Joints of the Skeletal System
Advanced Biology Fall 2012
Vocab Development
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Anul- ring
Arth- joint
Burs- bag, purse
Glen- joint socket
Labr- lip
Ov- egg-like
Sutur- sewing
Syn- with, together
Syndesm- band, ligament
Introduction
• Joints or articulations- functional junctions
between bones
– Bind parts of the skeletal system
– Allow for bone growth
– Permit parts of the skeleton to change shape
during childbirth
– Enable the body to move in response to skeletal
muscle contractions
Introduction cont…
• Joints vary in structure and function
– Classified both structurally and functionally
• Structurally by the type of tissue that binds the bones
at each junctions
• Functionally by the degree of movement possible
Introduction cont…
• Structural joint classifications
– Fibrous
– Cartilaginous
– Synovial
• Functional joint classifications
– Immovable (synarthrotic)
– Slightly movable (amphiarthrotic)
– Freely movable (diarthrotic)
3 types of Fibrous Joints
• Syndesmosis
– bones are bound by a sheet or bundle of dense
connective tissue
– Flexible & may be twisted
– Permits slight movement (amphiarthrotic)
– Ex: lies between the tibia & fibula
3 types of Fibrous Joints
• Sutures
– Only between the flat bones of the skull
– Bones are united by a thin layer of dense
connective tissue
– Immovable (synarthrotic)
3 types of Fibrous Joints
• Gomphosis
– Formed by the union of a cone-shaped process in
a bony socket
– Ligament surrounds the root & firmly attaches it
– Synarthrotic
– Ex: teeth
2 types of Cartilaginous Joints
• Synchondrosis
– Bands of hyaline cartilage unite the bones
– Many are temporary & disappear during growth
– Synarthrotic
– Ex: epiphyseal plates
– Ex: between manubrium & first rib
2 types of Cartilaginous Joints
• Symphysis
– Covered by a thin layer of hyaline cartilage & the
cartilage is attached to a pad of fibrocartilage
– Limited movement
– Ex: pubic symphysis
– Ex: intervertebral discs
Synovial Joints
• Most joints of the skeleton are synovial
• Allow free movement (diarthrotic)
• Consist of: articular cartilage, a joint capsule,
& a synovial membrane
Synovial Joints
• General Structure
– Articular cartilage- covers the ends of the bones
– Joint capsule- has 2 layers that hold together the
bones of the joint
– Synovial membrane-covers all surfaces with in the
joint capsule (only a few cell layers thick)
– synovial fluid- lubricates articular surfaces
– Menisci- divide the synovial joints into some small
compartments
Synovial Joints
• General Structure cont…
– purpose of the menisci is to help cushion the joint
– Bursae (bursa sacs)- found in certain types of
synovial joints
• Help cushion and provide protection for bones that are
close to the skins’ surface
• Helps ligaments and tendons glide smoothly over bones
Synovial Joints
• 6 types of synovial joints
– Ball-and-socket joints- hip joint & shoulder joint
– Condylar joint- where your finger bend (in
between the phalanges)
– Plane joints (gliding joints)- found in between your
carpals & tarsals
– Hinge joints- elbow & knee
– Pivot joint- between the axis and atlas, between
your radius and ulna
– Saddle joint- where the thumb joins the carpals
Types of Joint Movements
• Flexion- bending parts of a joint so that the
angle between them decreases and the parts
come closer together
– Ex: bending knee
• Extension- moving parts of a joint so that the
angle between them increases and the parts
move farther apart
– Ex: straightening the knee
Types of Joint Movements
• Hyperextension- used to describe the
extension of the parts at a joint beyond the
normal range of motion (usually causes injury)
• Dorsiflexion- movement at the ankle that
brings the foot closer to the shin
– Ex: rocking back on your heels
• Plantar Flexion- movement at the ankle that
brings the foot farther from the shin
– Ex: standing on your toes or walking
Types of Movements
• Abduction- moving a part away from the
midline or the axial line of the limb
– Ex: spreading your fingers or toes
• Adduction- moving a part toward the midline
or toward the axial line of the limb
– Ex: moving your fingers or toes closer together
Types of Movements
• Rotation- moving a part around an axis
– Medial rotation- turning of a limb toward the
midline
– Lateral rotation- turning of a limb away from the
midline
• Circumduction- moving part so that its end
follows a circular path
– Ex: moving a finger in a circular motion without
moving your hand
Types of Movements
