Thoracic Skeleton & Intercostal Space Flashcards
What is the thorax?
Body between neck and abdomen
What are the functions of the thorax? (4)
Protect internal organs
Actively involved in respiration
Conduit (oesophagus)
Attachment for important muscles
What is the sternum made up of? (Superior to inferior)
Manubrium
Body of sternum
Xiphoid process
How many pairs of ribs are there in a typical person?
12
How do the ribs curve?
Antero-inferiorly
What joins (most of) the ribs to the sternum?
Costal cartilage
What is the hole in the top of the thoracic cage called?
Superior thoracic aperture (inlet)
What is the hole in the bottom of the thoracic cage?
Inferior thoracic aperture (inlet)
How many vertebrae make up the spine?
31
What are the five regions of vertebrae? (S —> I)
Cervical
Thoracic
Lumbar
Sacral
Coccyx
How many thoracic vertebrae are there?
12
How are thoracic vertebrae named?
T
Followed by number (1-12)
Ordered from superior to inferior
Which vertebrae does a single rib articulate with?
Its own number vertebra and the one above
Which vertebrae would the 5th rib articulate with?
T5 and T4
What is the fancy name for a freely movable joint?
Diarthroses
What is the fancy name for an immovable joint?
Synarthroses
What is the fancy name for a slightly movable joint?
Amphiarthroses
Which ribs are the true ribs?
First 7
What are true ribs?
Ribs that directly articulate with sternum anteriorly
Which ribs are false?
8, 9, 10
What are false ribs?
Indirectly articulate with sternum via costal cartilage of the rib above (costal margin)
Which are the floating ribs?
11, 12
Describe floating ribs (3)
Ribs with no anterior articulation with sternum
Have costal cartilage caps
Embedded into abdominal muscles
Which ribs are typical?
3-9
What are the features of a typical rib? (5)
Head with two facets (articulation with vertebrae)
Neck
Tubercle (at neck-body junction, articulates with transverse vertebral process)
Curved body (antero-inferiorly)
Costal groove (internal surface running along inferior border)
Which ribs are atypical?
1, 2 and 10, 11, 12
Describe the first rib (5)
Broad and sharply curved
Flattened superior and inferior surfaces
2 grooves on superior surface
Single facet (T1 articulation)
Tubercle for anterior scalene attachment
Describe the second rib (2)
Two facets (T1 and T2)
Roughened areas for muscle attachments (serrated anterior and posterior scalene)
How many facets do the 10th, 11th and 12th rib have?
1
Describe the 11th and 12th rib (4)
Short
No neck/tubercle
Sharply curved
No anterior articulation
What joint is between the manubrium and body of the sternum?
Manubriosternal
What joint is between the xiphoid process and the body of the sternum?
Xiphisternal
What joints are in the sternum?
Manubriosternal
Xiphisternal
What joints are between the sternum and the costal cartilage?
Sternocostal
What type of joints are manubriosternal and xiphisternal joints?
Secondary cartilaginous/symphysis
What is the sternal angle?
Where manubrium meets body of sternum
Which rib meets the sternum at the sternal angle?
2nd
How is the first rib sternocostal joint different?
Broad, curved, very strong symphysis
The rest are highly strengthened synovial joints
What joint is between the ribs and the costal cartilage?
Costochondral
What type of joint are costochondral joints?
Primary cartilaginous/synchondroses
What joint is between the false ribs and costal margin?
Interchondral
What type of joints are formed between costal cartilages?
Plane synovial
What does the spinal cord run through in a vertebra?
Vertebral foramen
What do muscles and ribs attach to on a vertebra?
Spinous and transverse processes
What part of the vertebrae stack on each other?
Vertebral body
What structure is found between each vertebra?
Vertebral discs
What joints are between the vertebrae and posterior ends of the ribs?
Costovertebral
Costotransverse
What type of joints are costovertebral and costotransverse joints?
Plane synovial
What are the three layers of intercostal muscles?
External
Internal
Innermost
In what orientation do the external intercostal muscles run?
Antero-inferiorly (same as ribs)
In what orientation do the internal intercostal muscles run?
Postero-inferiorly (opposite to externals)
What runs below the 12th rib?
Subcostal VAN
What innervates the intercostal muscles, parietal pleura and skin?
Intercostal nerves
Which spinal root is sensory?
Dorsal
Which spinal root is motor?
Ventral
What do the intercostal arteries branch from?
Aorta posteriorly
Internal thoracic vessels anteriorly (subclavian behind sternum)
Where do the arteries for the 1st and 2nd rib come from?
Subclavian (costocervical arteries)
What do the intercostal veins drain into?
Azygos system
