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Joints of the Vertebral Column. Joints of the vertebral bodies Joints of the vertebral arches (Zygapophysial joints, Facet joints) Craniovertebral (atlanto-axial and atlanto-occipital) joints Costovertebral joints Sacroiliac joints .
4 synovial joints (2 above & 2 below)
2 symphyses (1 above & 1 below)
Each symphysis includes an intervertebral disc.
Symphyses(Secondary cartilaginous joints)
Designed for weight-bearing and strength.
The articulating surfaces of adjacent vertebrae are connected by intervertebral discs and ligaments.
The intervertebral disc consists of an outer anulus fibrosus, which
surrounds a central nucleus pulposus.
Anulus fibrosus consists of an outer ring of collagen surrounding a wider zone of fibrocartilage arranged in a lamellar configuration.
This arrangement of fibers limits rotation between vertebrae.
Nucleus pulposus (L. pulpa, fleshy) core of the intervertebral disc.
Fills the center of the intervertebral disc, is gelatinous, and absorbs compression forces between vertebrae.
Their semifluid nature is responsible for much of the flexibility and resilience of the intervertebral disc/column.
Provide strong attachments between the vertebral bodies
Unite them into a continuous semirigid column
Form the inferior half of the anterior border of the IV foramen.
In aggregate, the discs account for 20-25% of the length (height) of the vertebral column.
Most inferior functional disc is between L5 & S1
Thickness of the discs increases - Vertebral column descends.
Relative thickness (Disc thickness/Body size)- Range of movement
Most clear--- Cervical & Lumbar regions
Disc thickness most uniform in thoracic region.
The discs are thicker anteriorly in the cervical and lumbar regions, their varying shapes producing the secondary curvatures of the vertebral column.
The semifluid nature of the nucleus pulposus allows it to change shape and permits one vertebra to rock forward or backward on another, as in flexion and extension of the vertebral column.
A sudden increase in the compression load on the vertebral column causes the semifluid nucleus pulposus to become flattened.
The outward pushing of the nucleus is accommodated by the resilience of the surrounding anulus fibrosus.
Allows nucleus pulposus to herniate
Protrude into the vertebral canal, where it may press on the spinal nerve roots, spinal nerve, or even the spinal cord.
With advancing age, the water content of the nucleus pulposus diminishes and is replaced by fibrocartilage.
The collagen fibers of the anulus degenerate and, as a result, the anulus cannot always contain the nucleus pulposus under stress.
In old age the discs are thin and less elastic, and it is no longer possible to distinguish the nucleus from the anulus.
66 year old male
20 y old male
(ZYGAPOPHYSIAL JOINTS-FACET JOINTS
Plane synovial joints
between superior and inferior articular processes of adjacent vertebrae.
Those in the cervical region are especially thin and loose, reflecting the wide range of movement.
Accessory ligaments unite the laminae, transverse processes, and spinous processes and help stabilize the joints.
Zygapophysial joints permit gliding movementsbetween the articular processes.
Clefts (of Luschka
Lateral margins of the upper surfaces of typical cervical vertebrae; elevated into crests or lips.
May articulate with the body of the vertebra above to form small "uncovertebral" synovial joints.
Commonly develop between the unci of the bodies of C3 or 4-C6 or 7.
@ lateral and posterolateral margins of the intervertebral discs.
Considered as synovial joints by some; others; by others as degenerative spaces (clefts) in the discs occupied by extracellular fluid.
1= First rib
2 = Vertebral body of C7
3 = Spinous processes
4 = Uncinate process
5 = Uncovertebral
(apophyseal or Luschka's) joint
Joints between vertebrae are reinforced and supported by numerous ligaments, which pass between vertebral bodies and interconnect components of the vertebral arches.
Anterior and posterior longitudinal ligaments
On the anterior and posterior surfaces of the vertebral bodies.
Extend along most of the vertebral column.
Attached superiorly to the base of the skull
Extends inferiorly to the anterior surface of the sacrum
Along its length it’s attached to vertebral bodies & intervertebral discs.
On the posterior surfaces of vertebral bodies
Lines the anterior surface of the vertebral canal
Attached along its length to vertebral bodies &intervertebral discs.
