Module 1: The Thoracic Wall Flashcards
Diaphragm
Thin musculotendinous septum that separates the thoracic and abdominal cavities
Diaphragm function
Respiration
Contracts and its dome flattens to increases volume in thoracic cavity
Features of the diaphragm
Right dome
Left dome
Central tendon
Right and left crus
Right dome
Rises to upper border of fifth rib
Left dome
Rises to lower border of fifth rib
Central tendon
Where the peripheral muscle fibres of diaphragm attach to inferior margin of thoracic cage and lumbar vertebrae
Right crus
Originates from anterolateral surface of upper 3 lumbar vertebrae
Left crus
Originates from anterolateral surface of upper 2 lumbar vertebrae
Apertures of the diaphragm
Caval opening
Esophageal hiatus
Aortic hiatus
Caval opening
In central tendon at T8
Opening for IVC
Esophageal hiatus
In right crus at T10
Opening for esophagus
Aortic hiatus
Btwn left and right crus, anterior to T12
Opening for abdominal aorta
External intercostals
Fibres run anteroinferiorly from lower border of rib
Elevate ribcage during inspiration
Internal/innermost intercostals
Fibres run posteroinferiorly from upper border of rib
Depress rib cage during expiration
Injury to intercostal muscles
Results from twisting and reaching upwards causing swelling, pain and muscle tightness
Manubriosterbal joint
Sternal angle or angle of Louis
In line w 4th and 5th vertebrae
Easily palpable forming a clinical landmark
Xiphoid process
Attaches to sternal body at xiphisternal joint
In line w T9
Intervertebral discs
Annulus fibrosus
Nucleus pulposus
Annulus fibrosus
Outer ring of disc made of fibrocartilage
Resists shear forces
Nucleus pulposus
Gelatinous structure that resists compressive forces
DDx: Herniated (slipped) disc
Results from bulging of nucleus pulposus through weak spots of the annulus fibrosus
Symptoms: localized back pain, numbness and weakness along lower thoracic cage
What happens to the intervertebral disc if the annulus fibrosus ruptures completely?
The protruding nucleus pulposus can compress contents of the intervertebral foramen (spinal nerves)
Possible injuries to ribs
Rib fracture
Bruising
Inflammation of costal cartilage
DDx: Fractured rib
Crack or break in ribs caused by a direct blow to the chest
**break in costal cartilage can be considered a rib fracture
Symptoms: injury to internal organs, localized chest and back pain, pain associated with inhalation/exhalation