Skeletal System Comprehensive Review

Complete vocabulary flashcards covering skeletal functions, cells, bone tissue, axial and appendicular anatomy, ribs, joints, and foot arches.

Hematopoiesis (Hemopoiesis)

Blood cell production occurring in red bone marrow.

Hydroxyapatite

Mineral crystals primarily composed of calcium phosphate that give bone much of its hardness.

Ligament

A band of dense regular connective tissue connecting bone to bone.

Tendon

A band of dense regular connective tissue connecting muscle to bone.

Articular Cartilage

Cartilage (usually hyaline) covering bone surfaces at synovial joints that reduces friction and helps distribute loads.

Osteoblasts

Bone-forming cells that deposit new bone matrix during growth, remodeling, and repair throughout life.

Osteocytes

Mature bone cells residing in lacunae that maintain bone tissue and sense mechanical loading.

Osteoclasts

Multinucleated cells responsible for breaking down bone during bone resorption.

Bone Resorption

The physiological breakdown and removal of bone matrix by osteoclasts.

Bone Remodeling

The coordinated, lifelong process of removing old bone and forming new bone.

Intramembranous Ossification

The process of bone development directly within mesenchymal connective tissue without a pre-existing cartilage model.

Endochondral Ossification

The process of bone formation where pre-existing cartilage models are gradually replaced by bone tissue.

Parathyroid Hormone (PTH)

A hormone that raises blood calcium levels when low, in part by increasing calcium release from bone.

Calcitonin

A hormone that inhibits osteoclast activity and can lower blood calcium levels.

Compact Bone

Dense bone tissue that forms the protective outer cortex of bones.

Spongy Bone (Cancellous Bone)

Trabecular bone tissue composed of thin bony plates and struts with open spaces containing marrow and blood vessels.

Trabeculae

The thin bony plates, struts, and arches that form the lattice framework of spongy bone.

Osteon (Haversian System)

The repeating structural and functional unit of compact bone.

Central Canal (Haversian Canal)

The longitudinal canal in the center of an osteon containing blood vessels and nerve fibers.

Lamellae

Concentric rings or layers of mineralized bone matrix surrounding the central canal of an osteon.

Lacunae

Small cavities within the bone matrix that house osteocytes.

Canaliculi

Microscopic canals connecting adjacent lacunae, allowing cellular communication and exchange of nutrients and wastes.

Red Bone Marrow

Hematopoietic tissue responsible for producing red blood cells, white blood cells, and platelets.

Yellow Bone Marrow

Fat-storing adipose tissue situated primarily within the medullary cavities of adult long bones.

Long Bone

A bone classification characterized by having a longitudinal shaft and distinct expanded ends, being longer than it is wide.

Short Bone

A bone classification characterized by a roughly cube-like shape with approximately equal length and width, such as carpals and tarsals.

Flat Bone

A thin, typically curved bone providing broad surfaces for muscle attachment and protection of internal organs.

Irregular Bone

A bone with complex, specialized geometry that does not fit into long, short, or flat categories, such as a vertebra.

Sesamoid Bone

A specialized bone that develops embedded within a tendon, such as the patella.

Diaphysis

The tubular shaft forming the main central axis of a long bone.

Epiphysis

One of the expanded terminal ends of a long bone (plural: epiphyses).

Metaphysis

The transitional region between the diaphysis and epiphysis containing the growth plate in growing bones.

Medullary Cavity

The central hollow space inside the shaft of a long bone where bone marrow is stored.

Periosteum

The tough fibrous membrane covering the external surface of bones, except at articular joint surfaces.

Fossa

A shallow depression, furrow, or hollow on a bone surface.

Foramen

A natural opening, hole, or perforation through a bone that allows passage of nerves and vessels.

Meatus

A canal-like tube or passage penetrating through a bone.

Paranasal Sinus

A mucous membrane-lined, air-filled cavity within specific cranial and facial bones communicating with the nasal cavity.

Foramen Magnum

The large opening in the base of the occipital bone where the brainstem transitions into the spinal cord.

Axial Skeleton

The skeletal division comprising 80 bones along the central body axis, including the skull, ossicles, hyoid, vertebrae, ribs, and sternum.

Appendicular Skeleton

The skeletal division comprising the upper and lower limbs, shoulder (pectoral) girdles, and pelvic girdle.

Coronal Suture

The transverse fibrous joint of the skull uniting the frontal bone with the two parietal bones.

Sagittal Suture

The midline fibrous joint of the skull uniting the right and left parietal bones.

Lambdoid Suture

The posterior fibrous joint of the skull uniting the parietal bones with the occipital bone.

Mastoid Process

A rounded, conical bony prominence of the temporal bone located directly behind the ear.

Temporomandibular Joint (TMJ)

The bilateral synovial joint articulating the condyle of the mandible with the temporal bone.