Upper part of posterior
the longitudinal ligament
Connects C2 to
intracranial aspect of
the base of the skull
Along the tips of the spinous processes from C7 to the sacrum
2 sets of joints
Between atlas(C1) & occipital bone of the cranium
Between atlas and axis (C2)
A wider range of movement than in rest of the vertebral column.
Articulations: Occipital condyles, Atlas& Axis.
Superior articular surfaces of the lateral masses of the atlas
Synovial joints of the condyloid type
Nodding of the head, flexion and extension of the head occurring when indicating approval (the “yes” movement).
Sideways tilting of the head.
Flexion, with a little lateral flexion & rotation
3 atlanto-axial articulations
2 (right & left) lateral atlantoaxial joints – plane type joint
between inferior facets of lateral masses of C1 & superior facets of C2
1 median atlantoaxial joint – pivot type joint
between dens of C2 & anterior arch of atlas
Head turns from side to side, disapproval (“no” movement).
Cranium and C1 rotate on C2 as a unit.
During rotation of the head, dens of C2
axis or pivot held in a socket or collar formed
Anteriorly by anterior arch of the atlas
Posteriorly by transverse ligament of the atlas
A strong band extending between tubercles on the medial aspects of lateral masses of C1
Superior and inferior longitudinal bands
Cruciate ligament of the atlas
Tectorial membrane (Membrana tectoria)
Range of movement
Region & individual
The mobility primarily from the intervertebral discs.
The normal range of movement possible in healthy young adults is typically reduced by 50% or more as they age.
Although the movement between any two vertebrae is limited, the summation of movement among all vertebrae results in a large range of movement by the vertebral column.
A tear within the anulus fibrosus
Material of the nucleus pulposus can track
This material tracks into the vertebral canal or into the intervertebral foramen
Pressure on neural structures.
This is a common cause of back pain.
A prolapsed intervertebral disc may impinge upon the meningeal (thecal) sac, cord, and most commonly the nerve root, producing symptoms attributable to that level.
Neurological signs- Surgery
It is of the utmost importance that the level of the disc protrusion is identified before surgery. This may require MRI scanning and on-table fluoroscopy.
Part of the trunk inferoposterior to the abdomen
Area of transition between the trunk and the lower limbs
Inferiormost part of the abdominopelvic cavity.
Anatomically, the pelvis is the part of the body surrounded by the pelvic girdle (bony pelvis), part of the appendicular skeleton of the lower limb.
Surrounded by the superior pelvic girdle.
Occupied by inferior abdominal viscera, affording them protection.
Surrounded by the inferior pelvic girdle, which provides the skeletal framework for both the pelvic cavity and the perineum—compartments of the trunk separated by the musculofascial pelvic diaphragm.
A basin-shaped ring of bones that connects the vertebral column to the two femurs.
The pelvic bone is irregular in shape and has two major parts separated by an oblique line on the medial surface of the bone:
In infants and children, hip bones are 3 separate bones united by a triradiate cartilage at the acetabulum, the cup-like depression in the lateral surface of the hip bone, which articulates with the head of the femur.
After puberty, the ilium, ischium, and pubis fuse to form the hip bone. The two hip bones are joined anteriorly at the pubic symphysis (L. symphysis pubis) and articulate posteriorly with the sacrum at the sacroiliac joints to form the pelvic girdle.
Superior, fan-shaped part of the hip bone
Ala, or wing, of the iliumspread of the fan
Body of the ilium, the handle of the fan.
On its external aspect, the body participates in formation of the acetabulum.
The entire superior margin of the ilium is thickened to form a prominent crest (iliac crest) terminates anteriorly as the anterior superior iliac spine and posteriorly as the posterior superior iliac spine.
A prominent tubercle, tuberculum of iliac crest, projects laterally near the anterior end of the crest; the posterior end of the crest thickens to form the iliac tuberosity.
Inferior to the anterior superior iliac spine, rounded protuberance called anterior inferior iliac spine.
Posteriorly, the sacropelvic surface of the ilium has
an auricular surface and an iliac tuberosity articulation with sacrum.
Has a body and ramus (L. branch).
Body of the ischium forms the acetabulum
Ramus of the ischium forms part of the obturator foramen.
