Joints 1 PDF

2) Formation of part of urinary bladder Coronal (frontal) plane Horizontal plane Median (sagittal) plane 1) Median (sagittal) plane; vertical plane that passes in the midline of the body, dividing the body longitudinally into right and left equal halves 2) Paramedian (parasagittal) plan...

2) Formation of part of urinary bladder Coronal (frontal) plane Horizontal plane Median (sagittal) plane 1) Median (sagittal) plane; vertical plane that passes in the midline of the body, dividing the body longitudinally into right and left equal halves 2) Paramedian (parasagittal) plane; vertical plane parallel to the median plane, dividing the body into right and left unequal parts 3) Coronal (frontal) plane; vertical plane that passes at right angle to the median plane, dividing the body into anterior and posterior parts 4) Horizontal (transverse) plane; plane that passes at right angle to the median and coronal planes, dividing the body into upper (superior) and lower (inferior) parts Frontal Sagittal Horizontal Paramedian (coronal) plane (median) plane (transverse) plane (parasagittal) plane Sagittarius Corona (crown) Definition: a joint is the meeting of 2 bones or more, meeting of 2 cartilages or more, or meeting of bone and cartilage  Classification of Joints Fibrous Joints: the bones are connected by dense fibrous tissue that allows no movement (fixed immobile joint) Sutures Gomphosis Syndesmosis Present in the skull Present in the jaws Present in the inferior tibio-fibular joint Bones of skull are connected by a Root of the tooth is connected to Lower ends of tibia and fibula are thin layer of dense fibrous tissue the socket in mandible and connected together by dense called “sutural ligament” maxilla by dense fibrous tissue fibrous tissue called (obliterates in old age) called “periodontal ligament” “interosseous ligament” Gomphosis Periodontal ligament  Cartilaginous Joints : the bones are connected by cartilaginous tissue Primary cartilaginous joint Secondary cartilaginous joint Bones are connected by hyaline cartilage that Bones are connected by white fibrocartilage disappears in adulthood by ossification, so it that does not ossify with age, so it is a is a temporary joint permanent joint It allows no movement (immobile joint) It allows slight movement (limited mobility) Example; epiphyseal plate between epiphysis Example; inter-vertebral discs and symphysis and diaphysis of long bones in children pubis (joints in the midline) Epiphyseal plate Inter-vertebral disc Symphysis pubis  Synovial Joints: they are the most freely mobile joints, found mainly in the limbs Characteristics (structure): 1) Fibrous capsule; the joint has a cavity that is surrounded by a strong fibrous capsule, which is supported by strong ligaments 2) Articular cartilage; articular surfaces are covered by thin plates of hyaline cartilage (not visible in X-ray); Smooth and lubricated by synovial fluid Has no blood vessels or nerves Receives its nutrition from synovial fluid In old age it shows erosions without repair 3) Joint cavity; it is a potential cavity that contains very thin film of synovial fluid 4) Synovial membrane; it is a thin moist membrane that lines the capsule and covers all structures inside the joint except the articular surfaces, and secretes and absorbs synovial fluid 5) Synovial fluid; it is a pale yellow viscous fluid, having the following functions; a) Lubrication of articular cartilage b) Nutrition of articular cartilage c) Shock absorption (non-Newtonian fluid that condenses under pressure)  Articular disc of temporo-mandibular joint 6) Ligaments; the joint is supported by extra- capsular and intra-capsular ligaments 7) Structures that may be present inside the joint cavity; a) Articular disc; a disc of fibrocartilage that divides joint cavity into 2 compartments, e.g. temporo-mandibular joint b) Menisci (semilunar cartilages); inside knee joint c) Ligaments; e.g. cruciate ligament inside knee joint Cruciate ligament d) Tendon; e.g. long head of biceps inside shoulder joint Cruciate ligament Menisci of knee joint Long head of biceps Long head of biceps Long head of biceps Characters: Intra-articular structures: Some joints may contain: a) Articular disc b) Menisci c) Ligaments d) Tendons  Types and Varieties of Synovial Joints (According to axis of movement and shape of articular surfaces) [A] Non-axial (plane) Joints: the articular surfaces are flat (plane), allowing gliding movement e.g. superior tibio-fibular joint, intervertebral joints, inter-carpal and inter-tarsal joints Superior tibio-fibular joint Intervertebral joints B. Axial Joints: (1) Uni-axial Joints: move around single axis Hinge joint Pivot joint Moves around transverse axis, Moves around longitudinal axis, allowing allowing flexion & extension rotation Articular surface is trochlea-like in shape Articular surface is a central pivot surrounded by Example; elbow and ankle joints fibro-osseous ring Example; superior radio-ulnar joint (2) Bi-axial Joints: move around two axes perpendicular to each other a) Condylar or bicondylar joint: Two convex surfaces (condyles) articulate with two concave surfaces, e.g. knee joint One convex surface (condyle) articulates with one concave surface, e.g. temporo-mandibular joint Bicondylar joint Condylar joint b) Ellipsoid joint: one oval convex surface articulates with one oval concave surface, e.g. wrist joint c) Saddle joint: articular surfaces are concavo-convex, e.g. carpo-metacarpal joint of thumb, and sterno- clavicular joint (3) Multi-axial Joints: move around the 3 axes, allowing flexion, extension, adduction, abduction, medial rotation and lateral rotation Ball and socket joint: globular or spherical surface (ball) articulates with a concave surface (socket), e.g. shoulder and hip joints (this type is the most freely mobile joint in the body) Factors affecting stability of the joints 1) Shape and fitting of articular surfaces 2) Thickness and elasticity of the capsule 3) Position and strength of ligaments 4) Strength of muscles around the joint Shoulder joint Hip joint  Self-assessment A bone found embedded within the tendon of a skeletal muscle is considered as: A. Pneumatic bone B. Irregular bone C. Sesamoid bone D. Irregular bone The most freely mobile type of joints in the body is: A. Fibrous joint B. Primary cartilaginous joint C. Secondary cartilaginous joint D. Synovial joint The epiphyseal plate of a long bone is considered as: A. Fibrous joint B. Primary cartilaginous joint C. Secondary cartilaginous joint D. Synovial joint A synovial joint that rotates around a single vertical axis is described as: A. Hinge joint B. Plane joint C. Ellipsoid joint D. Pivot joint A synovial joint thatallows flexion and extension around a single horizontal axis is described as: A. Hinge joint B. Plane joint C. Ellipsoid joint D. Pivot joint The synovial joint variety that has the widest range of movement is: A. Hinge joint B. Saddle joint C. Ball and socket joint D. Condylar joint