PowerPoint ® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM 9 Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Joints PART 1

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Joints  Rigid elements of the skeleton meet at joints or articulations  Greek root “arthro” means joint  Articulations can be  Bone to bone  Bone to cartilage  Teeth in bony sockets  Structure of joints  Enables resistance to crushing, tearing, and other forces

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Classifications of Joints  Joints can be classified by function or structure  Functional classification – based on amount of movement  Synarthroses – immovable; common in axial skeleton – skull sutures  Amphiarthroses – slightly movable; common in axial skeleton – pubic symphysis, intervertebral discs, interrosseous membranes btwn. Radius/ulna, tibia/fibula  Diarthroses – freely movable; common in appendicular skeleton (all synovial joints) arms, legs, hands and feet plus the TMJ

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Classifications of Joints  Structural classification based on  Material that binds bones together  Presence or absence of a joint cavity  Structural classifications include  Fibrous – sutures, gomphosis (teeth in jaw), Fibrous tissue ossifies in middle age and is called a Synostoses – closed sutures  Cartilaginous – pubic symphysis etc.  Synovial - limbs, TMJ  SYNDESMOSIS – radius/ulna, tibia/fibula

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Fibrous Joints Figure 9.1a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gomphoses  Tooth in a socket  Connecting ligament – the periodontal ligament Figure 9.1c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Synchondroses  Hyaline cartilage unites bones  Epiphyseal plates Figure 9.2a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Synchondroses  Joint between first rib and manubrium Figure 9.2b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Symphyses  Hyaline cartilage – also present as articular cartilage Figure 9.2c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints  Most movable type of joint  All are diarthroses  Each contains a fluid-filled joint cavity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Synovial Joints  Articular cartilage  Ends of opposing bones are covered with hyaline cartilage  Absorbs compression  Joint cavity (synovial cavity)  Unique to synovial joints  Cavity is a potential space that holds a small amount of synovial fluid

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Synovial Joints  Articular capsule – joint cavity is enclosed in a two-layered capsule  Fibrous capsule – dense irregular connective tissue, which strengthens joint  Synovial membrane – loose connective tissue  Lines joint capsule and covers internal joint surfaces  Functions to make synovial fluid

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Synovial Joints  Synovial fluid  A viscous fluid similar to raw egg white  A filtrate of blood with added lubricants  Arises from capillaries in synovial membrane  Contains glycoprotein molecules secreted by fibroblasts  Synovial joints are subject to compressive forces. This acts like a “sponge”. When the pressure releases, fluid is absorbed into the joint, then when compressed again, it is squeezed out. This mechanism is called “weeping lubrication”

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Synovial Joints  Reinforcing ligaments  Often are thickened parts of the fibrous capsule  Sometimes are extracapsular ligaments – located outside the capsule  Sometimes are intracapsular ligaments – located internal to the capsule

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings A Typical Synovial Joint Figure 9.3a continuous

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings General Structure of Synovial Joints  Richly supplied with sensory nerves  Detect pain  Most monitor how much the capsule is being stretched

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Synovial Joints with Articular Discs  Some synovial joints contain an articular disc  Occur in the temporomandibular joint and at the knee joint  Occur in joints whose articulating bones have somewhat different shapes Figure 9.3c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Summary of Joint Classes Table 9.1 (1 of 2) Don’t need to know

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings How Synovial Joints Function  Synovial joints – lubricating devices  Friction could overheat and destroy joint tissue  Are subjected to compressive forces  Fluid is squeezed out as opposing cartilages touch  Cartilages ride on the slippery film

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Bursae and Tendon Sheaths  Bursae and tendon sheaths are not synovial joints  Closed bags of lubricant  Reduce friction between body elements  Bursa – a flattened fibrous sac lined by a synovial membrane  Tendon sheath – an elongated bursa that wraps around a tendon, it occurs in the carpal tunnel which is subject to overuse and causing Carpal Tunnel Syndrome

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Bursae and Tendon Sheaths Figure 9.4a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Joint Stabililty  Articular surfaces – seldom play a major role in joint stability  The elbow, the knee and the hip do provide stability  Ligaments – the more ligaments in a joint, the stronger it is  Muscle tone – the most important factor in joint stability  Keeps tension on muscle tendons

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Gliding Joints – Types of Movement  Flat surfaces of two bones slip across each other  Gliding occurs between  Carpals  Articular processes of vertebrae  Tarsals Figure 9.5a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movements  Increase or decrease angle between bones  Movements involve  Flexion and extension  Abduction and adduction  Circumduction

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movements Figure 9.5b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movements Figure 9.5c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movements Figure 9.5d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Angular Movements Figure 9.5e PLAY Movement of the pectoral girdle (a)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Rotation  Involves turning movement of a bone around its long axis  The only movement allowed between atlas and axis vertebrae  Occurs at the hip and shoulder joints

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Supination – forearm rotates laterally, palm faces anteriorly  Pronation – forearm rotates medially, palm faces posteriorly

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements Figure 9.6a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Dorsiflexion – lifting the foot so the superior surface approaches the shin  Plantar flexion – depressing the foot, pointing the toes

