deals with the anatomy of LS spine coccyx and sacrum. The sacrum and coccyx are two anatomical structures located near the bottom of your vertebral spinal column, below the fifth lumbar vertebra (L5).Below the sacrum is the coccyx, commonly known as the tailbone. The sacrum and coccyx are weight-bearing spinal structures.

1. 




2.  These are the five vertebrae
between the rib cage and the pelvis.
 It starts about five or six inches
below the shoulder blades, and
connects with the Thoracic spine at the
top and extends downward to the
Sacral spine.
Lumbar spine has 5 vertebrae,
labeled L1-L5.
T 12
S1
Scapula
( shoulder
blades)

3.  L1 to L4 are considered Typical Lumbar Vertebrae.
The large bodies are oval and the vertebral foramen is triangular.
The spinous process is stumpy and projects dorsally.
 L5 is considered Atypical Lumbar Vertebrae.
L
5
Atypical
Typical

4. Also known as Centrum
(Corpus vertebrae)
The bodies of the lumbar
vertebrae are massive,
sturdy, and designed to
withstand vertical compression.

5. Also known as Spinal foramen.
It is a large, triangular-shaped
opening located posterior to the
body. The spinal cord and several
nerves pass through the foramen.

6. Also known as neural arch.
It is formed by the two pedicles,
two Laminae, and Spinous
process.
 The arch encloses the posterior
portion of the vertebral
foramen.
Vertebral Arch

7. Pedicles of the vertebral arch are
posterior extensions from the lateral
sides of the body.
The two pedicles form the base
of the vertebral arch.

8. Lamina of the vertebral
arch are plates of bone that
extend from the pedicles.
The left and right lamina
and the spinous process form
the dorsal portion of the
vertebral arch.

9. The Spinous process is a
posterior projection from the
junction of the two lamina.
 Its thick, broad, quadrilateral
shape serves as an attachment
point for ligaments and muscles
that stabilize the back.

10. It is a long, thin, latero-
posterior projection that
originates near the junction
of the pedicle, lamina, and
superior articular process. It
also serves as an attachment
point for back muscles.

11. It is a superior projection
near the junction of the
pedicle and transverse
process. The facet is concave,
faces inward (medially), and
articulates with the inferior
articular facet on the vertebra
above.

12. It is an inferior projection
from the junction of the pedicle
and lamina.
 The facet is convex, faces
outward (laterally), and
articulates with the superior -
articular facet on the vertebra
below.

13. It is a thick pad of connective
tissue that helps hold adjacent
vertebrae together and acts as a
shock absorber.
The lumbar vertebrae help
support the weight of the body,
and permit movement.
Vertebrae articulate with one another via 2 ways ;

14. It is obliquely oriented,
cylindrically-shaped articular
surfaces.
Inferior articular process of
the vertebrae above always
lies posterior to the superior
articular process of the
vertebrae below. Intervertebral joint

15. They can be divided into two groups
1) Present throughout Vertebral
Column :
 Anterior Longitudinal Ligament.
Posterior Longitudinal Ligament.
 Ligamentum Flavum.
 Interspinous Ligament.
 Supraspinous Ligament.
Interansverse Ligament.
A
B
C
D
E
F

16.  Iliolumbar ligaments:
The lumbosacral joint (between L5
and S1 vertebrae) is strengthened by
the Iliolumbar ligaments. These are
fan-like ligaments radiating from the
transverse processes of the L5
vertebra to the ilea of the pelvis
2) Unique to Lumbar Spine : Iliolumbar Ligament

17. Iliohypogastric Nerve.
Ilioinguinal Nerve.
Genitofemoral Nerve.
Lateral Cutaneous Nerve of the Thigh.
Obturator Nerve.
Femoral Nerve.
*Nerve plexus which provides motor
and sensory nerves
*Spinal cord ends at approximately
L1-L2

19. SACRUM
The sacrum is a large bone located at
the terminal part of the vertebral canal,
where it forms the posterior aspect of
the pelvis.
 It is remarkably thick, which aids in
supporting and transmitting the weight
of the body.
The sacrum is formed by the fusion
of the five sacral vertebrae.
 It has an inverted triangular, concave
shape.
The bone consists of a base, apex
and four surfaces:

20. Apex : narrow caudal (towards the tailbone)
portion.
Base : broad superior portion where there is an
articulation with L5.
sacral promontory : prominent bulge on anterior
side of base.
superior articular processes : articulates with
inferior articular processes of L5.
sacral canal : continuation of vertebral canal
through fused arches of sacral vertebrae.
median sacral crest : fused spinous processes of
the first four sacral vertebrae.