Ischial tuberosity: large posteroinferior protuberance of ischium
Ischial spine: Small pointed posteromedial projection near the junction of the ramus and body
Lesser sciatic notch: Concavity between the ischial spine and the ischial tuberosity
Greater sciatic notch: Larger concavity superior to the ischial spine and formed in part by the ilium.
An angulated bone
Superior ramus helps form the acetabulum
Inferior ramus helps form the obturator foramen.
Pubic crest thickening on the anterior part of the body
Pubic tubercle Pubic crest ends laterally as a prominent swelling
Pecten pubis Oblique ridge@ lateral part of superior pubic ramus
The pelvis divided into greater (false) and lesser (true) pelves by the oblique plane of the pelvic inlet (superior pelvic aperture).
formed by the ischiopubic rami(conjoined inferior rami of the pubis and ischium) of the 2 sides.
These rami meet at the pubic symphysis, their inferior borders defining the subpubic angle.
The width of the subpubic angle is determined by the distance between the right and the left ischial tuberosities, which can be measured with the gloved fingers in the vagina during a pelvic examination.
Medial to the anterior inferior iliac spine is a broad, shallow groove which is bounded medially by the iliopubic eminence (or iliopectineal eminence), which marks the point of union of the ilium and pubis. It constitutes a lateral border of the pelvic inlet.The iliopectineal line is the border of the eminence.
Circular opening between abdominal cavity and pelvic cavity. Promontory of the sacrum protrudes into the inlet, forming its posterior margin in the midline.
Formed anteriorly by the pubic symphysis, posteriorly by the sacrum, and laterally by the iliopectineal line.
The blue line in this 3-D volume rendered CT image (above) represents the lineaterminales that separates the false pelvis, which is above it from the true pelvis below it. The false pelvis consists of the iliac wings and has no anterior wall. The pubis bones, sacrum and coccyx, and both ischium bones delimit the false pelvis.
Linea terminalis consists of the arcuate line, pecten pubis, pubic crest.
The pecten pubis forms part of the pelvic brim and the continuation on the superior ramus pubis of the lineaterminalis, forming a sharp ridge.
Arcuate line of the ilium is a smooth rounded border on the internal surface of the ilium.
It is immediately inferior to the iliac fossa. It forms part of the border of the pelvic inlet.
The primary joints
Sacroiliac joints & pubic symphysis
Sacroiliac joints link the axial skeleton and the inferior appendicular skeleton.
Lumbosacral & sacrococcygeal joints, although joints of the axial skeleton, are directly related to the pelvic girdle. Strong ligaments support and strengthen these joints.
Strong, weight-bearing compound joints
An anterior synovial joint
between the earshaped auricular surfaces of the sacrum & ilium
A posterior syndesmosis
between the tuberosities of the same bones
Differ from most synovial joints in that limited mobility is allowed, a consequence of their role in transmitting the weight of most of the body to the hip bones.
Sacroiliac ligaments ilia
Femurs –during standing-
Ischial tuberosities –during sitting-
Sacrum is actually suspended between the iliac bones
Firmly attached to iliac bones by posterior and interosseous sacroiliac ligaments.
Anterior part of the fibrous capsule of the synovial part of the joint.
Interosseous sacroiliac ligaments
Lie deep between the tuberosities of the sacrum and ilium.
Primary structures involved in transferring the weight.
Posterior sacroiliac ligaments
Posterior external continuation of the same mass of fibrous tissue.
Formed by the posterior sacroiliac ligaments joined by fibers extending from posterior margin of the ilium & base of the coccyx
Passes from posterior ilium, lateral sacrum & coccyx to ischial tuberosity, transforming the sciatic notch of the hip bone into a large sciatic foramen.
Sacrospinous ligament, from lateral sacrum & coccyx to ischial spine, further subdivides this foramen into greater and lesser sciatic foramina.
Most of the time, movement at the sacroiliac joint is limited by interlocking of the articulating bones and the sacroiliac ligaments.
By allowing only slight upward movement of the inferior end of the sacrum relative to the hip bones, resilience is provided to the sacroiliac region when the vertebral column sustains sudden increases in force or weight.
Secondary cartilaginous joint
Consists of a fibrocartilaginous interpubic disc & surrounding ligaments uniting the bodies of the pubic bones in the median plane. Interpubic disc is generally wider in women.
