ABNORMAL CONDITIONS OF THE SHOULDER JOINT. 



619 



flammation of the membranes of the brain, 

 and Dr. Smith* made the post-mortem ex- 

 amination. Upon entering the room his 

 attention was attracted by the appearances 

 which the shoulder joints presented. The de- 

 viations from the normal state were most 

 remarkable at the left side. The muscles of 

 the shoulder and arm were atrophied, the 

 acromion process projected considerably, and 

 the head of the humerus could be perceived 

 lying a little beneath the coracoid process, 

 the apex of which was in a line with the 

 bicipital groove of the humerus. The na- 

 tural roundness of the shoulder did not exist, 

 and the elbow could be readily brought into 

 contact with the side. The right shoulder 

 joint presented similar appearances, but in a 

 slighter degree; the head of the humenis was 

 not placed so directly beneath the coracoid 

 process ; but the flattened form of the shoul- 

 der, the atrophied muscles, and the projection 

 of the acromion, all indicated that the condi- 

 tion of the joint was nearly similar on both 

 sides. From the last circumstance, and the 

 absence of any external sign of disease, it was 

 concluded that the deformities were the result 

 of an original or congenital malformation. 



The anatomical examination of the joints 

 confirmed this opinion. Upon the left side 

 there existed scarcely any trace of an arti- 

 cular surface in the situation which the gle- 

 noid cavity occupies in the normal state ; 

 but there had been formed on the costal 

 surface of the scapula a socket of a gle- 

 noid shape, measuring an inch and half in 

 its vertical direction, and an inch and a 

 quarter transversely. It reached upwards to 

 the under surface of the coracoid process, 

 from which the head of the humerus was 

 merely separated by the capsular ligament, 

 there being no interval between the summit 

 of the abnormal socket and the coracoid pro- 

 cess. Around this socket the g/enoid liga- 

 ment, perfect in every respect, was continued 

 from the margin of that small portion of the 

 natural articulating surface which existed 

 upon the axillary margin of the bone, and to 

 the apex of which the tendon of the biceps 

 was attached. The capsular ligament was 

 perfect. The head of the humerus did not 

 present its natural spherical form ; it was of 

 an oval shape, its long axis corresponding 

 with that of the long axis of the shaft of the 

 bone. The shaft of the humerus was small 

 and seemingly atrophied, and the position of 

 the bone with respect to the coracoid and 

 acromion processes varied according as the 

 motion of rotation inwards or outwards was 

 imparted to the arm. During rotation out- 

 wards in this case the head of the bone 

 passed towards the acromion process, and 

 occupied the small portion that existed of the 

 glenoid cavity on the normal site; while 

 rotation inwards brought the head of the 

 humerus altogether beneath the coracoid 

 process, so that the finger could be easily 

 sunk into the outer portion of the socket.f 



* Smith on Fractures, &c. 



\ This species of locomotion of the articular head 



On the right side, although the condition of 

 the bones was somewhat different, the cha- 

 racteristic features of the deformity were 

 similar. 



In this case it was ascertained, that there 

 never had been any disease of either of the 

 shoulder joints at any period of the patient's 

 life, nor had they ever been the subject of in- 

 jury or accident of any description. The 

 position of the glenoid cavity in this case, 

 beneath the coracoid process, the remarkable 

 form of the head of the humerus, the presence 

 of a perfect glenoid ligament, the absence of 

 any trace of disease, and the existence of the 

 deformity upon each side, all indicate that the 

 nature of the malformation must have been 

 congenital, although but little of the early 

 history of the case was known. 



Congenital malformation of the shoulder joint, 

 with displacement of the head of the humerus on 

 the dorsum of the scapula. The second case 

 we think right to abstract from Dr. R. Smith's 

 work is also a very important one, equally 

 proving that a double congenital luxation of 

 the head of the humerus may be observed to 

 take place backwards on the dorsum of the 

 scapula, just as we have already shown that 



Fig. 442. 



Congenital taxation on the dorsum of the scapula. 



an analogous dislocation forwards has oc- 

 curred. 



of a bone representing the proper rotation which 

 should exist, is a consequence of the existing lax 

 state of the fibrous structures of the joint. We 

 have already noticed a similar condition of the liga- 

 ments, and a similar eft'ect, when describing a case 

 of congenital malformation of the radio-humeral 

 joint. See ELBOW JOINT, Vol. II. note to page 81, 

 where it is said "These movements did not con- 

 sist in a simple rotation of the radius on its longi- 

 tudinal axis, but a real change of the upper extre- 

 mity of the radius on the outer condyle of the 

 humerus. "j 



