Organization of the thorax: thoracic wall Flashcards
where is the AML (anterior medial line)
right down the front
down manubrium and sternum
through umbilicus
where is the MCL (midclavicular line)
passes through the midpoint of the clavicle parallel to the AML (on both sides)
where is the AAL (anterior axillary line)
runs vertically along the anterior axillary fold that is formed by the inferolateral border of the pectoralis major as it spans from the thoracic cage to the humerus in the arm
MAL (midaxillary line) where is it
runs from the apex (deepest part of the axillary fossa (armpit) parallel to the AAL
PAL (posterior axillary line) is where
parallel to the AAL is drawn vertically along the posterior axillary fold formed by the latissimus dorsi and teres major muscles as they span from the back to the humerus
SL where is this (scapular lines)
parallel to the posterior median line and intersect the inferior angles of the scapula
PML (posterior median line) is where
is a vertical line along the tips of the spinous processes of the vertebrae
what is the thorax and what is it composed of?
the superior part of the trunk lying between the root of the neck (superior thoracic aperture) and thoracic diaphragm (inferior thoracic aperture)
composed of thoracic wall (osteocartilaginous components, muscles, fascia, skin)
and the thoracic cavity (2 pulmonary cavities and central mediastinum)
what is the function of the thorax
protection underlying viscera
respiration
muscle attachment
what are the true ribs
1-7
attach directly the sternum
what are the false ribs
8-10
attach to the costal cartilage of rib above and form the infracostal (costal) margin
what are the floating ribs
11-12
not attached to the sternum
anteriorly end in muscle
what are the typical ribs
what are the anatomical features of typical ribs
3-9
Head- articulates with adjacent vertebral bodies
Neck- portion between the head and tubercle
Tubercle- junction of head and neck, articulates with transverse process
Angle - the anterolateral angulation of the body just lateral to the tubercle
shaft (body) - inferior portion has a concave internal surface called the costal groove
costal cartilage
what is the function of the costal groove
provides protection for intercostal vein, artery, nerve
what is the function of the costal cartilage
provides increased elasticity for thoracic wall
what is unique about the 1st rib
broad horizontal shaft with pronounced curvature
head has single facet for articulation with TV1
shaft contains grooves for subclavian artery and vein and scalene tubercle
what is unique about the 2nd rib
serratous anterior tuberosity on the superior surface
what is unique about the 10th rib
single articular facet for articulation with body of TV10
what is unique about 11th and 12th ribs
single articular facet on head
no neck/tubercle
where is the most common site of rib fractures and what are the most commonly broken ribs
near angle b/c this is weakest part of rib
middle ribs most common to break
what is flail chest
results from multiple ribs broken in 2 or more places
this causes a loose segment of thoracic wall which moves paradoxically during respiration
what are the components of the sternum
manubrium
body
Xiphoid process
manubrium parts
suprasternal notch
clavicular notch
lateral facets for articulation with costal cartilages of ribs 1 and 2
where is the sternal angle or angle of Louis located
at the manubriostenral joint
what costal cartilages does the body articulate with
costal cartilages of ribs 2-7
why is the sternal angle an important landmark
angle of Louis
because it demarcates the articulation of rib 2
also a horizontal plane passed from the sternal angle to the disc between T4-T5 marks the boundary between superior and inferior mediastinum and is called the Transverse Thoracic Plane.
what is special about the xiphoid process
cartilaginous but usually ossifies with age
lateral demi-facets for articulation with the costal cartilage of 7th rib
articulates with the body of the sternum
infrasternal angle
what is pectus excavatum
what is pectus carinatum
excavatum–> anterior thoracic wall sunken in
carinatum–> anterior thoracic wall protrusion or “pigeon” breast
anomalies resulting from malformation of sternum and ribs
can cause respiratory and cardiac problems
what are the borders (A, L, P) of the superior thoracic aperture (aka thoracic inlet)
clinical correlation?
Anterior- suprasternal (jugular) notch
Lateral-1st rib
posterior- 1st thoracic vertebra
superior aperture extends obliquely from 1st thoracic vertebra anteroinferiorly to the manubrium. The pleural space extends superiorly into the neck region. Thus, injury or surgery within this region may affect the pleural cavity and lungs (pneumothorax).
inferior thoracic aperture borders ? (aka thoracic outlet)
clinical correlation
Anterior- xiphisternal joint
Lateral- costal margin
Posterior- 12th thoracic vertebra and 11th and 12th rib
The inferior aperture extends obliquely from 12th thoracic vertebra anterosuperiorly to xiphisternal joint. The pleural space thus extends inferiorly to lie posterior to the abdominal region. Thus, injury or surgery in this region may affect the pleural cavity and lungs (pneumothorax).
which ribs only have 1 facet
1, 10, 11, 12
more rotational component and can move rib more than when you have more demifacets
what are the 5 articulations (joints) of the thoracic wall
Sternocostal Costochondral Interchondral Costovertebral Costotransverse
Sternocostal joint?
costal cartilage and sternum
7 pairs!!
what is unique about the 1st sternocostal joint
synchondrosis NO MOVEMENT
important in respiration b/c move the first rib and the rest of the ribs follow
what types of joints are the 2nd - 7th sternocostal joints
synovial plane joints
what is the costochondral joint and what type of joint is it?
why important clinically
articulation between rib and costal cartilage
synchondroses–> very little movement
***Frequently dislocated in trauma
what is the costovertebral joint
articulation between the rib head with vertebral bodies and intervertebral disc
synovial plane joints
what do the ribs 2-9 articulate with on the vertebra and what ligament supports this …
articulate with adjacent vertebral bodies and intervertebral disc
***an intra-articular ligament extends from the crest of the head to the intervertebral disc limiting movement of this joint
what do ribs 1, 10-12 articulate with on the vertebra
only with the body of the same numbered vertebra
what does the radiate ligament do?
supports the joint capsule of the rib head with the vertebra
what is the costotransverse joint
articulation between rib tubercle and vertebral transverse process
synovial joints
ribs 11-12 do not have costotransverse joints
what are the supporting ligaments of the costotransverse joint x3
lateral costotransverse ligament
superior costotransverse ligament
costotransverse ligament
the head of a typical ribs articulates with what?
and what does the costal tubercle articulate with ?
the head of a typical rib articulates with:
1) superior costal fascet of the thoracic vertebra of the same number (by its inferior articular facet)
2) the inferior costal facet of the vertebra above (by its superior articular facet)
3) the intervertebral disc between the two vertebrae
The costal tubercle articulates with the transverse process of the vertebra of the same number