Joints AKA “articulations” – functional junctions between bones Functions: –Bind parts of the skeletal system –Make bone growth possible –Permit parts of the skeleton to change shape during childbirth –Enable the body to move in response to skeletal muscle contractions

Types of Joints Fibrous joints Cartilaginous joints Synovial joints –Ball-and-socket joints –Condyloid joint –Gliding joints –Hinge joint –Pivot joint –Saddle joint

Fibrous Joints Between bones that closely contact each other Bones are joined by thin layer of dense connective tissue No big movement at these joints Where do you think they would be found?

Cartilaginous Joints Bones connected by hyaline cartilage (fibrocartilage) Limited movement Examples: intervertebral discs, symphysis pubis, rib 1 at the sternum

Synovial Joint Free movement Articular ends of bones are covered with hyaline cartilage (articular cartilage). Bones are held together with a surrounding, tubular capsule (joint capsule) of dense connective tissue. –Outer layer of ligaments –Inner lining of synovial membrane, which secretes synovial fluid that lubricates the joint

Synovial Joint, continued….. Some contain shock-absorbing pads of fibrocartilage, called menisci (meniscus, sing.) between articulating surfaces. Some have bursae, fluid-filled sacs which are lined with synovial membranes. (Bursae are commonly located between the skin and the underlying bony prominence.)

Types of Synovial Joints 1.Ball-and-socket joint --- allows for widest range of motion (Examples:????) 2.Condyloid joint –oval-shaped condyle of one bone fits into elliptical cavity of another –No rotation movement –EX: b/t phalanges and metacarpals 3.Gliding joint –Articulating surfaces are nearly flat –Allow sliding and twisting movement –EX: carpals and tarsals

Types of Synovial Joints, continued….. 4. Hinge joint –Convex surface of one joint fits into concave surface of another –Resembles hinged door, allowing movement in one plane only –Examples: ?????

Types of Synovial Joints, continued….. 5. Pivot joint –Cylindrical surface of one bone rotates within ring formed of bone and ligament –Movement is only rotation around a central axis –Example: Joint b/t proximal ends of radius and ulna

6. Saddle joint –Between bones with both convex and concave regions –Allows for variety of movement –Example: Joint b/t metacarpal and carpal of thumb Which metacarpal is this? What is the name of this carpal bone????

Types of Joint Movement 1.Flexion – bending 2.Extension – straightening 3.Dorsiflexion – bending foot toward shin 4.Plantar flexion – bending foot toward sole 5.Hyperextension – extension BEYOND anatomical position 6.Abduction – away from midline of body 7.Adduction – moving a part toward midline

Types of Joint Movement, continued….. 8. Rotation – moving around an axis 9. Circumduction – moving a part so its END follows a circular path 10. Pronation – turning hand posteriorly 11. Supination – turning hand anteriorly 12. Eversion – turning foot so sole faces laterally 13. Inversion – turning sole medially 14. Retraction – moving a part backward 15. Protraction – moving a part forward

Types of Joint Movement, continued… Elevation – raising a part 17. Depression – lowering a part