Structural Kinesiology, Joints, Skeletal, and Neuromuscular System Review

Comprehensive vocabulary flashcards covering anatomical terminology, planes and axes, joint mechanics and classification, skeletal system anatomy, and neuromuscular fundamentals.

Kinesiology

The study of motion or human movement, which examines the principles of anatomy, physiology, and mechanics in relation to human movement.

Structural Kinesiology

The study of muscles, bones, and joints as they are involved in the science of movement, focusing specifically on functional anatomy, movement patterns, and musculoskeletal relationships.

Anatomical Position

A standardized reference orientation of the body where the body is erect, feet are parallel and close, palms face forward, and thumbs point away from the body.

Prone Position

A body orientation defined as lying face-downward on the stomach.

Supine Position

A body orientation defined as lying face-upward on the back.

Anterior and Posterior

Anterior (ventral) describes a location in front or in the front part, whereas posterior (dorsal) describes a location behind, in the back, or in the rear.

Superior and Inferior

Superior (supra or cranial) describes a location above or higher in relation to another structure, whereas inferior (infra or caudal) describes a location below or lower in relation to another structure.

Medial and Lateral

Medial refers to relating to the middle or center, nearer to the median plane, whereas lateral refers to being on or to the side, further from the median plane.

Proximal and Distal

Proximal describes a position nearest the trunk or point of origin, whereas distal describes a position situated away from the center or point of origin.

Deep and Superficial

Deep describes a relative depth beneath or below the surface of muscle or tissue, whereas superficial describes a location near the surface of the body.

Limb-Specific Directional Terms

Specialized terms for body extremities including radial (lateral side of forearm/hand), ulnar (medial side of forearm/hand), and tibial (medial side of knee, leg, ankle, or foot).

Alignment Variations

Structural alignment terms including anteversion (abnormal forward rotation in transverse plane), retroversion (abnormal backward rotation in transverse plane), recurvatum (backward bending in sagittal plane), valgus (outward angulation of distal segment), and varus (inward angulation of distal segment).

Spinal Alignment Deviations

Structural deviations of the spine including kyphosis (increased outward spinal curve in sagittal plane), lordosis (increased inward spinal curve in sagittal plane), and scoliosis (lateral spinal curve in frontal plane).

Sagittal Plane

An imaginary cardinal plane (also known as anteroposterior plane) dividing the body vertically into left and right halves, in which forward and backward flexion and extension movements occur around a frontal axis.

Frontal Plane

An imaginary cardinal plane (also known as coronal plane) dividing the body vertically into front (anterior) and back (posterior) portions, in which side-to-side abduction, adduction, and side bending movements occur around a sagittal axis.

Transverse Plane

An imaginary cardinal plane (also known as horizontal plane) dividing the body into upper (superior) and lower (inferior) portions, in which twisting and rotational movements occur around a vertical axis.

Frontal Axis

An axis running laterally (side to side) through the body, perpendicular to the sagittal plane, around which flexion and extension movements rotate.

Sagittal Axis

An axis running anteroposteriorly (front to back) through the body, perpendicular to the frontal plane, around which abduction and adduction movements rotate.

Vertical Axis

An axis running longitudinally (top to bottom) through the body, perpendicular to the transverse plane, around which rotational movements rotate.

Range of Motion (ROM)

The area or angular distance through which a joint may normally be freely and painlessly moved.

Abduction and Adduction

Abduction is lateral movement away from the midline of the trunk in the frontal plane, whereas adduction is movement medially toward and/or across the midline in the frontal plane.

Flexion and Extension

Flexion is a bending movement that decreases the angle in a joint by bringing bones together in the sagittal plane, whereas extension is a straightening movement that increases the joint angle by moving bones apart.

Circumduction

A circular, cone-shaped movement of a limb that delineates an arc by combining flexion, extension, abduction, and adduction in sequence.

Internal and External Rotation

External rotation is rotary movement around the longitudinal axis of a bone away from the body midline in the transverse plane, whereas internal rotation is rotary movement toward the midline in the transverse plane.

