A complete handbook for the sanitary troops of the U S army and navy . oblongata is the enlarged upper end of the spinalcord lying just within the cranium, and containing the importantnerve centers presiding over the action of the heart and lungs. Itis also the part in which the nerves coming from each side of thebrain cross over to the opposite side of the spinal cord, so that aninjury of the brain above this crossing causes a paralysis on theopposite side of the body. The spinal cord (Fig. 2^,), like the brain, is enclosed in mem-branes and is a tail-like column of nervous tissue composed ch
A complete handbook for the sanitary troops of the U S army and navy . oblongata is the enlarged upper end of the spinalcord lying just within the cranium, and containing the importantnerve centers presiding over the action of the heart and lungs. Itis also the part in which the nerves coming from each side of thebrain cross over to the opposite side of the spinal cord, so that aninjury of the brain above this crossing causes a paralysis on theopposite side of the body. The spinal cord (Fig. 2^,), like the brain, is enclosed in mem-branes and is a tail-like column of nervous tissue composed chieflyof nerves bitt containing in its interior a central colimin of gray 56 ANATOMY AND PHYSlULOGY matter. A pair of nerves leave it opposite each vertebra, those ofthe cervical region being arranged in two groups. The upper groupsupplies the face and neck and the interior of the chest; one of themost important of the branches is the phrenic which controls themovements of the diaphragm. The lower group is known as thebrachial plexus and supplies the upper Fig. 22,— Lower Surface of Brain. C, Cerebellum; M, inedulla; P, pons. The dorsal nerves supply the chest wall, those of the lumbar andsacral regions go to the pelvis and lower extremities; one great cordwhich emerges from the pelvis on each side and passes down theback oi the thigh is called the sciatic nerve; it is often the seat ofthe neuralgic pain known as sciatica. As all the nerves of the bod} except those of the face must passthrough the spinal cord on their way to the brain it is evident that ifthe s])inal cord is cut completely across there must be paralysis of allthe parts below ; such a paralysis is called paraplegia. If the injuryis high enough up the nerves controlling the action of the heart and THE NERVOUS SYSTEM AND SPECIAL SENSES 57 lungs are involved and death quickly follows. As the motor nervesare cellected in the front part of the spinal cord and the sensorynerves in the back part, apartial
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfirstaidinillnessand
