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costae

Costae is the plural of costa, the ribs of the thoracic cage in human anatomy. The human rib cage normally comprises 24 ribs, arranged in 12 pairs, and provides protection for thoracic organs while contributing to respiration through its movement. Ribs are categorized as true (costae verae, 1–7), false (costae spuriae, 8–10), and floating (costae nurtae, 11–12) based on their cartilage connections.

Anatomically, each rib is a curved bone with a vertebral end and a sternal end. The head

Joints involving costae include costovertebral joints (rib head with vertebral bodies), costotransverse joints (rib tubercle with

Variations occur among individuals and species, but the 24-rib arrangement remains a standard reference in human

of
a
typical
rib
articulates
with
the
bodies
of
the
vertebrae
of
the
same
number
and
the
one
above,
via
two
articular
facets;
the
neck
lies
between
the
head
and
tubercle,
which
articulates
with
the
transverse
process
of
the
corresponding
vertebra.
The
anterior
end
connects
to
the
sternum
either
directly
via
costal
cartilage
(true
ribs)
or
indirectly
through
the
cartilage
of
the
rib
above
(false
ribs).
The
costal
cartilage
is
hyaline
cartilage,
contributing
to
the
elasticity
and
flexibility
of
the
rib
cage.
The
inferior
margin
of
each
rib
contains
a
costal
groove
that
houses
intercostal
arteries,
veins,
and
nerves.
the
transverse
process),
and
sternocostal
joints
(rib
cartilages
with
the
sternum
for
true
ribs).
The
anatomical
arrangement
supports
respiratory
mechanics,
permitting
expansion
and
compression
of
the
thoracic
cavity
during
breathing.
anatomy.