21. sacral hiatus :opening that
results from failure of laminae of
S5 to form and fuse.
lateral sacral crest : ridges on
either side of median sacral crest.
Sacral foraminae : Openings that
correspond to intervertebral formina.
There are anterior and posterior
foramina.
Ala : Wing-like extensions on either
side of base.
Auricular surface : Ear-shaped
surface of the sacroiliac joint.
Sacral tuberosity : Roughened area
dorsal to auricular surface where
ligaments that stabilize the
sacroiliac joint attach.

23. 1
2
3
5
Base

24. ARTICULATIONS
Lumbosacral Joint :
The upper border articulates
with the 5th Lumbar vertebra.
Sacrococcygeal Joint :
The inferior part articulates
with the Coccyx
Sacroiliac Joint :
Lateral part articulates with
the Hip bone(Ilium)
SACROILIAC JOINT
LUMBOSACRAL JOINT
SACROCOCCYGEAL JO

25. It is the joint between the sacrum and
the ilium bones of the pelvis, which are
connected by strong ligaments.
The joint is strong, supporting the
entire weight of the upper body. It is a
synovial plane joint with irregular
elevations and depressions that produce
interlocking of the two bones.
Sacroiliac joints are paired C-shaped
or L-shaped joints capable of a small
amount of movement that are formed
between the auricular surfaces of the
sacrum and the ilium bones.
 Their main job is to carry the weight
of your upper body when you stand or
walk and shift that load to your legs.

26. LIGAMENTS
 Anterior longitudinal ligament
 Iliolumbar ligament.
 Lumbosacral ligament.
 Sacroiliac ligaments:
 Sacrospinous ligament
 Sacrotuberous ligament
 Sacrococcygeal ligaments:

27. https://www.slideshare.net/venus88/biomec
hanics-of-lumbar-spine
sacrococcygeal ligaments:
Lumbosacral ligament.
1
2
3
4
5
6
7

28. SACRAL PLEXUS
 Superior & Inferior Gluteal Nerve.
 Nerve to the Quadratus Femoris.
 Nerve to the Obturator Internus .
 Post. Femoral Cutaneous Nerve.
 Perineal branches.
 Pudendal Nerve.
 Sciatic Nerve.
 Tibial Nerve.

29. The coccyx (also known as the
tailbone) is the terminal part of the
vertebral column. It is comprised of
four vertebrae, which fuse to
produce a triangular shape.
The coccyx is formed from four
rudimentary vertebrae and does
not contain a spinal canal,
pedicles, laminae or spinous
processes
it serves as the insertion site for
the muscles of the pelvic floor and
those that contribute to voluntary
bowel control and supports the
position of the anus.

30.  The coccyx consists of an apex, base, anterior surface,
posterior surface and two lateral surfaces.
 Base: It is located most superiorly, and contains a facet for
articulation with the sacrum.
 Apex : It is situated inferiorly, at the terminus of the vertebral
column.
 Lateral surfaces of the coccyx are marked by a small
transverse process, which projects from Co1.

31. ARTICULATIONS
 Sacrococcygeal Joint:
 It is a fibrocartilaginous joint
that connects the apex of the
sacrum to the coccyx. Movement
is passive minor flexion and
extension and the joint typically
fuses with age.

32. LIGAMENTS
 Anterior sacrococcygeal ligament :
 Deep posterior sacrococcygeal
ligament.
 Superficial posterior sacrococcygeal
ligament
 Lateral sacrococcygeal ligaments :
 Interarticular ligaments :

33. REFERENCE

34. Next : Jennifer D’S

35. The sacral plexus is a nerve
plexus which provides motor and
sensory nerves for the posterior
thigh, most of the lower leg and
foot, and part of the pelvis. It is
part of the lumbosacral plexus
and emerges from the lumbar
vertebrae and sacral vertebrae
(L4-S4)