Y khoa, y dược - Chapter 8: The musculoskeletal system

Chapter 8The Musculoskeletal SystemMusculoskeletal SystemThe soft connective tissues of the musculoskeletal system comprises of:TendonsLigamentsCartilageFasciaAs well as muscles, bones and joints The Skeleton206 Bones form the framework of the adult skeleton.AXIAL skeleton – comprises the skull, vertebral column, ribs and sternum.Consists of 80 bones The SkeletonAPPENDICULAR skeletonSupports appendagesComprises of shoulder girdle- scapula, clavicle and upper limbs, and pelvic girdle,-the innominate bones and lower limbsConsists of 126 bonesFunctions of the skeletonProvides shape and support for bodyProvides framework for all structuresProvides levers that are essential for movementForms attachment points for muscles Provides protection for vital internal organsRed bone marrow within bones manufacture blood cellsStores minerals, calcium and phosphorusTypes of BoneBone is hardest connective tissue in the bodyTwo main types:Compact – outer layer of boneCancellous – Inner layer of boneClassification of Bones TypesLong e.g. HumerousShort e.g. cuboidFlat e.g. SternumIrregular e.g. Facial bonesSesamoid e.g. PatellaBone GrowthThe replacement of old bone with new bone is called remodelling.Osteoclasts and Osteoblasts are intrinsic to this process RemodellingCertain vitamins and minerals are essential for bone remodellingAny deficiency in these vitamins or minerals will have an effect on the healing process and the bone’s strengthHormonesThese contribute to normal bone tissue activity Predominant hormones are:Parathyroid Hormone (PTH)CalcitoninHuman Growth HormoneSex HormonesInsulinGlucocorticoidsOsteoporosisOsteoporosis is a condition of porus bones Occurs when resorption is quicker than bone depositionMostly seen in female population due to the fall in oestrogen levels after the menopauseTreatment is focused on prevention rather than cure. e.g. Adequate calcium intake and exercise earlier in lifeOsteoarthritisCan be limited to a single joint and triggered by localised wear and tearArticular cartilage begins to break down and become thinner and roughenedAreas normally affected are weight bearing jointsUnfortunately drugs cannot repair damaged bone, they can help to reduce inflammation and control painOsteomalaciaBones are weakened by the loss of calcium and phosphorusBone calcification fails and bones become soft and therefore are easily deformedIn children this is called ricketsPrimary cause is shortage of Vitamin DBrittle Bone syndromeInherited disorder and there are four typesMain clinical signs are very fragile and brittle bones that fracture frequentlyThe severity of the disease will dictate the prognosisEarly recognition is vital for correct management What is Paget’s disease? Is there a cure?Postural DeformitiesSpine has two natural curves, in the lumbar region and thoracic regionThere are three types of postural deformity:KyphosisScoliosisLordosisIdentify what these deformities look like and roughly draw them for your portfolioNow identify how they might affect an individualSpina BifidaCongenital defect of the vertebral column, in which the laminae fail to unite at the midlineCan cause partial or complete paralysis, absence of reflexes and occurs when there is protrusion of meninges around spinal cordEvidence that associated with low levels of folic acid, in pregnancyFracturesA fracture is described as a bone that has broken either due to injury or diseaseDifferent types of fractures:SimpleCompoundComminutedGreenstickBuckleImpactedSpiralDepressedCrushPathologicalComplications of FracturesInfectionDelayed UnionMal-unionNon-unionAvascular necrosisShorteningInjury to nerves or tendons or major blood vesselsFat embolismCompartment syndromeTrauma Scenario- Fracture Right Leg Mr Robert Smith, a 34-year-old is brought into the emergency department by ambulance. He was a motorcyclist, involved in a road traffic accident, where his vehicle skidded on ice and he lost control of the motorbike. When he fell to the ground, the motorbike fell onto his right leg and he was unable to get up, there was a possibility that he experienced a brief loss of consciousness, although he was wearing a crash helmet.The emergency department had received prior warning of his imminent arrival, so a trauma team were assembled awaiting his arrival. At the scene of the accident it was noted that there was obvious deformity to his right lower leg and the ambulance crew had realigned the leg, after morphine analgesia, and applied an immobilisation splint to the leg.Vital signs on arrivalAirway & C-Spine - Clear, patient is talking. AVPU = A. C-Spine is immobilised with hard cervical collar, sandbags and tape.Breathing Spontaneous, respiratory rate is 20 / minCirculation Pulse rate 110, regular, BP 