102 Walter Sfaph-y : 



one lias costal processes on the seventh cervical vertebra— a small 

 chimpanzee. 



The causes that determine the development of cervical ribs appear 

 to be : — 



(1) Disuse of the upper liml)s for the purpose for which they were 



developed, viz., tpuidrupedal yn'ogiession. Tlie removal of 

 the weig'ht of the ])ody from the sides of the ribs has 

 allowed the tirst and upper ribs to become curved, and 

 thus an increased space has been afforded throu<^h which 

 the lung has migrated, hernia fashion, into the neck. 



(2) Hostile impulses assailing the established inauinuilian neck 



type; the chief of these arise from the presence of lung in 

 the neck. Nowhere amongst the mammals are jointed ribs 

 •seen except in association with lung and the function of 

 respiration. 

 The following changes have occurred in the huu)an neck : — 



(1) The bodies of the neck bones have been flattened by the 



weight of the head, and thereby the neck has lost mobility. 



(2) The erect position has caused the neck curves to be reduced 



and the neck and chest to ))e brought into more direct 

 line. 



Lateral Curvature of the Spine (Scoliosis). 



This condition is so extremely rare in (puidrupedal manuuals that 

 it may be said not to occur in such, aninaals. In man lateral curvature 

 is common, and, associated with cervical ribs, lateral curvature uuiy be 

 said to be the rule. The surgical treatment of cervical ribs is insepar- 

 able from a careful consideration of the part played by lateral 

 curvature. In the review of the necks of seals and porpoises, it has 

 been seen that disuse of the fore-limbs for progression on land is 

 accompanied by a profound atro]>hy of the pectoral liml)s. The term 

 involution of the nock may be applied to this atrophic condition. 

 The arms of Man that are associated with cervical ribs are in a state 

 of atrophy, and they have receded towards the head by the distance 

 occupied by the cervical ribs. It will be remembered that the fore- 

 limbs of the slowly moving lizards are near the head, in other AN'ords 

 in the early evolution of the neck the fore-limbs are near the head. 

 .Surgeons have repeatedly recorded that lervical ribs shut off by jires- 

 suro the arterial bUjod supply of the upper limbs, and Keen sh<n\s 

 an artery that is iiiucli iai^gcr in lumen on llic luoximal than on the 

 distal side of the cervical rib over which it ]jasses. Anatomy abounds 

 with evidence that during development arteries mould bone to their 

 service. Bones support and )>rotect the more delicate tissues of the 

 body, even the delicate convolutions of the brain leave their indented 



