Musculoskeletal Anatomy: Bone Types & Structure

Musculoskeletal Disorders and Anatomy of Bones

• Musculoskeletal disorders affect movement and stability.
• Bones provide movement, protection, blood cell production in marrow, and enable standing.

Types of Bones

• Long bones include the femur, tibia/fibula, humerus, radius/ulna, and are for weight bearing.
• Short bones like carpals/tarsals provide stability.
• Flat bones such as the sternum, cranium, ribs, and pelvis protect vital organs, with higher red cell production.
• Irregular bones such as the lower jaw and vertebrae don't fit into other categories.
• Sesamoid bones like the patella are short and irregular

Bone Structure

• Compact bone is dense and smooth, containing canals for nerves, blood vessels, and lymphatics.
• Spongy bone has a lattice-like structure termed trabeculae, filled with marrow.
• Red marrow handles hematopoiesis, forming RBCs, platelets, WBCs, and stem cells.
• Stem cells differentiate into precursors or blast cells, then normoblasts become Erythrocytes and myeloblasts become Granulocytes (Leukocytes).
• New cells enter sinusoids, draining into bone veins.
• Yellow marrow comprises fat cells.
• It can convert to red marrow during extreme blood loss or anemia cases.
• The diaphysis is the end portion of bone.
• The epiphysis includes the plate that allows bone growth in younger patients, and the line, the remnant after growth stops.
• The periosteum is the outer layer of the bone, providing area for tendon and ligament insertion and anchoring.
• The endosteum is the internal bone surface.
• Articular cartilage facilitates long bone articulation with epiphyseal surfaces.

Muscles

• Muscles contract for movement.
• Hyaline cushions the bone ends, acting as a shock absorber.
• The three muscle types are skeletal, cardiac, and smooth.
• Skeletal muscles are striated with dark and light bands.
• Fasciculi, bundled muscle fibers, attach to bone via tendons, connective tissue cords.
• Ligaments, fibrous connective tissue, stabilize joints.
• They aid against undesirable movements and crossing patterns prevent loose/unstable joints. Stretched ligaments increase the risk of joint dislocations, permanent damage if dislocated.
• Skeletal muscles control voluntary movement (while smooth muscles govern involuntary actions like vein dilation, constriction, and peristalsis).

Joints

• Synovial joints allow free movement with lubricating liquid that prevents friction and facilitate nutrient delivery.
• Covered with cartilage: Facilitation of nutrient provision from synovial fluid during movement.
• Bursae are fluid-filled sacs lined with synovial fluids that act as cushions.
• Non-synovial joints are joined by fibrous tissue and cartilage (less mobile than synovial joints).

Age-Related Differences

• Pediatrics have unfused sutures, epiphyses, and "Softer bones" that lead to greenstick fractures.
• Elderly may have osteoporosis, increased bony prominences, decreased joint elasticity, decreased ROM, slow movement, falls and fractures.

Reasons for Seeking Care / Musculoskeletal Assessment

• Pain, mobility issues, trauma, injury, deformities prompt care.
• Patient history covers location, swelling, stiffness, deformity, weakness, instability, function loss, color/temperature, other symptoms, response to treatment, PMH(Past Medical History).
• Age-related changes include decreased bone density, increased bone prominence, kyphotic posture (hunchback), wide gait with center-of-gravity shifts, cartilage degeneration, decreased ROM, muscle atrophy, decreased strength, and slow movement.
• Family history and genetic risk are considered.
• OPQRST (Onset, Provocation, Quality, Region/Radiation, Severity, Timing) and the 6 P's of poikilothermia or pressure (compartment syndrome) are assessed.

Inspection

• Posture should provide muscular and skeletal balance supporting structures, correcting poor posture that may cause compensatory damage. Note symmetry, deformity, swelling, discoloration, hyper/atrophy.
• Gait is assessed for fluidity, smoothness, and symmetry during walking.
• Joint mobility should be smooth, deliberate, accurate, and coordinated.
• Joint ROM shouldn't cause pain, should be symmetrical, measuring using a goniometer.
• Palpation examines sensation (numbness/paresthesia indicating nerve damage assessed with a paperclip), pulse (assessing perfusion, symmetry), and muscle tone/strength (normal tension/contraction and resistance rated 0-5).

Calcium & Phosphorus

• Calcium levels are 9.0 - 10.5, while phosphorus is 3.0 - 4.5, regulated by the thyroid and parathyroid.

