Trunk wall I Flashcards
trunk made up of:
- thoracic wall
- abdominal wall
thoracic cage: main parts
- 12 pairs ribs
- costal cartilage
- sternum
- 12 thoracic verterbrae
thorax: general features
- irregular shaped cylinder
- narrow superiorly, large opening inferiorly
- musculoskeletal wall: L/R pleural cavities, mediastinum
mediastinum: features
- thick soft tissue partition contains:
- esophagus
- heart
- trachea
- major nerves
- major blood vessels
pleural cavity:
- separated by mediastinum
- extends superiorly above first rib contains lungs
thorax: functions
- breathing
- protection of vital organs
- conduit
thoracic wall boundaries: posteriorly
12 thoracic vertebra and IV discs
thoracic wall boundaries: laterally
- ribs (12 per side) and intercostal
- muscles
thoracic wall boundaries: anteriorly
sternum
superior thoracic aperture boundaries: posteriorly
body of T1
superior thoracic aperture boundaries: laterally
medial margin rib 1
superior thoracic aperture boundaries: anteriorly
manubrium
superior thoracic aperture: contents
- upper limb and thorax: over 1st rib and superior part of pleural cavity as they enter/ exit mediastinum
- head and neck and thorax: more vertically
inferior thoracic aperture: features
- large and expandable
- margins: bone, cartilage, ligs closed by diaphragm
inferior thoracic aperture boundaries: posteriorly
body T12
inferior thoracic aperture boundaries: posterolaterally
rib 12, distal end rib 11
inferior thoracic aperture boundaries: anterolaterally
distal cartilaginous ends of ribs 7-10 (unite to form costal margin)
inferior thoracic aperture boundaries: anteriorly
xiphoid process
list (5) joints:
- costovertebral
- sternocostal
- interchondral
- manubriosternal
- xiphisternal
articulations of ribs 2-9:
head of rib w:
- 2 demi facets of body of own vertebra (superior costal facet)
- body above (inf costal facet)
rib tubercle w:
- TVP of own vertebra at transverse costal facet
variations: T1
facet + demifacet
variations: T9
1 demifacet
variations: T10
1 facet
variations: T11-12
1 facet, no transverse costal facet
typical ribs: eg and features
ribs 3-9:
- curved shaft
- ant end continuous w costal cartilage
- post end articulates w vertebral column (head, neck, tubercle)
shaft: superior margin (smooth, round) inferior margin (sharp, has costal groove)
angle: shaft lateral to tubercle forwards
typical rib: head
expanded, 2 articular surfaces separated by crest
typical rib: neck
short flat region separating head and tubercle
typical rib: tubercle
projects inferiorly:
- articular part: medial w oval facet -> facet of TVP
- non articular part: rough for lig attachment
atypical rib: rib 1
- flat (horizontal plane)
- broad sup/inf surfaces
- attach to manubrium
- 1 facet (only w body of T1)
- scalene tubercle (superior surface) separates two grooves: ant (subclavian v) post (subclavian aa)
- shaft roughened for attachments
atypical rib: rib 2
flat like rib 1, longer
atypical rib: rib 10
single facet for T10
atypical rib: ribs 11-12
no tubercles or necks - only articulates w body of own vertebra
- short, lil curve
- point anteriorly
costovertebral joints: consist of
- joints of heads of ribs
- costotransverse
costovertebral joints: joints and ligs allow
- rotation around longitudinal axes (mainly upper ribs)
- OR ascend/ descend relative to vertebral column (mainly lower)
joints of head of ribs: features
- 2 facets articulate: superior facet of own vertebra, inf facet of vertebra above
- 2 synovial compartments separated by intra-articular lig which: attach to crest of IV disc, separates 2 articular surfaces on head of rib
- single joint capsule around both synovial comp + lig
costotransverse joints:
synovial joint btw tubercle of rib and TVP of related vertebra
costotransverse joints: list ligs
- costotransverse
- lateral costotransverse
- superior costotransverse
costotransverse joints: movement
slight gliding
sternocostal joints: btw
btw 7 costal cartilages and sternum
sternocostal joints: classify rib 1 - maubrium
- synarthrosis
- fibrocartilaginous joint of 1st rib
sternocostal joints: classify 2-7th
synovial, reinforced by surrounding sternocostal ligs (thin capsule)
sternocostal joints: classify 2nd costal cartilage - sternum
- divided into 2 compartments by; intra-articular lig
- attaches 2nd costal cartilage - manubriosternal junction
interchondral joint: features
- costal cartilage of ribs 7-10
- indirect anchorage to sternum, help form smooth inf costal margin
- usually synovial, reinforced by interchondral ligs
manubriosternal and xiphisternal joint: features and movement
- btw manubrium + body,
- xiphoid process + body
- usually symphyses both
- slight angular movements btw manubrium + body during respiration
- joints ossify w age
intercostal spaces: btw
adjacent ribs, contains intercostal muscles
intercostal spaces: neurovascular bundle
- btw internal + innermost intercostals within costal groove
- intercostal vein/ artery/ nerve
costal groove: placement
- vein superior
- artery inferior to v
- nerve most inferior (not protected by groove)
intercostal spaces: endothoracic fascia
- contains variable fat
- deep to intercostal spaces
- separates structures from pleura
intercostal spaces: deep/ superficial fascia
- both superficial to intercostal spaces
- muscles of upper limb and back overlie the spaces
thoracic wall muscles are muscles that:
- fill/ support intercostal spaces
- pass btw sternum and ribs
- cross several ribs btw costal attachments
- reinforce thoracic wall
thoracic wall: muscles btw vertebra and ribs posteriorly and function
- levatores costarum
- serratus posterior/ inferior
- alter position of ribs + sternum to change thoracic volume during respiration
list intercostal muscles
- external
- internal
- innermost
external intercostals: features
- 11 pairs
extend from:
- inferior margin of rib -> superior margin rib below
- tubercles of ribs -> costal cartilage
- will continue as thin CT aponeurosis- external intercostal membrane
external intercostals: angular direction and function
- obliquely anteroinferiorly
- mostly inspiration
internal intercostals: features
- 11 pairs
- btw most inf lateral edge of costal groove -> superior margin rib below
- parasternal regions (btw costal cartilage) to angle of ribs posteriorly
- continues to vertebral column as internal intercostal membrane
internal intercostals: angular direction and function
- obliquely inferiorly
- mostly expiration
innermost muscles: features
- least distinct
- same orientation as internal intercostals
- most evident: lateral thoracic wall
- medial edge of costal groove -> deep surface rib below
- neurovascular bundles pass btw innermost/ internal
subcostal muscles:
- same plane as innermost intercostals: fibres parallel internal intercostals
- internal surface of one rib -> internal surface of next/ third rib below
- from angle of rib -> medial rib below
- more numerous in lower regions of post thoracic wall
transversus thoracis:
- deep surface ant thoracic wall
- same plane as innermost intercostals
- post aspect of xiphoid process/ inf part of body/ adjacent costal cartilage/ true lower ribs
- superiorly laterally
- insertion: lower borders of costal cartilage of ribs 3-6
- deep to internal thoracic vessels, secure vessels to wall
