E1 S1 (Lectures 1-6) PDF

1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf E1 S1 (Lectures 1-6).pdf Bone Development Description: The process of bone formation, which occurs through tw o main pathways: endochondra...

1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf E1 S1 (Lectures 1-6).pdf Bone Development Description: The process of bone formation, which occurs through tw o main pathways: endochondral ossification and membranous ossific ation. Key Points: Endochondral Ossification: Cartilage is replaced by bone. This is th e primary method for long bone development (e.g., tibia, femur). Diaphysis: The primary ossification center, forming during fetal de velopment. Epiphysis: The secondary ossification center, forming after birth. Sclerotomes: The mesenchymal cells that give rise to the vertebral column and contribute to bone development. Membranous Ossification: Mesenchyme directly differentiates into bone. This is the process for flat bone development (e.g., skull bone s). Wolff's Law Description: A principle that describes how mechanical stress influen ces bone growth and remodeling. Key Points: Mechanical Stress: Bone adapts to the forces placed upon it. Long Bones: Thinner shafts compared to cancellous/head areas. G rowth occurs only when compression is applied. Stunted Growth: Children with developmental disorders (e.g., Cere bral Palsy, Spina Bifida) may experience stunted bone growth due t o reduced stress. Calcium Levels: Increased stress leads to increased calcium deposi tion in bone. Osteopenia: After age 30, calcium levels naturally decline, leading t o a decrease in bone density. Osteoporosis: Most likely to occur in individuals who are sedentary, i nactive, or wheelchair-bound. Immobilization: Can lead to joint contracture (stiffening of joints). Fetal Development: Movement of the fetus is crucial for joint develo pment in utero. about:blank 1/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Bone Pathology Description: Conditions that affect bone health and development. Key Points: Rickets/Osteomalacia: Poor mineralization of bone, leading to weak bones. Osgood-Schlatter Disease: Overgrowth of bone at the tendon attac hment site, often due to repetitive stress. Spondylolysis: A fracture through the pars interarticularis (a portion of the vertebral arch). Spondylolisthesis: A "step-off" deformity where one vertebra slips fo rward on the vertebra below. Often associated with spondylolysis an d seen in athletes like gymnasts. Arthrogryposis Multiplex Congenita: A rare, autosomal recessive c ondition characterized by fused joints. Fracture Healing Description: The process by which a fractured bone repairs itself. Key Points: Primary Bone Healing: Occurs when the fracture is stable and mini mally displaced. Stages: 1. Hematoma Formation: Blood clots form at the fracture site. 2. Soft Callus Formation: Fibrocartilage and collagen fibers bridge t he fracture gap. 3. Hard Callus Formation: The soft callus is replaced by woven bon e. 4. Remodeling: The woven bone is remodeled into lamellar bone, re sembling the original bone structure. This process can take up to two years. Cox-2: An enzyme involved in the inflammatory response and bon e healing. Secondary Bone Healing: Occurs when the fracture is unstable or di splaced. Closed Reduction: A procedure to realign the fracture fragments w ithout surgery. Open Reduction and Internal Fixation (ORIF): A surgical procedure to realign and stabilize the fracture with implants. Malunion: The fracture heals in an improper alignment. Delayed Union: The fracture takes longer than expected to heal. Nonunion: The fracture fails to heal completely. about:blank 2/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Skeletal Muscle Fiber Types Description: Different types of muscle fibers with varying characteristi cs and functions. Key Points: Type I (Slow Twitch): Low power output, fatigue resistant, high mitoc hondrial content, oxidative phosphorylation. Examples: Postural muscles, soleus (calf muscle), finger flexors. Type IIA (Fast Twitch): Intermediate between Type I and Type IIB. Type IIB (Fast Twitch): High power output, glycolytic metabolism, ea sily fatigued. Examples: