Thoracic Cage

Question 1

sternum

Answer 1

flat, vertically elongated bone consisting of 3 parts:

• – manubrium (superior portion) = jugular notch; clavicular notches for clavicles; sternal angle to meet with body
• – body (middle portion) = costal notches for costal cartilage; xiphisternal joint to meet with xiphoid process
• – xiphoid process (inferior portion) = thin & varies in form; middle marker for liver, central tendon for diaphragm & inferior border of heart

Question 2

ribs

Answer 2

• curved, flat bones that form most of thoracic cage
• remarkably light in weight yet highly resilient
• each has a spongy interior containing bone marrow, which forms blood cells (hematopoietic tissue)
• three types of ribs:
• – true ribs (1st-7th) = directly attached to sternum with their own costal cartilages
• – false ribs (8th-10th) = have cartilages that are joined to cartilage of rib just superior to them; no direct contact to sternum
• — floating/false ribs (11th-12th) = no direct or indirect contact to sternum; end in posterior abdominal musculature

Question 3

three types of ribs

Answer 3

• – true ribs (1st-7th) = directly attached to sternum with their own costal cartilages
• – false ribs (8th-10th) = have cartilages that are joined to cartilage of rib just superior to them; no direct contact to sternum
• — floating/false ribs (11th-12th) = no direct or indirect contact to sternum; end in posterior abdominal musculature

Question 4

thoracic vertebrae and ribs articulation

Answer 4

• rib heads articulate with vertebral bodies

- rib tubercles articulate with transverse processes

Question 5

intervertebral joints

Answer 5

vertebrae; cartilaginous-symphysis joints

Question 6

costovertebral joints

Answer 6

ribs and vertebrae; joints of heads of ribs and costotransverse joints; synovial joint

Question 7

sternocostal joints

Answer 7

sternum and costal cartilages; synovial joints

Question 8

sternoclavicular joints

Answer 8

sternum and clavicle; synovial joints

Question 9

costochondral joints

Answer 9

ribs and costal cartilages; catilaginous joints

Question 10

interchondral joints

Answer 10

costal cartilages; synovial joints

Question 11

manubriosternal and xiphisternal joints

Answer 11

parts of the sternum in young people and sometimes are fused in elderly people; cartilaginous

Question 12

movement of thoracic wall during inspiration

Answer 12

contraction of diaphragm, which increases the vertical dimension of thoracic cavity (thoracic wall widens with forced inspiration)

Question 13

movement of thoracic wall during expiration

Answer 13

vertical diameter narrows and returns to neutral position due to elastic recoil of lungs (diagram relaxes and ascends)

Question 14

pump-handle movement

Answer 14

movement of upper ribs at costovertebral joints causes anterior ends of ribs to raise like pump handles (“pump-handle movement” increases AP diameter of thorax)

Question 15

bucket-handle movement

Answer 15

transverse dimension of thorax increases slightly when intercostal muscles contract, especially the most inferior ones (“bucket-handle movement”)

Question 16

flail chest

Answer 16

multiple rib fractures; thoracic wall move paradoxically

Question 17

thoracic outlet syndrome (TOS)

Answer 17

• vasculature and nerve supply to superior thoracic aperture compressed
• can compress subclavian artery and diminish radial pulse → numbness/tingling into upper limbs
• fracture of cervical ribs may cause TOS

Question 18

fracture of cervical ribs

Answer 18

ribs that articulate with C7 vertebrae can compress spinal nerves C8 & T1 or inferior trunk of brachial plexus
- may cause Thoracic Outlet Syndrome (TOS)

Question 19

fracture to lumbar ribs

Answer 19

less common; “T13” or L1 vertebrae

Question 20

injury to phrenic nerve

Answer 20

paralysis of diaphragm