Eversion and Inversion

Eversion is turning the sole of the foot outward or laterally in the frontal plane, whereas inversion is turning the sole medially into adduction in the frontal plane.

Dorsiflexion and Plantar Flexion

Dorsiflexion is flexion of the ankle resulting in the top of the foot moving toward the anterior tibia in the sagittal plane ($0\text{--}20^\times$ normal ROM), whereas plantar flexion is extension resulting in the foot/toes moving away from the body ($0\text{--}50^\times$ normal ROM).

Pronation and Supination

Pronation is rotational movement turning the forearm to a palm-down position where the radius crosses over the ulna ($0\text{--}80^\times$ normal ROM), whereas supination turns the palm to a face-up position where the radius is parallel to the ulna ($0\text{--}85^\times$ normal ROM).

Radial Deviation and Ulnar Deviation

Radial deviation is abduction at the wrist moving the thumb side toward the lateral forearm ($0\text{--}20^\times$ normal ROM), whereas ulnar deviation is adduction at the wrist moving the pinky side toward the medial forearm ($0\text{--}30^\times$ normal ROM).

Opposition and Reposition

Opposition is diagonal movement of the thumb across the palm to make contact with fingers for precision grip, whereas reposition is diagonal movement of the thumb returning to anatomical position.

Scapular Elevation and Depression

Elevation is superior movement of the shoulder girdle/scapula in the frontal plane (e.g., shrugging shoulders), whereas depression is inferior movement of the shoulder girdle in the frontal plane.

Scapular Protraction and Retraction

Protraction (abduction) is forward/lateral movement of the scapula away from the vertebral column in the horizontal plane, whereas retraction (adduction) is backward/medial movement toward the spine.

Scapular Upward and Downward Rotation

Upward rotation is rotational movement of the scapula where the glenoid fossa moves superiorly and laterally as the inferior angle moves laterally, whereas downward rotation moves the glenoid fossa inferiorly and medially.

Scapulohumeral Rhythm

The coordinated $2:1$ ratio movement between the glenohumeral joint ($120^\times$) and scapulothoracic joint ($60^\times$ upward rotation) required for full $180^\times$ arm elevation.

Horizontal Abduction and Horizontal Adduction

Horizontal abduction is movement of the humerus or femur in the horizontal plane away from the midline of the body, whereas horizontal adduction is movement in the horizontal plane toward the midline.

Joint (Articulation)

A connection structure where rigid elements of the skeleton meet (bone to bone, bone to cartilage, or teeth in sockets), allowing varying degrees of movement and stability.

Synarthrodial Joint

A functionally immovable joint serving primarily to provide stability and protection, structurally classified as fibrous (includes sutures and gomphoses).

Amphiarthrodial Joint

A functionally slightly movable joint balancing stability and flexibility, structurally classified as cartilaginous or fibrous (includes symphyses, synchondroses, and syndesmoses).

Diarthrodial Joint

A functionally freely movable joint containing a joint capsule, synovial membrane, joint cavity filled with synovial fluid, and articular cartilage.

Suture Joint

A synarthrodial fibrous joint found between cranial bones where interlocking bone margins are joined by dense fibrous connective tissue.

Gomphosis Joint

A synarthrodial fibrous joint where a conical process fits into a socket, specifically connecting teeth to dental sockets in the maxilla and mandible.

Syndesmosis Joint

An amphiarthrodial fibrous joint held together by strong ligaments or an interosseous membrane that permits minimal movement (e.g., inferior tibiofibular joint, coracoclavicular joint).

Symphysis Joint

An amphiarthrodial cartilaginous joint separated by a fibrocartilage disc that acts as a shock absorber and permits slight movement (e.g., symphysis pubis, intervertebral discs).

Synchondrosis Joint

An amphiarthrodial cartilaginous joint separated by hyaline cartilage that allows slight movement and often serves as a growth site (e.g., epiphyseal plates, costochondral joints).

Articular Cartilage

Resilient, compressible, and elastic hyaline cartilage covering the epiphyses of articulating bone ends to absorb shock, reduce friction, and facilitate smooth movement.

