. Cunningham's Text-book of anatomy. Anatomy. 550 THE NEKVOUS SYSTEM. Fossa Rhomboidea (floor of the fourth ventricle).—In its inferior part the floor of the fourth ventricle is formed by the dorsal surface of the open part of the medulla oblongata, whilst in its superior part it is formed by the dorsal surface of the pons (Fig. 482). The area thus constituted is lozenge-shaped, its widest part being opposite the superior ends of the restiform bodies or inferior peduncles of the cerebellum. A thick layer of gray matter, continuous with that which surrounds the central canal, is spread out like
. Cunningham's Text-book of anatomy. Anatomy. 550 THE NEKVOUS SYSTEM. Fossa Rhomboidea (floor of the fourth ventricle).—In its inferior part the floor of the fourth ventricle is formed by the dorsal surface of the open part of the medulla oblongata, whilst in its superior part it is formed by the dorsal surface of the pons (Fig. 482). The area thus constituted is lozenge-shaped, its widest part being opposite the superior ends of the restiform bodies or inferior peduncles of the cerebellum. A thick layer of gray matter, continuous with that which surrounds the central canal, is spread out like a carpet over the ventricular floor, and covering this is the usual ependymal layer, which lines all the ventricles of the brain. The area is circumscribed by definite lateral boundaries. Thus, below, it is bounded on each side by the clava, the cuneate tubercle, and the restiform body; whilst above, the lateral limits are formed by the brachia conjunctiva. The fossa rhomboidea is divided into two lateral and symmetrical portions by a median groove. Its lower narrow pointed portion between the two clavae receives the name of the pars inferior, or, from its fancied resemblance to the point of a pen, rry Inferior colliculus Trochlear nerve Velum medullare anterius with- - lingula Colliculus facialis Area acustica crossed by strise—«m medullares Fovea inferior - -^ Trigonum. hypoglossi. Brachinm conjunc- tivum - Fovea superior , Brachium pontis _Brachium con- junctivum Restiform body iae medullares --Area acustica Ala cinerea Funiculus separans Area postrema Obex ! Funiculus cuneatus Fig. 482.—Floor op the Fourth Ventricle. On the right side the right half of the cerebellum has been removed by cutting through its three peduncles and dividing it in the median plane. On the left side the left half of the cerebellum is drawn over to the left so as to expose the floor of the ventricle fully. the calamus scriptorius. Crossing each half of the floor, at its widest part, are seve
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
