Introduction to Clinically Oriented Anatomy-Joints
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The document provides an overview of joints in clinically oriented anatomy, classifying them into three types: fibrous, cartilaginous, and synovial, with synovial joints being the most common and freely movable. It details the structure and features of these joints, including components like joint capsules, synovial fluid, and types of movements. Additionally, it categorizes six major types of synovial joints based on their shapes and allowed movements.
Introduction to Clinically Oriented Anatomy-Joints
- 1. Introduction to Clinically Oriented Anatomy ــــــ Joints By: Hasan Arafat
- 2. Joints are unions between two or more bones or rigid parts of the skeleton • They exhibit a variety of forms and functions • They are classified according to the type of the material by which the articulating bones are united • They can be also classified according to mobility
- 3. Three general types of joints are recognized: fibrous, cartilaginous and synovial • These types differ in the manner of material by which each joint is made • Freely movable synovial joints are the most common type • Most of our movements happen at synovial joints • However, the other types perform a number of very important functions
- 4. Synovial joints • In Synovial joints, the articulating are united by a joint capsule • The joint capsule is composed of an outer fibrous layer lined by serous synovial membrane • The joint capsule encloses an articular cavity
- 5. Synovial joints (continued) • The joint cavity is a potential space that contains a small amount of lubricating synovial fluid • The lubricating synovial fluid is secreted by the synovial membrane that lines the fibrous layer of the joint capsule
- 6. Synovial joints (continued) • Inside the capsule, articular cartilage covers the articulating surfaces of the bones • All other internal surfaces are covered by synovial membranes • The periosteum investing the participating bones external to the joint blends with the fibrous layer of the capsule
- 8. Fibrous joints • The articulating bones are united b fibrous tissue • The amount of movement at this joint depends on the length of the fibers uniting the articulating surfaces • The sutures of the cranium are examples
- 10. Fibrous joints (continued) • Fibrous joints can be subdivided into 2 subtypes • A syndesmosis type unites the bones with a sheet of fibrous tissue, either a ligament or fibrous membrane • This type is partially movable • The interosseous membrane between the radius and ulna is an example
- 11. Dentatoalveolar syndesmosis: a fibrous joint in which a peg-like process fits into a socket articulation between the root of the tooth and the alveolar process of the jaw • It’s also called gomphosis or socket • Mobility at this joint indicates a pathological state, affecting the supporting tissue of the tooth • So, it’s normally immobile • However, microscopic movements here is related to proprioception
- 13. Cartilaginous joints • They are united by hyaline cartilage or fibrocartilage • Can be divided into 2 types • These types are primary cartilaginous joints, or synchondroses, and secondary cartilaginous joints, or symphyses
- 14. Cartilaginous joints (continued) • In synchondroses, the bones are joined by hyaline cartilage • Hyaline cartilage permits slight bending during early life • Primary cartilaginous joints are usually temporary unions • E.g. the growth plate
- 15. Cartilaginous joints (continued) • Symphyses are strong, slightly movable joints • They are united by fibrocartilage • E.g. intervertebral discs • They provide strength and shock absorption as well as considerable flexibility to the vertebral column
- 18. Features of Synovial joints • They the most common type • They provide free movement • They are joints of locomotion • Typical for limbs joints
- 19. Features of Synovial joints (cont) • They are reinforced by accessory ligaments • Accessory ligaments are either separate (extrinsic) or thickening portions of joint capsule (intrinsic)
- 20. Features of Synovial joints (cont) • They also contain fibrocartilaginous articular discs • They are also called meniscus • They are found where articulating surfaces are incongruous
- 22. Classification of Synovial joints • Six major types of synovial joints are classified according to the shape of articulating surfaces and the type of movement they permit • These types are plane joints, hinge joints, saddle joints, condyloid joints and ball-and-socket joints
- 23. 1. Plane joints • They are nonaxial • They permit gliding or sliding movements in the plane of the articular surfaces • The opposed surfaces are flat or almost flat • Movement is limited by their tight joint capsules
- 24. 1. Plane joints (cont) • They are numerous and are nearly always small • E.g. the acromioclavicular joint
- 26. 2. Hinge joints • Permit flexion and extension only • They are uniaxial • Movements at these joints happen in the sagittal plane around a transverse axis • Their joint capsules are thin
- 27. 2. Hinge joints (cont) • The joint capsule lax anteriorly and posteriorly where movement occures • The bones are joined by strong laterally placed collateral ligaments • The elbow is an example
- 30. Saddle joints • Permit abduction, adduction, flexion and extension • Biaxial joints, movements occur in sagittal and frontal planes • Circumduction is also available • E.g. carpometacarpal joint at the thumb
- 31. Condyloid joints • Permit flexion, extension, adduction and abduction • Biaxial Joints • The movement at the sagittal is greater than the frontal • More restricted circumduction • E.g. metacarbophalangeal joints
- 32. Ball and socket joints • Multiple axes and planes • Allow flexion, extension, abduction, adduction, medial and lateral rotation and circumduction • Spheroidal surface of one bone moves within the socket of another • E.g. hip joint
- 33. Pivot joints • Permit rotation around a central axis • Uniaxial joints • The rounded process of bone rotates within a sleeve or ring • E.g. the median atlantoaxial joint • The atlas rotates around the dens of the axis during rotation of the head
- 35. Synovial joints