Sternal Head

• O (origin)

  • Larger head arising from manubrium and body of the sternum
  • the adjacent parts of the upper 6 costal cartilages
  • the aponeurosis of the external oblique

  A) sternal head

  
• R (direction)

  • Horizontal and superolateral

  A) sternal head

  
• I (insertion)

  • Via a flat tendon to the lateral lip of the intertubercular groove (covering the long head of biceps tendon)
  • Forms the posterior lamina (layer) which passes upwards and behind the anterior lamina to the upper part of the groove

  A) sternal head

  
• A (actions)

  • Extends the flexed arm, especially against resistance to the anatomical position
  • adducts
  • medially rotates

  A) sternal head

  
• NS (nerve supply)

  • Medial pectoral nerve (C8, T1)
  • Lateral pectoral nerve (C5 - C7)

  A) sternal head