Human Anatomy: Introduction to the Skeletal System and Articulations

Comprehensive vocabulary flashcards covering the human skeletal system, bone anatomy, developmental classifications, markings, fractures, and joint articulations based on the lecture slides.

Osteology

The scientific study of bone structure and functions.

Hematopoiesis

The production of blood cells occurring within the skeletal system.

Locomotory System

A functional body system formed by bones, cartilages, and joints (the passive part or skeletal system) together with muscles (the active part or muscular system).

Skeleton (Etymology and Proportion)

Originating from the Greek word meaning 'dried up body', it accounts for $20\%$ of total human body weight.

Bone (Tissue Definition)

A living, highly specialized, and hard form of connective tissue that makes up most of the skeleton and serves as the chief supporting tissue of the body.

Exoskeleton

The external vertebrate skeletal structures including hairs, feathers, nails, teeth, and scales.

Endoskeleton

The internal skeleton of vertebrates, consisting of bones with cartilage and ligaments; subdivided into the axial skeleton and the appendicular skeleton.

Splanchnic Skeleton

Skeletal components associated with internal organs, consisting of the cartilages of the larynx, trachea, and bronchi, as well as the fibrous skeleton of the heart.

Sesamoid Bones

Sesame seed-shaped accessory bones located at the ends of long bones of the limbs that help tendons glide over bony surfaces, reduce wear and tear, and alter the direction of tendon pull.

Wormian Bones (Sutural Bones)

Small, irregular, worm-like bone fragments found situated along the sutures between the bones of the cranium.

Heterotopic Bones

Abnormal calcifications in soft tissues that are not normally present, such as those that form inside scars.

Axial Skeleton

The $80$ bones located along the long axis of the body, divided into the skull, vertebral column, and bony thorax (ribs and sternum).

Appendicular Skeleton

The $126$ bones comprising the upper and lower extremities along with their supporting girdles (shoulder girdle and pelvic girdle).

Compact Bone (Dense Bone)

The outer dense osseous layer that appears smooth and homogenous to the naked eye.

Spongy Bone (Trabecular or Cancellous Bone)

The internal osseous layer composed of needle-like spicules of bone (trabeculae) and numerous spaces, giving it a porous, sponge-like macroscopic appearance.

Woven Bone (Non-Lamellar or Immature Bone)

Immature bone characterized microscopically by a matrix containing a network of randomly oriented large collagen fibers.

Lamellar Bone

Mature, highly organized bone tissue that comprises all adult mature bones.

Intramembranous Ossification

The developmental process where mesenchymal bone models form during the embryonic period and direct ossification of mesenchyme occurs in the fetal period to produce membranous bones.

Endochondral Ossification

The developmental process where cartilage models form from mesenchyme during the fetal period and are subsequently replaced by bone tissue to form cartilaginous bones.

Long Bones

Tubular bones that are generally longer than they are wide, such as the humerus.

Short Bones

Cuboidal bones found exclusively in the wrist (carpus) and ankle (tarsus).

Flat Bones

Bones that typically perform protective functions, such as the cranial bones.

Irregular Bones

Bones possessing complex, variable shapes other than long, short, or flat, such as facial bones.

Pneumatic Bones

Bones containing internal air-filled cavities lined with mucous membrane, such as the frontal and maxillary bones.

Diaphysis

The middle tubular shaft or body of a long bone, composed of compact bone surrounding a medullary cavity containing yellow marrow.

Epiphysis

The two enlarged ends of a long bone composed of cancellous bone containing red marrow, with articular surfaces covered by hyaline cartilage.

Pressure Epiphysis

An enlarged articular portion of a long bone that transmits joint load, such as the head of the humerus or the condyles of the femur.

Traction Epiphysis (Apophysis)

A non-articular bony projection located at the site of muscle, tendon, or ligament attachment, such as the tubercles of the humerus or trochanters of the femur.

Atavistic Epiphysis

An independent bone that fuses with another bone during developmental processes, such as the coracoid process of the scapula.

Metaphysis (Epiphyseal Plate)

A zone of hyaline cartilage between the diaphysis and epiphysis of a growing bone responsible for longitudinal bone growth.

Epiphyseal Line

The visible line remaining between the diaphysis and epiphysis once growth stops and the epiphyseal cartilage undergoes complete endochondral ossification.

Periosteum

A highly vascular connective tissue membrane covering all bone surfaces except articular surfaces; responsible for appositional growth and serving as an attachment site for muscles and tendons.

Perforating Fibers (Sharpey's Fibers)

Bundles of collagen fibers that secure and anchor the periosteum to the underlying bone tissue.

Nutrient Foramina

Small oblique openings through the compact bone of the long bone shaft that permit the passage of blood vessels for internal nourishment.

Nutrient Arteries

Independent branches of adjacent extraperiosteal arteries that pass obliquely through nutrient foramina to supply the bone marrow, spongy bone, and deep compact bone.

Periosteal Arteries

Small arterial branches originating from the periosteum responsible for nourishing most of the compact bone.