110/70, Capillary refill <2secsDisability Patient Alert, GCS 15/15, Pupils equal and reactive to lightPMH NoneMedication None / Allergies ElastoplastScenario AnalysisDiscuss the scenario and the treatment required by Mr Smith.Whilst awaiting to be transferred, Mr Smith experiences severe pain in his right lower leg.What condition must be considered and how can it be treated?Treatment of FracturesMain principle of treating fractures is to immobilise them to allow the bone to remodel and repair itself so that function can be restored.Healing process depends on many factors including age of patient, extent of the fracture, and any predisposing medical problems.Developing & Delivering Expert CareClinical Signs Associated with Compartment SyndromeSevere painExtremely painful movements especially on passive extensionLimb may be coolPatchy pallor of limbSkin may look shiny, tense bulging muscleSensory deficitPulses might be present and gradually weaken NB: Necrosis can occur while pulses are presentAbsent pulses is a very late sign of compartment syndrome.Vigilance of a potentially affected limb has to be paramount.Important to note that vascular injury can only be identified in fully conscious patientsTypes of JointA joint is the place where two bones meet, there are three main types of joint within the skeletal system:Fixed (fibrous)Slightly movable (cartilaginous)Freely movable or synovial joints – 5 typesFreely Movable JointsBall and socketHinge jointGliding jointPivot jointSaddle jointRheumatoid ArthritisForm of arthritis that arises from the auto immune systemThe immune system attacks the body tissues, synovial membranes are attacked and they go on to degrade and malform the articular surfaces of the bonesGoutCondition caused by an excess of uric acid in the body, which is normally secreted in urineSubstance collects in the synovial fluid of a joint forming needle like crystals, can cause pain, swelling and redness in a jointInitial treatment will be with NSAID’s to reduce level of discomfort. To reduce risk in chronic phase, drug of choice is AllopurinolMuscular SystemIn order to create movement of the skeletal system, motion comes from the relaxation and contraction of muscles.3 types of muscular tissueSkeletalSmoothCardiacFunction of Skeletal Muscle5 main functionsContraction of muscles that produce movementPostural muscles maintain body in stable positionSkeletal muscle contraction helps to aid return of bleed to the heartAids temperature controlBoth muscles and tendons help to stabilise jointsStructure of Skeletal MuscleMuscle cells called fibres because of there cylindrical shape and long lengthMuscle cells appear striped due to actin and myosin filaments arrangementFibre is surrounded by a sarcolemma, which is the plasma membrane of a muscle cell that surrounds the sarcoplasm, the cytoplasm of a skeletal muscle cell How do Muscles Work?For muscles to move they need to be stimulated into action by a nerve impulseThis in turn causes the muscle to contract creating movementMotor nerves cause movement and break down into many nerve endings, each one stimulating a single muscle fibreMovementsThere are a number of movements that are created by muscles. It is important to have an understanding of the terminology used to describe movements as it can make it easier to documentFlexion Extension AbductionAdduction InversionEversion RotationSupination Pronation Dorsiflexion PlantarflexionOpposition Guillan Barre SyndromeCan occur one to three weeks following an initial infectionCause of Guillan Barre often identified as the Campylobacter infectionPatient may complain of muscle weakness and numbness in distal limbs. Gradually this ascends over several days or weeksTreatment depends on the severity of the conditionSome patients may require ventilationRecovery can be complete or incompleteAbnormal Contractions of Skeletal MuscleCrampStrainMyositisLigamentsThese are dense bundles of collagenous fibres that run in parallel lines. Their function is to connect bone to boneLigaments contain numerous sensory nerve cells, that are capable of responding to speed, movement and position of a joint, as well as to stretching and painWhen damaged, ligaments can become extremely painful and do not repair quickly due to limited blood supply Function of LigamentsChiefly to strengthen and stabilise the joint in a passive wayThey are different to muscles as they cannot actively contract, nor stretch. Although there are a few exceptions to this, with ligaments that contain a high proportion of yellow elastic fibresScenarioMelanie Devis, 45-year-old lady attends the emergency department following a fall in the garden 2 hours ago.On arrival to the emergency department she appears in a lot of pain and is protectively holding her left arm. She states that she took 