UCI BioSci D170 Joints Williams
Reading: Chapter 9
How can joints be classified by function?
Joints are classified by the amount of movement they allow. Functional classification.
Synarthroses - immovable joints.
Amphiarthroses - slightly movable joints.
Diarthroses - freely movable joints.
What characteristics of joints allow them to be classified by structure?
Joints are also classified by the material that binds the bones together and the
presence/absence of a joint cavity. Structural classification.
Fibrous - Adjoining bones united by collagen fibers.
Cartilaginous - Adjoining bones united by cartilage.
Synovial - Adjoining bones are separated by a joint cavity and covered w/ articular cartilage.
Enclosed within an articular capsule lined w/ synovial fluid.
What are the general characteristics of fibrous joints?
The bones are connected by fibrous, dense regular CT. Most are immovable or only slightly
movable.
Describe the characteristics of the following types of fibrous joints and give examples of each.
Suture – Bones are tightly bound by minimal amount of fibrous tissue; only occur b/w the
bones of the skull (tissue continuous w/ the periosteum). Ex. Coronal suture.
Syndesmosis – bones are connected by ligaments only: bands of fibrous tissue. Movement
allowed is proportional to length of connecting fibers. Ex. Interosseous membrane b/w the
radius and ulna.
Gomphosis – Peg-in-socket joint. Ex. Periodontal ligament, connecting the tooth w/ its socket.
What are the general characteristics of cartilaginous joints?
Just like the fibrous joint, the cartilaginous joint lacks a joint cavity; it is not highly movable.
Describe the characteristics of the following types of
cartilaginous joints and give examples of each.
Synchondroses – joints where hyaline cartilage unites the
bones. (Functionally) synarthroses. Ex. joint b/w first rib
and sternum.
Symphases – joints where fibrocartilage unites the bones.
Amphiarthroses that provide strength w/ flexibility.
What are the general characteristics of synovial joints?
, Alycia Edquilang, 4/21/20
They are highly movable (all diarthroses), contain a fluid-filled joint cavity, and consist of most
of the joints in the body.
Describe the general structures of synovial joints, making note of
the following structures.
Articular cartilage – hyaline cartilage that covers ends of
opposing bones. Absorbs compressive forces.
Joint (articular) cavity – potential space that holds a small
amount of synovial fluid.
Articular/joint capsule – 2-layered capsule that encloses the
joint cavity.
Fibrous layer – outer layer made of dense irregular CT that is
continuous w/ the periosteum of the joining bones.
Strengthens the joint.
Synovial membrane – inner layer made of loose CT. Covers the
internal joint surfaces not covered by cartilage and makes
synovial fluid.
Synovial fluid – Viscous liquid inside the joint cavity and
articular cartilages. Made of blood filtrate from the capillaries
of and glycoprotein secreted by the fibroblasts of the
synovial membrane. Lubricates the internal surfaces.
Reinforcing ligaments – Capsular(thickened parts of the fibrous
layer). Extracapsular(located just outside the capsule).
Intracapsular(internal to the capsule, like on the knee).
Nerves and vessels – articular capsule is innervated w/
sensory nerve fibers and the synovial membrane is
vascularized. Highly branched.
Articular disc/meniscus – a disc of fibrocartilage. Occurs in joints whose adjoining bone end
have different shapes(could lead to osteoarthritis). Disc improves the fit -> distributes the
loading forces and minimizes wear/damage. May allow 2 different movements at the same joint.
Bursae – a flattened fibrous sac lined by synovial membrane and filled w/ synovial fluid.
Tendon sheath – an elongated bursa (also contains synovial fluid) that wraps around a tendon.
Occur only in tendons subject to friction.
Name and describe the common types of body movements, and
know an example of each:
Gliding – when nearly-flat surfaces slip across each other.
Occurs b/w the carpals, tarsals, and flat articular processes of
vertebrae.
Flexion – decreases the angle b/w the bones.
Extension – increases the angle b/w the bones. Occurs at the
same joints as flexion does.
Hyperextension – bending a joint beyond its normal range of
motion.
Abduction – limb moves away from the midline. Ex. spreading
fingers/toes apart.
Adduction – limbs move toward the midline.
Circumduction – moving a finger/limb so that it “describes a
cone-shape.”
Rotation – turning movement around a longitudinal axis, along the transverse plane. Ex.
movement of the C1 and C2 vertebrae.
Medial rotation – (of the lower limb) limb’s anterior surface/front of the foot turns toward
the median plane of the body.
