5.Thoracic Skeleton Completed

Question 1

What is the thorax

Answer 1

Its an irregular shaped cylinder with a narrow opening
Superior thoracic aperture - which is open allowing continuity with the neck
Superiorly abd large. Opening= inferior aperture Inferiorly- closed by diaphram
Thoracic cavity enclosed by thoracic wall and diaphram is subdivided into:
Left and right plueral cavity- each surrounding a lung
The media sternum

Question 2

What is the mediastinum

Answer 2

Thick- flexible- soft tissue partition orientated longitudinally in medial sag Gita position
Contains- heart, oesophagus, trachea, major nerves and m blood vessels

Question 3

Breathing function

Answer 3

Breathing- most important function of thoracic cavity- contains lungs - diaphram, thoracic wall- ribs- for effectively moving air in/out of lungs

Question 4

What are the functions of the thoracic cavity ?

Answer 4

Breathing
Protection of vital organs
Conduit

Question 5

PROTECTING VITAL; ORGANS explanation

Answer 5

Thorax houses and protects heart,lungs,great vessels
Due to upward dome shape of diaphram thoracic wall offers protection to some important- abdominal viscerA
MUCH OF LIVER LIES UNDER RIGHT DOME Of diagram- stomach, spleen lie under left
Posterior aspects of superior poles of kind let lie on the diagram
Anterior to rib XII on right and to ribs XI XII LEFT

Question 6

CONDUIT FUNCTION

Answer 6

Media stern acts as conduit for structures that pass completely through thorax
From one body religion to another
Abd for structures that connect organs in thorax to other body regions

Question 7

WHAT ARE THE COMPONAT PARTS OF THIORCIC WALLS?

Answer 7

SKELETAL AND MUSCLE ELEMENTS
Posteriorly- made up of 12 thoracic vertebrae + thier intervening intevertenbral disks
Laterally - wall is formed by ribs 12 on each side
Anteriorly- wall made up of sternum, which consists of manubrium of sternum, body of sternum and xiphoid process

Question 8

Continues

Answer 8

The anterior distal end of each rib + composed if costal cartilage - contributes to mobility and elasticity of wall
All ribs- articulate with thoracic vertabre posteriorly
Most ribs from II TO IX have 3 articulations with vertebral column
Head of each rib articulate with body of its own vetebrae and body of v above- each articulate also with transverse process of its vertebra

Question 9

ARRICULATIONS CONTINUES

Answer 9

Anteriorly- costal cartilages of ribs 1 it V11 articulate with sternum
Cc of ribs V111 to x articulate with inferior margins of cc above them
Ribs X1 X11 - floating ribs- do not articulate with other ribs/cc/stern num- thier cc is small- only cover thier tips

Question 10

What is the superior thoracic aperture

Answer 10

Its completely surrounded by skeletal elements - consists of body of vetebrae t1 posteriorly, median margin of rib 1 on each side and the maubrium interiorly
The superior margin of madubrium+ same horizontal plane as intervertebral disks between vetebrae t11-T111

Question 11

DESCRIBE INFERIOR THORACIC APERTURE

Answer 11

= large/expandable
Ligaments form its margin
Its aperture is cooked by diagram and =structures passing between abdomen and thoracic pierce or pass posteriorly to the diagram
Skeletal elements of ia =
Body of vetebra tx11 posteriorly
Rib x11 and distal end of rib x1 posterolaterally
The distal cartilaginous ends of ribs v11 to x- which unite to form the coastal margin anterolaterally
The xiphoid process anteriorly

Question 12

What are the skeletal elements of the thoracic wall?

Answer 12

Consists of the thoracic vetebrae, intervertebral discs , ribs and sternum

Question 13

=how does the thoracic veterbrta articulate with ribs

Answer 13

Typical thoracic vetebrae has 3 sites on each side for articulation with ribs
- two Demi facets are located on superior/inferior aspects of the body for articulation with corresponding heads of adjacent ribs
The superior costal facet articulates with part of head of its own rib- inferior articulates with part of head of rib below
Ova;l facet- transverse costal facet at end of transverse process articulates worth turbicle of its own rib

Question 14

Continued

Answer 14

Superior COSTAL FACETS ON BODY OF VETEBRA T1 ARE COMPLETE- ARTICULATE with single facet of head of its own rib- the head of rib 1 doesn’t articulate with vetebra of cv11
VETEBRA TX- articulates with only its own ribs- lacks Demifacets on body
Vetebrae TX1 TX11 articulate only with heads of thier own ribs- lack transverse costal facets- have only scomplete facet on each side of body

Question 15

Ribs overview

Answer 15

12 pairs of ribs
Each terminating anteriorly in costal cartilage
Only cc of upper 7 ribs are known as true ribs- articulate directly with sternum
Remaining 5 pairs= false ribs
Cc of ribs V11 TO X articulate anteriorly with cc of ribs above
RIBS X1 X11 - have no anterior connevction with other ribs/sternum= floating ribs

Question 16

Describe a typical rib

Answer 16

Consists of curved shaft with anterior/posterior ends
Anterior- continuos with its cc
Posterior- articulates with the VETEBRA l column- is characterised by a head/neck/tubercle
Typical rib head- expanded somewhat- typically presents two articular surfaces seperated by a crest
Small superior surface- articulates with inferior costal facet on body of v above
Larger inferior facet- articulates with superior costal facet of its own v
Neck = short flat region of bone that separates head from tubercle

Question 17

Describe this tubercle

Answer 17

Projects posteriorly from junction of the neck with the shaft
Consists of two regions, an articular part and a non articular part
A part- medial/has oval facet for articulation with corresponding fact on the transverse process of the associated VETEBRA
THE RAISED NON- A part is roughened by ligament attachments

Question 18

Describe the shaft

Answer 18

Thin/flat
Superior margin is smooth
Inferior- sharp
Shaft bends forward just laterally to the tubercle at site termed- the angle
Inferior margin of internal surface is marked by a distinct costal groove

Question 19

What are the distinct features of the upper and lower ribs?

