. The anatomy of the domestic animals. Veterinary anatomy. 766 NERVOUS SYSTEM OF THE HORSE mm. in width, a little lateral to the ventral median fissure, and no groove is found here. In the greater part of the cervical region and the anterior part of the thoracic region there is a shallow dorsal intermediate groove (Sulcus intermedius dorsalis) a short distance lateral to the median groove. These grooves indicate the division of the white matter of the cord into columns to l)e described later. Examination of cross-sections of the spinal cord shows that it is a bilaterally symmetrical structure,
. The anatomy of the domestic animals. Veterinary anatomy. 766 NERVOUS SYSTEM OF THE HORSE mm. in width, a little lateral to the ventral median fissure, and no groove is found here. In the greater part of the cervical region and the anterior part of the thoracic region there is a shallow dorsal intermediate groove (Sulcus intermedius dorsalis) a short distance lateral to the median groove. These grooves indicate the division of the white matter of the cord into columns to l)e described later. Examination of cross-sections of the spinal cord shows that it is a bilaterally symmetrical structure, incompletely divided into right and left halves by a ventral fissure and a dorsal septum. The ventral median fisstire (Fissura mediana ven- tralis) is narrow and penetrates nearly to the middle of the dorso-ventral diameter of the cord. It is occupied by a fold of pia mater. The dorsal median septum (Septum medianum dorsale) is a partition which descends from the dorsal median groove to about the middle of the cord. It apparently consists of condensed neu- roglia with an admixture of pial tissue. The two halves of the cord are connected. Fig. 62S.—Ckosb-section of Spinal Cord in situ. Enlarged and in Part Schematic. 1, Dorsal column; S, lateral column; S, ventral column; 4i doraal horn; 5, ventral horn; 6, gray commissure; 7, white commissure; 5, central canal; 5, dorsal septum; iO, ventral fissure; i^, dorsal nerve-root; /5. ventral nerve-root. I3y spinal ganglion; 14, spinal nerve; 15, intervertebral foramen; 16, arch of vertebra; 17, epidural space; IS, dura mater (represented a little too thick); 19, ligamcntum denticulatum; 20, BO, longitudinal venous sinuses; £1, middle spinal artery; 22, body of vertebra. The subdural and subarachnoid spaces (black) are traversed by delicate trabec- ule. The outer part of the arachnoid and the pia mater are not shown. by commissures of gray and white matter. The gray commissure (Commissura grisea) is a transverse band of gray matter
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisherphiladelphialondon
