PowerPoint Presentation
JOINTS
JOINTSDefinition: A place where two or more bones get
articulated with one another is called a joint.Joints help to
connect different parts of skeleton and form a basic framework of
body.Study of structure and functions of various joints is called
arthrology. LIGAMENTS:At a joint the bones are connected to each
other by ligaments. Ligaments are tough, elastic fibrous connective
tissue bands or threads which connect bone to bone at a
joint.Ligaments keep the bones in proper position and avoid
dislocation of bones during the movement.SIGNIFICANCE OF
JOINTS:They help in locomotion.Joints also help in desirable
voluntary movements of body parts. Joints bring flexibility in
rigid skeleton.Some joints are protective and act as shock
absorbers.dr. aarif
dr. aarifJOINTSImmovable OR Fibrous ORSynarthrosesSlightly
movableORCartilagenousORAmphiarthrosesFreely
movableORSynovialORDiarthroses1. SUTURES2. GOMPHOSIS3.
SYNDESMOSIS1.SYNCHONDROSIS2. INTERVERTEBRAL3. PUBIC SYMPHYSIS1.
BALL & SOCKET2. HINGE3. GLIDING4. CONDYLOID5. SADDLE6.
PIVOT
dr. aarifSYNARTHROSESFEATURES :
The bones are united at the joints by thin or dense layer of
white fibrous connective tissue.
The white fibers are made up of a protein collagen.
These joints are fixed i.e. cannot permit any movement of
articulating bones.
Short and thick fibers do not allow movement of articulating
bones.
The line of fusion at joint is called sutureFUNCTIONS: Fixed
joints are primarily meant for growth and may permit molding during
childbirth.
Usually these joints are the places of growth. When growth
period is over these joints tend to ossify
dr. aarifSUTURES OF SKULL (SERRATE SUTURES)
These joints are found in flat and curved roofing bones of the
skull.
These joints are also called serrate joints because articulating
surfaces of the bones show serrated margins.
The bones are repeatedly interlocked. Therefore joints become
fixed and protective in function.
In young or newborn, the roofing bones of skull leave about six
gaps called fontanelles.Fontanelles permit flexibility for
parturition and brain growth.
At about 2 years of age the gaps are closed by ossification
4 Types : Coronal : Betn frontal & parietal
Sagittal Betn both parietals
Lambdoidal : Betn parital and occipital
Lateral : Betn temporal and parital
dr. aarifSYNDESMOSIS
It is the fibrous connective tissue that connects two bones.
E.g. tibia and fibula
dr. aarifGOMPHOSIS(Peg and Socket)
It is the characteristic of thecodont teeth.
The roots of the teeth are fixed in sockets (alveoli) of jaw
bones. The fibrous connections in this case are many short
periodontal ligaments.
dr. aarifAMPHIARTHROSESThese are called amphiarthroses because
they are neither fixed nor freely movable.
It is intermediate stage of joints when related to development
and movement. They allow some movement in response to compression,
tension or twisting. The line of fusion between articulating bones
is called synchondrosis or symphysis.
dr. aarifThe connecting material is a hyaline cartilage.
It is very soft and elastic with minimum strength. E.g.
Epiphyseal Plate: This epiphyseal plate is present between
epiphysis & diaphysis of long bones.It is a temporary joint
present in children and it gets ossified in adults.
This joint provides the sites and means for growth of the long
bones in children.
It also contributes to the flexibility in the endoskeleton of
children
SYNCHONDROSIS
dr. aarifThe connecting material is a fibrocartilage.
Fibrocartilage is an opaque, comparatively strong but flexible
structure, due to the presence of numerous white fibers of
collagen.
It is present between two pubic bones of the pelvic girdle.
The pubic bones are connected by a disc of fibrocartilage.
It allows slight movements as compression, bending, twisting
etc. It makes the joint more flexible.
In females, it helps to increase the size of the birth canal for
easy parturition.
In males, it is comparatively less flexible.
SYMPHYSIS
dr. aarifThese joints are present between the centers of
adjacent vertebrae of backbone.
The connecting discs are fibro-cartilaginous.
