Transcription
Introduction toOrthopedic AnatomyTraumatologyRHS 231Dr. Einas Al-EisaLecture 2
Types of JointsSynovialDiarthroidalFreely movableCartilagenousAmphiarthroidalSlightly movableFibrousSynarthroidalImmovable
Fibrous(Synarthroidal) Immovable joints
Synchodroses Fibrocatilagenous joint thatallows very slight movement
Fibrocartilagenous joint
Syndesmosis bones held together by strongligaments that allow minimal movementInferior tibiofibular joint
Synovial joint
Characteristics of Synovial Joints Articular end plate a thin layer ofcompact bone over the spongy bone(covering the ends of the bones)Covered by: Articular (hyaline) cartilage for shockabsorption, stability, improved fit for thesurfaces, lubrication
Characteristics of Synovial Joints Joint capsule a fibrous connectivetissue that surround the bony ends formingthe jointLined with: Synovial membrane loose,vascularized connective tissue thatsecretes synovial fluid into the joint cavityfor lubrication
Synovial joint
Characteristics of Synovial Joints Where additional support is needed, thejoint capsule is thickened to form tough,non-elastic ligaments to provideadditional support. Stability of a synovial joint is provided by:the capsule, ligaments, muscles & tendonsspanning the joint, and the congruency ofthe bone surfaces.
Types of synovial joints1) Plane (gliding) joint: consists of two flatsurfaces that glide over each other.Example: carpals & tarsals
Plane (gliding) Joint
Types of synovial joints2) Hinge joint: allow movement in oneplane (flexion / extension).Example: interphalangeal joints (hand),ulnohumeral joint (elbow)
Hinge Joint
Types of synovial joints3) Pivot Joint: allows a rotational movementaround a long axis.Example: superior & inferior radioulnar joint(pronation / supination), atlantoaxial jointat the base of the skull (rotation)
Pivot Joint
Types of synovial joints4) Condyloid joint: allows movement in twoplanes (flexion / extension and abduction/adduction) without rotation.Example: metacarpophalangeal joints
Condyloid Joint
Types of synovial joints5) Saddle joint: allows two planes ofmovement (flexion / extension, abduction /adduction).Example: only found at the carpometacarpaljoint of the thumb.
Saddle Joint
Types of synovial joints6) Ball-and-socket joint: allows movementin all three planes (flexion/extension,abduction/adduction, & rotation)Example: the hip and shoulder joints.
Ball-and-socket Joint
Architecture of bone(osseous tissue)1. Cortical (compact) bone:– the exterior dense layer of the bone– consists of hollow tubes called lamellae(collagen fibers that are arranged in layersand run in different directions)– A series of lamellae form an osteon orhaversian system (weight-bearing pillars)– Provides strength for weight bearing &stiffness in response to muscle tension
Osteon
Architecture of bone(osseous tissue)2. Cancellous (spongy) bone :– interior to cortical bone– consists of flat pieces of bone calledtrabeculae (collagen runs along the axis ofthe trabeculae)– Provides energy absorption & stressdistribution in response to loads– Not as strong as cortical bone (risk offracture in the elderly)
Types of Bones
Long Bones
Long Bones Consist of a shaft called diaphysis (madeof compact bone), which broadens out intothe epiphysis (made up of spongy boneinside a thin layer of compact bone) Offer support and leverage Example: humerus, radius, ulna, femur,tibia, fibula, metacarpals, metatarsals
Flat Bones
Flat Bones Consist of two layers of compact bone withspongy bone in between Protect internal structures and offer broadsurfaces for muscle attachments Example: ribs, illium, sternum, scapula
Short Bones Consist of spongy bone covered with athin layer of compact bone Play an important role in shock absorptionand transmission of forces Example: carpals of the hand and thetarsals of the foot
Irregular Bones Consist of spongy bone and thin exteriorlayer of compact bone Specialized functions such as supportingthe weight, protecting the spinal cord,dissipating loads Example: vertebrae, ischium, pubis
Sesamoid Bones Short type of bone embedded in a tendonor joint capsule Alter the angle of muscle insertion toincrease its mechanical advantage Example: the patella embedded in thequadriceps tendon, sesamoid bones withinthe flexor tendons of the great toe & thumb
Accessory ossicles Occur as variants of normal (only in fewindividuals, in addition to the normalbones). Can be mistaken as fractures, but areharmless. Example: the os trigonum behind the talus,the accessory navicular.
Growth of bone Long bones grow from the epiphyseal plate(growth plate) at each end. Both ends grow, but generally one end will growfaster than the other. Example: distal epiphysis of the femur &proximal epiphysis of the tibia contribute roughly60% of limb length, but proximal epiphysis of thehumerus contribute 80% of humeral length.
Muscles Agonists and antagonists oppose eachother, but still work as balanced groups. Muscles are contained within FascialCompartments. Swellingcompartment pressureischaemic pain
Forearm compartments Ventral compartment:¾median & ulnar nerves¾Radial & ulnar arteries Dorsal compartment:¾Less common and less serious¾Posterior interosseous nerve
Lower limb compartments Anterior (tibial) compartment:¾Deep peroneal nerve¾Anterior tibial artery Lateral (peroneal) compartment:¾Superficial peroneal nerve¾Rarely affected by compression
Lower limb compartments Superficial posterior compartment:¾Gastrocnemius & soleus muscles¾No important nerves or vessels Deep posterior compartment:¾Posterior tibial vessels and nerves¾Peroneal artery¾Serious consequences if damaged
Tendons Muscle action depends on the direction ofits tendon. Tendons do not tolerate frictionprotected by bursae or synovial sheets
NervesRoot lesionsPeripheral nerves(e.g., disc prolapse,spinal injury)(e.g., ulnar neuritis,median nerve compression)
Vulnerable peripheral nervesUpper limb Median nerve¾Most common: compression at the wrist(carpal tunnel)¾Fluid retention in pregnancy¾Repetitive movement (flexor tenosynovitis)¾Sensory distribution: thumb, index, andmiddle fingers, half the ring finger
Vulnerable peripheral nervesUpper limb Ulnar nerve:¾Most common: irritation at the elbow¾Sensory distribution: little finger & ulnar half ofthe ring finger Radial nerve:¾Vulnerable in the medial side of the upper arm(e.g., axillary crutches)¾Drop wrist (few sensory symptoms)
Vulnerable peripheral nervesLower limb Sciatic nerve:¾Posterior dislocation of the hip Common peroneal nerve:¾Trauma causing lesion as the nerve crossesthe neck of fibula Lumbar nerve roots¾Prolapsed intervertebral discs
Characteristics of Synovial Joints Articular end plate a thin layer of compact bone over the spongy bone (covering the ends of the bones) Articular (hyaline) cartilage for shock absorption, stability, improved fit for theFile Size: 2MBPage Count: 55
