Lecture 1.4 Articulations
Body Motions
•  Classes of Body Motions
–  Bones and muscles work together to
create movement
–  Work like levers
–  Disorders exist when movement is
impeded or painful
–  Remember Anatomical Position (AP)
•  Movements are often described in relation to
AP; movement away from, or back to AP
Rheumatoid arthritis (U), anatomical position (L)
Body Motions
•  Classes of Body Motions
–  These are important in the study
of muscles; all of these terms
will be used in lab unit 2
extensively!
–  Rotation
•  Movement of bone along its
longitudinal axis
•  Medial rotation; e.g. leg in figure
•  Lateral rotation; e.g. leg in figure
•  Right or left rotation; e.g. head
Rotation; Marieb
Body Motions
•  Classes of Body Motions
–  Circumduction
•  The distal end of the bone moves in a circle
while the proximal end of the bone remains
stationary
•  Like the baseball pitcher’s 360° windup
•  Complex movement; requires flexion,
abduction, extension, and then adduction!
–  Practice:
• 
• 
• 
• 
Rotate your torso right
Medially rotate your ankle
Laterally rotate your knee
Circumduct your index finger
Circumduction; Marieb
Body Motions
•  Classes of Body Motions
–  Abduct
•  Body part moved away from body
midline
•  Abduct means to take away; to abduct
takes away from the main body area
–  Adduct
•  Body part moved towards body
midline
•  Add means to increase– adduct adds
the body part to the main body area
Abduction, adduction; Marieb
Body Motions
•  Classes of Body Motions
–  Be sure to pronounce abduct and
adduct carefully; they sound so
close!
–  Practice:
• 
• 
• 
• 
Abduct your arm
Adduct your leg
Abduct your fingers
Can you adduct your head?
–  Many muscles have these words in
their names, e.g. adductor magnus,
abductor pollicis brevis
Abduction, adduction; Marieb
Body Motions
•  Classes of Body Motions
–  Flex
•  Bend and decrease the angle between
anterior surfaces of articulation
•  Exception: the knee and ankle; for these
joints, flexion is a decrease in the angle
between the posterior surface of the
articulating bone
•  Long definition, but very functional!
–  Extend
•  To return body part to anatomical
position after flexion
Flexion (U), flexion and extension (L); Marieb
Body Motions
•  Classes of Body Motions
–  Hyperextension
•  Continuation of extension beyond
anatomical position
–  Practice: • 
• 
• 
• 
Flex your arm, then extend it
Flex your fingers, then extend them
Can you flex your head?
Are you ready to try out for Cirque du
Soleil?
•  What body motion are the performers
exhibiting with their backs? Their heads?
Flexion by Cirque du soleil performers (U), hyperextension (L)
Body Motions
•  Classes of Body Motions
–  Retract
•  Movement, such as the mandible or
pectoral girdle (shoulders) backward
parallel to ground
–  Protract
•  Movement forward parallel to the
ground
–  Practice: •  Protract your mandible
•  Retract your pectoral girdle
Protraction, retraction; Marieb
Body Motions
•  Classes of Body Motions
–  Elevate
•  Raise the part; upward motion
–  Depress
•  Lower the part; downward motion
–  Evert
•  For the foot only; turn the sole laterally
–  Invert
•  For the foot only; turn the sole medially
•  Practice
–  Invert your foot
–  Elevate your shoulders
Elevate, depress (U), invert, evert (L); Marieb
Body Motions
•  Classes of Body Motions
–  Dorsiflex
•  For foot, toes point upwards
–  Like flexing the hand at the wrist
–  Plantar flex
•  For foot, toes point downwards
–  Like extending the hand at the wrist
•  Remember- the sole of the foot is called
the plantar surface
•  Plantar warts (not planter warts!) are on
the bottom of the foot
•  Practice
–  Dorsiflex your foot
–  Feel the good stretch!
Dorsiflexion, plantar flexion (U); Marieb, plantar wart (L)
Body Motions
•  Classes of Body Motions
–  Pronate
•  Palm pointing downward
–  Supinate
•  Palm pointing upwards
•  Some use these terms for the ankle,
showing poor ankle “posture”
•  Remember the musical “Oliver”? When
Oliver asked for “more soup, please?”
his hands are supinated. Get it?