These joints help in shock absorption and protect the spinal
cord from mechanical injury.
These joints make the vertebral column slightly flexible.
INTER VERTEBRAL JOINT
dr. aarifDIARTHROSES
These are called perfect joints due to the presence of all
well-developed structures needed for free movement.
These are most evolved and therefore freely movable type of
joints
It consists of, synovial cavity, synovial fluid, synovial
membrane, capsule, ligaments and articulating surfaces covered by
hyaline cartilage
dr. aarif
dr. aarifSynovial Membrane: It lines the synovial cavity and
forms a synovial capsule. The synovial membrane secretes synovial
fluid. It encloses fluid filled synovial cavity and protects
internal parts of joint.Synovial fluid: It is a clear, yellowish,
slimy and viscous fluid similar to lymph. The viscosity of fluid is
due to hyaluronic acid secreted by the cells of the synovial
membrane. It contains nutrients and mucus. The fluid lubricates the
joint and nourishes hyaline cartilage.The fluid also contains
phagocytes, which removes microorganisms and cellular
debris.Deficiency of this fluid causes arthrosclerosis.Hyaline
cartilage: It covers the end of articulating surfaces of bone and
avoids direct contact or friction between bones.Ligaments: The
joints are provided with capsular ligaments and numerous accessory
ligaments. Accessory ligament may be intra or extra capsular.
Ligaments avoid dislocation of bones and make the joints
stronger.
dr. aarif
dr. aarifThe spherical head of one bone fits into a cup-shaped
socket of other bone.
These joints are prone for easy dislocation or separation on
sudden strain.
These joint allow multi-axial movements.
The shoulder joint allows rotatory or circular movements (360)
and hip joint allows straight movement (180).Examples: Shoulder
joints, Hip joint etc. are examples of ball and socket joint.BALL
& SOCKET
dr. aarifSpoon shaped surface of one-bone fits into the concave
cavity of other bone.
There are strong collateral ligaments.
These joints resist dislocation.
These joints allow uniaxial movements and resemble with the
movements of door and window.
In elbow joint, the ulna works as hinges, so only forward
movement is possible.
In knee joint the patella or knee cap works as hinges so only
backward movement is possible.Examples: Elbow joints, Knee joints,
etc. are examples of hinge joint.
HINGE
dr. aarifThe articular bones are permitted for gliding or
sliding movements.
These joints allow non-axial movements, which are neither
back-forth nor side to side but irregular.
The articulating surface is convex so friction is
avoided.Examples: Intercarpal joints, Intertarsal joints, etc., are
examples of gliding joint.
GLIDING
dr. aarifThese are also called as ellipsoid joints.
Oval-shaped condyle of one bone fits into elliptical cavity of
other bone.
These joints allow biaxial movements i.e. forward backward and
side to side but not rotation. Examples: Radius carpal, Metacarpo -
phalangeal joints are examples of Condyloid joint.
CONDYLOID
dr. aarifThe characteristic of this joint is that the
articulating surfaces of bones are saddle shaped, i.e. each surface
has both concave and convex area.
Each surface is convex in one plane, concave in the
perpendicular plane.
It resembles with Condyloid joint but it allows greater freedom
of movement for the joint.
This joint allows biaxial movement.
It is the most flexible joint in the body. Saddle joint has
evolutionary significance in human evolution.
It increases grasping power of fingers and helps in skillful
work like writing, drawing, painting, etc.Examples: Edges of
metacarpal and first phalange of thumb is peripherally articulated
so saddle joint makes free movement. Carpo metacarpal joint of
thumb are examples of saddle joint.
SADDLE
20
dr. aarifArticular surfaces comprise of a central bony pivot
(dense) surrounded by an osteo-ligamentous ring. One bone remains
fixed while the other bone rotates freely around the pivot-shaped
process of fixed bone.
It allows uniaxial movement i.e. rotation. Examples: 1.
Atlanto-axial joint. Atlas moves along with skull around the
pivot-like odontoid process of axis. This joint allows rotation
movement of the skull
2. Radio Ulnar joint
PIVOT
