Articulations Joints Articulations Body movement occurs at joints
Articulations (Joints)
Articulations • Body movement occurs at joints (articulations) where 2 bones connect Joint Structure • Determines direction and distance of movement (range of motion) • Joint strength decreases as mobility increases
Naming of Joints • Usually derived from the names of the articulating bones. 9 -3
Joints Articulations • Point at which two bones join together – Allow movement – Transmit forces • Anatomy – Capsule or ligaments – Synovial membrane – Articular cartilage – Joint space filled with synovial fluid
Structural Classifications • • Bony Fibrous Cartilaginous Synovial
Functional Classifications • Synarthrosis: – no movement • Amphiarthrosis: – little movement • Diarthrosis: – more movement
Classifications • Structural Categories: – Fibrous – Cartilaginous – Synovial • Functional Categories: – Synarthroses—immoveable – Amphiarthroses—slightly moveable – Diarthroses—freely moveable
Synarthroses • Immoveable joints • Lack synovial cavity • Held together by fibrous connective tissue • Structural types: – Sutures – Syndesmoses – Gomphoses
Synarthroses • Sutures – Thin layer of dense fibrous connective tissue – Unites bones of skull • Syndesmosis – Joints where bones connected by ligaments – i. e. fibula/tibia and radius/ulna • Gomphosis – Conical process fits into socket and is held in place by ligaments – i. e. tooth in alveolus (socket), held in place by peridontal ligament
Amphiarthroses • Slightly moveable • Connected by hyaline cartilage or fibrocartilage • i. e. ribs to sternum or vertebrae
Diarthroses Synovial joints • Freely moveable • Ends of opposing bones are covered with articular cartilage • Separated by joint cavity • Components of joints enclosed in dense fibrous joint capsule
Synovial joint
Synovial Joint Anatomy • Articular capsule – Joint capsule – Consists of bundles of collagen and functions to maintain a relative joint position
Synovial Joint Anatomy • Synovial Membrane and Synovial Fluid – Lines the synovial joint(articular) capsule – Made of connective tissue with flattened cells – Synovial fluid acts as a lubricant. – Able to vary its viscosity (thicker with slower movements and it thins with faster movements)
Synovial Fluid • Contains slippery proteoglycans secreted by fibroblasts • Functions of Synovial Fluid 1. Lubrication 2. Nutrient distribution 3. Shock absorption
Synovial Joint Anatomy -Articular Cartilage • Hyaline cartilage: Found on the articular ends of our long bones • Pad articulating surfaces within articular capsules: – prevent bones from touching • Smooth surfaces lubricated by synovial fluid: – reduce friction – Fibrocartilage: cushioning type of cartilage • Found in the menisci in our knees, intervertebral disks, pubic symphysis -Elastic cartilage: • Found in the external ear
Synovial Joint Anatomy • Bursa – Fluid-filled sac of synovial tissue found in our synovial joints. – Found in between anatomical structures to reduce friction – Can become chronically inflammed
Synovial Joint Stabilization • Muscle tension is important in limiting unwanted joint movement • If joint capsule is overstretched, reflex contraction of muscles in the area prevent overstretching (Hilton’s Law)
Synovial Joint Stabilization • Joints that are shallow and fit poorly must depend on capsular structures or muscles for support
Synovial Joint Stabilization • Capsular and ligamentous tissue help to maintain anatomical integrity and structural alignment of synovial joints
Synovial Joints • 6 Types Synovial Joints: – – – Pivot joint Gliding joint Hinge joint Condyloid joint Ball-and-Socket joint Saddle joint
Types of Synovial Joints • Classified by the shapes of their articulating surfaces • Types of movement they allow – uniaxial if the bone moves in just one plane – biaxial if the bone moves in two planes – multiaxial (or triaxial) if the bone moves in multiple planes 9 -22
Uniaxial Joints permits movement around one axis and one plane • projection of one bone articulating with a ring/notch of another bone – examples - between vertebrate • allows only flexion and extension – examples – elbow, knee • knee joint – largest joint, most complex, most frequently injured
Biaxial Joints permits movement around two perpendicular axes and planes • Example – thumb • only saddle joint in the body • condyle fits into an elliptical socket • Example – between radius and carpals ellipsoidal
Multiaxial Joints permits movement around three or more axes and planes • most moveable joints • ball shaped head fits into concave depression • example - shoulder, hip – humeroscapular joint • most mobile joint – sacroiliac joint • hip joint • relatively flat articulating surface that allows gliding movement • example – between carpals – between tarsals – between vertebrate
Types of Joints (ellipsoidal)
Pivot Joints • Rotation only (monaxial) Figure 9– 6 (3 of 6)
Pivot Joint • Freely moveable joint in which bone moves around central axis, creating rotational movement • Radius, ulna
Gliding Joints • Flattened or slightly curved faces • Limited motion (nonaxial) Figure 9– 6 (1 of 6)
Gliding Joint • Allows bones to make sliding motion • Carpals and tarsals • Between vertebrae and spine
Hinge Joints • Angular motion in a single plane (monaxial) Figure 9– 6 (2 of 6)
Hinge Joint • Allows only flexion and extension • Convex surface of one bone fits concave surface of other • Knee, elbow, phalanges
Condyloid/Ellipsoidal Joints • Oval articular face within a depression • Motion in 2 planes (biaxial) Figure 9– 6 (4 of 6)
Condyloid Joint • ellipsoidal joint • Bones can move about one another in many directions, but cannot rotate • Named for condylecontaining bone • Metacarpals, phalanges
Ball-and-Socket Joints • Round articular face in a depression (triaxial) Figure 9– 6 (6 of 6)
Ball & Socket Joint • One bone has rounded end that fits into concave cavity on another bone • Widest range of movement possible • Hips, shoulders
Saddle Joints • 2 concave faces, straddled (biaxial) Figure 9– 6 (5 of 6)
Saddle Joint • Two bones have both concave and convex regions, shape of two bones complementing one another • Wide range of movement • Thumb = only saddle joint in body
Movements of Diarthroses • • • Flexion Extension Hyperextension Abduction Adduction Rotation Circumduction Elevation Depression • • • Supination Pronation Plantar flexion Dorsiflexion Inversion Eversion Protraction Retraction Opposition
Flexion/Extension
Abduction/Adduction • Abduction—moving a body part away from midline • Adduction—moving a body part toward the midline
Internal/External Rotation • Internal rotation— rotation towards the center of the body medial rotation • External rotation— rotation away the center of the body lateral rotation
Internal/External Rotation
Hip Internal Rotation
Plantar Flexion/Dorsiflexion
Supination/Pronation
Elevation/Depression
Inversion/Eversion
What are the structures and functions of the shoulder, elbow, hip, and knee joints… And what is the relationship between joint strength and mobility?
The Shoulder Joint • Also called the glenohumeral joint: – allows more motion than any other joint – is the least stable – supported by skeletal muscles, tendons, ligaments
Structure of the Shoulder Joint • Ball-and-socket diarthrosis • Between head of humerus and glenoid cavity of scapula
Shoulder
Socket of the Shoulder Joint • Glenoid labrum: – deepens socket of glenoid cavity – fibrocartilage lining – extends past the bone
Processes of the Shoulder Joint • Acromion (clavicle) and coracoid process (scapula): – project laterally, superior to the humerus – help stabilize the joint
Shoulder Ligaments • • • Glenohumeral Coracoacromial Coracoclavicular Acromioclavicular
Shoulder • Glenohumeral • Sternoclavicular • Acromioclavicular Glenohumeral joint
Shoulder Muscles • Also called rotator cuff: – supraspinatus – infraspinatus – subscapularis – teres minor
The Elbow Joint Figure 9– 10
The Elbow Joint • A stable hinge joint • With articulations between humerus, radius, and ulna
Articulations of the Elbow • Humeroulnar joint: – largest articulation – trochlea of humerus and trochlear notch of ulna – limited movement • Humeroradial joint: – smaller articulation – capitulum of humerus and head of radius
Elbow • Radiohumeral • Humeroulnar • Radioulnar
Elbow Muscle • Biceps brachii muscle: – attached to radial tuberosity – controls elbow motion Elbow Ligaments • Radial collateral • Annular • Ulnar collateral
Hand wrist The hand wrist comprise a number of different joint types: saddle, gliding and condyloid. Together, these joints give the hands & fingers a great deal of mobility
Wrist • Radiocarpal • Intercarpal • Carpalmetacarpal
Hand – Intermetacarpal – Metacarpalphalangeal – Interphalangeal
Hip joint: Coxal bone - femur
The Hip Joint • Also called coxal joint • Strong ball-and-socket diarthrosis • Wide range of motion
Structures of the Hip Joint • Head of femur fits into it • Socket of acetabulum • Which is extended by fibrocartilage acetabular labrum
Ligaments of the Hip Joint • • • Iliofemoral Pubofemoral Ischiofemoral Transverse acetabular Ligamentum teres
Sacroiliac joint
The Knee Joint Figure 9– 12 a, b
Articulations of the Knee Joint • 2 femur–tibia articulations: – at medial and lateral condyles – 1 between patella and patellar surface of femur
Menisci of the Knee • Medial and lateral menisci: – fibrocartilage pads – at femur–tibia articulations – cushion and stabilize joint – give lateral support
Locking Knees • Standing with legs straight: – “locks” knees by jamming lateral meniscus between tibia and femur
7 Ligaments of the Knee Joint • Patellar ligament (anterior) • 2 popliteal ligaments (posterior) • Anterior and posterior cruciate ligaments (inside joint capsule) • Tibial collateral ligament (medial) • Fibular collateral ligament (lateral)
TIBIOFEMORAL JOINT TIBIOFIBULAR JOINT
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