Joint Classification Flashcards
Classification, Levers, Receptors
Synarthroses (Fibrous Joints)
Suture - e.g., sagittal suture of the skull
Syndesmosis - e.g., tibia and fibula with interosseous membrane
Gomphosis - e.g., tooth in its socket
Definition: Synarthroses (Fibrous Joints)
Fibrous joints composed of bones that are united by fibrous tissue and are NONSYNOVIAL. Movement is minimal to none with the amount of movement permitted at the joint dependent on the length of the fibers uniting the bones
Definition: Suture
Synarthroses
Union of 2 bones by a ligament or membrane
Immovable Joint
Eventual fusion is termed Synostosis
Definition: Syndesmosis
Synarthroses
Bone connected to bone by a dense fibrous membrane or cord
Very little motion
Definition: Gomphosis
Synarthroses
Two bony surfaces connect as a peg in a hole
The teeth and corresponding sockets in the mandible/maxilla are the only gomphosis joints in the body
The periodontal membrane is the fibrous component of the joint
Amphiarthroses (Cartilaginous Joints)
Synchondrosis - e.g., sternum and true rib articulation
Symphysis - e.g., pubic symphysis
Definition: Amphiarthroses (Cartilaginous Joints)
Cartilaginous joints have hyaline cartilage or fibrocartilage that connects one bone to another. These are slightly moveable joints
Definition: Synchondrosis
Amphiarthroses
Hyaline Cartilage
Cartilage adjoins 2 ossifying centers of bone
Provides stability during growth
May ossify to synostosis once growth is completed
Slight motion
Definition: Symphysis
Amphiarthroses
Generally located at the midline of the body
Two bones covered with hyaline cartilage
Two bones connected by fibrocartilage
Slight motion
Diarthroses (Synovial Joints)
- Uniaxial Joint - Hinge, e.g., elbow joint; Pivot, e.g., atlantoaxial joint
- Biaxial Joint - Condyloid, e.g., metacarpophalangeal joint of a finger; Saddle, e.g., carpometacarpal joint of the thumb
- Multi-axial joint - Plane (gliding), e.g., carpal joints; Ball and Socket, e.g., hip joint
Definition: Synovial Joints (Diarthroses)
Provide free movement between the bones they join. They have 5 distinguishing characteristics:
1) Joint cavity
2) Articular cartilage
3) Synovial membrane
4) Synovial fluid
5) Fibrous capsule
They are the most complex and vulnerable to injury
Definition: Uniaxial
One motion around a single axis in one plane of the body. (Hinge, Pivot)
Definition: Biaxial
Movement occurs in 2 planes and around 2 axes through the convex/concave surfaces. (Condyloid, Saddle)
Definition: Multi-axial
Movement occurs in 3 planes and around 3 axes. (Plane/gliding, Ball-and-socket)
Definition: Fulcrum
Axis of Rotation
Definition: Force
The Effort
Definition: Load
The Resistance
Class 1 Levers
The fulcrum is between the force and the load.
E.g., a see-saw
There are very few class 1 levers in the body.
Class 2 Levers
The load is between the fulcrum and the effort.
E.g., a wheelbarrow
- The length of the effort arm is always longer than the resistance arm.
Class 3 Levers
The force is between the fulcrum and the load.
E.g., Elbow flexion
- The length of the effort arm is always shorter than the length of the resistance arm
Another example is Shoulder Abduction with weight at the wrist.
Class 3 levers are the most common type in the body.
They permit large movements at rapid speeds.
Free Nerve Endings: Location
Joint capsule, Ligaments, Synovium, Fat pads
Free Nerve Endings: Sensitivity
One type is sensitive to non-noxious mechanical stress; other type is sensitive to noxious mechanical or biochemical stimuli
Free Nerve Endings: Primary Distribution
All joints
Golgi Ligament Endings: Location
Ligaments, adjacent to ligaments’ bony attachment
Golgi Ligament Endings: Sensitivity
Tension or stretch on ligaments
Golgi Ligament Endings: Primary Distribution
Majority of joints
Golgi-Mazzoni Corpuscles: Location
Joint Capsule
Golgi-Mazzoni Corpuscles: Sensitivity
Compression of joint capsule
Golgi-Mazzoni Corpuscles: Primary Distribution
Knee joint, joint capsule
Pacinian Corpuscles: Location
Fibrous layer of joint capsule
Pacinian Corpuscles: Sensitivity
High frequency vibration, acceleration, high velocity changes in joint position
Pacinian Corpuscles: Primary Distribution
All joints
Ruffini Endings: Location
Fibrous layer of joint capsule
Ruffini Endings: Sensitivity
Stretching of joint capsule, amplitude and velocity of joint position
Ruffini Endings: Primary Distribution
Greater density in proximal joints, particularly in capsular regions
