb:Extending FORWARD to the xiphoid process
Discuss the crura of the diaphragm
2 crura-arising by vertebral column
1)The Rt crus:arises from the sides and front of the
bodies of the first or upper 3 lumbar
vertebrae and the intervertebral discs.
2)The Lt crus:arises from the sides and front of the
bodies of the first or upper 2 lumbar
vertebrae and the intervertebral discs.
Discuss the arcuate ligaments of the diaphragm
5 arcuate ligaments-arising from the arcuate ligaments lateral to the crura (i.e.,lateral to the crura the diaphragm arises from the:)
1)The medial arcuate ligament(2 ligaments)
+extends from the sides of the body the 2nd lumbar
vertebra to the tip of the transverse process of the
1st lumbar vertebra.
+bridges over psoas major muscle.
2)The lateral arcuate ligaments(2 ligaments)
+extends from the tip of the transverse process of the
1st lumbar vertebra to the lower border of the
12th rib.
+bridges over quadratus lumborum
3)The median arcuate ligament(1 ligament)
+which crosses over the anterior surface of the aorta
+connects the medial borders of the two crura
What is the nerve supply of the diaphragm?
1st/The phrenic nerve
I)Motor nerve supply:(1)Comes from the Rt and Lt phrenic nerve(C3,4,5).
(2)Each phrenic nerve supplies approximately half of the
diaphragm.Thus,functionally,the diaphragm operates as
two hemidiaphragms.
II)Sensory nerve supply:The phrenic nerves supply the:(1)Parietal pleura
(2)Peritoneum covering
the central surfaces of
the diaphragm.
2nd/The lower six intercostal nerves
Supply the periphery of the diaphragm.
Discuss the intercostal nerves
.Origin:
These nerves are the anterior rami of the first 11 thoracic spinal nerves.
.Course:
(1)Each intercostal nerve enters an intercostal space between the parietal pleura
and the posterior intercostal membrane.
(2)It then runs forward inferiorly:(a)to the intercostal vessels in the subcostal
groove of the corresponding rib.
(b)between the innermost intercostal and internal
intercostal muscles
.Distribution:
I)The 1st 6 nerves
-are distributed within their intercostal spaces.
-The 1st intercostal nerve:(a)joins the brachial plexus by a large branch that is
equivalent to the lateral cutaneous branch of
typical intercostal nerves.
(b)the remainder of the 1st intercostal nerve
+is small
+and an anterior cutaneous branch does not
exist.
-The 2nd intercostal nerve:(a)Course:Joins the medial cutaneous nerve of the
arm by a large branch named the
Intercostobrachial nerve, which is
equivalent to the lateral cutaneous branch
of other nerves.
(b)Function:(1)Supplies the skin of the
+armpit
+upper medial side of the arm.
(2)In coronary artery disease, pain is
referred along this nerve to the
medial side of the arm.
II)The 7th-11th intercostal nerves(peritoneal sensory branches)
-Supply the:(1)skin and the parietal peritoneum covering the outer and inner
surfaces of the abdominal wall, respectively, plus the
(2)anterolateral abdominal wall muscles (which include the
external oblique, internal oblique, transversus abdominls, and
rectus abdominis muscles).
-Run to the parietal peritoneum.
-Distribution:(a)The 7th to 9th intercostal nerves leave the anterior ends of
their intercostal spaces by passing deep to the costal cartilages
therefore,leaving the thoracic wall to enter the anterior
abdominal to supply dermatomes in the anterior abdominal
wall,muscles….etc.
-The 10th and 11th nerves:pass directly into the abdominal wall
.Function:
I)supply the entire thoracic wall.
II)An Intercostal nerve not only supplies areas of skin but also supplies the ribs, costal cartilages, intercostal muscles, and
parietal pleura lining the intercostal space.
III)With the exceptions noted,the firsts intercostal nerves supply the
(1)skin and the parietal pleura covering the outer and inner surfaces of
each intercostal space, respectively.
PLUS
(2) the intercostal muscles of each intercostal space and
(3) the levatores costarum and
(4) serratus posterior muscles
.Branches:
• Rami communicants:connect the intercostal nerve to a ganglion of the sympathetic trunk.The gray and white rami are
adjacent to one another.
• The collateral branch:runs forward inferiorly to the main nerve on the upper border of the rib below.
• The lateral cutaneous branch:reaches the skln on the side of the chest. It divides into an anterior and a posterior branch.
• The anterior cutaneous branch:which is the terminal portion of the main trunk, reaches the skin near the midline.
It divides into a medial and a lateral branch.
• Muscular branches:run to the intercostal muscles.
• Pleural sensory branches:go to the parietal pleura.
• Peritoneal sensory branches(7th to11th intercostal nerves only):run to the parietal peritoneum.
Discuss the internal thoracic artery
.Function
The Internal thoracic artery supplies the anterior wall of the body from the clavicle to the umbilicus.
.Origin
It Is a branch of the first part of the subclavian artery in the neck.
.Course
(1) It descends vertically on the pleura behind the costal cartilages, a fingerbreadth lateral to the sternum. and
(2) ends in the sixth intercostal space by dividing into the:(a)superior epigastric artery
(b) musculophrenic artery
.Branches
(1)Two anterior intercostal arteries:supply the upper six intercostal spaces.
(2)Perforating arteries:accompany the terminal branches of the corresponding intercostal nerves.
(3)The pericardiophrenic artery:accompanies the phrenic nerve and supplies the pericardium.
