Bones and the Skeletal System Review

Flashcards covering key vocabulary related to bones, cartilage, the skeletal system structure (axial and appendicular skeleton, bones of the skull, vertebral column, thoracic cage, upper and lower limbs), and types of joints and their movements.

Chondrocytes

The cells found within cartilage.

Lacuna

A space where each chondrocyte is located within the cartilage matrix.

Hyaline Cartilage

A type of cartilage that is flexible and resilient, found in articular cartilage, costal cartilage, and respiratory cartilage.

Elastic Cartilage

A highly bendable type of cartilage, found in the epiglottis and the outer ear.

Fibrocartilage

A type of cartilage that resists compression and tension, found in the knee menisci and the annulus fibrosus of intervertebral discs.

Bone Tissue

A type of connective tissue within bones, characterized by an extensive ECM made up of organic (e.g., cells) and inorganic (e.g., mineral salts/hydroxyapatites) components for tensile strength and hardness.

Osteogenic Cells

Stem cells found in bone tissue.

Osteoblasts

Cells that deposit organic material in bone tissue.

Osteocytes

Mature bone cells surrounded by the bone matrix.

Osteoclasts

Cells responsible for breaking down bone tissue.

Flat Bones

Bones that are thin and may be slightly curved.

Irregular Bones

Bones with elaborate and complex shapes.

Long Bones

Bones characterized by a shaft and two ends.

Short Bones

Cube-shaped bones, including sesamoid bones.

Compact Bone

The solid-looking external layer of all bones and the bulk of the diaphysis, containing many passageways for vessels and nerves; its structural unit is the osteon.

Osteon

The structural unit of compact bone.

Spongy Bone (Trabecular Bone)

Bone found in short, flat, and irregular bones and the bulk of the epiphysis, whose structural units are flat trabeculae, forming a network of 'little beams'.

Trabeculae

Flat structural units forming a network in spongy bone.

Red Marrow

The site of blood cell generation, found at birth in all marrow, and in adults, remains in the trabeculae of spongy bone in the axial skeleton, girdles, and proximal epiphysis of the humerus and femur.

Yellow Marrow

Dormant bone marrow that replaces red bone marrow in the limbs between ages 8 and 18, containing many fat cells (adipocytes).

Diaphysis

The tubular shaft of a long bone.

Epiphysis

The ends of a long bone.

Epiphyseal Line

Located between the diaphysis and epiphysis of a long bone.

Axial Skeleton

The long axis of the body, including the skull, vertebral column, and thoracic cage.

Appendicular Skeleton

Composed of the bones of the upper and lower limbs, including the pectoral girdle and pelvic girdle.

Cranial Bones

Eight bones that enclose and protect the brain and provide attachment for some head and neck muscles; examples include frontal, parietal, temporal, and occipital bones.

Facial Bones

Bones that form the framework for the face, provide cavities for sense organs, openings for air/food passage, anchor teeth, and attach facial muscles; examples include mandible, maxillae, and zygomatic bones.

Cranial Vault (Calvaria)

The skullcap, forming the superior, lateral, posterior parts of the skull, and the forehead.

Base (of Skull)

The floor of the skull, located inferiorly.

Fossae

Prominent bony ridges internally dividing the skull into distinct depressions (anterior, middle, posterior).

Foramina, Canals, and Fissures

Approximately 85 named openings in the skull that provide passages for structures like the spinal cord, blood vessels, and cranial nerves.

Parietal Bones

Two paired cranial bones forming the bulk of the cranial vault.

Temporal Bones

Two paired cranial bones located inferior to the parietal bones, forming the inferolateral portion of the skull, with regions including squamous, mastoid, tympanic, and petrous.

Frontal Bone

An unpaired cranial bone that forms the forehead and roofs of the orbits (anterior portion of the skull); contributes to the anterior cranial fossa.

Occipital Bone

An unpaired cranial bone that forms the posterior portion of the cranium and cranial base, holding the cerebellum in the posterior cranial fossa.

Sphenoid Bone

An unpaired cranial bone that spans the width of the cranial floor, resembling a butterfly/bat, and contains the sella turcica.

Ethmoid Bone

An unpaired deeply situated cranial bone lying between the nasal and sphenoid bones, forming most of the medial bony region between the nasal cavity and orbits.

Coronal Suture

A major suture between the parietal bone and the frontal bone.

Squamous Suture

A major suture between the parietal bone and the temporal bone.

Sagittal Suture

A major suture between the two parietal bones.

Lambdoid Suture

A major suture between the parietal bones and the occipital bone.

Superciliary Arches

Formed by the frontal bone, they lie deep to the eyebrow.

Foramen Magnum

A large opening located at the base of the occipital bone.

Occipital Condyles

Protuberances on the occipital bone that articulate with the superior facets of the atlas (C1), forming the atlanto-occipital joint.

Sella Turcica

A formation in the superior surface of the sphenoid bone that houses the pituitary gland.

Cribriform Plate

The superior surface of the ethmoid bone containing olfactory foramina for olfactory nerves.

