11. Bone & Soft Tissue

Vocabulary flashcards covering bone structure, fracture types, healing stages, metabolic bone diseases, pharmacologic agents, soft-tissue injuries, compartment syndrome, heterotopic ossification, myopathies, and arthritic disorders.

Periosteum

Membrane covering the outer surface of bone that supports marrow and nurtures hematopoietic stem cells.

Endosteum

Membrane lining the internal surfaces of bone.

Cortical (compact) bone

Dense outer layer that makes up about 80 % of skeletal tissue and forms the shafts of long bones.

Trabecular (spongy) bone

Intermeshing thin plates containing bone marrow; comprises about 20 % of skeletal tissue.

Osteoblast

Immature bone cell that deposits osteoid and minerals; forms new bone.

Osteoclast

Multinucleated cell that secretes acids and enzymes to break down bone (resorption).

Osteoid

Newly formed, unmineralized bone matrix composed mainly of collagen and protein.

Bone remodeling

Continuous process of bone resorption by osteoclasts and formation by osteoblasts.

Traumatic fracture

Bone break caused by a sudden impact or high-energy event.

Stress (fatigue) fracture

Partial or complete break in normal bone exposed to repeated abnormal stress, common in runners and military recruits.

Insufficiency fracture

Fracture occurring when normal stress is applied to bone of reduced integrity (e.g., osteoporosis).

Pathologic fracture

Break in fragile bone weakened by disease such as neoplasm or metabolic disorder.

Epiphyseal fracture

Fracture through a growth center in children or adolescents.

Open (compound) fracture

Fracture in which bone pierces the skin.

Comminuted fracture

Bone is broken into more than two fragments.

Transverse fracture

Fracture line at right angles to the long axis of bone, usually from shearing force.

Oblique fracture

Angled fracture line resulting from torsional forces.

Spiral fracture

Curved fracture line produced by twisting forces.

Segmental fracture

Free bone fragment exists between the main fragments.

Avulsion fracture

Piece of bone pulled off by a tendon or ligament, common in children.

Impacted fracture

Fragments driven into each other, often from falls.

Torus (buckle) fracture

Bulging of long bone cortex without a break, typically in children.

Greenstick fracture

Bone bends and partially breaks on one side; common in pediatrics.

Hematoma formation

First stage of fracture healing (days 1–5); blood clot forms and inflammation begins.

Fibrocartilaginous callus

Second healing stage (days 5–11) where collagen fibers and soft callus reconnect bone ends.

Bony callus formation

Third stage (days 11–28); soft callus is mineralized into hard, immature bone.

Bone remodeling (healing)

Final, months-to-years stage where osteoclasts and osteoblasts reshape bone to normal contours.

Osteoporosis

Chronic progressive disease marked by low bone mass, impaired quality, and increased fracture risk.

Osteopenia

Lower than normal bone mass but not low enough to be classified as osteoporosis.

Osteomalacia

Softening of adult bone due to defective mineralization from calcium, vitamin D, or phosphate deficiency.

Osteopetrosis

Abnormally increased bone density due to defective osteoclast resorption.

Paget disease (osteitis deformans)

Second most common metabolic bone disorder; accelerated bone resorption followed by disorganized formation, producing enlarged but fragile bone.

Bone Mineral Density (BMD)

Measurement of mineral content in bone; assessed with T-scores and Z-scores.

Bisphosphonates

First-line drugs that inhibit osteoclast-mediated bone resorption (e.g., alendronate, zoledronic acid).

Selective Estrogen Receptor Modulator (SERM)

Drug (e.g., raloxifene) that binds estrogen receptors to exert estrogen-like bone-protective effects.

Teriparatide

Synthetic parathyroid hormone used up to two years to stimulate new bone formation.

Denosumab

Monoclonal antibody that blocks osteoclast development; given twice yearly.

Calcitonin

Hormone therapy that binds osteoclasts to decrease bone resorption; available as nasal spray or injection.

Strain

Stretching or tearing of a musculotendinous unit from excessive demand.

Sprain

Injury to ligamentous structures around a joint due to abnormal stretch or stress.

Grade I sprain

Minimal fiber tearing, mild pain, little swelling, no joint instability.

Grade II sprain

Partial ligament tear with moderate pain, swelling, and some joint instability.

Grade III sprain

Complete ligament rupture causing gross instability; often needs surgery.

Dislocation

Complete loss of joint congruity with separation of articulating surfaces.

Subluxation

Partial dislocation where joint surfaces maintain some contact.

Tendinopathy

Chronic tendon pathology presenting with pain and impaired performance.

Tendinosis

Degenerative changes in a tendon from repetitive micro-trauma without inflammation.

Tenosynovitis

Inflammation of the synovial sheath surrounding a tendon.

Synovitis

Inflammation of a joint's synovial membrane leading to excess fluid.

Hemarthrosis

Bleeding into a joint space, usually after severe trauma.

Ganglion

Ballooning of a joint capsule or tendon sheath wall forming a cystic mass.

Bursitis

Inflammation of a bursa causing pain and limited movement.

Myofascial compartment syndrome

Condition where increased pressure within a closed muscle compartment compromises circulation and function.

Fasciotomy

Surgical decompression procedure that cuts fascia to relieve compartment pressure.

Heterotopic ossification (HO)

Abnormal bone formation in soft tissues, often after trauma or surgery.

Myositis ossificans

Subtype of HO with bone forming inside bruised or inflamed muscle tissue.

Critical illness myopathy (CIM)

Severe muscle weakness and atrophy associated with prolonged ICU stays.

Myopathy

Any disease of muscle characterized by nonspecific weakness due to metabolic, hormonal, autoimmune, or other causes.

Myofascial pain syndrome

Chronic regional pain disorder featuring trigger points within taut bands of skeletal muscle.

Trigger point (TrP)

Hyperirritable, tender spot in a muscle that elicits referred pain on compression.

Pannus

Destructive vascular granulation tissue in rheumatoid arthritis that erodes cartilage and bone.

Osteoarthritis (OA)

Degenerative joint disease with progressive cartilage loss, osteophyte formation, and joint pain.

Rheumatoid arthritis (RA)

Chronic systemic autoimmune disease causing symmetrical polyarticular inflammation and joint destruction.

Swan-neck deformity

Hyperextension of the PIP joint with flexion of the DIP joint, common in RA hands.

Boutonniere deformity

Flexion of the PIP joint with hyperextension of the DIP joint in RA.

Disease-modifying anti-rheumatic drugs (DMARDs)

Medications (e.g., methotrexate) that slow RA progression by modifying immune response.

Biologics

Targeted RA therapies that block cytokines to dampen immune activity (e.g., TNF-α inhibitors).

Pagetic steal syndrome

Neurologic complication where hypervascular Paget bone diverts blood away from neural tissue.

T-score

BMD comparison to a young healthy adult mean; used to diagnose osteopenia or osteoporosis.

Z-score

BMD comparison to an age-matched population mean.