•20 PBINOIPLES OP TETEBINAEY SUKGERT 



How do hone wounds heal f 



Same as fractures, through an ossifying granulation 

 -tissue, involving the periosteum, bone, and marrow (see the 

 -" Healing of Fractures ")• 



How do cartilage wounds heal 9 



By proliferation of the perichondrium. In the wound is 

 first seen a fibrous deposit, which later changes into an ossify- 

 ing callus. When proli,feration of the perichondrium starts, 

 new cartilaginous tissue is also formed by cartilage cells 

 adjoining the wound, while those cartilage cells close to the 

 -cartilage wound undergo fatty degeneration. 



Hoiv do peripheral nerves heal ? 



The powers of regeneration of peripheral nerve tissues 

 are good. Provided the ends have been united artificially, 

 new nerve fibres formed by the old nerve fibres of the central 

 stump grow into the peripheral stump. A club-shaped swell- 

 ing (fibroneuroma) forms at the end of the central stump, 

 -chiefly due to a growth of the neurilemma, when the ends of 

 the cut nerve are separated by a distance of half to one inch 

 •(often seen in neurectomy). 



How do wounds of the brain and spinal cord heal ? 



Here no regeneration of the nerve substance occurs, but 

 a connective tissue scar forms. 



How do wounds of non-vascular tissues, as the cornea and 

 articular cartilage, heal f 

 It resembles the healing of vascular tissues. Leucocytes 

 -emmigrate from sclera and conjunctiva, followed by cell 

 proliferation of the fixed cells, with formation of fibroblasts, 

 -and then change into connective tissue, but vascularization 

 ■springs from the adjoining sclera. In articular cartilage, the 