Calcium Homeostasis

• The Parathyroid Hormone (PTH) regulates calcium, promotes bone resorption/formation, increases osteoblast activity.
• Calcitonin inhibits bone breakdown, preventing high calcium with drugs like Miacalcin/Fortical.
• Calcitriol (Vitamin D Hormone) enhances calcium/phosphorus absorption, affecting bone health.
• Phosphorus: Elevated levels may result in calcium excretion.
• Vitamin D is essential for calcium absorption and bone growth.
• Growth hormone stimulates bone growth till adulthood.
• Glucocorticoids increase bone resorption promoting osteoclast activity.
• Estrogen slows bone destruction, HRT can increase cardiovascular and cancer risks.
• Androgens loss leads to increased bone remodeling.
• Thyroxine (T3) regulates bone turnover/mineral density.
• Insulin stimulates bone cells to Osteocalcin boosting glucose metabolism.
• Calcium homeostasis regulates calcium flow to & from bones and is maintained at the kidneys using liver, and skeletal system.

Diagnostic Testing

• X-rays confirm abnormalities, removing jewelry/clothing and shielding reproductive organs.
• CT scans image bone/soft tissue, detecting blockages or tumors checking pregnancy, allergies to shellfish/amiodarone, creatinine, and holding metformin when needed.
• MRI utilizes magnetic fields/radio waves, with precautions against metal, implantable devices, and claustrophobia, checking for patches, NPO before, and expected loud noises.
• Arthrograms image tendons, ligaments, muscles, joints, cartilage after IV contrast, checking anticoagulant use and post-procedure pain after.
• Bone Mineral Density (DEXA Scan) detects low bone density measuring osteoporosis with T-scores.
• Normal: 0, Osteopenia: -1 to -2.4, Osteoporosis: -2.5 or lower
• Bone scans use radioactive material identifying cancer, infection, trauma.
• Cold spots indicate cancer (low absorption), while hot spots reveal fractures, infection, or metabolic disease (high absorption).
• Procedures include pregnancy/breastfeeding precautions, fluid loading, and avoiding bismuth medications.
• Electromyography (EMG) assesses motor neurons and muscle health via needle electrodes; abnormal results indicates ALS or inflammation, avoiding lotions/caffeine and checking pacemakers and bleeding issues.
• Arthroscopy is for joint examination, precautions include assessing anticoagulation, pregnancy, NPO for 12 hours, avoiding arthrogram.

Metabolic Bone Diseases and Osteoporosis

• Osteoporosis may occur, with common sites at the wrist, hip, and spine.
• Fluid color and consistency should be monitored with arthroscopy, with ice packs applied for 24 hours.
• Metabolic signs and symptoms for bone diseases include pain, abormal gait, immobility, crepitus, stiffness, weakness, warmth, and deformity.
• T-scores diagnose osteoporosis.
  • 1.0 to -2.5 indicates osteopenia and ≤ -2.5 indicates osteoporosis. Clinical indicators include dowager's hump, lost height, acute back pain, spinal movement issues, constipation, respiratory deficits, fracture locations at the T8-L3, radius, and femur, along with fear of falls or fallophobia.
• Adequate calcium, Vitamin D, sunlight, increased exercise, and bone density testing are required to reduce the risk of osteoporosis.

Paget's Disease and Osteogenesis Imperfecta

• Paget's Disease is characterized by stages of bone destruction, disorganized structure, and hardened bone.
• Clinical manifestations include enlarged skulls, fractures, skin changes, gout, and elevated alkaline phosphatase and uric acid.
• Surgical interventions include surgical removal of affected bone and joint and insertion of pins/rods.
• Bisphosphonates decreases osteoclastic activity and renal calcium release from bones in addition to oral or IV medications for suppressing the disease.
• Patient instructions when undergoing treatment for Paget's Disease: Monitor GI and renal function and take on empty stomach.
• Osteogenesis Imperfecta: Genetic brittle bone disorder showing autosomal dominant COL1A1/COL1A2 gene defects. • Symptoms: Bone fragility, short stature, blue sclerae, hearing loss, discolored teeth. Bisphosphonate, braces, PT/OT are suggested for management, needing careful handling when changing diapers.

Osteomyelitis and Bone Tumors

• Osteomyelitis stems from bacterial/fungal infection spread, can be identified with elevated WBC/ESR and confirmed with bone biopsy as the new Gold Standard.
• Osteomyelitis symptoms include fever, swelling, tenderness, erythema, draining ulcers, intense bone pain, elevated WBC/ESR, and sinus tract formation.
• Treatment of Osteomyelitis: Long-term antibiotics, infection control, hyperbaric oxygen, sequestrectomy/debridement, bone grafts, microvascular bone transfers, muscle/skin flaps, or amputation might occur.
• Benign bone tumors are asymptomatic and discovered through routine x-rays, classified as chondrogenic, osteogenic, fibrogenic.
• Malignant bone tumors primarily start in the bone themselves and may sometimes originate elsewhere.

