ANATOMY IN A NUTSHELL. 



237 



and gives attachment to the Triangularis sterni muscle. The lateral border 

 of the gladiolus articulates with the cartilages of the second, third, fourth, fifth, 

 sixth, and seventh rib; however the second and seventh cartilages articulate 

 partly with the bones above and below. This portion of the bone articulates 

 with the manubrium above and the ensiform or xiphoid appendix below. 



The ensiform appendix, cartilaginous hi youth but is partly ossified above 

 in the adult. The chondro-xiphoid ligament is attached to its anterior surface, 

 while the Diaphragm and the Triangularis sterni are attached to its posterior 

 surface. It articulates above with the gladiolus. Laterally the aponeurosis 

 of the abdominal muscles are attached. The superior angle of the lateral 

 border has a demi-facet for the cartilage of the seventh rib. Its apex may be 

 bifid below or may present a foramen, and it gives attachment to the linea 

 alba. 



Attachment of Muscles: — Nine pairs and one single muscle. The 

 Pectoralis major, Sterno-cleido-mastoid, Sterno-hyoid, Sterno-thyroid, Tri- 



PLATE XCV. 



LATERAL MASS 

 COSTOTRANSVERSE 

 FORAMEN 



SURFACE 



FORAMEN FOR 

 VERTEBRAL ARTERY 



The Atlas 



annularis sterni, aponeurosis of the External oblique, Internal oblique, Trans- 

 versalis, Rectus muscles, and Diaphragm. 



Ossification: — From six centers. One for the manubrium (fifth or 

 sixth month.) One for each of the four pieces of the gladiolus. The ones 

 for the first two pieces of the gladiolus appear at the sixth or SEVENTH 

 month. The one for the third piece appears at the ninth month, and the 

 one for the fourth piece appears during the first year after birth. The 

 one for the ensiform appendix appears between the SECOND and eighteenth 

 years. The manubrium and the lower three pieces of the gladiolus may have 

 two centers each, thus making ten centers of ossification for the sternum. 

 The pieces of the gladiolus join at about the age of puberty, while the glad- 

 iolus rarely joins the manubrium and the ensiform remains cartilaginous even 

 in advance life. 



Articulation. — With the clavicles and seven costal cartilages on each 

 side. 



