T3 L4. Principles of articulation (PB).pptx

204: Musculoskeletal and immune systems (Theme 3) Lecture 4. Dr Peter Bush [email protected] Gray’s Anatomy online: http://www.bartleby.com/107/70.html 204: Musculoskeletal and immune systems The principals of articulation: fibrous, cartilaginous, and synovial joints Dr Peter Bush p.g.bu...

204: Musculoskeletal and immune systems (Theme 3) Lecture 4. Dr Peter Bush [email protected] Gray’s Anatomy online: http://www.bartleby.com/107/70.html 204: Musculoskeletal and immune systems The principals of articulation: fibrous, cartilaginous, and synovial joints Dr Peter Bush [email protected] Gray’s Anatomy online: http://www.bartleby.com/107/70.html Definitions Articulation from Latin articulus meaning a joint Joint from Latin junctura meaning a joining Arthrosis from Greek meaning joint An articulation or joint or arthrosis is a point of contact between: neighbouring bones bone and cartilage bone and teeth Summary  Different types of joints classified by: - structure - function - movement  Example of ‘shoulder’ articulation: glenohumeral sternoclavicular acromioclavicular Summary  Different types of joints classified by: - structure - function - movement  Example of ‘shoulder’ articulation: glenohumeral sternoclavicular acromioclavicular Joint classification  Structural classification Presence or absence of a synovial cavity and the type of connective tissue. Described as either fibrous, cartilaginous, or synovial  Functional classification Based on the degree of movement permitted: Synarthrosis (immovable) Amphiarthrosis (partially moveable) Diarthrosis (freely moveable) Fibrous joints  No synovial cavity  Held together by a fibrous connective tissue  Permits little or no movement (synarthrosis/amphiarthrosis)  Three types of fibrous joint: 1. Suture 2. Syndesmosis 3. Interosseous membrane Fibrous joints - suture  Unite skull bones  Thin layer of dense connective tissue  Irregular  Interlocking edges provide strength, permit no movement (synarthrosis)  Ossification of a suture forms a synostosis e.g. left & right sides of frontal bone fuse ~6 years of age Fibrous joints - syndesmosis  More connective tissue than seen in a suture  Crosses a greater distance than a suture  Connective tissue typically arranged into bundles (ligament)  Typically permit slight movement (amphiarthrosis)  Examples: 1. Tibia 2. Fibula Anterior tibiofibular ligament gomphosis (or Dentoalveolar) Fibrous joints – Interosseous membranes  Sheet of dense connective tissue  Binds adjacent long bones  Amphiarthrosis  Two main examples between the radius and ulna in forearm, and tibia and fibula in the leg Tibia Fibula Interosseous membrane Cartilaginous joints  No synovial cavity  Held together by a fibrocartilage or hyaline cartilage  Permits little or no movement (synarthrosis/amphiarthrosis)  Two types of cartilaginous joint: 1. Synchrondosis 2. Symphysis Cartilaginous joints - synchrondosis  The connective tissue is hyaline cartilage  Synarthrosis  Example: epiphyseal plate (growth plate) Epiphysis Epiphyseal plates  At skeletal maturity the epiphysis, metaphysis and epiphyseal plate fuse forming a synostosis Cartilaginous joints - symphysis  Connective tissue is fibrocartilage  Adjacent bones lined with hyaline cartilage, but with a broad disc of fibrocartilage connects the bones  Amphiarthrosis  All symphysis occur in the midline of the body: Junction of the manubrium and sternum Intervertebral discs Pubic symphysis Synovial joints  Synovial (joint) cavity between articulating bones  Freely moveable - diarthrosis  Layer of hyaline cartilage called articular cartilage Synovial cavity Articular cartilage Synovial joint structure Articular cartilage  Covers the bones at synovial joints  Avascular  Composed of collagen and proteoglycan  Orientation of collagen structure imparts resistance to compression & an extremely low resistance surface Synovial joint structure Articular capsule  Encapsulates a synovial joint  Composed of two layers  Outer fibrous membrane connects to periosteum Flexibility permits movement Fibres arranged into bundles – high tensile strength  Inner layer termed synovial membrane areolar connective tissue rich in elastic fibres occasionally contains structural articular fat pads Synovial joint structure Synovial fluid  Secreted by synovial membrane  Rich in hyaluronic acid, secreted by fibroblast-like cells, and interstitial fluid from blood plasma  Lubricates articular surface – reducing friction  Provides some shock-absorbing properties  Supplies nutrition to, and removes waste products from the avascular articular cartilage  Phagocytes remove microbes and debris Synovial joint structure Accessory ligaments  Intracapsular ligaments lie within the joint capsule - Excluded from synovial fluid by folds in synovial membrane - e.g. anterior