Download Thoracic vertebrae

Thoracic
vertebrae
Thoracic vertebrae
General plan of a vertebra
Features of thoracic vertebrae
Spinous process palpation
Articulations
General plan of a vertebra
A vertebra in general
is formed of a body
and a vertebral arch
Vertebral arch
Encloses the vertebral
foramen (= hole L.)
Vertebral arch
is formed of two
pedicles (little feet,
pes = foot L.)
Vertebral arch
is formed of two
pedicles (little feet,
pes = foot L.)
and two laminae (thin
plates).
Vertebral arch
The arch has several
processes
Vertebral processes
The processes are
4 articular
Vertebral processes
The processes are
4 articular
2 transverse
Vertebral processes
The processes are
4 articular
2 transverse
1 spinous
Features of thoracic vertebrae
Costal facets
vertebral canal
body
processes
Costal facets
The essential
characteristic
feature of a thoracic
vertebra is the
presence of a costal
facet (place for
articulation with the
rib) on the body of
the vertebra
Costal facets
The presence of the
costal facet on the
body of the thoracic
vertebra distinguishes
it from vertebrae of
other regions in the
vertebral column
cervical
thoracic
lumbar
Costal facets
A thoracic vertebra
has costal facets on
the body and
transverse processes
Costal facets
A thoracic vertebra
has costal facets on
the body and
transverse processes
except T11 and T12,
which has no costal
facets on their
transverse processes
Costal facets
In vertebrae from T2
to T9, two demi(half) facets are
located on each side
of the body
½
½
Costal facets
The
superior
facet is for
articulation
with the
head of its
own rib
X
X
Costal facets
The
inferior
facet is for
articulation
with the
head of the
rib inferior
to it
X
X
X+1
Costal facets, T1
Since the head of
the first rib carries
a single facet
Costal facets, T1
the body of T1 has
a single costal
facet on each side
for the head of the
first rib
Costal facets, T1
In addition, it
carries a demifacet for the head
of the second rib
Costal facets, T10 - T12
Each side of the
body of T10-T12
has a single facet
for the head of the
corresponding rib
Costal facets
In other words,
the heads of ribs
1, 10, 11, & 12
articulate solely
with the body of
the vertebra to
which they
correspond
numerically
Vertebral canal
The vertebral canal of
a thoracic vertebra is
circular
Cervical
Lumbar
Small & triangular
Large & triangular
Vertebral canal
Note the size of the
vertebral canal
Vertebral body
The body of a
thoracic vertebra is
heart-shaped
Vertebral body
The body of a
thoracic vertebra is
heart-shaped,
meaning a player’s
card heart or lover’s
heart rather than the
anatomical heart
Thoracic
Vertebral body
Comparison
Cervical
Lumbar
Kidney-shaped
Transversly elongated
Vertebral body
In vertebrae of the
middle of the series
(T5-T8), the left side
of the body is slightly
flattened
Vertebral body, T5 - T8
In this region, the descending
thoracic aorta is directly in contact
with the bodies to the left of the
midline
Spinous process
The spinous
processes of thoracic
vertebrae are long
and tapered
They vary in their
obliquity
T1, T2, T11, and T12
have spinous
processes that are
almost horizontal
T3, T4, T9, and T10
have oblique spinous
processes
Spinous process
In vertebrae of the
middle of the
series (T5-T8), the
spinous processes
are almost vertical
Spinous process, palpation
The spinous
processes of thoracic
vertebrae are
palpated in the
midline posteriorly
Spinous process, palpation
However, since the
thoracic spines
run downwards
are joined by thick
supraspinous
ligaments
are covered by fairly
thick skin
they are not easy to
examine individually
Spinous process, palpation
If the index finger of
the examining hand is
moved downwards at
the back of the neck
while the vertebral
column is flexed, the
spines project much
more
Vertebra prominans
The first spinous
process that is visible
and palpable is that of
C7.
Therefore, C7 is
called the vertebra
prominans although
the spinous process
of T1 may be more
prominent
Spine levels
The spine of T2
lies against the
superior angle of
the scapula
Spine levels
The spine of T3 lies
against the spine of
the scapula
Spine levels
The spine of T7 lies
against the inferior
angle of the scapula
Articulations
Thoracic vertebrae
articulate with each
other by means of a
secondary
cartilaginous joint
between the bodies
Articulations
Thoracic vertebrae
also articulate with
each other by means
of a plane synovial
joint on each side
between superior and
inferior articular
processes
Intervertebral disc
The disc between the
bodies
has an outer circular
fibrous part called
anulus fibrosus
(anulus = ring L.), and
an inner softer part
called nucleus
pulposus.
Disc prolapse
If the anulus is torn
(most frequently
posteriorly), the
nucleus may bulge
out and press on
spinal nerves
Site of prolapse
Disc
prolapse
Site of prolapse
Intervertebral foramen
When two adjacent
vertebrae are
articulated, an
intervertebral
foramen is formed
bounded above and
below by the pedicles
Intervertebral foramen
A spinal nerve
emerges from the
foramen.
Thoracic spinal nerves
In the thoracic region
T1 spinal nerve
emerges between the
1st and 2nd thoracic
vertebra and T12
spinal nerve between
the 12th thoracic
vertebra and the 1st
lumbar vertebra
Thoracic spine
lateral projection - dried specimen
Note
superior articular process
inferior articular process
pedicle
body of vertebra
spinous process
transverse process
inferior vertebral notch
Thoracic spine,
lateral projection
Note
superior articular process
inferior articular process
site of intervertebral disc
pedicle
body of vertebra
rib
transverse process
inferior vertebral notch
Thoracic spine
antero-posterior projection - dried specimen
Note
superior articular
process
inferior articular
process
pedicle
spinous process
transverse process
Thoracic spine
antero-posterior peojection
Note
transverse process
pedicle
body
site of intervertebral
disc
spinous process
ribs