Answer 19

Rib 1- flat in horizontal plane- has broad superior/interior surfaces
From its articulation with veterbra t1 it slopes Inferiorly to the attatchment to the manubrium of sternum
Head articulates with only the body of vetebra t1 and therefore has only 1 articular surface
The tubercle has a facet for articulation witch the transverse process
Superior surface of rib- characterised by 2 distinct tubercles : scalene, separate the 2 smooth grooves that crosses the rib around midway along the shaft
Anterior groove is caused by the subclavian vein
Posterior groove is cused by the subclavian artery

Question 20

RIB 11

Answer 20

Is flat
Twice as long as rib 1
Articulates with vertebral column in typical way of mostly ribs

Question 21

RIBS X

Answer 21

HEAD OF RIB X HAS SINGLE facet for articulation with its own vetebra

Question 22

RIBS X1 X11

Answer 22

BOTH OBLY ARTICULATE WITH BVODIES OF THIER OWN VETEBRA
HAVE NO TUBERCLES /NECKS
Short, have little curve, pointed anteriorly

Question 23

Sternum describe Timon

Answer 23

Adult sternum consists of 3 major elements
The broad/superiorly positioned manubrium of sternum
The narrow/longitudinally orientated body of sternum
Small/Inferiorly positioned xiphoid process

Question 24

Describe the manubrium of sternum

Answer 24

Forms part of bony framework of neck and thorax
Superior surface of m is expanded laterally
Bears distinct/palpable jugular (supra sternal) notch in the midline
On either side of notch is a large oval fossa for articulation with the clavicle
Immediately inferior to the fossa- on each lateral surface of manubrium is a facet for the attatchment of the first cc
At lower end of lateral border is a demifacer for articulation with upper half of the anterior end of the second distal cartilage

Question 25

Body of sternum

Answer 25

Flat
Lateral margins of bos have articular facets for cc
Superiorly each lateral margin has demifact for a with inferiors aspect of second cc
Inferior to this df = 4 facets for articulation with the cc of ribs 111 to vi
At the inferior end of bos =demifacet for a with upper df on 7th cc
Inferior end of bos is attached to xiphoid process

Question 26

Xiphoid process

Answer 26

Smalles part of sternum
Variable shape
Can w=be wide/thin/pointed/bifilar/curved/perforates
On each side of units lateral margin is a demifacte for articulation with inferior end of 7th cc

Question 27

What is the cistovetebral joint?

Answer 27

Typical rib articulated with\
Body of adjacent v- forming joint with head of rub
The transversest process ion its related vetebra forming costotransverse joints
They are synovial; joints between tubercle of rib and transverse process of related vetebra
Capsule surrounding each joint= thin

Question 28

Costoveterbral joints
Joint with head of rib

Answer 28

-Two facets on head of rib articulate with the superior facet on body of its own vetebra and with the interior facet on the body of the vetebra above
-Joint is divided into two synovial compartments by an intaaritcular liga,nets which separates the two articular surfaces on head of rib
- the two s compartments + thier intervening ligament are surrounded by a single joint capsule attcatcjed to the outer margins of the combine a surfaces of head and vertebral column

Question 29

Costivertebral/ costotransverse joints

Answer 29

The Joint is stabilised by 2 string extracapsularligaments , that span the space between the transverse process and rib on the medial and lateral sides of joint
- costotranssverse ligament- is medial to the joint + attatches the neck of rib to transverse process
The lateral costotransverse ligament- is lateral to the joint and attaches to the tip of the tp to the toughened non- articular part of tubercle of the rib
- 3rd ligament, superior costotransverse ligament- attacthment the superior surface of the neck of rib to the transverse process of the vetebra above

Question 30

Sternocostal joints

Answer 30

Are between 7 cc and the sternum
The joint between rib 1 and the maubrium is not synovial
Consists of fibro-cartilaginous connection between the maubrium and the cc
The second to 7th joints are synovial- have thin capsules- reinforced by surrounding sternocostal ligaments
The joint between 2nd cc and sternum is divided into two copmartments by an intraarticular ligament which attatches the second cc to the junction of the manubrium and bos

Question 31

Interchondral joints

Answer 31

Occur between the cc of adjacent ribs
Mainly between the cc of ribs v11 to x
IJ provide indirect anchorage to sternum
Contributes to formation of a smooth inferior costal margin
Usually synovial
Thin fibrous capsules are reinforced by iNTERCHONDRAL ligaments

Question 32

Manubriosternal and xiphisternal joints

Answer 32

Are the joints between the manubrium and the bos and between the bos and xiphoid process
Ar cartilaginous joints - symphysis
Where only a thin layer old hyaline cartilage covers the articular surfaces
Often become ossified with age