(4)Mediastinal arteries:supply the contents of the anterior mediastinum(e.g.,the thymus)
(5)The superior epigastric artery:enters the rectus sheath of the anterior abdominal wall and supplies the rectus muscle as far
as the umbilicus.
(6)The musculophrenic artery:runs around the costal margin of the diaphragm and supplies the lower intercostal spaces and
the diaphragm.
Discuss the intercostal veins
.Feature
The intercostal veins correspond to the arteries.
.Drainage
(1) The corresponding posterior intercostal veins drain posteriorly into the azygos or hemiazygos veins
(2) The anterior intercostal veins drain anteriorly into the internal thoracic and musculophrenic veins.
Discuss the drainage of the intercostal arteries
(1) The corresponding posterior intercostal veins drain posteriorly into the azygos or hemiazygos veins
(2) The anterior intercostal veins drain anteriorly into the internal thoracic and musculophrenic veins.
What is the drainage of the posterior intercostal veins?
The corresponding posterior intercostal veins drain posteriorly into the azygos or hemiazygos veins
What is the drainage of the anterior intercostal veins?
The anterior intercostal veins drain anteriorly into the internal thoracic and musculophrenic veins.
Discuss the Thoracic Wall Lymph Drainage
I)The lymph drainage of the skin of the anterior chest wall:passes to the anterior axillary lymph nodes
II)The lymph drainage of the skin of the posterior chest wall:passes to the posterior axillary nodes.
III)The lymph drainage of the intercostal spaces:passes forward to the internal thoracic nodes, situated along the internal
thoracic artery, and posteriorly to the posterior Intercostal nodes and the
para-aortic nodes in the posterior mediastinum.
What is the lymph drainage of the skin of the anterior chest wall?
passes to the anterior axillary lymph nodes
What is the lymph drainage of the skin of the posterior chest wall?
passes to the posterior axillary nodes.
What is the lymph drainage of the intercostal spaces?
(1) passes forward to the internal thoracic nodes, situated along the internal thoracic artery, and
(2) posteriorly to the posterior intercostal nodes and the para-aortic nodes in the posterior mediastinum.
Discuss tube thoracotomy
.Insertion site
The preferred insertion site for a tube thoracostomy is the fourth or fifth intercostal space at the anterior axillary line.
The tube is introduced through a small incision.
.Related anatomy
(1)The neurovascular bundle changes its relationship to the ribs as it passes forward in the intercostal space.
(2)In the most posterior part of the space, the bundle lies in the middle of the intercostal space.
(3)As the bundle passes forward to the rib angle, it becomes closely related to the costal groove on the lower border of the rib
above and maintains that position as it courses forward.
(4)The introduction of a thoracostomy tube or needle through the lower intercostal spaces is possible provided that the presence
of the domes of the diaphragm is remembered as they curve upward into the rib cage as far as the fifth rib (higher on the
right). Avoid damaging the diaphragm and entering the peritoneal cavity and injuring the liver, spleen, or stomach.
What is the preferred insertion site for tube thoracotomy?
The preferred insertion site for a tube thoracostomy is the fourth or fifth intercostal space at the anterior axillary line.
The tube is introduced through a small incision.
What is the related anatomy of tube thoracotomy?
(1)The neurovascular bundle changes its relationship to the ribs as it passes forward in the intercostal space.
(2)In the most posterior part of the space, the bundle lies in the middle of the intercostal space.
(3)As the bundle passes forward to the rib angle, it becomes closely related to the costal groove on the lower border of the rib
above and maintains that position as it courses forward.
(4)The introduction of a thoracostomy tube or needle through the lower intercostal spaces is possible provided that the presence
of the domes of the diaphragm is remembered as they curve upward into the rib cage as far as the fifth rib (higher on the
right). Avoid damaging the diaphragm and entering the peritoneal cavity and injuring the liver, spleen, or stomach.
Discuss thoracotomy
.Definition
Thoracotomy is making an incision through the thoracic wall into the pleural space.
.Indication
This may be a lifesaving procedure in patients with penetrating chest wounds with uncontrolled intrathoracic hemorrhage.
.Technique
(1)After preparing the skin in the usual way, the physician makes an incision over the fourth or fifth intercostal space,extending
from the lateral margin of the sternum to the anterior axillary line.
(2)Whether to make a right or left Incision depends on the site of the injury.
(3)The chest should be entered from the left side for access to the heart and aorta.
(4)The following tissues will be incised:
(a) skin,
(b) subcutaneous tissue,
(c) serratus anterior and pectoral muscles,
(d) external intercostal muscle and anterior intercostal membrane,
(e) internal intercostal muscle,
(f) innermost intercostal muscle,
(g) endothoracic fascia, and
(h) parietal pleura.
(5)Avoid the:
(a)internal thoracic artery-which runs vertically downward behind the costal cartilages about a fingerbreadth lateral to the
margin of the sternum, and the
(b)intercostal vessels and nerve-which extend forward in the subcostal groove in the upper part of the intercostal space.
Discuss the orientation lines
Several imaginary lines are sometimes used to describe surface locations on the anterior and posterior chest walls:
• The midsternalline lies in the median plane over the sternum.
• The midclavicular line runs vertically downward from the midpoint of the clavicle.
• The anterior axillary line runs vertically downward from the anterior axillary fold.
• The posterior axillary line runs vertically downward from the posterior axillary fold.
• The midaxillary line runs vertically downward from a point situated midway between the anterior and posterior axillary folds.
• The scapular line runs vertically downward on the posterior wall of the thorax, passing through the infe- rior angle of the
scapula (arms at the sides)
