Injury Classification and Biomechanics

Vocabulary flashcards covering injury classifications, mechanical stresses, tissue mechanics, fracture configurations, ligament/muscle strain grading, and skin/nerve pathologies.

Intrinsic Injury

An injury originating internally, such as a viral or bacterial infection.

Extrinsic Injury

An injury caused by tissue being stressed to the point of mechanical failure due to excessive external force.

Primary Injury

A direct immediate consequence of excessive force or trauma.

Secondary Injury

A delayed injury occurring some time after initial trauma as an accommodation to the primary injury.

Acute Injury

Mechanical failure of soft tissue due to excessive force occurring in a single bout, characterized by sudden onset and short duration.

Chronic Injury

Mechanical failure of soft tissue due to repeated micro-trauma occurring over an extended period of time, characterized by gradual onset and prolonged duration.

Microtrauma

Microscopic damage to a tissue's structures.

Macrotrauma

An exacerbated injury resulting from repetitive loading.

Open Injury

An exposed injury that breaks the surface of the skin.

Closed Injury

An unexposed injury that does not involve disruption of the skin surface.

Load (Stress)

An external or internal force acting on a tissue.

Deformation (Strain)

The extent of deformation a tissue undergoes when subjected to loading.

Yield Point

The point on a load-deformation curve where the applied load exceeds the mechanical capabilities of the tissue, reaching its elastic limit and resulting in mechanical failure.

Tension

A mechanical force creating a pulling action that tries to elongate the structure.

Compression

A mechanical force creating a pushing action that tends to shorten the structure.

Bending

Loading applied about an axis, representing a combination of tensile and compressive forces.

Shear Force

A force that acts parallel to the surface of a structure.

Torsion

A load applied to a structure causing it to twist about an axis.

Cortical Bone

The hard outer shell of bones and the diaphyseal region.

Cancellous Bone

Spongy bone enclosed within the outer cortical bone.

Bone Loading Hierarchy

The relative strength of bone under mechanical stresses: strongest in compression, weak in tension, and weakest in shear ($\text{Compression} > \text{Tension} > \text{Shear}$).

Fracture

Any disruption in the continuity of the bone or periosteum.

Transverse Fracture

A bone fracture caused by a direct blow.

Spiral Fracture

A bone fracture caused by rotation on a planted foot.

Oblique Fracture

A bone fracture occurring when one end of the bone is fixed while the other experiences sudden torsion.

Comminuted Fracture

A fracture in which bone breaks into multiple fragments, typically caused by a blow or fall in an awkward position.

Depressed Fracture

A fracture occurring in flat bones as a result of a direct blow.

Greenstick Fracture

An incomplete fracture occurring on the convex side of a bone in a skeletally immature individual.

Longitudinal Fracture

A bone fracture that splits along the length of the bone, typically caused by jumping from a height.

Serrated Fracture

A fracture caused by a direct blow that results in jagged bone edges.

Contrecoup Fracture

A fracture occurring on the side opposite to the point of impact.

Impacted Fracture

A bone fracture resulting from a compressive force applied along the long axis of the bone.

Epiphyseal Growth Plate

A cartilaginous disk located near the end of long bones responsible for bone growth; injury can cause premature closure and loss of bone length.

Periostitis

Inflammation of the periosteum, usually resulting from a contusion.

Tendon

A highly collagenous, non-contractile structure that executes joint motion by transmitting mechanical forces from muscles to bones.

Ligament

An inert, non-contractile structure containing elastic fibers that joins bones together and provides stability to joints.

First-Degree Ligamentous Injury

Mild overstretching of the ligament without tissue disruption, displaying a firm end feel and no joint instability.

Second-Degree Ligamentous Injury

Partial disruption or macrotearing of the ligament, displaying a definite (soft) end feel and slight to moderate joint instability.

Third-Degree Ligamentous Injury

Complete disruption of the ligament, displaying no end feel and severe joint instability.

First-Degree Muscle Injury

Overstretching or microtearing of muscle or tendon fibers causing mild loss of strength, swelling, ecchymosis, and point tenderness.

Second-Degree Muscle Injury

Further stretching and partial tearing of muscle or tendon fibers, presenting with more severe symptoms and greater loss of function.

Third-Degree Muscle Injury

Complete rupture of a muscle or tendon characterized by severe symptoms, complete loss of muscle function, and a possible palpable defect.

Myositis

Inflammation of muscle tissue.

Fasciitis

Inflammation of fascia within the muscle.

Myositis Ossificans

Bone formation within muscle tissue due to repetitive trauma, which can resorb over 9 to 12 months.

Bursitis

Inflammation of a bursa, a fluid-filled sac situated in areas where friction occurs between bony prominences and tendons.

Neuropraxia

A transient and reversible loss of nerve function secondary to trauma or irritation, causing short-lived sensory and motor deficits lasting seconds to two weeks.

Blister

A skin injury resulting from excessive friction and shear forces causing fluid accumulation beneath the skin surface.

Abrasion

A skin injury involving scraping or damage to the superficial layer of the skin.

Avulsion (Skin)

A skin injury characterized by the pulling or tearing away of skin tissue from its source.

Laceration

A skin injury characterized by irregular tearing of the skin.

Puncture

A skin injury caused by the penetration of a sharp object through the skin.

Contusion (Skin)

A closed skin injury resulting from a direct compressive force or traumatic blow.