THE HUMERUS. 185 
tuberosity (tuberculum minus) by a well-defined furrow, called the bicipital groove 
suleus intertubercularis), from the circumstance that the tendon of origin of the 
long head of the biceps muscle 
is lodged within it. The small 
tuberosity lies in front of the 
outer half of the head ; it forms 
a pronounced elevation, which 
fades into the shaft below. 
The surface of this tuberosity 
is faceted above and in front 
for the insertion of the sub- 
scapularis muscle, whilst ex- 
ternally it forms the prominent 
inner lip of the bicipital groove. 
Below the head and tuberosities 
the shaft of the bone rapidly 
contracts, and is here named 
the surgical neck (collum chirur- 
gicum) owing to its liability to 
fracture at this spot. 
The shaft, or body (corpus 
humeri), is cylindrical in its 
upper half. On it the bicipital 
groove may be traced down- 
wards and slightly inwards, 
along its anterior surface. The 
edges of the groove, which are 
termed its lips, are confluent 
above with the great and small 
tuberosities respectively. Here 
they are prominent, and form 
the crests of the great and 
small tuberosities (criste tuber- 
culi majoris et minoris). In- 
feriorly the lips of the bicipital 
groove gradually fade away, the 
inner more rapidly than the 
outer, which latter may usually 
be traced down to a rough 
elevation placed on the outer 
side of the shaft about its 
middle, called the deltoid emi- 
-nence. Into the outer lip of the 
bicipital groove are inserted 
the fibres of the pectoralis 
‘Inajor muscle ; hence it is some- 
times described as the pectoral 
ridge. To the floor of the groove 
the latissimus dorsi is attached; 
whilst the teres major muscle 
is inserted into the inner lip. 
The deltoid eminence (tuber- 
ositas deltoidea), to which the 
powerful deltoid muscle is 
attached, is a rough, slightly 
elevated V-shaped — surface, 
eect on the outer side of the 
Heap 
Supraspinatus ¢ if) 
hs fh 
GREAT TUBEROSITY 
Subscapularis 
LESSER 
TUBEROSITY 
Latissimus dorsi 
Pectoralis major 
Teres major 
Coraco-brachialis 
—— —— ARTERIAL FORAMEN 
Brachio-radialis 
Brachialis anticus 
EXTERNAL 
EPICONDYLIC——yy 
RIDGE y 
INTERNAL EPICONDYLIC 
RIDGE 
Extensor carpi radialis 
longior 
RADIAL FOSSA 
Tendon of exten- 
sor muscles 
EXTERNAL 
EPICONDYLE 
CaPITELLUM 
CORONOID FOSSA 
Pronator radii teres 
INTERNAL 
EPICONDYLF 
Tendon of flexor 
muscles 
TROCHLEA 
Fia. 128.—ANTERIOR VIEW OF THE RIGHT HUMERUS. 
Shaft about its middle. The anterior limb of. the V is parallel to the axis of the 
shaft, and is continuous with the outer lip of the bicipital groove above, whilst the 
