Anatomy and Physiology Marieb’s Human Anatomy and Physiology Ninth Edition Marieb w Hoehn Chapter 8 Joints Lecture 15 65 min, 38 slides

Lecture Overview Functions of joints Classification of joints Types of joints Types of joint movements Some representative articulations

Functions of Joints (Articulations) Form functional junctions between bones Bind parts of skeletal system together Make bone growth possible Permit parts of the skeleton to change shape during childbirth Enable body to move in response to skeletal muscle contraction A “joint” joins two bones or, parts of bones, together, regardless of ability of the bones to move around the joint

Some Useful Word Roots Arthros – joint Syn – together (immovable) Dia – through, apart (freely moveable) Amphi – on both sides (slightly moveable) Some Examples: Synarthrosis – An immovable joint Amphiarthrosis – A slightly movable joint Diarthrosis – Freely movable joint Functional Classification (Very S-A-D) Examples of synostoses: union of l/r mandible and frontal bones, cranial sutures in old age, epiphyseal lines. What does the term ‘synostosis’ mean?

Classification of Joints How are the bones held together? How does the joint move? 3 answers 3 answers Structural Functional Fibrous Joints dense connective tissues connect bones between bones in close contact synarthrotic immovable amphiarthrotic slightly movable diarthrotic freely movable Cartilaginous Joints hyaline cartilage or fibrocartilage connect bones Synovial Joints most complex allow free movement have a cavity

Joint Classification Structural Classification of Joints Fibrous Cartilaginous Synovial (D) Gomphosis (S) Synchondrosis (S) Gliding (N) Suture (S) Symphysis (A) Hinge (M) Pivot (M) Syndesmosis (A) Condyloid (B) (S) = Synarthrosis (A) = Amphiarthrosis (D) = Diarthrosis (N) = Nonaxial (M) = Monaxial (B) = Biaxial (P) = Polyaxial Saddle (B) Mnemonic for fibrous joints: “Go sue synde for telling a fib” Mnemonic for cartilaginous joints: “Cartilage either synchs or swyms” (sinks or swims) Mnemonic for types of synovial joints, in order from least movable to most movable: “Geeky Humans Play Competitive Saddle Ball” Ball/Socket (P) This would be a really good chart to know for the exam!

Fibrous Joints No synovial cavity (space between bones) fibrous CT little or no movement Figure from: Hole’s Human A&P, 12th edition, 2010 3 Types Gomphosis Suture Syndesmosis Syndesmosis (desmos = band or ligament; to bind) long fibers connect bones amphiarthrotic (slightly movable) distal ends of tibia and fibula radius and ulna broad sheets or bundles Mnemonic for types of fibrous joints: “Go sue synde for telling a fib”

Fibrous Joints Suture (sewing together) between flat bones synarthrotic thin layer of connective tissue connects bones Gomphosis (bolting together) cone-shaped bony process in a socket tooth in jawbone peg-in-socket synarthrotic Figure from: Hole’s Human A&P, 12th edition, 2010

Cartilaginous Joints No synovial cavity hyaline or fibrocartilage little or no movement Figure from: Hole’s Human A&P, 12th edition, 2010 2 Types Synchondrosis Symphysis Synchondrosis bands of hyaline cartilage unite bones epiphyseal plate (temporary) between manubrium and first rib (sternocostal) synarthrotic (no movement) A rib dislocation (slipping rib syndrome) or dislocation of a sternocostal joint is the displacement of a costal cartilage (ribs 2-7) from the sternum. A rib separation refers to a dislocation of a costochondral junction between the rib and its costal cartilage. Sternocostal joints Mnemonic for cartilaginous joints: “Cartilage either synchs or syms” (sinks or swims) Costochondral joints

Cartilaginous Joints Symphysis pad of fibrocartilage between bones pubic symphysis (or symphysis pubis) joint between bodies of vertebrae amphiarthrotic Figure from: Hole’s Human A&P, 12th edition, 2010

