DISSECTION OF THE HEAD AND NECK 243 



(For a description of the course of the vessels in the meninges and 

 in the cord itself, see article " Spinal Cord" in last edition of Wood's 

 Reference Hand-book of the Medical Sciences.) 

 Veins. 



(a) Internal spinal veins (Vv. spindles internae). 



(b) Posterior external spinal veins (Vv. spinales externae posteriores) . 



(c) Anterior external spinal veins (Vv. spinales externae anteriores). 



(d) Intervertebral veins (Vv. intervertebrales) . 



External Morphology of Spinal Cord. 



What is the shape of the spinal cord! How is it curved? 

 Note the position and extent of each of the following : 



(a) Cervical portion (pars cervicalis). 



(aa) Cervical enlargement (intumescentia cervicalis). 



(b) Thoracic portion (pars thoracalis) (0. T. dorsal portion). 



(c) Lumbar portion (pars lumbalis). 



(ca) Lumbar enlargement (intumescentia lumbalis). 



(d) Medullary cone (conus medullaris). 



(da) Swelling due to terminal ventricle (ventriculus terminalis). 



(e) Terminal thread (filum terminale). 



On the surface of the cord observe the following grooves : 



(a) Anterior median fissure (fissura mediana anterior). 



(b) Posterior median sulcus (sulcus medianus posterior). 



(c) Anterior lateral sulcus (sulcus lateralis anterior). 



(d) Posterior lateral sulcus (sulcus lateralis posterior). 



(e) Posterior intermediate sulcus (sulcus intermedius posterior) (0. T. 



paramedian furrow). 



(/) Anterior intermediate sulcus (sulcus intermedius anterior) (incon- 

 stant). 



Between these grooves the funiculi of the spinal cord (funiculi medullae 

 spinalis ) . 



(a) Anterior funiculus (funiculus anterior) (0. T. anterior column). 



(b) Lateral funiculus (funiculus lateralis) (0. T. lateral column). 



(c) Posterior funiculus (funiculus posterior) (0. T. posterior column). 



Transverse Sections of Spinal Cord. (Fig. 101.) 



Sections of the spinal cord (sectiones medullae spinalis) 

 should next be studied. With a sharp, thin knife, cut through 

 the cord transversely at the following levels: (1) just below 

 roots of fourth pair of cervical nerves, (2) through middle of 

 cervical enlargement, (3) through middle of thoracic cord, (4) 

 through middle of lumbar enlargement, and (5) through conus 

 terminalis. In the sections observe the differentiation into white 

 matter (substantia alba) and gray matter (substantia grisea). 



