_1.H._, Atlas; _7.H._, seventh cervical vertebra; _1.R._, first
thoracic vetrebra; _6.R._, sixth rib; _12.R._, twelfth thoracic
vertebra; _13.R._, last rib; _1.L._, first, _6.L._, last lumbar
vertebra; _K_, sacrum; _1.S._, first coccygeal vertebra; _6.K._,
sixth costal cartilage; _x_, wing of atlas; _1_, scapula; _1′_,
cartilage of scapula; _2_, spine of scapula; _3_, acromion; _4_,
humerus; _4′_, external condyle of humerus; _5_, external tuberosity
of humerus; _6_, deltoid tuberosity; _7_, ulna; _8_, olecranon; _9_,
radius; _10_, carpus; _11_, accessory carpal bone; _12_, metacarpus;
_13_, phalanges; _14_, sternum; _14′_, manubrium; _14″_, xiphoid
cartilage; _15_, ilium; _16_, external angle of ilium; _16′_,
internal angle of ilium; _17_, tuber ischii; _18_, femur; _19_,
trochanter major; _20_, patella; _21_, tibia; _21′_, external
condyle of tibia; _22_, tarsus; _23_, distal end of fibula; _24_,
tuber calcis; _25_, metatarsus; _26_, phalanges. (After
Ellenberger-Baum, Anat. für Künstler.)
]
The =lumbar vertebræ=, six in number, are much longer than in the horse.
The =bodies= are much constricted in the middle, expanded at either end,
and bear rudimentary ventral crests. The fourth and fifth are usually
the longest. The =intervertebral foramina= are often double in the
anterior part of the series, and are very large further back. The
=articular processes= are large, and their facets are more strongly
curved than in the horse. The =transverse processes= all curve forward.
They are separated by considerable intervals, and form no articulations
with each other or with the sacrum. Their borders are thin and
irregular, and often bear projections of variable size and form. The
first is the shortest and the length increases to the fifth, the last
being considerably shorter. The =spinous processes= are relatively low
and wide, the last being the smallest; their summits are moderately
thickened.
The =sacrum= is longer than that of the horse. It consists originally of
five segments, but fusion is more complete and involves the spinous
processes, which are united to form a =median sacral crest=, with a
convex thick and rough margin. =A lateral crest= is formed by the fusion
of the articular processes. The =pelvic surface= is concave in both
directions, and is marked by a central =groove=, which indicates the
course of the middle sacral artery. The =inferior sacral foramina= are
large. The =wings= are quadrangular, short, compressed from before
backward, and high dorso-ventrally. They have an extensive anterior
surface, which is concave from side to side, and non-articular. The
posterior surface is rough, and bears a triangular area below for
articulation with the ilium. The body of the first segment is very wide,
and the entrance to the sacral canal correspondingly wide and low. The
=anterior articular processes= are large, and are concave and
semicylindrical in curvature internally. The =lateral borders= are thin,
sharp, and irregular. The =apex= is wider than in the horse, and the
posterior end of the crest forms a pointed projection over the opening
of the sacral canal.
The =coccygeal vertebræ= are longer and better developed than in the
horse. The first five or six have complete arches and spinous processes.
The transverse processes are relatively large in the anterior part of
the series, in which there are also anterior articular processes (which
do not articulate), and a pair of ventral spines which form a hæmal
groove for the middle coccygeal artery.
Vertebral curves: The cervical curve is very slight and is concave
dorsally. The thoracic and lumbar regions form a gentle curve, concave
ventrally. The promontory is more pronounced than in the horse,
especially in subjects in which the sacrum is inclined upward behind.
Another promontory occurs at the junction of the sacrum and first
coccygeal vertebræ.
Length: The following table gives the lengths of the regions of a
shorthorn cow of medium size:
Cervical 47 cm.
Thoracic 75 cm.
Lumbar 40 cm.
Sacral 24 cm.
Coccygeal 75 cm.
———————
261 cm.
Variations: Sometimes fourteen thoracic vertebræ and fourteen pairs of
ribs are present; reduction to twelve with the normal number of lumbar
vertebræ is very rare. According to Franck, there are sometimes seven
lumbar vertebræ with the normal number in the thoracic region. The
number of coccygeal vertebræ may vary from sixteen to twenty-one.