Soup-inate? Silly, but it works!
•  Practice
–  Supinate your hand
–  Pronate your ankle
Pronation, supination
Joints
•  Joints
–  3 types of joints based on
structure
•  Classified by the material that
holds the joints together, or the
presence or absence of a joint
cavity
–  3 types of joints based on
their function
•  Classified by the amount of
movement at the joint
Knee joint (Marieb)
Joints
Function
•  Synarthroses
•  Amphiarthroses
•  Diarthroses
(think S.A.D.)
Structure
•  Fibrous
•  Cartilaginous
•  Synovial
Hip joint (L), knee joint (R)
Joints
•  Joints Classified by
Function –  Synarthroses
•  Immoveable joints
•  Sing: synarthrosis
–  Amphiarthroses
•  Slightly moveable joints
–  Diarthroses
•  Freely moveable joints
Remember- joints, or articulations are
where bones come together. You’ll learn
about many joints that you probably would
not have thought of as a joint! Like this –>
•  Joints Classified by
Structure
–  Fibrous joints
•  No joint cavity, bones held
together by fibrous tissue
–  Cartilaginous joints
•  Bones held together by
cartilaginous tissue
–  Synovial joints
•  Has a joint cavity, ligaments,
and articular capsule
Knee joint (U), Xray of teeth (L)
Joints
Joint classes; Marieb
Joints
•  Joints Classified by Structure;
Fibrous joints
–  Sutures
•  Synarthrotic joints
•  Irregular joints between the flat
bones of the cranium
•  Strength is added by the
interlocking edges
•  Fibrous connective tissue is
between bones, continuous with
periosteum of the skull bone and
the dura mater (tough membrane
that surrounds brain ) in places
Sutures; Marieb
Joints
–  Sutures
•  Some sutures fuse, to form one bone, called a synostosis
–  Frontal bone is example; was 2 bones in baby, 1 bone in adult
– Various suture types seen:
serrate, lap, and plane
sutures
– Similar to the way
woodworkers make wood
joints
Suture types
Joints
–  Syndesmosis
•  Amphiarthrotic or diarthrotic
•  Long bones held together with
interosseous ligaments/
membrane
•  Example: articulation between
tibia and fibula at distal end
•  Also found between radius and
ulna for length of shaft
–  Is an attachment point for
some deep muscles in the
forearm
Syndesmosis, fibula and tibia (U), radius and ulna (L); Marieb
Joints
–  Gomphosis
•  Teeth in alveolar sockets in mandible
and maxilla= dentoalveolar joint
•  Synarthrotic joints
•  Periodontal disease results in
loosening of teeth
Gomphoses; Marieb
Joints
•  Joints Classified by Structure; Cartilaginous joints
–  Symphysis
•  Pl: symphyses
•  Amphiarthrotic joint held together with fibrocartilage
–  Of the 3 types of cartilage, this is the toughest
•  All on the midline of the body
Symphyses; Marieb
Joints
–  Symphysis
•  Fibrocartilage pad providing cushion between 2 bones
–  Intervertebral discs (below, left) between all vertebrae except C1 and C2
•  Ends of bones covered with hyaline articular cartilage, but the joint
is held together with fibrocartilage capsule
–  Pubic symphysis (below, right) between 2 pubic bones
Symphyses; Marieb
Joints
–  Synchondrosis
•  Hyaline cartilage forms joint between bones
•  Synarthrotic or amphiarthrotic joints
•  Cartilage between growing bone segments (epiphyseal plate) –  Synarthrotic
–  After growth stops at maturity, becomes a synostosis
•  Between sternum and 1st rib Synchondroses; Marieb
Synovial Joints
•  Joints Classified by Structure;
Synovial Joints
–  Functionally diarthrotic
•  May be slightly moveable to very
mobile
•  Space between articulating bones =
joint cavity or synovial cavity
•  Bone ends covered with articular
cartilage (hyaline cartilage)
•  Articular capsule surrounds the entire
joint
–  Fibrous capsule: outer layer of dense
irregular connective tissue (lots of tough
collagen)
–  Inner synovial membrane, composed of
areolar connective tissue*
*Don’t worry; you’ll learn these tissue types later!
