sternum and ribs

Question 1

muscles attached to the manubrium of the sternum

Answer 1

sternocleidomastoid

sternohyoid

Question 2

attachment of the sternocleidomastoid and function

Answer 2

anterior manubrium and clavicle -> temporal

head rotation and flexion

Question 3

attachment of sternohyoid and function

Answer 3

posterior manubrium -> inferior border of hyoid

depress hyoid

Question 4

muscles attached to the manubrium and body

Answer 4

pectoralis major

Question 5

attachments and function of the pectoralis major

Answer 5

clavicle and anterior manubrium and body to humerus

flexion and adduction of humerus

Question 6

sections of the sternum

Answer 6

manubrium
mesosternum
xiphoid process

Question 7

notches of the sternum

Answer 7

jugular notch
clavicular notch
costal notch (7)

Question 8

other features of the sternum

Answer 8

transverse ridges

sternal angle

Question 9

non-metric traits of the sternum

Answer 9

sternal foramen
xiphoid foramen
manubriocostal/sternal synostosis
bifid/trifid xiphoid process

Question 10

what is pectus excavation

Answer 10

failure of fusion of the thoracic plates
can cause compression of viscera
more common in males
associated with other connective tissue disorders (marfans syndrome)

Question 11

what is pectus carinatum

Answer 11

overgrowth of costal cartilage so sternum goes into a bowed position
difficulties when breathing
difficult to identify post-mortem (sometimes a straighter sternum)

Question 12

basics of the ribs

Answer 12

1-7 true ribs - articulate directly with sternum
8-10 false ribs - articulate with costal margin
11-12 floating ribs - terminate in abdominal musculature
all proximally articulate with vertebrae
increase in length 1-7
decrease in length 7-12

Question 13

describe features of a typical rib

Answer 13

superior and inferior articular facet
head
neck
tubercle (articular facet)
angle
costal groove (cranial (blunt) and cuadal (sharper) edges on either side)
sternal end

Question 14

atypical features of rib 1

Answer 14

single articular facet
oriented in transverse plane (no angle)
rough surface superiorly for muscle attachment
scalene tubercle - SCALENUS ANTERIOR: from transverse processes of C3-C6
grooves for subclavian vessels

Question 15

attachment and function of scalenus anterior

Answer 15

transverse processes of C3-C6 to scalene tubercle of 1st rib

raise ribs, flexion and rotation of neck

Question 16

atypical features of rib 2

Answer 16

begins to deviate inferiorly

ridge for attachment of SCALENUS POSTERIOR: from transverse processes C5-C7

Question 17

attachment and function of scalenus posterior

Answer 17

transverse process of C5-C7 to ridge on 2nd rib

raises ribs, flexion and rotation of neck

Question 18

atypical features of rib 11

Answer 18

single articular facet
slight angle
shallow costal groove
lacks tubercle

Question 19

atypical feature of rib 12

Answer 19

single articular facet
short
no angle
shaft tapers to a point

Question 20

non metric traits of ribs

Answer 20

cervical and lumbar ribs
bifid ribs
fused ribs
osteophitic ribs

Question 21

sequencing ribs

Answer 21

1-7 increase in size, 8-12 decrease
atypical
3 still slightly hooked
3-6 flattened anterior sternal end - terminate into costal cartilage
7-9 more cylinder shaped
7-8 on horizontal surface head will rise
upper ribs have longer and more slender necks
*rib 10 only has one articular facet and flat will be in direct contact with surface

Question 22

features of the costal cartilage

Answer 22

12 pairs
hyaline cartilage
contribute to the mobility and elasticity of the thoracic region
upper 6 pairs articulate directly with sternum via synovial joints
7-12 form costal margin

Question 23

describe a costochondral joint

Answer 23

direct between rib and cartilage
periosteum and pericardium are continuous
no movement

Question 24

describe a costosternal joint

Answer 24

1st joint between cartilage joint 1 and sternum is primary cartilaginous so has the potential to synostoses
can’t have MATRICAL manubriosternal and manubriocostal
can’t have SCLEROTIC manubriocostal and manubriosternal
2-7/8 = synovial
9+10 = rarely synovial

Question 25

changes in rib with age

Answer 25

increasing - continued ossification - morphological change of sternal end - direct ossification of costal cartilage
*rib 4

Question 26

4th rib method - Iscan et al., 1984

Answer 26

pit depth
pit shape
rim and wall
stages 0-8