• Supination- rotation of the forearm so the palm is
upward
• Pronation- rotation of the forearm so the palm is
down
• Eversion- turning the foot so the plantar surface
faces laterally
– Ex: big toe pushed down, little toe up
• Inversion- turning the foot so the plantar surface
faces medially
– Ex: big toe up, little toe down
Types of Movements
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Protraction- moving a part forward
Retraction- moving a part backward
Elevation- raising a part
Depression- lowering a part
Shoulder Joint
• Ball and socket joint
– Consists of the humerus & glenoid cavity
• Ligaments
– Coracohumeral ligaments
• Connects the coracoid process of the scapula to the
humerus
– Glenohumeral ligaments (3)
• Connect the glenoid cavity to the neck of the humerus
• Ligaments…
– Transverse Humeral Ligament
• Across the humerus
• several bursae
• Labrum
• Can perform: flexion, extension, adduction,
abduction, rotation, and circumduction
Elbow Joint
• 2 articulations
– Hinge joint between the humerus & ulna
– Planar joint between the ulna and humerus (only when elbow is bent,
not when in anatomic position)
• Ligaments
– Ulnar collateral ligament
• Connects the humerus to the ulna
– Radial collateral ligament
• Connects the humerus to the radius
– Anular ligament
• Connects the ulna to the radius at the head of the radius
• Movements: flexion & extension
– Supination and pronation of forearm is allowed by the anular ligament
Hip Joint
• Ball and socket joint
• Consists of:
– Head of the femur
– Acetebulum of the hip bone
• Major Ligaments
– Iliofemoral ligament
• Strongest ligament in the body
• Connects the iliac spine to the femur
– Pubofemoral ligament
• Runs from the superior pubis to the iliofemoral ligament
– Ischiofemoral ligament
• Runs from the ischium to the joint capsule
Hip Joint
• Movements:
– Flexion, extension, adduction, abduction, rotation,
and circumduction
Knee Joint
• Largest and most complex synovial joint
• Consists
– Femur
– Tibia
– Patella
– Lots of ligaments
Knee Joint
• Ligaments (these strengthen the joint capsule)
– Patellar ligament
• Extends from the patella to the tibia
– Oblique popliteal
• Connects the lateral condyle of the femur to the head of the tibia
– Arcuate popliteal
• Extends from the lateral condyle of the femur to the head of the
fibula
– Tibial collateral (MCL)
• Connects the medial condyle of the femur to the medial condyle
of the tibia
– Fibular Collateral (LCL)
• Connects the lateral condyle of the femur and the head of the
fibula
Knee Joint
• Cruciate ligaments
– Help prevent displacement of the articulating surfaces
– Stretch upward and cross between the tibia and femur
– Anterior cruciate ligament (ACL)
• Runs from the anterior side of the tibia to the lateral condyle
of the femur
– Posterior cruciate ligament (PCL)
• Connects the posterior side of the tibia to the medial
condyle of the femur
Knee Joint
• 2 menisci
– Separate the articulating surfaces of the femur
and tibia & help keep them aligned
• Several bursae
• Movement: flexion, extension, and some
rotation
Joint Disorders
• Sprains
– Overstretching or tearing of connective tissues
associated with a joint
– Painful & swollen, restricts movement
• Bursitis
– Inflammation of the bursa
– Caused by overuse or a sudden increase in activity
– Ex: tennis elbow
Joint Disorders cont…
• Arthritis
– Causes inflamed, swollen, and painful joints
– More than 100 different types
– Can be part of other syndromes
– Most common types are: rheumatoid , osteo,
Lyme
Joint Disorders cont…
• Rheumatoid Arthritis (RA)
– Autoimmune condition
– Painful & debilitating
– Synovial membrane becomes hard and forms a
mass
– Over time joints can ossify
– Usually a systemic illness
Joint Disorders cont…
• Osteoarthritis
– Degenerative disorder
– Most common type of arthritis
– Usually occurs with aging
– Articular cartilage disappears slowly
– Painful & restricts movement
– NSAIDS are used to treat it along with regular
exercise
Joint Disorders cont…
• Lyme Arthritis
– Caused by lyme disease and is intermittent
– Antibiotic treatments early on can help treat it
• Arthritis may also be associated with other
bacterias like strep, staph, gonorrhea,
tuberculosis
• AIDS may also be associated with arthritis
because it is an autoimmune disorder
Joint Disorders cont…
• Other types of arthritis
– Gout
– Juvenile RA
– Scleroderma
– Systemic lupus erythemoatosus
– Kawasaki disease
– Strep A infection
• http://youtu.be/HxJO8GaoZrk shoulder
• http://youtu.be/dZiDd6e4drc acl