SOME ERRORS IN THE DIVISIONS OF THE BONES. 579 
scabrous canal (scaber canalis), placed at right angles to it, 
at the antero-inferior part of the body of the humerus. The 
outer side is excavated and smooth ; the inner rather 
prominent and roughened, and presents a small scabrous 
eminence, — the scabrum tuberculum (dim. of tuber, a 
little swelling). Lower down we have the medullary foramen, 
direction downwards. 
Superior Extremity, — Larger than the inferior ; it has a 
head and four tubercles. The head is the hemispherical, 
smooth part projecting posteriorly; it articulates with the 
glenoid process (from Greek n. r\rjvri } the socket of a joint), 
which it much exceeds in extent of superficies. Into the 
irregular indented groove by which the head is surrounded 
is fixed the capsular ligament (from L. n. capsula, and dim. 
of capsa, a chest) ; anteriorly, the head is surmounted by four 
tubercles. Three directly in front are anti-articular; they 
have between them two smooth grooves, which, as well as 
themselves, are covered with cartilage. They serve as a 
pulley for the flexor brachii tendon to play over. The outer 
articular tubercle is joined by a protuberant ridge with the 
tuberosity. The fourth or outer tubercle serves to guard 
against dislocation. 
Inferior Extremity . — Displays a specimen of diarthrodial or 
pulley-like articulation (from Greek , bia , through, and apdpov , 
a limb). It consists of two condyles, ( L . n. condylus, a 
knuckle) separated anteriorly by a canal (canalis condylorum), 
which commences at the scaber canalis, slightly and 
gradually increasing in depth and width, until it abruptly 
terminates at the posterior part of the bone, in a deep ovoid 
fossa, the piscina or pond, into which the olecranon 
(utXerri, ulna, and upavov, the head), is received. On the inner 
and outer sides of the condyle, we have two processes like 
the sides of a drum. The outer is concave, forming a sort of 
cup-shape, and porous ; the inner is slightly convex, having 
a foramen in its centre. These, for the sake of distinction, 
might be called the tympanoid processes, (from Greek , 
Tvpuravov , a drum, and elbos , like). The outer condyle is the 
largest, and projects more behind and before than the inner. 
The inner condyle, the smaller, is divided by a canal (canalis 
condyli), running parallel to the canalis condylosum. The 
condyles meet at an angle above the piscina, and there run 
into union with the bone. 
In the young bone, the head, condyles, and tubercles, are 
epiphyses. (E7n, upon, <pvio , I grow). 