Malignant Bone Tumors

• They are typically located in 10-30 year age.
• Osteosarcoma risk factors include radiation, chemotherapy, Paget's disease, benign bone lesions, or inherited conditions like Li-Fraumeni's syndrome; can result in death in about 2 years.
• Ewing Sarcoma is a rare bone malignancy affecting children and young adults.
• Bone-seeking cancers metastasize from lung, thyroid, breast, or prostate to commonly affected bone sites like the pelvis, femur, ribs, and vertebrae.
• Chondrosarcoma arises from cartilaginous tissue, causing dull pain, better outcomes than osteosarcoma.
• Fibrosarcoma: Arises from fibrous tissue, Symptoms: Slow onset, local tenderness, possible palpable mass Tumor excision Complications: Delayed wound healing, infection, hypercalcemia, requires pain management.

Non-Surgical and Surgical Management of Bone Tumors

• Management: pain control, local analgesics, chemotherapy, radiation, bisphosphonates, and psychosocial support.
• Surgical management is recommended to either excise or reduce the tumor through interventional radiology, thermal/gas ablation, and psychological support.
• Grief counseling is helpful to accept possible death and dying.

Other Musculoskeletal Disorders:

• Dupuytren's contracture is a thickening of tissue beneath skin, with cords causing finger bending, which may need breaking using a needle, enzyme injection, and surgery.
• Ganglion cysts are benign swellings on joints or tendons, with a thick, sticky fluid, often clearing on their own with drainage in severe cases.
• Morton's neuroma affects the ball of the foot, commonly between the third/fourth toes, requiring arch supports, injections, exercises, and surgery.
• Plantar fasciitis is a treated self inflammation of thick tissue band from heel to toes.
• Osteoarthritis causes cartilage deterioration treated with weight management, activity modification, NSAIDs, joint supplements, glucosamine, and chondroitin.

Conservative and Nursing Care for Musculoskeletal Disorders

• Surgery may be needed if conservative therapies fail (ex: failed TJR).
• Considerations should be given to preoperative assessments - EKG, metabolic profile, coagulation studies, CBC, Pain management.
• Postoperative assessments should be performed using pain level, VS, temperature, Labs (H&S), neurovascular assessment, and wound drainage to assess any abnormalities
• Post-operative patient teaching should address the use of pain medication as prescribed, proper administration of medication, and monitoring for + bleeding precautions.
• Nursing care should include pain meds as needed, wound care, mobilization, antiembolic compression stockings, anticoagulant therapy, CPM and proper positioning
• The home environment should also be adapted for home use by limiting high Vitamin K in certain dietary restrictions.

Rheumatoid Arthritis

• Rheumatoid arthritis is a chronic, progressive, inflammatory autoimmune condition that may result in joint deformity, attacking all organs with tissue.
• Management includes: stiff - applies heat, red/inflamed - applies cold, NSAIDS - pain/inflammation, Methotrexate (DMARD)= suppressed immune system, but must not be pregnant while taking as it is an infection and must be controlled with control medication daily, and conserve energy.

Juvenile Idiopathic Arthritis

• Etiology*:
• Multifactorial etiology:
• Infectious or environmental agents trigger abnormal inflammation in a genetically susceptible child.
• Heterogeneous group of diseases classified by exclusion due to the lack of one definitive test.
• Symptoms*: Stiffness is worse in the AM
• Limp or functional adaptations to prevent pain.
• Joints affected present with swelling, loss of mobility and tenderness to touch (sometimes, but usually erythema).
• Exacerbation of symptoms when subjected to stressors/Growth is restricted.
• Interventions*:
• Proper medication technique: NSAIDS, Cytotoxic agents (Methotrexate), Biologic agents (Etanercept, adalimumab & abatacept), Corticosteroids.
• Individualized interventions to accommodate: Physical and Occupational Therapy, Pain relief, Medicine Administration and application (Heat/Moist Cloth), Fitness, Exercise, Splinting tools, Stress-free sleep.

Fracture Clinical Manifestations and Neurovascular Assessment

• Bone alteration (change) : short/deformity, crepitus; part affected's ability: skin wounds & bruising, swelling.
• All major body functions assessed quickly to assess immediate life risk If movement causes pain = hold mobility.
• Neurovascular assessment should identify altered sensation, circulation, motor activity.

Fractures

• Classifications*: Comminuted Greenstick Oblique Open Spiral Stress Transverse

Bone Healing Stages

• Definition*: Body's natural process: Repairs broken bone across site of fracture.
• Fracture triggers Hematoma formation: 1-3 days post fracture.
• Decreased Blood circulation & Bone Necrosis: Occur 3 days- 2 weeks.
• Body creates new vascular tissue to replace: Callus (3-6 weeks).
• Next Bone Repair: Bone remodeling: 3-8 weeks.
• Finally, total fixation occurs when Fracture Complications take place: 4 months-1 year.
• Adverse Effects*: Result from initial fracture, or healing complications:
• Deficient blood volume (hypovolemia), hemorrhage, fat/wound blockage, embolism, thromboembolism.
• Fat Embolism*
• Tachycardia
• Dyspnea
• Abnormal breath sounds Pleuritic chest pain Cyanosis Anxiety Confusion (AMS/Low Oxygen)
• Avascular Necrosis (AVN)*
• Death of femoral head due to fracture complication or alcohol condition as a comorbidity.

