1118 



THYROID GLAND. 



opening into the pharynx, the oesophagus, or 

 into the top of the trachea. 



Santorini (Observ. Anat. 175-i), recognizes 

 the thyroid as a single gland, and makes men- 

 tion of its median column as previously known 

 to Morgagni, though it was probably dis- 

 covered by Bidloo or Lalonette. He details 

 the failure of his efforts to discover a duct, 

 though he had several times detected an 

 orifice at the anterior angle of the glottis, into 

 which a bristle could be passed ; and yet re- 

 marks that the thyroid gland may be urged to 

 expel its secretion by the pressure of the 

 sub-hyoidean muscles, the throbbings of the 

 carotids, and the contractions of the oeso- 

 phagus. 



Haller (Element. Physiolog. 1766), in his 

 account of the thyroid, gives a good descrip- 

 tion of the median column, and of the several 

 varieties which it presents ; four times only 

 has he found it absent ; most frequently 

 existing on the left side ; sometimes, however, 

 on the right. He relates some experiments 

 of Lalonette, in which it appeared as if the 

 glandular cavities had been distended by 

 inflation with air, and also the lymphatic vessels 

 proceeding from them. The result of this coarse 

 proceeding he explains, and probably cor- 

 rectly, by supposing that the distended cavities 

 were those of the areolar texture, and not the 

 secreting vesicles. He remarks that, even 

 according to Lalonette' s testimony, no secre- 

 tion can ever be pressed out of the thyroid 

 gland into the cavity of the larynx ; or if any 

 appear it seems to be nothing more than the 

 contents of some mucous follicles. After 

 detailing the struggles and efforts of various 

 anatomists to discover an efferent duct, he 

 states at last that several inquirers, among 

 whom he mentions Ruysch in particular, had 

 adopted the only possible remaining opinion, 

 that a peculiar fluid was elaborated in the 

 gland, which being received into the radicles 

 of the veins, was returned into the blood. 

 This view, which laborious, and thoughtful, 

 and sagacious men were then slow to entertain, 

 is now universally adopted ; and it seems cer- 

 tainly a matter of wonder that it was not 

 sooner arrived at. May we not, however, 

 question whether, in regard to other glands, a 

 process somewhat similar does not also occur, 

 whether certain complementary products of 

 secretory action are not formed in the gland, 

 and afterwards absorbed and carried off by 

 venous and lymphatic radicles ? 



Meek el's description of the thyroid is as 

 complete as could be accomplished by the 

 most consummate anatomical skill, while un- 

 aided by the achromatic lens. I need not 

 refer to his well known pages, further than to 

 notice a suggestion which he offers, viz., that 

 as the median column is much more deve- 

 loped in the infant than in the adult, the 

 excretory duct may exist at that period (in 

 the median column), and become obliterated 

 as age advances. 



In proceeding beyond this period, we come 

 to the anatomists of our own day ; several of 

 whom have advanced our knowledge con- 



siderably respecting the thyroid and other 

 ductless glands. To none, however, are we 

 more indebted than to Mr. Simon ; whose 

 musterly and philosophical Essay on the 

 Thymus contains the best account of the 

 anatomy and physiology of these organs that 

 has yet been given. 



BIBLIOGRAPHY. Wharton, Adenographia. Mor- 

 gagni, Adversaria Anatomka. Hailer, Elemeita 

 Physiologies. Meckel and Cruveilhier's works on 

 Descriptive Anatomy. Quain and Sharpey's Ana- 

 tomy. Todd and Bowman, Physiological Anatomy. 

 Simon's paper in Pliilos. Transact. 1844, on Com- 

 parative Anatomy of Thyroid. Various parts of the 

 essay of the same author on the Thymus gland. 

 Henle, Allgemeine Anatomic. CEster'len, Beitra'ge 

 zur Physiologie. 



( C. Handfield Jones. ) 



TIBIO-FIBULAR ARTICULATIONS. 



The bones of the leg, throughout the 

 greater part of their length parallel and con- 

 tiguous to each other only, are in contact by 

 their extremities. At the points of contact the 

 two tibio-fibular articulations, a superior and 

 an inferior, are situated. 



SUPERIOR TIBIO-FIBULAR ARTICULATION. 

 The head of the fibula is in contact with 

 the external tuberosity of the tibia. The for- 

 mer is furnished with an articulating surface 

 which has an aspect upwards, forwards, and in- 

 wards, whilst the articular facet on the latter 

 is placed rather towards the posterior part of 

 the tuberosity of the tibia, and is directed 

 downwards, backwards, and outwards. Both 

 surfaces are almost perfectly plane, their form 

 is circular, and they are encrusted with arti- 

 cular cartilage ; hence this articulation is to be 

 referred to the class arthrodia. 



a. The ligaments of this joint are two in 

 number, named, from their relative positions, 

 anterior and posterior ligaments. 



1. The anterior ligament of the superior 

 tibio-fibular articulation, is composed of a fas- 

 ciculus of white fibrous bands, which are all 

 parallel to each other. It passes from the 

 tibia downwards and outwards to the head of 

 the fibula, running in front of the synovial 

 membrane of the articulation which it defends. 

 The extensor digitorum communis muscle 

 covers this ligament anteriorly. 



2. The posterior ligament follows a similar 

 direction on the posterior aspect of the joint; 

 but the fibres which compose it are neither so 

 numerous nor so strong as those of the pre- 

 ceding; this ligament is covered posteriorly 

 by the poplitaeus muscle. 



Lastly, the tendon of the biceps (flexor 

 cnirin), by its attachment to the head of the 

 fibula, contributes, in no inconsiderable de- 

 gree, to the security of the articulation. 



b. Synovial membrane. There is nothing, in 

 the anatomical disposition of the synovial 

 membrane of this articulation, which requires 

 any particular notice ; but the surgeon should 

 remember that it is always in close proximity 

 to the serous sac of the knee joint, and that 

 in many instances the two synovial membranes 

 communicate with each other. The synovial 



