chapter 02 week 2 lecture 1
- 1. PTHA 1513 FUNCTIONAL ANATOMY Week 2: Lecture 1 Elaine Wilson, PT
- 2. Today’s Theme Song
- 3. Goals for Today Describe the components of the axial versus appendicular skeleton Define the primary components found in bone Describe the 5 types of bones found in the human skeleton Describe the 3 primary classifications of joints and give an anatomic example of each Identify the components of a synovial joint
- 4. Goals for Today - cont’d Describe the seven different classifications of synovial joints in terms of mobility (degrees of freedom) and stability Provide an anatomic example of each of the 7 different classifications of synovial joints Describe the 3 primary materials found in connective tissue Explain how tendons and ligaments support the structure of a joint Explain how muscles help to stabilize a joint Describe the effects of immobilization on the connective tissues of a joint
- 5. CHAPTER 2 Structure & Function of Joints
- 6. Axial versus Appendicular Skeleton Axial skeleton Skull, hyoid bone, ribs, and vertebral column Forms central, semi-rigid bony axis of body Appendicular skeleton Bones of appendages—or extremities Includes scapula in upper extremity and pelvis in lower extremity
- 7. Bone Tissue Types Cortical (compact) bone Dense and extremely strong Typically lines outermost bone portion Absorbs compressive forces Cancellous bone Porous and lightweight Typically composes inner bone portions Redirects forces toward weight-bearing sources
- 8. Bone Anatomy Diaphysis Central shaft of bone, a thick hollow tube Composed mostly of cortical bone Epiphyses Portions of bone arising from diaphysis Primarily composed of spongy bone Transmits weight-bearing forces across body
- 9. Bone Anatomy – cont’d Articular cartilage Lines articular surface of each epiphysis Acts as shock absorber between joints Periosteum Thin, tough membrane covering long bones Secures attachment of muscles and ligaments to bone
- 10. Bone Anatomy – cont’d Medullary canal Central hollow tube within long bone diaphysis Stores bone marrow; provides passage for arteries Endosteum Membrane that lines medullary canal surface Houses cells important for forming and repairing bones
- 11. Bone Types Long bones Contains an obvious axis or shaft Expanded bone portion at each shaft end Examples include femur, humerus, and radius Short bones Length, width, and height are about equal An example includes carpal bones of the hand
- 12. Bone Types – cont’d Flat bones Typically flat or slightly curved Often base for expansive muscular attachments Examples include scapula and sternum Irregular bones Wide variety of shapes and sizes Sesamoid (appear similar to sesame seed) Encased within muscle tendons Protect the tendon and increase the muscle’s leverage
- 13. Joint Classification Synarthrosis Junction between bones allowing little to no movement Primary function: firmly bind bones together and transmit forces from one bone to another Amphiarthrosis Formed primarily by fibrocartilage and hyaline cartilage Allow limited amounts of motion Primary function: provide shock absorption
- 14. Joint Classification – cont’d Diarthrosis (synovial joint) Articulation that contains a fluid-filled joint cavity between two or more bones Includes seven uniquely functioning categories All synovial joints share seven common attributes
- 15. 7 Common Elements of Synovial Joints 1. Synovial fluid: provides joint lubrication and nutrition 2. Articular cartilage: dissipates and absorbs compressive forces 3. Articular capsule: connective tissue that surrounds and binds the joint together Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 16. 7 Common Elements of Synovial Joints – cont’d 4. Synovial membrane: produces synovial fluid 5. Capsular ligaments: thickened regions of connective tissue that limit excessive joint motion 6. Blood vessels: provide nutrients to the joint 7. Sensory nerves: transmit signals regarding pain and proprioception Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 17. Synovial Joint Classification Hinge joint Allows motion in only one plane about a single axis of rotation, similar to the hinge of a door Ex- the humeroulnar joint (elbow) Pivot joint Allows rotation about a single longitudinal axis of rotation, similar to the rotation of a doorknob Ex- the proximal radioulnar joint
- 18. Synovial Joint Classification – cont’d Ellipsoid joint Convex elongated surface mated with a concave surface Allows motion to occur in two planes Ex- radiocarpal (wrist) joint Ball-and-socket joint Articulation between spherical convex surface and cup-like socket Allows wide ranges of motion in all three planes Ex- hip joint
