Joint Anatomy Flashcards
A Joint
The location at which two or more bones make contact.
They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally. Joints come in specific shapes that help determine their range of motion.
An articulation
is considered a union or junction of two or more bones and is commonly called a joint.
Classification of Joints [3]
Joints are mainly classified structurally and functionally. Structural classification is determined by how the bones connect to each other, while functional classification is determined by the degree of movement between the articulating bones.
- Structural classification
- Functional classification
- Biomechanical classification
Structural classifications [3]
Structural classification names and divides joints according to how the bones are connected to each other.
- Fibrous joints are connected by dense connective tissue, consisting mainly of collagen.
- Cartilaginous joints are connected entirely by cartilage (fibrocartilage or hyaline).
- Synovial joints are not connected.
Functional Classification [3]
Joints can also be classified functionally, by the degree of mobility they allow.
- Synarthrosis permits little or no mobility. Most synarthrosis joints are fibrous joints (e.g. The Skull).
- Amphiarthrosis permits slight mobility. Most amphiarthrosis joints are cartilaginous joints (e.g. vertebrae).
- Diarthrosis permits a variety of movements. All diarthrosis joints are synovial joints (e.g. hip, elbow, stifle), and the terms “diarthrosis” and “synovial joint” are considered equivalent by Terminologia Anatomica)
Biomechanical Classification Joints [3]
Biomechanical Classification Joints can also be classified based on their anatomy or on their biomechanical properties. According to the anatomic classification, joints are subdivided into simple, compound and complex, depending on the number of bones involved.
- Simple Joint: 2 articulation surfaces (e.g. shoulder joint, hip joint)
- Compound Joint: 3 or more articulation surfaces (e.g. radiocarpal joint)
- Complex Joint: 2 or more articulation surfaces and an articular disc or meniscus (e.g. stifle joint)
The joints: Synovial joints
-Most common / movable type of joints
The joints: Synovial joints
This structure is ideal due to the following 5 components
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The joints: Synovial joints
Six types of synovial joints
1) Gliding [ex: carpals-wrists] 2 flat surfaces. Least amount of movement in all directions. Has a fluid-filled sac called a bursa between articulating edges.
2) Hinge [ex: elbow
The joints: Synovial joints
Six types of synovial joints
1) Gliding [ex: carpals(wrists)] 2 flat surfaces. least amount of movement in all directions. Has a fluid-filled sac called a bursa between articulating edges.
2) Hinge [ex: elbow(humeroulner)] like a door hinge, allowing flexion and extension in just one plane.
3) Pivot [head rotation (atlantoaxial)] one bone rotates around the surface of another like a jar and its lid
4) Ellipsoids aka condyloid [wrist(radiocarpal)] two bones fit together with an odd shape (ex: an ellipse) one bone is concave and the other convex
5) Ball and Socket [hip joint (coxofemoral)] sphere=>bowl. Wide range of movement (circumduction)
6) Saddle [thumb (in humans)] two surfaces, each with a concave and convex surface. Hence, saddle-shaped.
The joints: Fibrous joints
- connects bones along a tight-knit suture line
- these are found between the bones of the skull and the bones of the pelvis
- the union of the spinous process and vertebrae are fibrous joints
- movement is limited to the minimal amount of stretch afforded by receptors within suture lines
The joints: Cartilaginous joints
- covered with cartilage, such as hyaline or fibrocartilage to allow movements between bones more than a fibrous joint, but less than a synovial joint.
- ex: joint between the manubrium and the sternum
- cartilaginous joints also form the growth regions of immature long bones and the intervertebral discs of the spinal column
- also join bones along a line commonly called a symphysis, such as that joining the right and left halves of the pelvis at the pubic bone
- the pubic symphysis moves during childbirth (whelping in dogs) due to the release of specific hormones
- multiple litters may cause this joint to become lax in some
Common Joint Dysfunctions
- Some common joint dysfunctions include osteoarthritis AKA degenerative joint disease, hip and elbow dysplasia, inflammation due to strain or injury to supporting ligaments or tendons, and desiccation of joint fluid associated with age or nutrition
- many of these conditions can benefit from the rejuvenating effects of massage
- massage can help to restore or enhance circulation, remove waste products stored at the site of injury, or encourage mobility and stiff joints