Diarthrotic joints; Marieb
Synovial Joints
•  Synovial Joints
•  Articular capsule –  Fibrous capsule; the outer connective
tissue layer adds strength
–  Inner synovial membrane produces
the fluid
–  Synovium is the fluid in the joint
»  Synovium lubricates the joint; the
fluid is viscous (meaning slippery),
acts as a shock absorber, nourishes
the tissues
»  In the knee, which is the largest
joint in the body, there’s less
than 3 mL of synovium
•  Bursae –  Sacs of fluid within the joint capsule,
outside the joint cavity
Diarthrotic joints; Marieb
Synovial Joints
•  Synovial Joints
•  Tendon Sheaths
–  Tubular or elongated bursae
which surround the tendons
where they pass bony surfaces
–  On tendons that are subject to
much friction, or pass through
narrow spaces
•  Fat pads
–  Cushions joint structures
–  Also fills spaces created when
joint changes shape
Tendon sheaths in shoulder joint (U), fat pads seen under patella in knee joint (L); Marieb
Synovial Joints
•  6 Types of Synovial Joints:
–  Gliding or Plane
–  Hinge
–  Condyloid or Ellipsoidal
–  Saddle
–  Pivot
–  Ball and Socket
Some large and/or complicated joints may have some components
of more than one joint type; e.g. may be primarily ball and socket,
but have some gliding components
Synovial joints; Marieb
Synovial Joints
•  Gliding or Plane Joints
–  Articular surfaces are nearly flat (e.g. the facets) allowing gliding
only
–  Allows nonaxial or translational movement.
•  Nonaxial means having no axis of movement; flat bones moving side to
side
–  Found between carpals, tarsals, articular processes of vertebrae
–  Also between ribs and the facets of the thoracic vertebrae
Gliding joints; Marieb
Synovial Joints
•  Hinge Joints
–  Allows uniaxial movement; movement in one axis only
–  Allows simple flexion and extension movement at joint
–  Ankle, elbow, knee joints, finger and toe joints (not knuckles),
temporomandibular joint (hinge of jaw)
Hinge joints; Marieb
Synovial Joints
•  Examples of Complex Hinge Joints
Hinge joints; elbow (UL), knee (UR),; Marieb
Synovial Joints
•  Condyloid or Ellipsoidal Joints
–  Angular movement in 2 directions; moves back and forth and side
to side (biaxial) (abduct/adduct and flex/extend)
–  Characterized by a condyle of one bone in a fossa or elliptical
cavity of the other –  Wrist joint; articulation between radius and proximal carpals, as
well as metacarpals and proximal phalanx (knuckles)
–  Atlas-occipital articulation
Condyloid joints; Marieb
Synovial Joints
•  Saddle Joints
–  Angular movement in 2 directions; (biaxial)
–  Differs from condyloid joint in the shape of the articulating bones;
saddle joints have saddle-shaped bones, but movement is same
–  Trapezium and thumb metacarpal
•  Our opposable thumb is made possible by this joint; what makes us and
other great apes able to do what we do with our hands!
Saddle joints; Marieb
Synovial Joints
•  Saddle Joints
•  Also includes the sternoclavicular joint
–  Put your left hand fingers on your clavicular notch. Put your finger
slightly lateral to the notch to feel the prominent right sternoclavicular
joint. Move your right arm around, shrug your shoulders. Feel the
wide range of motion allowed at this joint? Saddle joints; Marieb
Synovial Joints
•  Pivot Joints
–  Allows rotary movement in one
plane (uniaxial)
–  Atlas-axis (C1 and C2)
articulation (no disc between)
–  Radius and ulna at proximal end,
allowing supination/pronation
Pivot joints; Marieb
Synovial Joints
•  Ball and Socket Joints
–  Angular movement in all directions (biaxial), combined with
pivotal rotation = multiaxial
–  Shoulder and hip joints both have a rounded head (ball) which fits
into a socket in the articulating bone
Ball and Socket joints; Marieb
Synovial Joints
•  Examples of Ball and Socket Joints
Note the smooth, rounded heads of both
the humerus (L) and the femur (R),
covered with hyaline cartilage
Ball and Socket joints, shoulder (L), hip (R), ; Marieb
Synovial Joints
•  The Knee Joint
–  A hinge joint, but not simple
•  Rounded femoral condyles allow some
rolling and gliding movements
•  Rotary movement due to alignment of hip
and foot
–  Largest joint in the body, and probably
the most highly stressed joint in the
body
•  Less stable than other hinge joints, due to
the rotation
Xray of the knee
Synovial Joints
•  The Knee Joint
–  3 joints:
•  Patellofemoral joint
–  Partly synovial-gliding
•  Lateral tibiofemoral joint
–  Synovial hinge type
•  Medial tibiofemoral joint
–  Synovial hinge type
This is one of the best knee
diagrams; study it well! Which leg is it- right or left?