- 19. Synovial Joint Classification – cont’d Plane joint Articulation between two relatively flat bony surfaces Allows limited amount of motion; may slide and rotate in many different directions Ex- intercarpal joints of the hand Saddle joint One concave and one convex surface Allows extensive motion, primarily in two planes Ex- carpometacarpal joint of the thumb
- 20. Synovial Joint Classification – cont’d Condyloid joints Articulation between a large, rounded, convex member and a relatively shallow concave member Most often these joints allow 2 degrees of freedom Ex- tibiofemoral (knee) joint Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 21. Composition of Connective Tissues All connective tissues supporting the joints of the body are composed of fibers, ground substance, and cells These biologic materials are blended in various proportions on the basis of the joint’s mechanical demands Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 22. Fiber Types Type I collagen fibers Thick, rugged fibers that resist elongation Compose ligaments, tendons, and fibrous capsules Type II collagen fibers Thinner and less stiff than type I fibers Provide a flexible woven framework for maintaining the general shape and consistency of structures
- 23. Fiber Types – cont’d Elastin Elastic in nature Resist (tensile) forces but have more “give” when elongated Can be useful in preventing injury because they allow the tissue to “bend, but not break”
- 24. Ground Substance and Cells Ground substance Composed primarily of glycosaminoglycans (gags), water, and solutes Allows body fibers to exist in a fluid-filled environment, dispersing repetitive forces Cells Responsible for the maintenance and repair of tissues that constitute joints
- 25. Types of Connective Tissue Four basic types of connective tissue form the structure of joints: Dense, irregular connective tissue Articular cartilage Fibrocartilage Bone Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 26. Dense, Irregular Connective Tissue Binds bones together and restrains unwanted movement of joints Composes ligaments and the tough external layer of joint capsules Primarily type I collagen fibers, low elastin fiber content Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 27. Articular Cartilage Resists and distributes compressive and shear forces transferred through articular surfaces Covers the ends of articulating bones in synovial joints High type II collagen fiber content; fibers help anchor the cartilage to bone Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 28. Fibrocartilage Provides support and stabilization to joints Provides shock absorption by resisting and dispersing compressive and shear forces Composes the intervertebral discs of the spine and the menisci of the knee Multidirectional bundles of type I collagen Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 29. Bone Forms primary supporting structure of the body and provides a rigid lever to transmit muscle force to move and stabilize the body Forms internal levers of musculoskeletal system Specialized arrangement of type I collagen providing a framework for hard mineral salts
- 30. Functional Considerations: Tendons and Ligaments The fibrous composition of tendons and ligaments is similar , but arrangement and functions differ significantly Tendons connect muscle to bone and convert muscular force into bony motion, with parallel alignment of collagen fibers Ligaments connect bone to bone and maintain a joint’s structure, with irregular crossing patterns of collagen fibers
- 31. Functional Considerations: Active Joint Stabilization Bony conformation and ligamentous networks provide static stability Muscles function as active stabilizers Muscles cannot respond as quickly as ligaments to external force, but allow a graded and more controlled response Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 32. Immobilization and Connective Tissues Joint immobilization increases stiffness and decreases tissue ability to withstand forces Immobilization may be necessary but makes joints susceptible to injury/instability Rehabilitation programs involve a relatively quick return to weight bearing and possibly specific strengthening exercises Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
- 33. Summary Each type of joint has specific functional capabilities Range of motion and relative stability of a joint depend on bony structure, surrounding muscles, and connective tissues Trade-off between stability and mobility of a joint Every joint in the body must find the balance between mobility and stability to function properly
- 34. Homework Please read Chapter 3 in textbook prior to lecture/lab on Thursday 01/26/12 Quiz #2: Chapters 3 & 4 – Tuesday 01/31/12