Synovial Joints * Diarthrotic (freely movable) Structural features of diarthrotic joints - joint cavity* - articular cartilage - synovial membrane - synovial fluid - reinforcing ligaments, bursae and tendons - Articular cartilage in young, healthy joints is about 2 mm thick. - Articular discs form in some joints and arise from the inner joint capsule. These are found in the temporomandibular, sternoclavicular, acromioclavicular, and distal radioulnar joints. - A meniscus (as in the knee joint) extends only partway across a joint with a gap between them, although functionally the menisci are the same as articular discs. - Normal synovial fluid contains 3-4 mg/ml hyaluronan (hyaluronic acid), a polymer of disaccharides composed of D-glucuronic acid and D-N-acetylglucosamine joined by alternating beta-1,4 and beta-1,3 glycosidic bonds [2]. Hyaluronan is synthesized by the synovial membrane and secreted into the joint cavity to increase the viscosity and elasticity of articular cartilages and lubricate the surfaces between synovium and cartilage.[3] Synovial fluid also contains lubricin secreted by synovial cells. It is chiefly responsible for so-called boundary-layer lubrication, which reduces friction between opposing surfaces of cartilage. There is also some evidence that it helps regulate synovial cell growth.[4] Synovial fluid: Lubricates, distributes nutrients, and absorbs shock

Synovial Joints * Diarthrotic (freely movable) Structural features of diarthrotic joints - joint cavity* - articular cartilage - synovial membrane - synovial fluid - reinforcing ligaments, bursae and tendons - Articular cartilage in young, healthy joints is about 2 mm thick. - Articular discs form in some joints and arise from the inner joint capsule. These are found in the temporomandibular, sternoclavicular, acromioclavicular, and distal radioulnar joints. - A meniscus (as in the knee joint) extends only partway across a joint with a gap between them, although functionally the menisci are the same as articular discs. - Normal synovial fluid contains 3-4 mg/ml hyaluronan (hyaluronic acid), a polymer of disaccharides composed of D-glucuronic acid and D-N-acetylglucosamine joined by alternating beta-1,4 and beta-1,3 glycosidic bonds [2]. Hyaluronan is synthesized by the synovial membrane and secreted into the joint cavity to increase the viscosity and elasticity of articular cartilages and lubricate the surfaces between synovium and cartilage.[3] Synovial fluid also contains lubricin secreted by synovial cells. It is chiefly responsible for so-called boundary-layer lubrication, which reduces friction between opposing surfaces of cartilage. There is also some evidence that it helps regulate synovial cell growth.[4] Figure from: Martini’s Visual A&P, 1st edition, 2011 Synovial fluid: Lubricates, distributes nutrients, and absorbs shock

Joint Classification Structural Classification of Joints Fibrous Cartilaginous Synovial (D) Gomphosis (S) Synchondrosis (S) Gliding (N) Suture (S) Symphysis (A) Hinge (M) Pivot (M) Syndesmosis (A) Condyloid (B) (S) = Synarthrosis (A) = Amphiarthrosis (D) = Diarthrosis (N) = Nonaxial (M) = Monaxial (B) = Biaxial (P) = Polyaxial Saddle (B) Mnemonic for fibrous joints: “Go sue synde for telling a fib” Mnemonic for cartilaginous joints: “Cartilage either synchs or swyms” (sinks or swims) Mnemonic for types of synovial joints, in order from least movable to most movable: “Geeky Humans Play Competitive Saddle Ball” Ball/Socket (P) This would be a really good chart to know for the exam!

Types of Synovial Joints Mnemonic for types of synovial joints (least movable to most movable): “Geeky Humans Play Competitive Saddle Ball” Gliding (Plane) Joint between carpals between tarsals between vertebrae Hinge Joint elbow knee between phalanges Gliding joints – carpals, tarsals, articular processes of the vertebrae. Hinge joints – elbow, knee, and interphalangeal joints. Flat surfaces move past one another (nonaxial) Angular open/close motion (monaxial) Figure from: Hole’s Human A&P, 12th edition, 2010

Types of Synovial Joints Pivot Joint between proximal ends of radius and ulna Saddle Joint between carpal and metacarpal of thumb sternoclavicular joint Pivot joint: atlantoaxial and proximal radioulnar joints. Saddle joint: trapeziometacarpal joint (allows for opposable thumb) and sternoclavicular joint. Rotation around long axis (monaxial) Angular motion (biaxial) Figure from: Hole’s Human A&P, 12th edition, 2010

