Thorax Flashcards
Region of the body between the neck and the abdomen
Separated from the abdomen by the diaphragm
Flattened antero-posteriorly and rounded at the sides
Thorax
Framework of the walls of the thorax
Thoracic cage
Functions of thoracic cage
- Protect vital thoracic and abdominal organs
- Provides attachment of neck, back upper limb, and abdominal musculature
Covered on the outside by skin and by muscles attached the shoulder girdle to the trunk
Thoracic wall
Lining of thoracic wall
Parietal pleura
Bones forming the thoracic cage
- Anteriorly: sternum and costal cartilages
- Posteriorly: vertebral column
- Laterally: ribs and intercostal spaces
Bones forming the thoracic wall
- Anteriorly: sternum and costal cartilages
- Posteriorly: vertebral column
- Laterally: ribs and intercostal spaces
- Superiorly: suprapleural membrane
- Inferiorly: diaphragm
2 thoracic apertures
Thoracic inlet/ superior thoracic aperture
Thoracic outlet/ inferior thoracic aperture
Boundaries of thoracic inlet
Anteriorly: superior border of the manubrium
Posteriorly: T1 vertebra
Laterally: medial border of the 1st pair of ribs and their costal cartilages
thoracic aperture Where esophagus, trachea, and many vessels and nerves pass through
Thoracic inlet
Thoracic aperture where closed by the diaphragm
Thoracic outlet
Boundaries of thoracic outlet
Anteriorly: xiphisternal joint
Posteriorly: T12 vertebra
Anterolaterally: costal cartilages of 7th to 10th ribs (costal margin)
Posterolaterally: 11th and 12th ribs
Spaces between the ribs
12 ribs, therefore 11 ______ – numbered for the rib superior to the space
Intercostal spaces
3 muscles of respiration
External intercostal muscles
Internal intercostal muscles
Innermost intercostal muscles
Neurovascular bundle
Intercostal vein
Intercostal artery
Intercostal nerve
3 major spaces of thoracic cavity
Mediastinum and 2 pulmonary cavities
Thoracic cavity space where it Contains heart, trachea, thymus, esophagus, and lymph nodes
Mediastinum
2 membranous sacs, one on each side of the thorax between the lungs and the thoracic walls
Pulmonary cavity
Bone that Lies in the midline of the anterior chest wall
sternum
Another term for sternum
Breastbone
Type of bone: sternum
Flat bone
3 parts of sternum
Manubrium
Body of the sternum
Xiphoid process
Articulating surfaces of manubrium
Clavicle
1st costal cartilage
Body of sternum
Upper part of the 2nd costal cartilage
Articulating surfaces of body of the sternum
Manubrium
Xiphoid process
2nd to 7th costal cartilages
scalloped borders where costal cartilages articulate
Costal notches
Thin plate of cartilage that ossifies at proximal end during adult life
xiphoid process
Articulating surfaces of xiphoid process
Body of sternum
Joints of the sternum
Sternoclavicular
Manubriosternal
Xiphisternal
Type of joint: sternoclavicular
synovial joint: saddle
Type of joint: manubriosternal
Secondary cartilaginous joint
Type of joint: xiphisternal
Primary cartilaginous joint
Articulations of: sternoclavicular
Manubrium + clavicle
Articulations of: manubriosternal
Manubrium + body of sternum
Articulations of: xiphisternal
Body of sternum + xiphoid process
Important clinically because this serves as the point from which all costal cartilages and ribs are counted
Sternal angle/angle of Louis
Invertebral disc opposite of sternal angle
T4 and T5
12 pairs of curved, flat bones that form most of the thoracic cage that Serves as attachment for muscles
Ribs
Rib
can cause pressure on lower trunk of brachial plexus -> pain and muscle wasting
exert pressure on subclavian artery -> interfere with circulation
Cervical rib
Arises from anterior tubercle of transverse process of C7; May have anterior free end, or connect with 1st rib via fibrous band, or articulate with 1st rib
Cervical rib
3 categories of ribs
