Notes on Clavicle and Scapula Development

Clavicle Development

  • Origin: Neural crest
  • Ossification: Intramembranous
  • The clavicle is one of the first bones to ossify, beginning at approximately the 5th week of development.
  • Development is Runx2 dependent. Mutations in Runx2 can affect clavicle development.

Scapula Development

  • Ossification Centers: The scapula develops from 7 ossification centers:
    • 1 for the body.
    • 2 for the coracoid process.
    • 2 for the acromion.
    • 1 for the vertebral border.
    • 1 for the inferior angle.
  • Cellular Origins:
    • Dermomyotome
    • Lateral plate mesoderm
    • Neural crest
  • Ossification Types:
    • Intramembranous ossification occurs in the body.
    • Endochondral ossification occurs in the articular regions.
  • Timeline of Ossification:
    • The majority of the body is ossified at birth.
    • Postnatal ossification begins around 15-18 months.
    • The coracoid process completes ossification around 20 years of age.