Types of Synovial Joints Ball-and-Socket Joint hip shoulder Condyloid Joint between metacarpals and phalanges between radius and carpals Condyloid: radiocarpal and metacarpalphalangeal joints. Movement around 3 axes and in between (multiaxial) Angular motion (biaxial) Figure from: Hole’s Human A&P, 12th edition, 2010

Movement of Synovial Joints *All movements are based upon The body being in anatomical position All axial and appendicular joints being in full extension when in anatomical (zero) position Important to define which joint you are examining before trying to define movement

Flexion and Extension Usually occur in the sagittal plane Flexion – decrease in angle between bones and parts come together (usually in direction of greatest mobility) Extension – increase in angle between bones and parts move further apart (usually after flexion) Hyperextension – Extension beyond the anatomical position (limited by tendons/ligaments/bones) Lateral Flexion – movement from side-to-side (in the frontal plane)

Flexion and Extension Figure from: Martini, Anatomy & Physiology, Benjamin Cummings, 2004

ABduction, ADduction, and Circumduction Usually occur in the frontal plane ABduction – movement away from midline ADduction – movement toward midline Circumduction – Movement of the distal end of a limb in a circle

ABduction, ADduction, and Circumduction Figure from: Martini, Anatomy & Physiology, Benjamin Cummings, 2004

Rotation, Pronation/Supination Circumduction is actually a combination of flexion, abduction, extension, and adduction. (Special movement – doesn’t fit into the other categories) Bone revolves around its own longitudinal axis Figures From: Marieb & Hoehn, Human Anatomy & Physiology, 9th ed., Pearson, 2013

Special Movements of Synovial Joints Anterior/posterior movement in the transverse plane Superior/inferior movement in the coronal plane Figures From: Marieb & Hoehn, Human Anatomy & Physiology, 9th ed., Pearson, 2013

Special Movements of Synovial Joints Figure from: Martini, Anatomy & Physiology, Benjamin Cummings, 2004

Joint Classification Structural Classification of Joints Fibrous Cartilaginous Synovial (D) Gomphosis (S) Synchondrosis (S) Gliding (N) Suture (S) Symphysis (A) Hinge (M) Pivot (M) Syndesmosis (A) Condyloid (B) (S) = Synarthrosis (A) = Amphiarthrosis (D) = Diarthrosis (N) = Nonaxial (M) = Monaxial (B) = Biaxial (P) = Polyaxial Saddle (B) Mnemonic for fibrous joints: “Go sue synde for telling a fib” Mnemonic for cartilaginous joints: “Cartilage either synchs or swyms” (sinks or swims) Mnemonic for types of synovial joints, in order from least movable to most movable: “Geeky Humans Play Competitive Saddle Ball” Ball/Socket (P) This would be a really good chart to know for the exam!

Review

Shoulder (Glenohumeral) Joint Figure from: Hole’s Human A&P, 12th edition, 2010 ball-and-socket head of humerus glenoid cavity of scapula loose joint capsule bursae ligaments prevent displacement very wide range of movement (but not as stable as hip) Aka: humeroscapular joint

Shoulder Joint Figure from: Hole’s Human A&P, 12th edition, 2010 Glenohumeral joint – greatest range of motion of any joint. Glenoid labrum is fibrocartilaginous. Most stability provided by muscles with the help of ligaments and tendons. Shoulder separation = partial or complete tearing of acromioclavicular joint.

Rotor Cuff * Rotator cuff muscles = the SITS muscles * * *

Elbow Joint hinge joint (1) gliding joint (2) flexion and extension Figure from: Hole’s Human A&P, 12th edition, 2010 hinge joint (1) trochlea of humerus trochlear notch of ulna humeroulnar joint gliding joint (2) capitulum of humerus head of radius humeroradial joint radioulnar joint (annular lig.) flexion and extension many reinforcing ligaments stable joint Largest and strongest articulation at elbow is the humeroulnar joint. Muscles that extend the elbow under control of radial nerve (in radial groove of humerus). Biceps brachii tendon attaches at radial tuberosity to supinate and flex the elbow. Upward twisting motion on arm when epiphyseal growth has not been completed, e.g., in children, may cause a partial dislocation called nursemaid’s elbow. Which arm, and which view, are we looking at here?