The knee; Marieb
Synovial Joints
•  The Knee Joint
–  Semilunar cartilages (menisci) are pads of fibrocartilage
–  They absorb some of the stress, padding the condyles of the femur
where they meet the tibia
•  Lateral meniscus between lateral condyle of femur and tibia
•  Medial meniscus between medial condyle of femur and tibia
–  Transverse ligament connects the two menisci anteriorly and
posteriorly. It’s not labeled on this diagram. You label it!
Menisci; Marieb
Synovial Joints
•  The Knee Joint
–  Cruciate ligaments form an
X in the interior of the knee
joint
–  Are intracapsular ligaments
(within the joint capsule)
–  Anterior cruciate ligament
(ACL)
–  Posterior cruciate ligament
(PCL)
–  They act as restraining straps,
preventing undesirable
movements
–  Lock knees when standing
Cruciate ligaments; Marieb
Synovial Joints
•  The Knee Joint
–  Cruciate ligament damage
–  Anterior cruciate is more
commonly damaged; is just
weaker
ACL tear heals slowly if at all.
Often need graft from Achilles
tendon or patellar ligament to
replace/repair
Cruciate ligaments; Marieb, X-ray of repair
Synovial Joints
•  The Knee Joint
–  Collateral ligaments
•  Extracapsular ligaments;
outside of the joint capsule –  Fibular collateral
ligament
•  On lateral surface; also
called lateral collateral
ligament
–  Tibial collateral ligament
•  On medial surface, also
called medial collateral
ligament
•  Most common football
injury, torn when hit/tackled
on side of knee
Collateral ligaments; Marieb
Synovial Joints
•  The Knee Joint
–  Fibular collateral ligament
•  Lateral surface; run from
lateral epicondyle of femur to
head of fibula
–  Tibial collateral ligament
•  On medial surface; run from
medial epicondyle of femur to
medial surface of tibia
–  Both reinforce and stabilize
the knee only at full
extension
•  Also limit anterior and
posterior movement of femur,
align femur and tibia, prevent
hyperextension of knee
Collateral ligaments; Marieb
Synovial Joints
•  The Knee Joint
–  Quadriceps tendon
•  Upper; runs from quadriceps
muscle to patella
–  Patellar ligament
•  Lower portion; runs from
patella to tibial tuberosity
–  These two structures are
continuous
Why does a single stretch of
connective tissue have two
names? Because tendons connect
_____ to _____ and ligaments
connect _____ to _____.
The knee; Marieb
Synovial Joints
•  The Knee Joint
–  Bursae of knee
•  Sacs of fluid which reduce friction
•  Composed of a sac of CT with an
inner synovial membrane
•  Keep tendons from rubbing on
bones; note placement between
tendons/ligaments and underlying
bones
•  At least a dozen bursae associated
with each knee
Joint cracking does not cause arthritis or enlarged joints. Does aggravate those around you.
When two
opposing bones are pulled apart, a vacuum is created. The gas in the fluid forms a bubble that then
immediately collapses, creating the noise.
Bursae of knee joint; Marieb
Synovial Joints
•  The Knee Joint
•  Bursitis
–  Chronic inflammation of bursae
by trauma, infection such as TB
or syphilis, or RA
–  Olecranon bursitis, or
“student’s elbow” occurs from
repeatedly leaning on the elbow
on hard surfaces
–  Long ago, bursitis was common
in the knee of women who
scrubbed floors for a living,
hence the colloquial name
“washer-woman’s knee”)
–  Infrapatellar fat pad
•  Infra- means ‘below;’ is deep and
inferior to the patella
Pre-patellar bursitis (UL), olecranon bursitis (UR), and fat pads of knee joint (L); Marieb
End 1.4
Next:
1.5 Muscle
Anatomy