776 



NORMAL ANATOMY OF THE HIP-JOINT. 



Such are the phenomena in animals in which 

 the heart has not the faculty of taking on an 

 augmented state of irritability, with this lessened 

 degree of stimulus. But in those animals which 

 do possess this faculty, a property which con- 

 stitutes the power of hibernation, the heart con- 

 tinues the circulation of the blood, more slowly 

 indeed, but not less perfectly, although its arte- 

 rial character be diminished and its stimulant 

 property impaired. No repletion of the pul- 

 monary veins and of the left auricle, no sense 

 of oppression is induced, and the animal is not 

 roused ; the respiration continues low, the tem- 

 perature falls, and the animal can bear, for a 

 short period, the abstraction of atmospheric air. 



All the phenomena of hibernation originate, 

 then, in the susceptibility of augmented irritabi- 

 lity. The state of sleep, which may be viewed 

 as the first stage of hibernation, induces an im- 

 paired degree of respiration. This would soon 

 be attended with pain, if the irritability of the 

 heart were not at the same time augmented, so 

 as to carry on the circulation of a less arterial 

 blood, and the animal would draw a deep sigh 

 would augment its respiration or awake. 

 Occasional sighs are, indeed, observed in the 

 sleep of all animals, except the hibernating. In 

 these, the circulation goes on uninterruptedly, 

 with a diminished respiration, by the means of 

 an augmented irritability. There is no stagna- 

 tion of the blood at the heart ; consequently, no 

 uneasiness; and the animal becomes more and 

 more lethargic, as the circulation of a venous 

 blood is more complete. This lethargy is even- 

 tually interrupted by circumstances which break 

 ordinary sleep, as external stimuli or the calls 

 of appetite. 



It still remains for me briefly to discuss the 

 question, what are the hibernating animals? 

 1 must first advert to the fact, on which I have 

 already insisted, that hibernation does not pre- 

 sent itself in an equal degree in all the hiber- 

 nating tribes. All animals sleep periodically, 

 in the night or in the day. Some sleep for 

 several days together, especially after taking 

 food, and in the cool seasons of the year, as the 

 hedgehog. Perhaps the bat may be the only 

 animal which sleeps profoundly the winter 

 through, without awaking to take food. 



These remarks prepare us for a more just 

 view of hibernation and of hibernating animals 

 than is, as I believe, usually taken. 



Of the hibernating animals the most unequi- 

 vocal are the bat, the hedgehog, the marmot, 

 the hamster, the dormouse. It has been said 

 that the bear and beaver belong to the num- 

 ber, but this is extremely doubtful. It has 

 been said also that the swallow belongs to the 

 hibernating class, but this is incorrect. The 

 cold-blooded animals, the Chelonian, the Sau- 

 rian, the Ophidian, and the Batrachian tribes, 

 all, however, indubitably pass the winter in a 

 state of apathy and lethargy. Some of the 

 fishes also become lethargic during the cold 

 season. The same remark applies to some of 

 the molluscous and insect tribes. 



BIBLIOGRAPHY. -//Mw/er, An. (Economy, Owen's 

 edition, p. 131. Lond. 1837. Spallansani, Mem. 



sur la Respiration, par Senebier. Gcnev. 1803 ; 

 or Eng. translat. Edinb. 1804. De Saissy, Re- 

 cherchesexp. sur les Anim.Hivernans., Lyons, 1808. 

 Mangili, Essai sur la Lethargie periodique. Milan, 

 1807. Edwards, snr les Aa;ens Physiques. Paris, 

 1824, or Dr. Hodgkin's English transl. Prunelle, 

 Recherchcs sur les phenom. et sur les causes du 

 sommeil hivernal. Ann. du Mus. t. xviii. Bertfiold, 

 Miiller's Archiv. 1837, p. 67. MUller's Physiology, 

 passim. 



(Marshall Hall.) 



HIP-JOINT, NORMAL ANATOMY 

 OF (in human anatomy). Fr. articulation 

 ilio-femorale ; Germ. Huft gelenk. This joint 

 belongs to the class of enarthrodial or ball and 

 socket joints, being formed by the adaptation 

 of the head of the femur to the acetabulum of 

 the os innominatum. These bones are con- 

 nected by a very powerful capsular ligament, 

 which again is completely covered by strong 

 and thick muscles, under the influence of which 

 the various motions of the joint are performed. 

 We propose to examine seriatim the several 

 textures entering into the formation of this 

 joint, and lastly to consider the motions of 

 which it is susceptible. 



The bones. Of the two bones which in the 

 adult enter into the formation of this joint, the 

 os innominatum contributes by the acetabulum, 

 and the femur by its head. 



The acetabulum (cotyloid cavity : Germ, die 

 Pfanne) is the cup or socket which receives the 

 head of the femur, and is admitted to be the 

 deepest articular cavity in the body. Prior to 

 the adult period of life this cavity serves as 

 the centre of union for the three bones of 

 which the os innominatum is formed, viz., the 

 ilium, ischium, and pubis. These, however, 

 do not enter equally into the acetabulum, inas- 

 much as the ischium contributes in the pro- 

 portion of rather more than two-fifths, the ilium 

 of about two-fifths, whilst the pubis yields ra- 

 ther less than one-fifth. 



Although the acetabulum is situated nearly 

 in the centre of the separated os innominatum, 

 it has a different position in relation to the 

 entire pelvis. The union of the ossa innomi- 

 nata at the symphysis pubis, and the comple- 

 tion of the pelvis by the addition of the sacrum 

 posteriorly, place the acetabular cavities on 

 either side upon the antero-external aspect of 

 the pelvis, so that a line drawn horizontally 

 from the one to the other would pass through 

 the union of the anterior with the two posterior 

 thirds of the antero-posterior diameter of the 

 pelvis. The aspect of each acetabulum is out- 

 wards and very slightly forwards as well as 

 downwards. 



Kach cavity is surrounded for about four- 

 fifths of its circumference by a sharp but strong 

 lip or margin (supercilium acetabuli), leaving 

 opposite the obturator foramen a notch of 

 considerable extent (incisura acetabuli) di- 

 rected from without downwards, forwards, and 

 inwards, the deepest part of which is smooth 

 and gives passage to nerves and vessels. This 

 notch corresponds to the junction of the pubis 

 and ischium ; and we may here observe that 

 the margin of the acetabulum exhibits a slight 