Gastrocnemius (calf muscle), finger extensors. Motor Units Description: The functional unit of muscle contraction, consisting of a motor neuron and all the muscle fibers it innervates. Key Points: Motor Unit: One alpha motor neuron and all the muscle fibers it inne rvates. Muscle Fiber Type: All muscle fibers within a motor unit are the sa me type (e.g., slow twitch, fast twitch). Size: Smaller Motor Units: Fewer muscle fibers, smaller motoneuron, fi ne movements (e.g., eye muscles). Larger Motor Units: More muscle fibers, larger motoneuron, gross movements (e.g., lumbricals). Recruitment: Motor units are recruited based on size, with the small est units recruited first and the largest units recruited last. Poliomyelitis Description: A viral infection that can damage alpha motor neurons, l eading to muscle weakness and paralysis. Key Points: Alpha Motor Neuron Death: The virus destroys alpha motor neurons. Initial Function: Individuals may initially function normally, but as th ey age, the surviving motor neurons may not be able to maintain m etabolic activity to innervate the extra muscle fibers. Post-Polio Syndrome: A condition that develops years after polio, c haracterized by muscle weakness, fatigue, and pain. Axon Degeneration: Axons to extra muscle fibers die, causing mus cle weakness. about:blank 3/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Muscle Force Generation Description: Factors that influence the force a muscle can generate. Key Points: Cross-Sectional Area: The larger the cross-sectional area of a mus cle, the greater the force it can generate. Myoarchitecture: The arrangement of muscle fibers. Pennation Patterns: The angle of muscle fibers relative to the tend on. Sex: Men generally have higher muscle mass than women. Age: Muscle mass declines with age (sarcopenia). Muscle Contraction Types/Roles Description: Different types of muscle contractions and their roles in movement. Key Points: Agonist: The primary muscle responsible for a movement. Antagonist: The muscle that opposes the agonist. Co-Contraction: Simultaneous contraction of both agonist and ant agonist to stabilize a joint. Synergist: Muscles that assist the agonist in performing a movemen t or two muscles contracting together to perform a movement that neither can perform alone. Substitution: The use of a muscle to carry out a movement when it i s not normally the prime mover. Factors Affecting Muscle Function Description: Factors that influence muscle function and performance. Key Points: Single Joint vs. Multi-Joint Muscles: Single Joint Muscles: Primarily responsible for movements at a sin gle joint. Multi-Joint Muscles: Control or perform complex movements invol ving multiple joints. Length-Tension Curve: A muscle generates the greatest tension wh en it is at its optimal length. Passive Insufficiency: A multi-joint muscle is stretched from both e nds, limiting the range of motion at each joint. Active Insufficiency: A multi-joint muscle is contracted from both e nds, limiting the range of motion at each joint. about:blank 4/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Muscle Responses to Changes in Ac tivity Description: How muscle adapts to changes in activity levels. Key Points: Initial Response: Gains of Strength: Neural Factors: Increased recruitment and rate of firing of motor units. Increased synchronization of motor units. Increased activation of agonists. Decreased activation of antagonists. Improved coordination of motor units and muscles involved. Losses of Strength: Neural Factors: Decreased activity, mobilization, or atrophy. Delayed Response: Gains of Strength: Hypertrophy of Muscle Fibers: Increased synthesis of contractile proteins. Increased density of capillary beds. Losses of Strength: Muscle Atrophy: A decrease in muscle mass. Muscle Contracture: A shortening and stiffening of muscle, often due to immobilization. Peripheral Nerves Description: Nerves that transmit signals from the central nervous sys tem to the periphery. Key Points: Peripheral Nerve Injuries: Neurapraxia: A temporary loss of nerve conduction at the site of in jury. The nerve is still intact, but conduction is disrupted. Axonotmesis: A more severe injury where