* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Bones, cartilage, joints, dislocations and fractures Costo = rib Chondro = cartilage Bone functions include support and protection of the body and vital organs, calcium metabolism, RBC formation and attachment Cartilage is less rigid and is located where mobility of the skeleton is required i.e. at joints All joins are compromising – i.e. there is compromise between stability and mobility ↑ Stability = ↓ mobility and vice versa All joint compromise profiles are different Fibrous joints: Syndesmoses: ~ mobility; ↑ stability; links bones with fibrous (e.g. interosseous) membranes e.g. proximal and distal tibiofibular syndesmosis with IOM Sutures: ↓ mobility; ↑ stability; sites of bone fusion e.g. the coronal and sagittal sutures of the skull bones Fontanelles: wide sutures of the neonatal skull, separated by fibrous membrane, divided into anterior, posterior and lateral; permit the sliding of bones over each (=moulding) other during birth, and therefore facilitating the passage of the neonatal skull through the birth canal (especially between the coccyx and pubic symphysis). Remain open until ~18 months with visible pulsation (absence of pulsation/sinking membrane upon dehydration due to reduced CSF) Cartilaginous joints: Primary: synchondroses Joined by hyaline (articular) cartilage Only present in growing long bones; ossified and fused after full growth Permit growth in length e.g. epiphyseal growth plate Secondary: symphyses Fibrocartilage Strong, ~ mobility e.g. intervertebral disc – contains outer annulus fibrosus (criss-crossing fibrous laminae of type I and II collage that ↑ stability) and inner nucleus pulposus (90 % water in neonates, decreases with age stiffness) which allows shock absorption. Each disc allows small movement in all directions, with the summation of these movements allowing for considerable movement of spine Both synchondroses and symphyses can slip: slipped femoral epiphysis and discs SYNCHONDROSIS PATHOLOGY: X RAY: normal epiphyseal growth plate slightly visible as a line dividing the epiphysis (head) and the metaphysis (neck) of the femur. Slippage of the epiphysis is characterized by increased EGP visibility and altered interrelation of epiphysis and metaphysis SYMPHYSIS PATHOLOGY: Disc herniation (e.g. into spinal cord) is painful and can damage the spinal cord, causing sensory or motor loss in areas innervated by the damaged fibres. Synovial joints: associated with 8 features: 1. Articulation of 2+ bones 2. Articular surfaces covered by hyaline cartilage 3. Surrounded by a capsule a. Superficial fibrous layer (strong) b. Deep synovial membrane ( synovial fluid) 4. Contain a joint cavity (filled with SF absorbing shock, nourishing and lubricating joint) 5. Supported by fibrous ligaments which ↑ stability and strength 6. Associated with skeletal muscle/fibrous tendons a. Tendons insert ONTO bones lying at EITHER SIDE of the joint i.e. tendon has to cross a joint in order to move it e.g. bicep contraction elbow joint flexion 7. Associated with bursae which prevent joint friction a. Either extensions of joint cavity or separate closed sacs (e.g. anterior to patella) 8. Other special features e.g. articular disc in TMJ joint 5 synovial joint subtypes: 1. Plane – minimal movement of flat surfaces in one plane a. e.g. acromioclavicular joint 2. UNIAXIAL flexion + extension or rotation a. Pivot – e.g. atlanto-axial joint b. Hinge - e.g. elbow joint 3. BIAXIAL - ~ mobility in 1 plane>other planes a. Saddle – e.g. carpometacarpal joint b. Condyloid – (flexion/extension + abduction/adduction + circumduction) e.g. metacarpophalangeal joint 4. Ball & socket – MULTIAXIAL mobility by fitting of rounded head into a concavity a. e.g. hip joint and shoulder joint (the former has a deeper socket and is therefore a tighter fit, more stable/less mobile and less prone to dislocation than the latter). Mobility: synovial>cartilaginous>fibrous Stability: fibrous>cartilaginous>synovial Hypermobility can be natural or pathological Range of movement (flexion/extension + abduction/adduction + internal/external rotation) of shoulder joint > hip joint Pathology: Ligament injurty/slipped disc with retention of articular surfaces in their normal anatomical interrelationship Subluxation: partial dislocation with reduced area of contact between articular surfaces Dislocation: complete loss of contact between articular surfaces Commonly: craniovertebral, TMJ, shoulder, elbow, acromioclavicular, hip, PIP/DIP, knee, pubic symphysis and ankle joints Temporomandibular joint (TMJ): Bilateral synovial articulation between mandibular fossa and the articular tubercle (eminence) of the temporal bone superiorly and the head of the condylar process of the mandible inferiorly Contains an articular disc Dislocation: head of condylar process of mandible displaces and becomes stuck anterior to the articular tubercle of the temporal bone Unilateral chin displaced to contralateral side Bilateral chin remains central Nerve and arterial supply to joints: High sensory nerve supply (pain, touch, temp, proprioception) Arterial supply – articular branches - from large arteries e.g. popliteal artery. Periarticular anastomoses common Dislocation can damage articular branches, causing loss of distal pulses which indicates compromised blood flow to areas distal to the joint (e.g. damage to popliteal branches can prevent perfusion to the foot necrosis amputation).