816 



ABNORMAL CONDITIONS OF THE HIP-JOINT. 



elongated. The psoas magnus and iliacus in- 

 ternus are relaxed, as are also the other muscles 

 inserted into the trochanter minor."* 



From the foregoing opinions Mr. Todd dis- 

 sents in the following words : " To admit of 

 the head of the femur being ' forced towards 

 the superior and external part of the aceta- 

 balum,' and of its ascending ' on the external 

 face of the os ilium,' it will be obvious to 

 those who carefully examine the mechanism of 

 the articulation, that the thigh must be ex- 

 tended on the trunk, and the dislocating force 

 applied externally and inferiorly, so as to pro- 

 duce what may be termed an excess of ad- 

 duction. To the limb assuming such positions, 

 which appear to me to be quite essential to- 

 wards the production of this dislocation m the 

 manner described by Bayer, some considerable 

 obstacles exist. In the first place, I believe it 

 seldom happens that a person who falls from a 

 height will reach the ground with the thigh 

 extended on the trunk ; in the descent the 

 superior power of the flexor muscles will pre- 

 dominate, and at the moment of the appli- 

 cation of force to the limb it will be more or 

 less in a bent position. It is scarcely neces- 

 sary to observe that this circumstance must 

 materially influence the direction in which the 

 head of the bone will be protruded from the 

 articulating cavity. 



" Secondly, should the thigh and leg be com- 

 pletely extended at the time that the force is 

 applied, it is probable that the other limb will 

 be extended also, and will thus prevent a move- 

 ment of the stricken limb inwards beyond a 

 certain point ; or, in other words, the opposite 

 limb will prevent that extent of adduction 

 inferiorly which is necessary to remove the 

 head of the femur from the acetabulum, and to 

 admit of its being forced upon the anterior 

 convex surface of the dorsum ilii. But whether 

 the opposite limb be extended or not, it must 

 oppose a certain limit to adduction, if that 

 term can be applied with propriety to a 

 lateral movement of the lower extremity, by 

 which it is carried beyond the middle line of 

 the body. 



" Sir Astley Cooper attributes this direction 

 of the limb to the circumstance of the injury 

 being inflicted when the knee and foot are 

 actually turned inwards ; however, it appeal's 

 to me that muscular action is also in favour of 

 the limb assuming this position. 



" If it be admitted that the thigh is generally 

 in a state of demiflexion when the force causing 

 this dislocation is applied, it must also be ad- 

 mitted that in this state the pyriformis, ob- 

 turatores, and gemini have but little effect as 

 rotators, the power of these muscles as such 

 being greater or less, according as the junction 

 of their fibres with the femur approaches 

 or deviates from a right angle; and that the 

 power of the anterior portion of the glutseus 

 medius and of the tensor fascia? latae, as 

 rotators inwards, is increased in this position, 

 the angle which their fibres form with the 

 thigh-bone being augmented ; thus the last- 



* Lectures of Boyer, p. 156. 



mentioned muscles will appear to possess 

 much influence in determining the inverted po- 

 sition of the limb, as they must draw forwards 

 the trochanter major and external side of the 

 thigh, at the moment in which the head of the 

 bone escapes from the acetabulum. 



" The inclination of the thigh forwards and 

 inwards which constitutes so remarkable a fea- 

 ture of this dislocation, may be attributed 

 partly to the tension of the psoas magnus, the 

 iliacus internus, and the pectinalis, and also 

 to the peculiar form of the surface of the 

 pelvis, to which the upper part of the femur 

 is applied ; but certainly not as Mr. Samuel 

 Cooper has asserted, to the tense state of the 

 triceps and gracilis, for these muscles are re- 

 laxed." 



Anatomical characters of the luxation of the 

 head of the thigh-bone on 'the dorsum ilii. The 

 appearances which have been noticed in the 

 anatomical examination of the hip-joints of 

 individuals who, having had a luxation of this 

 articulation, have died very soon afterwards 

 of other severe injuries received at the same 

 time, may be collected from the study of some 

 facts of this nature already published. Of 

 these none gives us a better idea of the recent 

 effects of a dislocation upwards and backwards 

 on the dorsum ilii than the case related by the 

 late Mr. Todd, in the third volume of the Dub- 

 lin Hospital Reports, which is as follows : 



Case. In the summer of 1818, a robust 

 man, in attempting to escape from his bed- 

 room window in the second floor of a lofty 

 house, fell into a flagged area, by which acci- 

 dent his cranium was fractured, and his left 

 thigh dislocated upwards and backwards. 



The dislocation was reduced without diffi- 

 culty ; however, an extensive extravasation of 

 blood having taken place on the brain, the 

 patient lingered in a comatose state for about 

 twenty-four hours, and then died. On the 

 day after dissection was performed, and the 

 following appearances were observed in the in- 

 jured joint and the parts contiguous to it. 



On raising the glutaeus maximus, a large 

 cavity filled with coagulated blood was found 

 between that muscle and the posterior part of 

 the glutaeus medius. This was the situation 

 which had been occupied by the dislocated 

 extremity of the femur. The glutxus medius 

 and minimus were uninjured. The pyriformis, 

 gemini, obturatores, and quadratus were com- 

 pletely torn across. Some fibres of the pec- 

 tinalis were also torn. The iliacus, psoas, and 

 adductors were uninjured. The orbicular liga- 

 ment was entire at the superior and anterior 

 part only, and it was irregularly lacerated 

 throughout the remainder of its extent. The 

 inter-articular ligament was torn out of the de- 

 pression on the head of the femur, its attach- 

 ment to the acetabulum remaining perfect. 

 The bones had not sustained any injury. 



Cruveilhier, in the 28th and 29th livraisons 

 of his valuable work on Pathological Anatomy, 

 has given two cases of what he considers to be 

 old luxations of the head of the femur up- 

 wards and outwards on the dorsum ilii, which 

 had been left unreduced ; the history of thest- 



