194 Proceedings of the Royal Irish Academy. 



origin, strength, and connexions of this ligament are variable. I saw 

 it of the thickness of a coarse thread only, made up of an arterial and 

 venous stem, and a pair of bundles of connective tissue ; usually it is 

 flat and broad towards its insertion, cylinchical medially, and knotty 

 by its including several fatty lobes." Luschka says,*' ''That only 

 exceptionally does it form in man a membranous sagittal septum, which 

 completes the partition of the synovial cavity of the knee into two 

 lateral halves, a partition partly begun by the crucial ligaments." 

 Robertsf adds little more in his monograph. Hyrtl remarks, "In 

 spite of its slendemess and often thread-like proportions, this band is 

 called the mucous ligament ; it is often absent or appears knotty from 

 including fat, or it includes a fibrous string which conveys blood ves- 

 sels to the patella, these seem to fill vacant spaces in the joint." 

 Cloquet describes it as an adipose canal. 



Before bringing forward the details of my own observations, I wish 

 to explain the following division which I have adopted. 



Class I. Contains those cases where the ligament formed a com= 

 plete septum across the joint. 



Class II. Where it formed a partial septum. 



Class III. Where it existed as a coarse thread or threads. 



Class lY. "Where the ligament was absent. 



To this I have added notes on the comparative anatomy of the 

 ligament. 



The total number of cases occurring in each class, together with 

 the average strain it took to break them, is as under : — 



Class I. There were 9 cases (22-A- per cent.), average strain, 

 21.24 lbs. 



Class II. There were 9 cases (22|- per cent.), average strain, 

 15.00 lbs. 



Class III. There were 19 cases (47i- per cent.), average strain 

 9.19 lbs. 



Class IV. There were 3 cases (7 J per cent.) 



Class Y. There were 20 cases. 



In Class I. the measurements were taken in this manner : — 



Anteriorly. From the marsupium to the femoral notch. 



Posteriorly. Prom the anterior crucial ligament to the femoral 

 notch. 



Above. The femoral attachment. 



Below. From the marsupium to the anterior crucial ligament. 



* Niu" aiisnahmweise bildet das ligamentiim mucosiuoi beim Mensclien ein 

 membraiioses sagittal gestelltes Septum -welclies die scbon drnxb die ligamentum 

 cruciatum eingeleitete sondenmg des gelenkes in zwei seitenbalftenvervollstandigt, 

 Anat. des Menscben, 1865, Bd. 3, pt 1, p. 376. [I am indebted to Dr. Macalister 

 for the translations], 



t Untersucbungen iiber die anatomie und mecbanik des kniegelentes, Giessen, 

 1855. 