Degrees of Freedom

The number of cardinal planes in which a diarthrodial joint can move, categorized as uniaxial ($1$ degree), biaxial ($2$ degrees), or multiaxial ($3$ degrees).

Arthrodial Joint

A nonaxial diarthrodial (gliding/plane) joint characterized by flat bony surfaces that permit limited sliding or back-and-forth movements without angular rotation (e.g., carpal bones, tarsometatarsal joints).

Condyloidal Joint

A biaxial diarthrodial joint where an oval head fits into an elliptical cavity, allowing movement in two planes (flexion/extension and abduction/adduction) without rotation (e.g., radiocarpal wrist, knuckles).

Enarthrodial Joint

A multiaxial diarthrodial (ball-and-socket) joint with a spherical head fitting into a cup-shaped depression, permitting movement in all three planes and circumduction (e.g., shoulder, hip).

Ginglymus Joint

A uniaxial diarthrodial (hinge) joint consisting of a cylindrical projection fitting into a trough, permitting a wide range of motion only in the sagittal plane (e.g., humeroulnar elbow, knee, ankle).

Sellar Joint

A biaxial diarthrodial (saddle) joint with reciprocally concave-convex surfaces permitting movement in two planes plus opposition (e.g., carpometacarpal joint of the thumb).

Trochoid Joint

A uniaxial diarthrodial (pivot) joint consisting of a rounded surface articulating within a ring, permitting rotation around a single long axis in the transverse plane (e.g., proximal radioulnar, atlantoaxial joints).

Davis's Law

A physiological law stating that soft tissue gradually increases in length when placed under appropriate tension, and gradually shortens when maintained in a loose or shortened state.

Proprioception

The subconscious mechanism by which the body regulates posture and movement by responding to stimuli originating in proprioceptors embedded in joints, tendons, muscles, and the inner ear.

Motor Control

The process by which bodily actions and movements are organized and executed through neural integration of sensory information and precise, timed muscle activation.

Close-Packed Position

The specific joint position characterized by maximum contact area, maximum congruency, maximum tension in ligaments/capsule, minimal joint volume, and maximum mechanical stability.

Open-Packed Position

The joint position (also known as loose-packed) where ligaments and capsular structures are in their slackest position, joint surface contact is minimal, and joint distraction is maximized.

Axial Skeleton

The central skeletal division consisting of $80$ bones that form the central axis to protect vital organs, including the skull, spinal column, sternum, ribs, hyoid bone, and ear ossicles.

Appendicular Skeleton

The skeletal division consisting of $126$ bones forming the upper and lower extremities and their shoulder and pelvic girdles, primarily functioning in body movement.

Hemopoiesis

The process of blood cell formation occurring within red bone marrow located in spongy bone regions such as the vertebrae, femur, humerus, ribs, and sternum.

Long Bones

Bones characterized by a long cylindrical shaft (diaphysis) and protruding ends (epiphyses) containing a medullary cavity, functioning primarily as levers for movement (e.g., humerus, femur, tibia, radius).

Short Bones

Small, solid, cube-shaped bones with large articular surfaces composed primarily of spongy bone, providing shock absorption and limited, precise movements (e.g., carpals and tarsals).

Flat Bones

Bones with broad, curved surfaces varying from thick to thin that provide organ protection and large areas for muscle attachment (e.g., ilium, ribs, sternum, clavicle, scapula).

Irregular Bones

Bones with complex shapes that do not fit long, short, flat, or sesamoid categories, serving diverse purposes throughout the body (e.g., vertebrae, ischium, pubis, maxilla).

Sesamoid Bones

Small, round specialized bones embedded within tendons that protect tendons from excessive wear and improve the mechanical advantage of musculotendinous units (e.g., patella).

Diaphysis and Epiphysis

Diaphysis is the long cylindrical shaft portion of a long bone formed by hard compact cortex bone, whereas epiphysis refers to the enlarged ends shaped specifically to articulate at joints.

