Bones & Joints 2023-1.ppsx

Bones & Joints CHAPTER 7 PG 176-TOP 181 & BOTTOM 210-214 Objectives • • • • • • Learn what bone is composed of & how bones function Learn the definitions of joints & ligaments Learn the basic terminology associated with joints Recognize the various types of joints Learn the characteristics of s...

Bones & Joints CHAPTER 7 PG 176-TOP 181 & BOTTOM 210-214 Objectives • • • • • • Learn what bone is composed of & how bones function Learn the definitions of joints & ligaments Learn the basic terminology associated with joints Recognize the various types of joints Learn the characteristics of synovial joints Discuss joint movements and learn the terminology used to describe it Functions of Bone • • • • • Support Protection Leverage / Locomotion Storage Hematopoiesis (See text on pg 177) Bone • Living tissue composed of cells (osteoblasts) in an intercellular matrix composed of collagen fibers embedded in a ground substance made of protein and polysaccharides • Matrix is hardened via ossification -> infiltrated by calcium & phosphate in the form of hydroxyapatite crystals Bone • Osteoblasts within the ossified matrix are now call osteocytes • Osteoclasts are multinucleated cells that work with osteoblasts to remodel bone by removing bone where it’s not needed; they also allow the body to take calcium from bones when it’s needed to raise levels of calcium in the blood Bone Structure • Cancellous Bone (Spongy Bone)  Spicules (trabeculae) of bone arranged around spaces filled with bone marrow  Light weight but very strong • Compact Bone  Tightly compacted cylinders of bone = haversian systems each composed of concentric layers of ossified matrix arranged around a central haversian canal w/ osteocytes between the layers of bone of each system  Very heavy, dense & strong; makes up the shafts of long bones & outside layer of all bones Bone Structure • Periosteum – covers outer surfaces of bones; outer layer is a fibrous membrane & the inner, boneforming, layer containing osteoblasts enables bones to increase in diameter and aids in healing of fractures (fx) • Endosteum – lines interior surfaces of bones; also contains osteoblasts • You can read about the blood supply to bone and bone formation on page 180 • You should know the parts of a bone (Fig. 7.3 on page 181) Joints • Junctions between bones • Vary in their ability to move • Terminology Arthro- and articular refer to joints Arthrology is the study of joints Types of Joints • Fibrous (Synarthrosis) - immovable  Securely united by dense fibrous connective tissue (collagen)  Ex: sutures between skull bones • Cartilaginous (Amphiarthrosis) - slightly movable  Mild rocking movement  Ex: Vertebral discs, pelvic & mandibular symphyses • Synovial (Diarthrosis) - freely movable  Ex: stifle, elbow, shoulder, coxofemoral Synovial Joints • Articular surfaces  Bone surfaces that rub together w/in the joints • Articular cartilage  Thin, smooth layer of hyaline cartilage lying on top of the articular surfaces of bones -> aids in movement & reduces friction • Joint Cavity / Joint Capsule  Fluid filled “space” between the joint surfaces that is enclosed by a fibrous capsule  Inner layer of joint capsule = synovial membrane • Ligaments – bands of fibrous connective tissue in & around some synovial joints -> join bones to bones & stabilize joints Arthrocentesis • Collection of synovial fluid from the joint for analysis (sterile skin prep & needle) • Fibroblasts of synovial membrane produce GAGs (primarily hyaluronic acid) -> secreted into synovial fluid -> viscosity • Protection & nourishment of articular cartilage, lubrication of the joint (reduces friction) Synovial Joint Movement • • • • • Flexion – decreases angle between 2 bones Extension – increases angle between 2 bones Adduction – toward the median plane Abduction – away from the median plane Rotation – twisting on a part’s axis (pronation & supination) • Circumduction – movement in a circle (of the distal end of an extremity) Types of Synovial Joints • Categorized according to type of joint surface and movements possible • 4 basic types – Hinge (ginglymus) – atlanto-occipital & elbow joints – Gliding (arthrodial) – carpus – Pivot (trochoid) – C1-C2 (atlanto-axial) – Ball and socket (spheroidal) – shoulder & coxofemoral (hip) joints Review • • • • • • Structure & function of bone Definition of joints & ligaments Basic terminology associated with joints Describe the various types of joints Characteristics of synovial joints List and define the terminology used to describe joint movement http://www.lbah.com/canine/arthritis.htm