sternum and ribs Flashcards
muscles attached to the manubrium of the sternum
sternocleidomastoid
sternohyoid
attachment of the sternocleidomastoid and function
anterior manubrium and clavicle -> temporal
head rotation and flexion
attachment of sternohyoid and function
posterior manubrium -> inferior border of hyoid
depress hyoid
muscles attached to the manubrium and body
pectoralis major
attachments and function of the pectoralis major
clavicle and anterior manubrium and body to humerus
flexion and adduction of humerus
sections of the sternum
manubrium
mesosternum
xiphoid process
notches of the sternum
jugular notch
clavicular notch
costal notch (7)
other features of the sternum
transverse ridges
sternal angle
non-metric traits of the sternum
sternal foramen
xiphoid foramen
manubriocostal/sternal synostosis
bifid/trifid xiphoid process
what is pectus excavation
failure of fusion of the thoracic plates
can cause compression of viscera
more common in males
associated with other connective tissue disorders (marfans syndrome)
what is pectus carinatum
overgrowth of costal cartilage so sternum goes into a bowed position
difficulties when breathing
difficult to identify post-mortem (sometimes a straighter sternum)
basics of the ribs
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
describe features of a typical rib
superior and inferior articular facet head neck tubercle (articular facet) angle costal groove (cranial (blunt) and cuadal (sharper) edges on either side) sternal end
atypical features of rib 1
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
attachment and function of scalenus anterior
transverse processes of C3-C6 to scalene tubercle of 1st rib
raise ribs, flexion and rotation of neck
atypical features of rib 2
begins to deviate inferiorly
ridge for attachment of SCALENUS POSTERIOR: from transverse processes C5-C7
attachment and function of scalenus posterior
transverse process of C5-C7 to ridge on 2nd rib
raises ribs, flexion and rotation of neck
atypical features of rib 11
single articular facet
slight angle
shallow costal groove
lacks tubercle
atypical feature of rib 12
single articular facet
short
no angle
shaft tapers to a point
non metric traits of ribs
cervical and lumbar ribs
bifid ribs
fused ribs
osteophitic ribs
sequencing ribs
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
features of the costal cartilage
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
describe a costochondral joint
direct between rib and cartilage
periosteum and pericardium are continuous
no movement
describe a costosternal joint
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
changes in rib with age
increasing - continued ossification - morphological change of sternal end - direct ossification of costal cartilage
*rib 4
4th rib method - Iscan et al., 1984
pit depth
pit shape
rim and wall
stages 0-8