the axon is damaged, b ut the nerve sheath remains intact. Wallerian degeneration occurs distal to the injury site. Neurotmesis: A complete severance of the nerve. Wallerian degen eration occurs in the distal segment. Wallerian Degeneration: The degeneration of the axon and Schwan n cells distal to a nerve injury. about:blank 5/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Energy Expenditure in Orthopedic I mpairments Description: The increased energy cost of walking with orthopedic im pairments. Key Points: Decreased Gait Efficiency: Impairments can lead to less efficient wa lking patterns. Increased Oxygen Cost: The body requires more oxygen to maintai n a certain walking speed. Increased Heart Rate: The heart works harder to compensate for th e increased energy demands. Amputation Level: The higher the level of amputation, the greater th e oxygen cost and the slower the walking speed. Effects of Aging on the MSK System Description: The changes that occur in the musculoskeletal system w ith age. Key Points: Sarcopenia: Loss of muscle mass. Osteoporosis: Decreased bone density. Joint Stiffness: Reduced range of motion. Decreased Strength and Endurance: Reduced muscle strength and ability to perform physical activities. Clinical Anatomy Review Description: A review of clinically relevant anatomical structures and their relationships. Key Points: Glenohumeral Joint: The joint between the humerus (upper arm bo ne) and the glenoid fossa (socket of the scapula). Reinforcing Ligaments: Coracohumeral ligament and glenohumer al ligaments. SITS Muscles: The rotator cuff muscles: supraspinatus, infraspinatus, teres minor, and subscapularis. Erb Palsy: A type of brachial plexus injury that affects the nerves sup plying the shoulder and arm. Suprascapular Nerve Injury: Can cause weakness in the supraspin atus and infraspinatus muscles. about:blank 6/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Radial Nerve Injury: Can occur due to a midshaft fracture of the hu merus. Leads to loss of wrist and finger extension and weakness in s upination. Ulnar Nerve Injury: Can occur at the cubital tunnel (elbow). Leads to weakness in finger flexion of the 4th and 5th fingers, wrist flexion, an d loss of interossei and hypothenar eminence muscles. Median Nerve Injury: Can occur within the carpal tunnel. Leads to se nsory innervation deficits in the "money distribution" area of the han d. Femoral Head Blood Supply: The blood supply to the femoral head i s important for its health. Femoral Triangle: A region in the thigh that contains the femoral art ery, vein, and nerve. ACL vs. MCL: The anterior cruciate ligament (ACL) and medial collat eral ligament (MCL) are important ligaments in the knee. Common Fibular Nerve vs. Tibial Nerve: The common fibular nerve and tibial nerve are the two main branches of the sciatic nerve. Upper Extremity - Shoulder Description: The anatomy and function of the shoulder joint. Key Points: Glenohumeral Joint: A ball-and-socket joint that allows for a wide r ange of motion. Rotator Cuff Muscles: The SITS muscles, which help to stabilize the s houlder joint and control movement. Scapulothoracic Joint: The articulation between the scapula and th e thoracic cage. Acromioclavicular Joint: The joint between the acromion process of the scapula and the clavicle. Erb-Duchenne Palsy Description: A type of brachial plexus injury that affects the nerves su pplying the shoulder and arm. Key Points: Nerve Injury: Injury to the upper trunk of the brachial plexus, typicall y caused by traction or stretching. Presentation: Characterized by a "waiter's tip" deformity, with the ar m adducted, internally rotated, and the forearm pronated. Suprascapular Nerve about:blank 7/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Description: A nerve that supplies the supraspinatus and infraspinatu s muscles. Key Points: Injury: Can be injured due to compression or trauma. Presentation: Weakness in shoulder abduction and external rotatio n. Radial vs. Ulnar vs. Median Nerve Description: The three main nerves of the forearm and hand, each wit h distinct functions. Key Points: Radial Nerve: Supplies the extensor muscles of the wrist and fingers. Injury: