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2499 pages added, reviewed or updated during the last month (last updated: 19/4/2021)

2499 pages added, reviewed or updated during the last month (last updated: 19/4/2021)


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first (1st) rib (anatomy)

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The first rib is the most superior within the thoracic cavity. It is atypical in structure:

  • head:
    • single articular facet for synovial joint with upper hemifacet on lateral body of T1
    • relatively small
    • reinforced by typical radiate ligament
  • neck:
    • slopes superiorly and slightly posteriorly to join the shaft
    • relations:
      • anterior ramus of eighth cervical nerve on superior surface
      • anterior ramus of first thoracic nerve on inferior surface
      • posterior to anterior on thoracic surface: stellate ganglion or sympathetic chain, supreme intercostal vein, superior intercostal artery. These structures are in contact with the apposing cervical pleura.
  • tubercle:
    • in anatomical position, most posterior point of rib
    • medial facet for synovial joint articulation with first thoracic vertebra transverse process
    • laterally provides attachment for;
      • lateral costotransverse ligament
      • costalis muscle
      • longissimus muscle
  • angle: there is no angle as it has effectively fused with the tubercle
  • shaft: see submenu
  • general points:
    • the first rib is bent into a very tight curve to turn 180 degrees from vertebra to sternum
    • in the anatomical position, the rib is inclined 45 degrees to the horizontal

Last reviewed 01/2018

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