Superior & inferior margins of the symphysis
Superior pubic ligament connects the superior aspects of the pubic bodies and interpubic disc.
Inferior (arcuate) pubic ligamenta thick arch of fibers connects the inferior aspects of the joint components, rounding off the subpubic angle as it forms the apex of the pubic arch.
L5 & S1 articulate
Anterior intervertebral (IV) joint formed by L5/S1 IV disc
between their bodies
2 posterior zygapophysial joints (facet joints)
between the articular processes of these vertebrae
Fan-like iliolumbar ligaments radiating from the transverse processes of the L5 vertebra to the ilia.
Secondary cartilaginous joint with an intervertebral disc.
Fibrocartilage & ligaments join apex of the sacrum base of coccyx.
Anterior & posterior sacrococcygeal ligaments
long strands that reinforce the joint.
Sexual differences are related mainly
Heavier build and larger muscles of most men
Adaptation of the pelvis (particularly the lesser pelvis)
in women for parturition (childbearing).
The difference between the male and female pelvis
Difference Between Male & Female Pelvis
Although anatomical differences between male and female pelves are usually clear cut, the pelvis of any person may have some features of the opposite sex.
Gynecoid pelvis normal female type; its pelvic inlet typically has a rounded oval shape and a wide transverse diameter.
Android pelvis (masculine or funnel-shaped) in a woman may present hazards to successful vaginal delivery of a fetus.
In forensic medicine (the application of medical and anatomical knowledge for the purposes of law), identification of human skeletal remains usually involves the diagnosis of sex.
Size of the lesser pelvis important in obstetrics
Because it is the bony canal through which the fetus passes during a vaginal birth.
To determine the capacity of the female pelvis for childbearing, diameters of the lesser pelvis are noted radiographically or manually during a pelvic examination.
Antero - posterior diameters:
Anatomical antero-posterior diameter =11cm
from the tip of the coccyx to the lower border of symphysis pubis.
Obstetric antero-posterior diameter = 13 cm
from the tip of the sacrum to the lower border of symphysis pubis as the coccyx moves backwards during the second stage of labour.
Bituberous diameter = 11 cm
between the inner aspects of the ischial tuberosities.
Bispinous diameter = 10.5 cm
between the tips of ischial spines.
Antero -posterior diameters:
Anatomical antero-posterior diameter (true conjugate) = 11cm
from the tip of the sacral promontory to the upper border of the symphysis pubis.
Obstetric conjugate= 10.5 cm
from the tip of the sacral promontory to the most bulging point on the back of symphysis pubis which is about 1 cm below its upper border. It is the shortest antero-posterior diameter.
Diagonal conjugate= 12.5 cm
i.e. 1.5 cm longer than the true conjugate. From the tip of sacral promontory to the lower border of symphysis pubis (or inferior pubic ligament)
True (obstetrical) conjugate
From Middle of the sacral promontory
To Posterosuperior margin (closest point) of the pubic symphysis
Narrowest distance through which the baby's head
must pass in a vaginal delivery.
This distance, however, cannot be measured directly during a pelvic examination because of the presence of the bladder.
Measured by palpating sacral promontory with the tip of the middle finger, using the other hand to mark the level of the inferior margin of the pubic symphysis on the examining hand.
After the examining hand is withdrawn, the distance between the tip of the index finger (1.5 cm shorter than the middle finger) and the marked level of the pubic symphysis is measured to estimate the true conjugate, which should be 11.0 cm or greater.
Transverse diameter is the greatest distance between the linea terminalis on either side of the pelvis.
Fractures of the bony pelvic ring are almost always multiple fractures or a fracture combined with a joint dislocation.
Pelvic fractures can result from direct trauma to the pelvic bones, such as occurs during an automobile accident, or be caused by forces transmitted to these bones from the lower limbs during falls on the feet.
Region of the sacroiliac joints
Alae of the ilium
25 Year Old Male with displaced fracture of the sacrum andsymphysis pubis.
The most severe pelvic fractures separate the two sides of the pelvis from each other.
Pelvic fractures may cause injury to pelvic soft tissues, blood vessels, nerves, and organs.
Fractures in the pubo-obturator area are relatively common and are often complicated because of their relationship to the urinary bladder and urethra, which may be ruptured or torn.