346 LABORATORY MANUAL OF HUMAN ANATOMY 



Thalamencephalon. 



This part of the diencephalon includes (1) the thalamus, (2) 

 the metathalamus, and (3) the epithalamus. 



Thalamus (O. T. Optic Thalamus). 



The upper and medial surfaces of the thalamus may now be 

 examined. Observe 



^a) Pulvinar (pulvinar) ("cushion"). 



(b) Anterior tubercle of the thalamus (tuberculum anterius thalami). 



(c) Medullary stria (stria medullaris) (0. T. stria fornicis or stria pine- 



alis). 



(d) Epithelial chorioid layer (lamina chorioidea epithelialis) . 



This covers the thalamus where it appears to be, but is not, in 

 the lateral ventricle. 



Metathalamus. 



Behind and beneath the thalamus observe 



(a) Medial geniculate body (corpus geniculatum mediale) (0. T. internal 



geniculate body). This has to do chiefly with the auditory conduc- 

 tion path. 



(b) Lateral geniculate body (corpus geniculatum laterale) (0. T. external 



geniculate body). This has to do with the visual conduction path. 



Epithalamus. 



Here the student should study 



(a) Pineal body (corpus pineale) (0. T. conarium, or epiphysis cerebri). 



(b) Pineal recess (recessus pinealis). 



(c) Suprapineal recess (recessus suprapinealis) . 



(d) Habenula (0. T. peduncle of the pineal body). 



(e) Commissure of the habenulae (commissura habenularum) . 



(f) Trigone of the habenula (trigonum habenulae). 



Third Ventricle (Ventriculus tertius). 



This has been cut in two in the median plane, and its roof, 

 tela chorioidea ventriculi tertii, with the lamina chorioidea epi- 

 thelialis, has been removed. The student should now study the 

 following structures and openings : 



(a) Entrance to the aqueduct of the cerebrum (aditus ad aquaeductum 



cerebri). 



(b) Posterior commissure of the cerebrum (commissura posterior [cere- 



bri]) (above the aditus ad aquaeductus cerebri). 



(c) Interventricular foramen of Monro (foramen interventriculare [Mon- 



roi]). One on each side, connecting ventriculus tertius with ven- 

 triculus lateralis. 