Frontal Bone

The single anterior cranial bone forming the forehead, superior rims of the orbits, and anterior cranial floor.

Parietal Bones

The pair of cranial bones forming the upper lateral sides and roof of the skull.

Temporal Bones

The paired cranial bones situated on the lateral sides and base of the skull, surrounding the external acoustic meatus.

Occipital Bone

The posterior cranial bone forming the back of the head and the base of the skull surrounding the foramen magnum.

Sphenoid Bone

A butterfly-shaped central cranial bone spanning across the cranial floor and articulating with nearly all other cranial bones.

Ethmoid Bone

A delicate cranial bone positioned between the eyes contributing to the orbital medial walls, cribriform plate, and nasal septum.

Maxillae

The pair of facial bones that fuse at the midline to form the upper jaw and anterior hard palate.

Mandible

The single facial bone forming the lower jaw; the largest and only movable bone of the adult skull.

Zygomatic Bones

The paired cheekbones that also contribute to the lateral borders and floors of the orbits.

Palatine Bones

The paired L-shaped facial bones forming the posterior third of the hard palate and lateral nasal cavity walls.

Vomer

The slender, ploughshare-shaped facial bone forming the inferior-posterior portion of the bony nasal septum.

Perpendicular Plate of the Ethmoid

The vertical thin bony lamina of the ethmoid forming the superior part of the nasal septum.

Inferior Nasal Conchae

The paired, scroll-like bones projecting inward from the lateral walls of the nasal cavity that warm, moisten, and filter inhaled air.

Lacrimal Bones

The smallest and most fragile paired facial bones, located in the anterior medial wall of each orbit near tear drainage canals.

Hyoid Bone

A U-shaped bone in the anterior neck supporting the tongue that does not directly articulate with any other bone.

Cervical Vertebrae

The seven vertebrae of the neck region (designated C1 through C7).

Thoracic Vertebrae

The twelve vertebrae of the mid-back (designated T1 through T12) that articulate with the ribs.

Lumbar Vertebrae

The five large, weight-bearing vertebrae of the lower back (designated L1 through L5).

Sacrum

A triangular pelvic bone formed by the anatomical fusion of five sacral vertebrae.

Coccyx

The terminal tailbone composed of fused rudimentary coccygeal vertebrae.

True Ribs

Rib pairs 1 through 7, which articulate directly with the sternum via individual costal cartilages.

False Ribs

Rib pairs 8 through 12, whose anterior costal cartilages either attach indirectly to the rib above or do not attach at all.

Floating Ribs

Rib pairs 11 and 12, lacking any anterior attachment to the sternum or costal margin.

Manubrium

The superior, triangular portion of the sternum articulating with the clavicles and first pair of ribs.

Body of Sternum (Gladiolus)

The elongated, central bony segment of the sternum.

Xiphoid Process

The small cartilaginous and bony inferior projection of the sternum.

Clavicle

The S-shaped collarbone connecting the sternum medially to the acromion of the scapula laterally.

Scapula

The triangular flat bone known as the shoulder blade overlying the posterior thoracic cage.

Humerus

The longest and largest bone of the upper limb, forming the skeleton of the upper arm.

Radius

The lateral long bone of the forearm on the thumb side when in anatomical position.

Ulna

The medial long bone of the forearm on the pinky-finger side when in anatomical position.

Carpals

The eight short bones of the wrist: scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, and hamate.

Metacarpals

The five small long bones forming the framework of the palm, numbered I through V from thumb to little finger.

Phalanges

The individual bones comprising the fingers or toes, typically consisting of proximal, middle, and distal segments.

Hip Bone (Coxal Bone)

The large, flaring bone of the pelvic girdle formed by the developmental fusion of the ilium, ischium, and pubis.

Femur

The thigh bone; the longest, heaviest, and strongest bone in the human body.

Patella

The triangular sesamoid bone that protects the anterior knee joint; commonly known as the kneecap.

Tibia

The larger, medial, weight-bearing bone of the lower leg, commonly called the shinbone.

Fibula

The slender, lateral bone of the lower leg primarily serving as a site for muscle attachments.

Tarsals

The group of seven short bones forming the ankle and proximal foot: calcaneus, talus, cuboid, navicular, and three cuneiforms.

Calcaneus

The heel bone; the largest and strongest of the tarsal bones.

Talus

The second largest tarsal bone, articulating superiorly with the tibia and fibula to transmit weight to the foot.

Metatarsals

The five miniature long bones forming the intermediate metatarsal region of the foot between the tarsals and phalanges.

Medial Longitudinal Arch

The highest and most prominent dynamic arch of the foot, extending along the medial foot margin from heel to ball.

Pes Planus

The structural foot deformity characterized by flattening or loss of the medial longitudinal arch (flatfoot).