Can be damaged by a midshaft fracture of the humerus. Presentation: Loss of wrist and finger extension, weakness in supin ation. Ulnar Nerve: Supplies the flexor muscles of the 4th and 5th fingers, t he intrinsic muscles of the hand, and the sensory innervation of the li ttle finger and half of the ring finger. Injury: Can occur at the cubital tunnel (elbow). Presentation: Weakness in finger flexion of the 4th and 5th fingers, wrist flexion, loss of interossei and hypothenar eminence muscles. Median Nerve: Supplies the flexor muscles of the wrist and fingers (e xcept the little finger), the thenar muscles, and the sensory innervati on of the thumb, index finger, middle finger, and half of the ring finge r. Injury: Can occur within the carpal tunnel. Presentation: Sensory innervation deficits in the "money distributio n" area of the hand. Lower Extremity Description: The anatomy and function of the lower extremity. Key Points: Hip Joint: A ball-and-socket joint that allows for a wide range of mo tion. Knee Joint: A hinge joint that allows for flexion and extension. Ankle Joint: A hinge joint that allows for dorsiflexion and plantarflexi on. Foot: Composed of the tarsals, metatarsals, and phalanges. Dermatomes Description: Areas of skin innervated by a specific spinal nerve root. about:blank 8/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Key Points: Sensory Innervation: Each spinal nerve root supplies a specific area of skin. Clinical Significance: Dermatome mapping can help to identify the level of a spinal nerve injury. Imaging of the MSK System Description: Different imaging modalities used to evaluate the muscu loskeletal system. Key Points: Radiography (X-Ray): Uses ionizing radiation to produce images of bones and some soft tissues. Advantages: Widely available, relatively inexpensive, good for visu alizing bone structures. Disadvantages: Limited soft tissue detail, ionizing radiation exposu re. Indications: Fractures, dislocations, arthritis, bone tumors. Computed Tomography (CT): Uses X-rays to create cross-sectional images of the body. Advantages: Excellent detail of bone and soft tissues, can be used to create 3D reconstructions. Disadvantages: Higher radiation exposure than X-ray, not as good for visualizing soft tissues as MRI. Indications: Complex fractures, spinal stenosis, tumors, infections. Magnetic Resonance Imaging (MRI): Uses a strong magnetic field a nd radio waves to create detailed images of soft tissues and bones. Advantages: Excellent soft tissue detail, no ionizing radiation expos ure. Disadvantages: Expensive, can be time-consuming, contraindicat ed in patients with certain implants (e.g., pacemakers, cochlear im plants). Indications: Ligament and tendon injuries, muscle tears, nerve entr apment, tumors, spinal cord injuries. Ultrasound: Uses sound waves to create images of soft tissues and bones. Advantages: No ionizing radiation exposure, relatively inexpensive, portable, can be used to guide procedures (e.g., injections). Disadvantages: Limited depth of penetration, operator-dependen t. Indications: Tendonitis, bursitis, muscle strains, nerve entrapment, fluid collections. about:blank 9/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Nuclear Medicine: Uses radioactive tracers to create images of met abolic activity in the body. Advantages: Can detect early changes in bone metabolism, can be used to evaluate bone tumors and infections. Disadvantages: Uses ionizing radiation, not as detailed as other im aging modalities. Indications: Bone tumors, infections, stress fractures. X-Ray Densities Description: The different densities of tissues that can be visualized o n radiographs. Key Points: Air: The least dense, appears black on radiographs. Fat: Slightly denser than air, appears dark gray on radiographs. Water: Denser than fat, appears gray on radiographs. Bone: Denser than water, appears white on radiographs. Metal: The most dense, appears very white on radiographs. Ultrasound Frequencies Description: The relationship between ultrasound frequency and ima ge resolution. Key Points: Low Frequency: Penetrates deeper tissues but has poorer resolution. High Frequency: Penetrates shallower tissues but