Compartment Syndrome

Occurs when tissue increases pressure with blood vessels which in turn impedes blood and Oxygen circulation creating tissue death & hypoxemia, requires fasciotomy/immediate physician notification, assessed 6 p's, & incisions on medial/lateral aspects of limb.

• ACS (Acute Compartment Syndrome) Can be aggravated through*

• Burns

• Vascular injury

• Penetration Injury

• Infusion Therapy

• Animal Bites

• Bleeding Disorders

• Bone Fracture

• Complications include motor weakness, infections, paresthesia

• Myoglobinuric*

• High energy fracture

• Extreme workout

• Flank pain

• Rhabdomyolysis*

• High compress fracture

• Lack of oxygen to Tissues/Muscle = renal Failure/ high Potassium Treatment = Ivf, Diuretics

Hip Fractures and Fracture Interventions

• Fractures: Upper 1/3 Femur
• Involve the head of the femur or the acetabulum (Intracapsular hip fracture) Extracapsular happens outside hip joint Assessment: C-ABC’S
• Goals Include*
• Preventions for Injury by:
• Abduction splints with bed pillow.
• Careful re positioning to not harm joint by adduction.
• NO flexing operative area 90 degree or sit without chair support.
• Teach legs not to be crossed.
• Perform Neurovascular Checks.
• Items must be high up; no bending

Impaired skin/pain:

• Inspect, administer medications, apply assistive mobility like utilized trapeze & overhead frame, assess immobility such as DVT & skin Breakdown

Interventions

• Reduction: Realignment of bone ends. Immobilization
• Closed surgical or Open Surgical with immobilization.
• Reduction, Bandages cast, traction as intervention
• *Amputations and Meniscus Tears Amputations (Surgical Removals)**:
• Hemorrhage, infection, phantom pains due to Limb/Neuroma, and extreme muscle contraction.
• Wrapping/Amputations*:
• Band parts correctly
• Reduce swelling
• Prone placement

Traumatic Amputation

• Wrap with sterile clothing
• Place H2O in bag
• Never position DIRECTLY.

Meniscus Tears and Carpal Tunnel

Meniscus:

• Tearing results in popping sensation
• Clicking/no extending
• Surgical repair may be in store

Management

• CTS: Pressure in Nerval Median
• Predominantly in sleep states, repetitive strain as in sports, & genetics.
• Non Surgical: DRUG and immobilize
• Surgical: Cut or nerve removal

Pediatric Conditions and Castings:

• Casting*: Frequent replacements throughout healing. Parents informed and educated on maintenance, skin risk, devices, hydration, fiber + nutrition, activity promotion, but strict action by children.

Immobilization: Is critical and requires significant intervention, especially in this patient population.

• Stages Of Growth Can Halt In Mobilization Of Muscle Tone*

Developmental Dysplasia of the Hip (Pediatric)

A common condition: Femoral head dislocated due to shallow growth and subluxated complete dislocation that is manifested with infant signs.

Assess: unequal fold gluteal, motion restriction and short limbs.

Pediatric treatment

Pavlik harness/spica cast 6-12 weeks. In addition, surgery may be necessary.

• *Slipped capital femoral epiphysis (SCFE)**: Posterior & Inferior with ages, boys>girls Symptom: thigh/groin/knee
• Assessment* May appear at high rates Rotation ability lost Bear to weight

Interventions

Bear to weight to avoid necrosis. Muscular Dystrophy:

1. Group muscle wasting

• membrane or vascular breakdown
• Diagnse By: CK Labs*

Manifestations

respiratory decline, limb damage may fall.

TX

Prevent decline, steroid and decrease inflation.

Duchenne Muscular Dystrophy (DMD):

1. Muscle groups become weak.

Differential Patterns for Early Muscle Deterioration and Scoliosis are prevalent and often associated with it.

Structural Alterations

Alterations 10+ in Spine. Neuromuscular conditions. Idiopathic (not known).

Clinical diagnoses include

Assessment & treatment, bracing and surgery

Congenital Clubfoot

Classifications:

• Talipes Varus in internal twisting
• Talipes Valgus: eversion
• Talipes Calcaneus: superior/dorsal flex
• Treatment and Intervention*
• Serial Casts/Surgery
• Teaching parents intervention action

Brain (CP) Palsy

Involves muscles, sensations, and learning & permanent disability. Spasticity is persistent, which results in exaggerated reflexes and extremities that limit the contraction. Dykenetic is slow, which includes distortion and speech. Ataxia is a wide-based gait.