Page:The New International Encyclopædia 1st ed. v. 14.djvu/430

* NERVOUS SYSTEM AND BRAIN. 380 NERVOUS SYSTEM AND BRAIN. cenilinj; jiaiictal convoliitii)ii is tlic inlra-parietal sulcus. The portion of the parietal lobe above the horizontal part of the .sulcus is known as (b) the superior-parietal convolution, and is con- tinuous with the ascending pari- etal. That part of the lobe be- low the horizontal arm of the sulcus is divided by a vertical silcus into (c) an anterior part, the supraniarginal convolution, and (d) a jjosterior i)art. the angular convolution. The occipihil lobe is separated from the iipijer part of the pari- etal lobe by the parietooccipital lis>ure. while it is more or less continuous with the lower part of the parietal lobe and with the tenipero-splicnoidal lobe by small connecting convolutions. The lobe is rather indefinitely divided by two small transverse fissures into first, second, and third occipital convolutions. The tcmpero-sphenoidal lohe lies in the middle fossa of the skull and is bounded above and in front by the Sylvian fissure. Pos- teriorly, connecting convolutions nnife it with the parietal and OC- space. J'os't. p'erf. .s^j., imsterior perforated space; Vh. sur. ctnb., under sur- ninit-il 1<ilw.« It- is divided by two face of cerebellum; Mtd. obi., medulla obUmgata : L,m. Jiss., lonsitudiiial Cl|iiiai loues. it is un meu m i«o jg^,,^^. ,.„^p „,,; corpus callosum; Pit. bihi. pituitary body; Infumlih., horizontal sulci into three convo- infundibulum; Aut. per/, up., anterior perforated space; Tub. ciiic.. tuber Intions called from above down- ctnereum : /'ost. dir. St/t. riss., posterior division of Sylvian fissure: Corjio. vvni-<1 tlio first spiond and third «"''., corpora albicantia : ('■ni. crrf., crura cerebri; roup. .«)*. M., temporo- waul, the lii.sl, setonii, .um uiiiu g^e„(,ij;ji ,ot,e; Occip. lo., occipital lobe; Pons Var., pons Varolii teinpero-sphenoidal convolutions. The central lobe or Ultinil of Rcil is situated parallel to the curve of the surface of the brain, in the depth of the fissure of Sylvius, and com- separating the marginal or first frontal con- C^szircvrrU cipilal, the calcarine, the collateral, and the dentate. The calloso-marginal is the longest of these fissures, begins on the superior surface just behind the mid-point, and runs forward Nort./}es. Corp^calL. Pron.Zo. PU-bdy. InfuncUb. •Ant.perTsp. Tub.ctne. PosLdiv.Syl.ftsr. ~-Corpo. cU6i. O'u.cere. ^^Temp.sph.lo,. Occip. lo. BASE OF THE BRAIX. Frmi. In., frontal lobe; Bn., bulb: Olf. tr., olfjictory tract; Fiss. Si/l, lityjure of Sylvius; Ojt. tic, optic nerve; Op. com., optic commissure; O/i' fr., opiic tract; Ttinp. uph. lo., temptiro-spbenoidal lobe; Int. ped. sp., interiH;duncular posed of five or si. rather small convolutions •frU-parsuL Coll ml.- Z-^lmipjvl volution from the gj'rus fornicatus, which lies just over the corpus callosum. The quadrate lobule lies between the calloso-marginal sulcus and the parieto-occipital sulcus. The cuneus or occipital lobule lies between the parieto-oc- cipital sulcus in front and aliove and the cal- carine sulcus below. The unciniite gyrus lies be- low the .Sylvian fissure and the dentate sulcus, while below it is separated from the tempero- sphenoidal lobe by the collateral sulcus. The tempero-sphenoidal lobe is continuous with the already described lobe of the same name in the outer surface of the cerebrum. It presents two convolutions in addition to those already de- scribed on its outer surface. The under surface of the cerebrum shows some ini]iortant features, which, passing from before biiekward, are as follows: (1) the longitudinal fissure, separating the frontal lobes. (2) The corpus callosum, appearing in the depth of the longitudinal fissure and serving as a great transverse commissure connecting the two hemi- spheres. (3) The olfactory nerve with its ex- panded extremity the olfactory- bulb, lying in a groove in the under surface of the frontal lobe. (41 The fissure of Sylvius, separating the anterior from the midille lobe. (.5) The anterior perforated space — so called from the perforations for the passage of blood-vessels — is the under surface ..„n; Si/I ni<« .Sylvian llssurc; /in., insula; (Vdiij, claus- of the corpus striatum (see below). (fi) The ■ rum; (//o. /»i//., tflobus pallidas; /'.ir. n*«., parallel lis. ,,j(„j,,,rv l.odv or hvpophvsis cerebri. (7) The ,urc; .'.,</ Itmp. ,ul., secoml temporal sulcus. infutwliliulum " is a narrow" tube of gray matter The internal surface of the cerebrum is less connecting the pituitary!)ody with (S) the distincllv marked olT into lobes than the ex- tuber einereum. an eminence of gray malter lying tcrnal surface. The fissures on the intern.il l)etween the diverging cerebral peduncles (!)) surface arc the lalloso-marginal, the parieto-oc- The corpora aDiicantia or coriiora maiiullarm Tin: nBAI.N VIEWEn FROM BF.niSn A FBOXTAI. BECTIOS THHOllill TUK Kli;llT UEMISFIIEKK TAKE.S JI^ST BEHIND THE (JCTIC CUIASMA. Call. m. »u/., calloBo-marKinal flssnro: T^il. rent., lateral vciilrlclc; lorp. call., c.irpus callosum: lldii /"r.c., b.i.lv of fornix; Thai., llialamus; .;rp (r.. opIic tr.ict; -Vur. amiiij., nucleus anivgdala; Op. c/ii., optic cldasma; Ant. hip/m., anieri.ir end of ldp|««'auipU9 nn^or projecting into llie dei-ccndini; cornu of the lateral vcntrlelu; Voll »ii/., collat. eral sulcus; hit. par. .ttil., intr:it>arielal sulcus; Jto. siil.. liolandic sulcus; S'lic caiid., nucleus candatus: Sir. mnl , stria medullarls: A'rf. c.//>., external capsule; /'i/di., luilu-