400mg of Ibuprofen prior to attending the emergency dept but it has not made any difference to the level of pain she is experiencing O/E The left shoulder appears deformed compared to the right sideThere is no apparent swelling although evidence of some bruising is beginning to show. There is a superficial graze over the shoulder region.Scenario Analysis & ExerciseDistal pulses are present in the brachial region. There is tenderness over the whole shoulder and it is difficult to differentiate where the point of maximum tenderness is. Sensation and perfusion appear normal. There is no parasthesia over the upper left arm (known as the artillery badge sign, which is associated with problems with the axillary nerve) It is difficult to assess the range of movement, due to pain and the deformity to shoulderX-ray- Shows an anterior dislocation of the left shoulder What treatment does this patient require?What important information needs to be conveyed to the patient prior to discharge?Shoulder Dislocations2 Types of shoulder dislocation, anterior and posterior.Anterior – Relatively common occurrence.Common mechanism of injury is a patient who has fallen onto an outstretched arm.There is risk of injury to the axillary nerve.Shoulder DislocationsPosterior dislocation – Less common with displacement of the head of the humerous backwardsMechanism of injury can include fall, or direct blow to the shoulder. Can occur in epileptics during a seizure, or in patients who have been jolted following an electric shock In both cases there is a loss of range of movement and risk of recurrence is high. TreatmentPrompt diagnosis needs to be made after a thorough assessmentDiagnosis often made from the clinical picture but needs to be confirmed by X-rayDislocation then needs to be reduced, following local protocol and methodsArm needs to be supported after dislocation reduced and re X-rayed. SprainsInjuries in the neighbourhood of joints consist usually in the tearing of a ligament, often accompanied by a muscle tear. This results in pain and swellingTreatment is to try and restore function as quickly as possible. Rest, Ice, Compression and Elevation are usually recommendedHealth Education is vitally important on care of the ankle following an injury to prevent recurrence CartilageCartilage consists of a dense network of collagen fibres and elastic fibres, these form a tough, firm tissue Cartilage is able to endure more stress than some other connective tissues There are three types of cartilageFasciaFascia made from white, fibrous dense connective tissue and can be found in all parts of the body.Fascia has different names depending on the structure that it surrounds. Epimysium- surrounds whole musclePerimysium- surrounds bundles/ fascicles of fibresEndomysium – surround the muscle fibres / cells Superficial FasciaThis is a continuous sheet of fibrous connective tissue and is found between the dermis of the skin and the deep fascia of the muscle.It is also called the subcutaneous layer.It’s function is to help skin move over underlying structuresAlso a passageway for nerves, blood vessels and lymph vessels.Helps to conserve body heat.Deep FasciaThis is a sheet of dense connective tissue that is wrapped around a muscle, forming an inelastic sheath to hold it in place.It’s function to to help assist muscle action through the tension and pressure it provides.Also provides a broad surface for muscle attachment.TendonsThese are formed from muscle and fascia combining together and extending beyond the end of muscle into flat bands or round cords.They are very strong, they have poor blood supply very few nerves.Made from white fibrous dense connective tissue.Function is to connect muscle to bone via the periosteum Injuries to Tendons2 main types of injuries occur to tendonsRupture / DivisionTear – This occurs when they are stretched to 5% or more beyond their normal length (Purcell 2004)Achilles Tendon RuptureSecond most ruptured tendon in the body. Occurs when there is sudden plantarflexion of the foot.Treatment is either through surgical or conservative management. In both methods the objective is enable the tendon ends to reunite by approximating them and holding in position to encourage healing. ConclusionThis presentation has explored the various components that comprise the Musculoskeletal system. The Musculoskeletal system consists of many different aspects, it is important to have a solid understanding of all elements in order to deliver expert carePatients can present with both acute and chronic complaints, commonly patients present due to pain. In practice patients may have more than one problem to the Musculoskeletal system that needs to be addressed. For treatment of complaints further information can be obtained from minor injury textbooks.