Periosteum and Endosteum

Periosteum is a dense fibrous membrane covering the outer diaphysis surface, whereas endosteum is a fibrous membrane lining the inside cortical wall and medullary cavity.

Osteoblasts, Osteoclasts, and Osteocytes

Osteoblasts are specialized cells that build new bone tissue, osteoclasts are cells that resorb and break down old bone tissue, and osteocytes are mature bone cells that regulate bone growth.

Spongy Bone vs Compact Bone

Spongy (cancellous/trabecular) bone makes up $20\times$ of the skeleton and consists of porous trabeculae housing marrow for hematopoiesis, whereas compact (cortical) bone makes up $80\times$ of the skeleton and consists of dense parallel collagen lamellae and Haversian canals.

Wolff's Law

The law stating that bone in a healthy individual adapts to applied mechanical loads by remodeling to become thicker and stronger under increased stress, or weaker with decreased loading.

Bone Processes vs Cavities

Bone processes are outward elevations or projections forming joints or serving as attachment points, whereas bone cavities are depressions, hollows, or openings containing soft tissues, vessels, or nerves.

Aggregate Muscle Action

The cooperative action of skeletal muscles functioning in coordinated groups rather than independently to achieve specific joint movements.

Intrinsic and Extrinsic Muscles

Intrinsic muscles originate and insert entirely within the body part on which they act for fine precision control, whereas extrinsic muscles originate proximal/outside the body part on which they act for gross, powerful movements.

Action

The specific movement of a joint resulting from a concentric contraction of a muscle that crosses that joint.

Innervation

The segment of the nervous system responsible for providing electrical motor stimuli to muscle fibers within a specific muscle or muscle portion.

Tendon, Fascia, and Aponeurosis

A tendon is a tough fibrous cord connecting muscle to bone; fascia is a fibrous sheet enveloping/binding body structures; and an aponeurosis is a sheet-like tendinous expansion connecting muscle to bone or binding muscles together.

Origin and Insertion

Origin is the proximal, least movable muscle attachment closest to the body midline, whereas insertion is the distal, most movable muscle attachment farthest from the midline.

Isometric Contraction

A static muscle contraction where active tension develops within the muscle without any change in muscle length or joint angle.

Isotonic Contraction

A dynamic muscle contraction where active tension causes or controls joint movement through a change in muscle length, classified as concentric or eccentric.

Concentric Contraction

An isotonic contraction where the muscle shortens under active tension as its force overcomes applied resistance, accelerating movement against gravity or resistance.

Eccentric Contraction

An isotonic contraction where the muscle lengthens under active tension as resistance overcomes muscle force, decelerating or controlling movement in a controlled manner.

Agonist Muscle

A muscle or muscle group (prime mover) primarily responsible for producing a specified joint motion through concentric contraction.

Antagonist Muscle

A muscle located on the opposite side of a joint from the agonist that performs the opposite joint motion, relaxing to allow movement or contracting eccentrically to control motion.

Stabilizer Muscles

Muscles that contract to fixate or stabilize a body region to establish a firm base for distal limbs to exert force (also called fixators).

Synergist Muscles

Muscles that assist agonists in refined movement by controlling direction and ruling out undesired motions (also called guiding muscles).

Sensory Neurons, Motor Neurons, and Interneurons

Sensory neurons transmit impulses from body parts to the spinal cord and brain, motor neurons transmit impulses away from the central nervous system to muscles, and interneurons process and integrate information between sensory and motor neurons.

Kinesthesis

The conscious awareness of the position and movement of the body and limbs in three-dimensional space.

Sprain vs Strain

A sprain is a stretch or tear injury affecting joint ligaments, whereas a strain is a stretch, tear, or rip affecting a muscle, fascia, or tendon.

Severity Grades of Strains and Sprains

Grade $1$ involves mild stretching/damage of fibers with slight pain/tenderness; Grade $2$ involves moderate partial tearing with painful ROM and joint laxity; and Grade $3$ involves severe complete rupture/tear with major instability or complete loss of function.