True (Vertebrosternal)
False (Vertebrochondral)
Floating (Vertebral, free)
Ribs
- Attach anteriorly to the sternum through their own costal cartilages
- Directly connect to sternum
True ribs
Ribs
- Attached anteriorly to each other and to the 7th rib by means of their costal cartilages and small synovial joints
- Costal cartilages are connected to the cartilage of the rib above them
- Indirectly connect to sternum
False ribs
Ribs
- No anterior connections, no connection with sternum
- Rudimentary cartilage at posterior abdominal musculature
Floating ribs
2 types of rib
Typical and Atypical
3rd to 9th ribs
long, twisted, flat bone
rounded, smooth superior border and a sharp, thin inferior border
Typical rib
Parts of typical rib
Head
Neck
Tubercle
Shaft/Body
Part of typical rib: wedge shaped; has 2 facets for articulation – separated by crest of the head
Head
Part of typical rib: constricted portion that connects head with the shaft
Neck
Part of typical rib: prominence on outer surface of rib; at junction of neck and body
Tubercle
Part of typical rib: thin, flattened; twisted on its long axis
Shaft/Body
Internal border of shaft which houses the intercostal vein, artery, and nerve
Costal groove
Angle of shaft where ribs turn anterolaterally
Costal angle
2 parts of tubercle
Articular part and Non-articular part
2 facets of head
Superior and inferior
Atypical ribs
1st, 2nd, 10th, 11th, and 12th ribs
broadest, shortest, most sharply curved of the 7 true ribs
1st rib
Why is the 1st rib clinically significant?
Clinically significant because the subclavian vessels and branches of the brachial plexus pass through its superior border
Rib
- thinner, less curved body, longer than 1st rib
- atypical feature: rough area on upper surface – tuberosity for serratus anterior
2nd rib
Ribs that are short but no neck and tubercle
11th and 12th ribs
Rib with no costal angle and costal groove
12th rib
ribs with only 1 facet
1st and 10th rib
Articulations of the rib
Costovertebral
Costochondral
Interchondral
Sternocostal
Type of joint: costovertebral
synovial joint: plane
Type of joint: chostochondral
primary cartilaginous joint
Type of joint: interchondral
synovial joint: plane
Type of joint: STERNOCOSTAL - 1st costal cartilage + manubrium sterni
primary cartilaginous joint
Type of joint: STERNOCOSTAL - 2nd-7th costal cartilages + body of sternum
synovial joint: plane
Articulations of costochondrla
lateral end of costal cartilage with sternal end of rib
T or F: In children: ribs are high elastic –> fractures are rare
T
Weakest part of ribs in adults
costal angle
Most commonly fractured ribs
5th to 10th ribs
accumulation of air in the pleural space
pneumothorax
Multiple rib fractures may allow a sizable segment of the anterior and/or lateral thoracic wall to move freely
Flail chest
Movements of thoracic wall and the diaphragm increases the intrathoracic volume and diameters of the thorax
Inspiration
2 types of inspiration and expiration
Quiet and forced
Movement: when diaphragm contracts, domes become flattened and diaphragm is lowered
Vertical Diameter
Downward-sloping ribs are raised at sternal ends
anteroposterior diameter is increased
lower end of sternum is thrust forward
Pump-handle movement
Ribs curve downward as well forward around the chest wall
Bucket handle movement
Maximum increase in capacity of thoracic cavity occurs
Forced inspiration
Every muscle that can raise the ribs are brought into forced inspiration
scalenus anterior, scalenus medius, and the sternocleidomastoid
Decrease of the capacity of the thoracic cavity
Expiration
muscles – play a minor role in pulling down lower ribs in quiet expiration
serratus posterior inferior muscles
muscles – play a minor role in forced expiration
serratus posterior inferior and latissimus dorsi