Metaphysial and Epiphysial Arteries

Arteries that supply the ends of bones, arising predominantly from the arterial networks supplying the adjacent joints.

Periosteal Nerves

Sensory nerves densely innervating the periosteum that carry pain fibers highly sensitive to tension and tearing.

Vasomotor Nerves

Nerves supplying bone that regulate marrow blood flow by causing the constriction or dilation of intraosseous blood vessels.

Epicondyle

A bony eminence situated superior to a condyle, such as the epicondyle of the humerus.

Line (Linea)

A narrow, linear ridge or elevation on a bone, such as the soleal line of the tibia.

Malleolus

A rounded process of bone, such as the lateral malleolus.

Protuberance

A prominent projection or swelling of bone, such as the external occipital protuberance.

Spine (Bone Marking)

A sharp, thorn-like process projecting from a bone, such as the spine of the scapula.

Trochanter

A very large, blunt elevation found on the femur, such as the greater trochanter of the femur.

Trochlea

A smooth, grooved articular process that acts like a pulley, such as the trochlea of the humerus.

Tubercle

A small, raised bony eminence, such as the greater tubercle of the humerus.

Tuberosity

A large, rounded elevation on a bone, such as the ischial tuberosity.

Crest (Crista)

A prominent ridge or border projecting from a bone.

Condyle

A large, rounded articular prominence, such as a femoral condyle.

Head (Bone Marking)

A rounded articular projection supported by a more constricted portion of a bone known as the neck.

Facet (Articular)

A smooth, flat articular surface on a bone that is usually covered with cartilage.

Capitulum

A small, round articular head, such as the capitulum of the humerus.

Fissure (Bone)

A narrow, slit-like opening passing through or between bones.

Foramen

A round or oval opening or hole through a bone.

Fossa (Pit or Fovea)

A shallow depression located in or on a bone.

Meatus (Canal)

An elongated foramen or tunnel-like passageway through a bone.

Sinus (Bone)

An air-filled cavity within a bone lined with a mucous membrane.

Hamulus

A hook-shaped bony process.

Cornu

A horn-shaped bony process.

Simple Fracture (Closed Fracture)

A bone fracture in which the broken bone does not penetrate through the skin.

Compound Fracture (Open Fracture)

A fracture in which broken bone fragments pierce and penetrate through the skin.

Comminuted Fracture

A fracture in which the bone splinters and shatters into multiple small fragments.

Spiral Fracture

A break produced by twisting forces, causing the fracture line to follow a twisted path along the bone shaft.

Greenstick Fracture

An incomplete break in which one side of the bone fractures while the opposing cortex bows.

Impacted Fracture

A fracture pattern where one broken end of the bone is forcefully driven into the other broken end.

Colles' Fracture

A fracture occurring at the distal portion of the radius.

Pott's Fracture

A fracture involving either or both distal ends of the tibia and fibula at the level of the malleoli.

Avulsion Fracture

A fracture occurring when a small portion of bone is torn off by a contracting muscle, tendon, or ligament.

Depressed Fracture

A fracture where the broken portion of bone is driven inwards, commonly observed in cranial injuries.

Arthrology

The scientific and anatomical study of joints and articulations.

Synarthroses

Joints that are immovable.

Amphiarthroses

Joints that permit slight movement.

Diarthroses

Freely movable joints.

Suture (Joint)

A fibrous joint held together by strong connective tissue, found exclusively between the bones of the skull.

Syndesmosis

A fibrous joint in which articulating bones are united by a sheet of fibrous tissue, such as an interosseous membrane.

Gomphosis

A specialized peg-and-socket fibrous joint binding the root of a tooth to its bony alveolar socket.

Synchondrosis

A primary cartilaginous joint united by hyaline cartilage that permits slight bending during early development, such as between the diaphysis and epiphyses.

Symphysis

A secondary cartilaginous joint united by a pad of fibrocartilage that is strong and slightly movable, such as the intervertebral discs or pubic symphysis.

Synovial Joint

A freely movable joint characterized by a joint cavity containing lubricating synovial fluid, articular cartilage, and an enclosed articular capsule with a synovial membrane.

Plane Joint

A uniaxial synovial joint with flat opposing surfaces that permits gliding or sliding movement, such as the acromioclavicular joint.

Hinge Joint

A uniaxial synovial joint permitting movement restricted to flexion and extension, such as the elbow, knee, and ankle joints.

Condyloid Joint

A biaxial synovial joint allowing movement in two directions, such as the temporomandibular joint (TMJ) and metacarpophalangeal joint (MCPJ).

Saddle Joint

A biaxial synovial joint in which opposing bone surfaces are saddle-shaped, such as intertarsal and carpal joints.

Ball and Socket Joint

A multiaxial synovial joint permitting multidirectional movement and rotation, such as the hip and shoulder joints.

Pivot Joint

A uniaxial synovial joint permitting rotational movement around an axis, such as the atlanto-axial joint and superior radioulnar joint.

Hilton's Law

The anatomical principle stating that the nerves supplying a joint also supply the muscles that move that joint or the skin covering their distal attachments.