has better resoluti on. Congenital Deformities of the Spine and Scoliosis Description: Congenital deformities of the spine, including scoliosis, lo rdosis, and kyphosis. Key Points: Scoliosis: A lateral curvature of the spine. Normal Spinal Curvatures: The spine has natural curves, including kyphosis (thoracic curve) and lordosis (lumbar curve). Idiopathic Scoliosis: The most common type, with no known caus e. Pathologic Scoliosis: Caused by an underlying condition, such as a tumor or infection. Treatment: Conservative: Observation, physical therapy exercises. about:blank 10/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Bracing: For moderate curves (20-45 degrees). Surgery: For severe curves (>45 degrees). Klippel-Feil Syndrome: A rare condition characterized by fusion of t wo or more cervical vertebrae. Triad: Low posterior hairline. Short, webbed neck. Limited cervical range of motion. Associations: Scoliosis, winged scapula, genitourinary abnormaliti es. VACTERL Syndrome: A rare condition characterized by a combinatio n of birth defects. Components: V: Vertebral anomalies. A: Anal atresia. C: Cardiac defects. T: Tracheo-esophageal fistula. E: Esophageal atresia. R: Renal abnormalities. L: Limb abnormalities. Neural Tube Defects - Spina Bifida: A birth defect that occurs when the neural tube fails to close completely during pregnancy. Types: Occulta: Asymptomatic, often with a tuft of hair over the affected area. Cystica: Meningocele: Protrusion of the meninges, covered by skin. Myelomeningocele: Protrusion of the meninges and spinal cor d/nerves, covered by skin. Myeloschisis: Protrusion of the meninges and spinal cord, witho ut skin covering. Scoliosis Treatment Description: Treatment options for scoliosis, based on the severity of t he curve and other factors. Key Points: Cobb Angle: A measurement used to quantify the severity of scoliosi s. Treatment: Mild Scoliosis (45 degrees): Surgery. Surgical Options: Rods are often used to stabilize the spine and corr ect the curvature. Congenital Scoliosis: Surgery is often the most effective treatment. Congenital Kyphosis: Bracing is ineffective, surgery is the treatment of choice. Scoliosis Angles Description: The different angles used to classify the severity of scolio sis. Key Points: Cobb Angle: >10 degrees indicates scoliosis. Scoliometer: A device used to measure spinal curvature. A reading greater than 7 correlates to a Cobb angle of 20 degrees. Mild Scoliosis (45 degrees): Surgery. >50 degrees: Respiratory compromise. >75 degrees: Cardiovascular compromise. Quiz Yourself Description: A self-assessment quiz to test your knowledge of congen ital deformities of the spine and scoliosis. Key Points: VACTERL Syndrome: Review the components of VACTERL syndrome. Scoliosis Treatment: What is the treatment for each Cobb angle? 45 degrees: Surgery. Random Other Things Description: Additional information related to congenital deformities of the spine and scoliosis. Key Points: Caudal Regression Syndrome: A rare condition characterized by inc omplete development of the lower spine and limbs. Klippel-Feil Syndrome Association: A high yield association of Klipp el-Feil syndrome is Sprengel's Deformity (a condition where the sca pula is abnormally high). about:blank 12/13 1/16/25, 10:18 PM E1 S1 (Lectures 1-6).pdf Spina Bifida Association: Many individuals with spina bifida have hy drocephalus (a buildup of fluid in the brain). Table of Congenital Deformities Condit Description Key Features Treatment ion Lateral curvat Observation, Scoliosi ure of the spi Cobb angle >10 degrees bracing, sur s ne gery Klippel Observation, Fusion of two Low posterior hairline, short webbe -Feil Sy physical the or more cervi d neck, limited cervical range of m ndrom rapy, surger cal vertebrae otion e y Vertebral anomalies, anal atresia, Multidiscipli VACTE Combination cardiac defects, tracheo-esophag nary care, s RL Syn of birth defec eal fistula, renal abnormalities, lim urgery as ne drome ts b abnormalities eded Failure of the Observation, Spina B neural tube t Occulta, cystica (meningocele, my surgery, sup ifida o close comp elomeningocele, myeloschisis) portive care letely Diagram of Scoliosis about:blank 13/13