Elbow Joint Malgaigne's luxation - Partial dislocation of the head of the radius of the arm beneath the annular ligament of the radius. Also called nursemaid's elbow. Figure from: Hole’s Human A&P, 12th edition, 2010

Hip (Coxal) Joint ball-and-socket joint head of femur acetabulum Figure from: Hole’s Human A&P, 12th edition, 2010 ball-and-socket joint head of femur acetabulum heavy joint capsule many reinforcing ligaments less freedom of movement than shoulder joint, but very strong Hip joint = coxal joint. Fibrocartilage pad inside acetabulum; acetabular labrum = projecting rim of fibrocartilage that deepens acetabulum. Articular capsule is extremely dense and strong. Four ligaments stabilize the joint: iliofemoral, pubofemoral, ischiofemoral (these are thickenings of capsule), and the transverse acetabular ligament that crosses the acetabular notch. Ligament of femoral head originates at transverse acetabular ligament and attaches at fovea capitis. Fovea capitis and ligamentum capitis (teres)

Hip Joint From: Saladin, Anatomy & Physiology, McGraw Hill, 2007 Figure from: Hole’s Human A&P, 12th edition, 2010 From: Saladin, Anatomy & Physiology, McGraw Hill, 2007

Knee (Tibiofemoral) Joint Figure from: Hole’s Human A&P, 12th edition, 2010 largest, most complex joint medial and lateral condyles of distal end of femur medial and lateral condyles of proximal end of tibia femur articulates anteriorly with patella (patellofemoral joint) modified hinge joint flexion/extension/little rotation strengthened by many ligaments and tendons menisci (fibrocartilage discs) separate femur and tibia bursae Permits flexion, extension, and limited rotation. Menisci are fibrocartilagenous pads. Patella is embedded in the tendon of the quadriceps superiorly and in the patellar ligament inferiorly. Popliteal ligaments reinforce knee’s posterior surface. ACL and PCL attach the intercondylar area of tibia to femoral condyles. Anterior and posterior refer to point of origin on tibia. ACL and PCL limit anterior and posterior movement of femur and maintain alignment of femoral and tibial condyles. Stabilizing tibial collateral and fibular collateral ligaments tighten only upon full extension of knee. (Tibial collateral ligament is firmly attached to the medial meniscus.) At full extension, medial meniscus is jammed between the tibia and femur, locking the knee. Unlocking the knee requires contraction of the popliteus (medial rotation of tibia).

Knee Joint retinaculae Figure from Martini, Anatomy & Physiology, Prentice Hall, 2001

Knee Joint Deep posterior view, extended From: Saladin, Anatomy & Physiology, McGraw Hill, 2007 (Meniscus = crescent) Deep posterior view, extended Figure from Martini, Anatomy & Physiology, Prentice Hall, 2001

Knee Joint Deep anterior view, flexed Figure from Martini, Anatomy & Physiology, Prentice Hall, 2001

Life-Span Changes Joint stiffness is an early sign of aging Regular exercise can prevent stiffness Changes in symphysis joints of vertebral column diminish flexibility and decrease height Synovial joints lose elasticity

Clinical Application – Joint Disorders Sprains damage to cartilage, ligaments, or tendons associated with joints forceful twisting of joint Bursitis inflammation of a bursa overuse of a joint Arthritis inflamed, swollen, painful joints Rheumatoid Arthritis (RA) Osteoarthritis (OA) Gout

Rheumatoid Arthritis (RA) Boutonniere’s deformity (swan neck). Result of autoimmune attack on the joints From: Saladin, Anatomy & Physiology, McGraw Hill, 2007

Joint Prostheses Prostheses used in knee replacement Figures from: Saladin, Anatomy & Physiology, McGraw Hill, 2007 Be sure to check out the ExRx Articulations link on the Web site to get familiar with joint movements.

Review Because the bones of the skeleton are rigid, movement can only occur at articulations (joints) Joints can be classified by Structure (newer style) Function (older style) A structural classification of joints includes: Fibrous joints Cartilaginous joints Synovial joints

Review A functional classification of joints includes Synarthroses (no movement) Amphiarthroses (little movement) Diartrhoses (free movement) Important movements of joints to be familiar with Flexion/Extension and Hyperextension Abduction/Adduction and Circumduction Supination/Pronation Rotation Dorsiflexion/Plantar flexion