Reading: Chapter 9
How can joints be classified by function?
Joints are classified by the amount of movement they allow. Functional classification.
Synarthroses - immovable joints.
Amphiarthroses - slightly movable joints.
Diarthroses - freely movable joints.
What characteristics of joints allow them to be classified by structure?
Joints are also classified by the material that binds the bones together and the
presence/absence of a joint cavity. Structural classification.
Fibrous - Adjoining bones united by collagen fibers.
Cartilaginous - Adjoining bones united by cartilage.
Synovial - Adjoining bones are separated by a joint cavity and covered w/ articular cartilage.
Enclosed within an articular capsule lined w/ synovial fluid.
What are the general characteristics of fibrous joints?
The bones are connected by fibrous, dense regular CT. Most are immovable or only slightly
movable.
Describe the characteristics of the following types of fibrous joints and give examples of each.
Suture – Bones are tightly bound by minimal amount of fibrous tissue; only occur b/w the
bones of the skull (tissue continuous w/ the periosteum). Ex. Coronal suture.
Syndesmosis – bones are connected by ligaments only: bands of fibrous tissue. Movement
allowed is proportional to length of connecting fibers. Ex. Interosseous membrane b/w the
radius and ulna.
Gomphosis – Peg-in-socket joint. Ex. Periodontal ligament, connecting the tooth w/ its socket.
What are the general characteristics of cartilaginous joints?
Just like the fibrous joint, the cartilaginous joint lacks a joint cavity; it is not highly movable.
Describe the characteristics of the following types of
cartilaginous joints and give examples of each.
Synchondroses – joints where hyaline cartilage unites the
bones. (Functionally) synarthroses. Ex. joint b/w first rib
and sternum.
Symphases – joints where fibrocartilage unites the bones.
Amphiarthroses that provide strength w/ flexibility.
What are the general characteristics of synovial joints?
, Alycia Edquilang, 4/21/20
They are highly movable (all diarthroses), contain a fluid-filled joint cavity, and consist of most
of the joints in the body.
Describe the general structures of synovial joints, making note of
the following structures.
Articular cartilage – hyaline cartilage that covers ends of
opposing bones. Absorbs compressive forces.
Joint (articular) cavity – potential space that holds a small
amount of synovial fluid.
Articular/joint capsule – 2-layered capsule that encloses the
joint cavity.
Fibrous layer – outer layer made of dense irregular CT that is
continuous w/ the periosteum of the joining bones.
Strengthens the joint.
Synovial membrane – inner layer made of loose CT. Covers the
internal joint surfaces not covered by cartilage and makes
synovial fluid.
Synovial fluid – Viscous liquid inside the joint cavity and
articular cartilages. Made of blood filtrate from the capillaries
of and glycoprotein secreted by the fibroblasts of the
synovial membrane. Lubricates the internal surfaces.
Reinforcing ligaments – Capsular(thickened parts of the fibrous
layer). Extracapsular(located just outside the capsule).
Intracapsular(internal to the capsule, like on the knee).
Nerves and vessels – articular capsule is innervated w/
sensory nerve fibers and the synovial membrane is
vascularized. Highly branched.
Articular disc/meniscus – a disc of fibrocartilage. Occurs in joints whose adjoining bone end
have different shapes(could lead to osteoarthritis). Disc improves the fit -> distributes the
loading forces and minimizes wear/damage. May allow 2 different movements at the same joint.
Bursae – a flattened fibrous sac lined by synovial membrane and filled w/ synovial fluid.
Tendon sheath – an elongated bursa (also contains synovial fluid) that wraps around a tendon.
Occur only in tendons subject to friction.
Name and describe the common types of body movements, and
know an example of each:
Gliding – when nearly-flat surfaces slip across each other.
Occurs b/w the carpals, tarsals, and flat articular processes of
vertebrae.
Flexion – decreases the angle b/w the bones.
Extension – increases the angle b/w the bones. Occurs at the
same joints as flexion does.
Hyperextension – bending a joint beyond its normal range of
motion.
Abduction – limb moves away from the midline. Ex. spreading
fingers/toes apart.
Adduction – limbs move toward the midline.
Circumduction – moving a finger/limb so that it “describes a
cone-shape.”
Rotation – turning movement around a longitudinal axis, along the transverse plane. Ex.
movement of the C1 and C2 vertebrae.
Medial rotation – (of the lower limb) limb’s anterior surface/front of the foot turns toward
the median plane of the body.
