80 ' OSTEOLOGY. 
but the eleventh occasionally displays the same arrangement, in which case it is 
not always easy to distinguish between them. 
LUMBAR VERTEBRA. 
The lumbar vertebre (vertebra lumbales), five in number, are the largest of 
the movable vertebrae. They have no costal articular facets, nor are their trans- 
verse processes pierced by 
a foramen. In this way 
they can be readily dis- 
tinguished from the mem- 
bers of the cervical and 
Inferior articular process thoracic series. 
Mammiillary process The body is kidney - 
Accessory process Shaped in outline, and of 
large size. The transverse 
diameter is usually about 
'f Transverse 2 half greater; than the 
> process antero-posterior width. 
The anterior thickness is 
Superior articular Slightly greater than the 
process posterior, beimg thus 
adapted to the anterior 
convex curve, of; thie 
column in this region. 
The pedicles, directed 
horizontally backwards, 
are short and stout; the 
superior notches are 
shallow, but deeper than 
in the dorsal region; the 
inferior grooves are deep. 
The lamine are broad, and 
Mamnillary-process nearly vertical, sloping but 
shghtly. They support 
on their lower margins 
the inferior articular pro- 
cesses. The spinal foramen 
is large and triangular. 
The spinous processes, 
spatula shaped, with a 
thickened posterior 
margin, project backwards 
and shehtly downwards. 
The transverse processes, 
Inferior articular process more slender than in the 
_ dorsal region, pass hori- 
Fic. 61.—THirp LUMBAR VERTEBRA FROM ABOVE, AND FROM THE 5 
eg a zontally outwards, with a 
slight backward inclina- 
tion. Arising from the junction of the pedicles with the laminz in the higher 
members of the series, they tend to advance so as to become fused with the outer 
side of the pedicle and back of the body in the two lower lumbar vertebrae. In 
these latter vertebrie the superior intervertebral groove is carried obliquely across 
the upper surface of the base of the transverse process. The transverse processes 
lie in line with the external tubercles of the lower thoracic vertebrae, with which 
they are serially homologous, and are to be regarded as representing the costal 
element. Placed on their base posteriorly, and just external to and below the 
superior articular processes, are the small accessory tubercles (processus accessoril) 
which are in series with the inferior tubercles of the lower thoracic vertebrae. The 
Spine 
(35, 
Lamina 
uy 
Pedicle 
Transverse process 