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Inversion – turning the sole medially  Eversion – turning the sole laterally Figure 9.6c PLAY Movement of the ankle and foot (a)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Protraction – nonangular movement of jutting out the jaw  Retraction – opposite movement to protraction Figure 9.6d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Elevation – lifting a body superiorly  Depression – moving the elevated part inferiorly Figure 9.6e

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Special Movements  Opposition – movement of the thumb to touch the tips of other fingers Figure 9.6f

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Hinge Joint – movement in one axis only like the elbow Figure 9.7b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Pivot Joint – proximal radio-ulnar Figure 9.7c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Ball and Socket  Ball-and-socket joints  Spherical head of one bone fits into round socket of another  Classified as multiaxial – allow movement in all axes  Shoulder and hip joints

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Ball-and-Socket Joint Figure 9.7f PLAY Movement of the glenohumeral joint (a)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Shoulder Joint Figure 9.8a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joints  Shoulder (Glenohumeral) joint  The most freely movable joint lacks stability  Articular capsule is thin and loose  Muscle tendons contribute to joint stability

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Rotator Cuff  The rotator cuff is made up of four muscles and their associated tendons  Subscapularis  Supraspinatus  Infraspinatus  Teres minor  Rotator cuff injuries are common shoulder injuries

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The shoulder joint Figure 9.8b, c

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Shoulder Joint Figure 9.8d, e

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joints  Elbow joint  Allows flexion and extension  The humerus’ articulation with the trochlear notch of the ulna forms the hinge  Tendons of biceps and triceps brachii provide stability

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Elbow Joint Figure 9.9a, b Understand the features that are common to all joints

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joints  Hip joint  A ball-and-socket structure  Movements occur in all axes  Limited by ligaments and acetabulum  Head of femur articulates with acetabulum  Stability comes chiefly from acetabulum and capsular ligaments  Muscle tendons contribute somewhat to stability

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Frontal Section and Anterior View of the Hip Joint Figure 9.11a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Posterior View of the Hip Joint Figure 9.11c, d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joints  Knee joint  The largest and most complex joint  Primarily acts as a hinge joint  Has some capacity for rotation when leg is flexed  Structurally considered compound and bicondyloid  Two fibrocartilage menisci occur within the joint cavity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sagittal Section and Superior View of Knee Joint Figure 9.12a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Sagittal Section and Superior View of Knee Joint Figure 9.12b Helps prevent lateral displacement Helps prevent ant/post displacement

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Knee Joint  Capsule of knee joint  Covers posterior and lateral aspects of the knee  Covers tibial and femoral condyles  Does not cover the anterior aspect of the knee  Anteriorly covered by three ligaments  Patellar, medial, and lateral retinacula

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Anterior View of Knee Figure 9.12c AKA lateral collateral ligament AKA medial collateral ligament

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Posterior View of Knee Joint Figure 9.12d

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Knee Joint  Intracapsular ligaments  Cruciate ligaments  Cross each other like an “X”  Each cruciate ligament runs from the proximal tibia to the distal femur  Anterior cruciate ligament  Posterior cruciate ligament

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Anterior View of Flexed Knee Figure 9.12e, f

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 9.13a Knee Joint  Cruciate ligaments  Prevent undesirable movements at the knee joint

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joint  Ankle Joint  A hinge joint between  United inferior ends of tibia and fibula  The talus of the foot  Allows the movements  Dorsiflexion and plantar flexion only

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Selected Synovial Joints  Temporomandibular joint (TMJ)  Lies anterior to the ear  Head of the mandible articulates with the mandibular fossa  Two surfaces of the articular disc allow two kinds of movement  Hinge-like movement  Superior surface of disc glides anteriorly  A condition that commonly leads to neck pain, ear problems and pain when opening the mouth is called temporomandibular disorder or “TMJ”

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Temporomandibular Joint Figure 9.16a, b

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Disorders of Joints  Structure of joints makes them prone to traumatic stress  Function of joints makes them subject to friction and wear  Affected by inflammatory and degenerative processes

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Joint Injuries  Sprains – ligaments of a reinforcing joint are stretched or torn  Dislocation – occurs when the bones of a joint are forced out of alignment  Torn cartilage – common injury to meniscus of knee joint  Bursitis – inflammation of a bursa do to injury or friction  Tendonitis – inflammation of a tendon sheath

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Inflammatory and Degenerative Conditions  Arthritis – describes over 100 kinds of joint- damaging diseases  Osteoarthritis – most common type “wear and tear” arthritis  Rheumatoid arthritis – a chronic inflammatory disorder  Gouty arthritis (gout) – uric acid build-up causes pain in joints  Lyme disease – inflammatory disease often resulting in joint pain

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Joints Throughout Life  Synovial joints develop from mesenchyme  By week 8 of fetal development, joints resemble adult joints  Outer region of mesenchyme becomes fibrous joint capsule  Inner region becomes the joint cavity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Joints Throughout Life  During youth – injury may tear an epiphysis off a bone shaft  Advancing age – osteoarthritis becomes more common  Exercise – helps maintain joint health