302 AVES. 



which is analogous to the ulnar nerve, and the under the biceps muscle, along the back of the 



other soon divides again into nerves which are thigh, about the middle of which it becomes 



v * 



similar to the median and mmculo-cutaneous. divided into the tibial and the peroneul nerves. 



The median dips down amongst the muscles on " The tibial nerve, even before it arrives in 



the middle of the fore-arm, to which it gives the ham, separates into several branches, which 



branches, and afterwards runs along the inter- pass on each side of the bloodvessels, and are 



osseous space, passes under the annular ligament chiefly distributed to the muscles on the back 



of the carpus, and is distributed to the short of the leg. Two of these branches, however, 



muscles of the digiti. The branch analogous to are differently disposed of; the one accom- 



the musculo-cutaneous nerve, is expanded upon panics the posterior tibial artery down the leg, 



the muscles on the upper edge of the radius. passes over the internal part of the pulley, and 



" The ulnar nerve, although it appears to be is lost in small filaments and anastomoses, with 

 incorporated with the median on the upper arm, a branch of the peroneal nerve on the inner side 

 can be easily separated from it, and traced to its of the metatarsus ; the other branch runs down 

 proper origin in the brachial plexus. After this on the peroneal side of the leg, along the deep- 

 nerve leaves the median, it turns over the end seated flexors of the toes, passes in a sheath 

 of the foramen to get upon the edge of the formed for it on the outer edge of the moveable 

 ulna. It gives filaments to the muscles in this pulley of the heel, and proceeds under the 

 situation ; but its chief branch runs down flexor tendons along the metatarsal bone, to be 

 superficially upon the ligaments of the quills in distributed to the internal part of the two ex- 

 company with a vein, and goes ultimately to ternal toes, 

 be lost upon the ulnar edge of the hand. " The peroneal nerve is directed to the outer 



" The third cord furnished by the brachial part of the leg ; it dips above the gastrocnemii 

 plexus, supplies the place of the radial nerve, muscles, and runs through the same liga- 

 It detaches several filaments to the muscles on mentous pulley that transmits the tendon of the 

 the inside and back of the scapula. It gives biceps muscle ; it then detaches some large 

 off also the articular nerve, and then winds filaments to the muscles on the anterior part 

 round the humerus between the extensor mus- of the leg, under which it divides into two 

 cles, to which it furnishes some large filaments, branches, which proceed close together, in corn- 

 On coming to the outside of the humerus, it pany with the anterior tibial artery to the fore 

 sends a branch between the integuments of the part of the ankle-joint, at which place they 

 fold of the wing. The nerve now turns round separate ; one passes superficially over the 

 the neck of the radius, beneath the muscles, outer part of the joint, the other goes first 

 and forms two branches ; of which one passes under the transverse ligament which binds 

 under the muscles to the outer side of the ulna, down the tendon of the tibialis anticus muscle 

 along which it runs superficially to the hand ; on the tibia, and then over the inner part of the 

 the other branch passes on the radial side, but joint, below which it divides into two branches, 

 more deeply amongst the muscles, goes under the one is distributed to the inner side of the 

 the annular ligament of the carpus, proceeds metatarsus and the tibial side of the pollex, 

 between the branches of the metacarpus, and is and to the next toe ; the other turns towards 

 finally lost on the back of the digiti." The same the centre of the metatarsal bone, and pene- 

 anatomist describes the course of the nerves of the trates the tendon of the tibialis anticus just 

 posterior extremities as follows. at its insertion, and then rejoins the branch 



" Although Cuvier has given a more accurate of the peroneal nerve it accompanied down the 



description of the nerves of the lower extremity leg. They continue their course together again 



than those of the wing, it nevertheless needs in the anterior furrow of the metatarsal bone ; 



correction in several particulars. and at the root of the toes, separate once more, 



" The obturator and femoral nerves arise and proceed to the interspaces of the three 



from the same plexus which is formed by the anterior toes, and each divides into two fila- 



two last lumbar nerves, by a communicating ments, which run along the sides of the toes to 



branch from the first sacral pair. The obtu- the nail." Rees' Cyclopedia, Art. Birds. 



rator nerve passes through the upper part of the The great sympathetic nerve of birds resem- 



foramen ovale, and is distributed to the muscles bles, in many particulars, that of mammals, 



around the hip-joint, especially the adductor. It enters the cranium by the same orifice as 



The femoral nerve passes out of the pelvis in that by which the nervus vagus and the glosso- 



company with the artery, over the upper edge pharyngeal make their exit ; it there unites 



of the ilium. It divides into three branches, with the fifth and sixth pair of nerves. At the 



which are dispersed among the muscles and base of the cranium the first ganglion, or su- 



integuments on the anterior and inner part of perior cervical, is of a lenticular form, and 



the thigh. Some of these filaments are long, communicates at once with the ninth and eighth 



and descend superficially for a considerable pairs of nerves, so as to seem as if it were 



way upon the limb. blended with them. The remainder of the 



" The ischiatic nerve is composed of the five chain of cervical ganglions are very remarkably 

 superior sacral nerves ; and as soon as it de- situated, being lodged on either side in the 

 parts from the plexus, even within the pelvis, canal of the vertebral artery formed by the trans- 

 is easily separable into its primary branches, verse processes ; into which it passes, or from 

 Immediately after it passes through the ischi- which it escapes above, at the third cervical 

 adic foramen, it sends filaments to the muscles vertebra, while below the sympathetic again 

 on the outer part of the thigh ; it then proceeds becomes conspicuous at the commencement of 