and posterior cruciate ligaments of the knee  Extracapsular ligaments lie outside the joint capsule - e.g. fibular and tibial collateral ligaments of the knee Synovial joint structure Accessory articular discs  Fibrocartilage pads lie between articular cartilage of some synovial joints e.g.meniscus of the knee  Called meniscii or articular discs  Help maintain joint stability  Direct the flow of synovial fluid  Meniscal tears (common in athletes) Synovial joint structure Nerve and blood supply  Nerve endings same as those that supply associated muscles  Distributed to the articular capsule and associated ligaments  Pain and proprioception  Many components of the synovial joint are avascular  Rely on numerous branching of arteries and veins to supply associated tissue Synovial joint structure Bursae and tendon sheaths  Moving parts of joints can cause friction  Bursae are fluid filled sacs lined with synovial like membrane  Bursae cushion movement between body parts  Tendon sheaths are similar to bursae  Specialised membranes that wrap around tendons  Especially where many tendons come together and/or pass through a synovial joint capsule Summary  Different types of joints classified by: - structure - function - movement  Example of ‘shoulder’ articulation: glenohumeral sternoclavicular acromioclavicular Types of synovial joints - movement  Planar  Hinge  Pivot  Condyloid  Saddle  Ball & Socket Types of synovial joints - planar  Surfaces flat or slightly curved  Permit back and forth, and side to side movements  Examples include: - intercarpal joints (between carpal bones at the wrist) - intertarsal joints (between tarsal bones at the ankle) Types of synovial joints - hinge  Concave surface of one bone fits the convex surface of another  Permits motion in a single axis (flexion and extension)  Examples include: - knee joints - elbow joints Types of synovial joints - pivot  Rounded or pointed surface of one bone pivots inside a ring formed by the other bone and a ligament  Permits rotation in it’s longitudinal axis (monoaxial)  Examples include: - radioulnar joints - atlanto-axial joint annular radial notch ligament radius ulna Types of synovial joints - pivot Types of synovial joints - condyloid  Convex oval projection of one bone fit into the oval depression of the other.  Permits movement around two axis (biaxial; flexion and extension, and abduction and adduction)  Examples include: - wrist joint - metacarpophalangeal joints Types of synovial joints - saddle  One bone fits into the saddle shaped bone it opposes  Modified condyloid joint  Permits movement around two axis (biaxial; flexion and extension, abduction and adduction, (sometimes limited rotation))  Examples include: trapezium - carpometacarpal joint metacarpal Types of synovial joints ball and socket  Ball-like surface of one bone fits into the cup-like depression of the other  Triaxial movement around three planes (triaxial; flexion and extension, abduction and adduction, and rotation)  Examples include: - shoulder joint - hip joint Summary  Different types of joints classified by: - structure - function - movement  Example of ‘shoulder’ articulation: glenohumeral sternoclavicular acromioclavicular Joint systems example  Interactions between humerus, scapula, clavicle, and sternum, allow wide ranging movement. The component joints include: acromioclavicular ar l u c lavi c o n ster glenohumeral Glenohumeral (shoulder) joint  Synovial ball and socket joint  Joint between the proximal humerus and the scapula (glenoid fossa)  Due to the shallowness of the glenoid cavity, it is the most mobile joint in the body  Glenoid labrum; a narrow rim of fibrocartilage – deepens glenoid Stabilised by three ligaments: glenohumeral coracohumeral transverse humeral Four associated bursae steadmanhawkins.com Glenohumeral joint – rotator cuff muscles  Most strength from rotator cuff muscles supraspinatus infraspinatus teres minor subscapularis  Join the scapula with the humerus  Encircle the joint and fuse with joint capsule steadmanhawkins.com Acromioclavicular joint  Technically a synovial gliding joint (planar) but it acts like a pivot  Joint between the acromion (part of the scapula) and the clavical Stabilised by three ligaments: acromioclavicular coracoacromial coracolclavicular (conoid and trapezoid) Allows the movement of the scapula, permitting greater arm rotation (above the head) Sternoclavicular joint  Synovial saddle joint  Medial clavicle fits into a hollow formed by the superlateral surface of the manubrium and the medial costal cartilage of the first rib.  Fibrocartilagenous articular disc divides the joint into two synovial cavities  Reinforced by interclavicular, anterior, and posterior sternoclavicular ligaments Although a saddle joint – is capable of triaxial movement – all movement is passive The end.