Crista Galli

A projection of the ethmoid bone.

Mandible

The lower jawbone, the largest and strongest facial bone, containing the alveolar process for lower teeth attachment.

Alveolar Process (Mandible)

The part of the mandible containing sockets for the lower teeth.

Mandibular Condyle

The part of the mandibular rami that articulates with the temporal bone to form the temporomandibular joint (TMJ).

Temporomandibular Joint (TMJ)

The joint formed by the articulation of the mandibular condyle with the temporal bone.

Vomer

An unpaired facial bone that forms the inferior portion of the bony nasal septum.

Maxillae

Paired facial bones that articulate with all other facial bones except the mandible, contain the largest paranasal sinuses (maxillary sinuses), and have alveolar processes for upper teeth attachment.

Maxillary Sinuses

The largest paranasal sinuses, located within the maxillae.

Zygomatic Bones

Paired facial bones that form the bulk of the cheek via the zygomatic arch.

Zygomatic Arch

Formed in part by the zygomatic bones, contributing to the prominence of the cheek.

Nasal Bones

Paired facial bones that form the anterior bridge of the nose.

Lacrimal Bones

Paired facial bones found on the medial part of the orbit.

Inferior Nasal Conchae

Paired facial bones that form part of the lateral walls of the nasal cavity.

Palatine Bones

Paired facial bones that form the posterior part of the hard palate and posterolateral walls of the nasal cavity.

Hyoid Bone

A U-shaped bone located between the mandible and larynx; it has no direct articulation with other bones and serves as an attachment for tongue and anterior neck muscles.

Vertebral Column (Spinal Column/Spine)

Made up of 26 bones, it transmits the weight of the trunk to the lower limbs, surrounds and protects the spinal cord, and serves as attachment sites for neck and back muscles.

Intervertebral Discs

Cushion-like pads located between vertebrae that act as shock absorbers.

Cervical Vertebrae

The 7 vertebrae of the neck region (C1-C7), often characterized by triangular vertebral foramina and bifid spinous processes (except C7).

Thoracic Vertebrae

The 12 vertebrae of the thoracic region (T1-T12), having thin spinous processes that point inferiorly, circular vertebral foramina, and costal facets for rib articulation.

Lumbar Vertebrae

The 5 vertebrae of the lower back (L1-L5), characterized by large, thick bodies and short, rounded spinous processes, containing triangular vertebral foramina.

Sacrum

A triangular structure formed by five fused vertebrae, located inferior to the lumbar vertebrae, and articulates with the coxal bones to form the sacroiliac joint.

Coccyx

The most inferior region of the vertebral column, a small triangular structure formed by 3-5 fused vertebrae, articulating superiorly with the sacrum.

Atlas (C1)

The first cervical vertebra, which articulates with the occipital condyles; it has a large vertebral foramen, no spinous process, and no body.

Axis (C2)

The second cervical vertebra, containing the dens (odontoid process) that fits into the atlas, forming the atlanto-axial joint, which allows head rotation.

Dens (Odontoid Process)

A tooth-like projection on the axis (C2) that articulates with the atlas (C1).

Atlanto-axial Joint

The joint formed between the atlas (C1) and axis (C2), allowing rotation of the head.

Sacroiliac Joint

The joint formed where the lateral surface of the sacrum articulates with the hip bones.

Thoracic Cage (Thorax)

A protective structure surrounding organs in the chest cavity and supporting the pectoral girdle and upper limbs, made up of thoracic vertebrae, ribs, sternum, and costal cartilages.

True Ribs

The superior 7 pairs of ribs that attach directly to the sternum via costal cartilages.

False Ribs

The inferior 5 pairs of ribs that attach indirectly to the sternum (or not at all).

Sternum

A flat bone lying in the anterior midline of the thoracic cage, composed of three sections: manubrium, body, and xiphoid process. (Breastbone)

Manubrium

The superior section of the sternum.

Xiphoid Process

The most inferior section of the sternum.

Pectoral Girdle (Shoulder Girdle)

Consists of the clavicle (anteriorly) and scapula (posteriorly), providing attachment for the upper limb to the trunk and great mobility due to its articulation with the axial skeleton via the clavicle and the shallow glenoid cavity of the scapula.

Clavicle

The anterior bone of the pectoral girdle.

Scapula

The posterior bone of the pectoral girdle.

Glenoid Cavity

A shallow socket in the scapula that the head of the humerus fits into, contributing to the great mobility of the upper limb.

Humerus

The single bone of the arm (brachium), extending from shoulder to elbow, with a rounded head that fits into the glenoid cavity of the scapula.

Radius

The primary forearm bone contributing to the wrist joint (lateral bone), with a radial head articulating with the ulna proximally.

Ulna

The main forearm bone forming the elbow joint with the humerus (medial bone), whose posterior olecranon forms the 'elbow bone'.

Olecranon

The posterior projection of the ulna, forming the 'elbow bone'.

Carpus

The part of the hand skeleton composed of 8 short bones called carpals. (Wrist)

Metacarpus

The part of the hand skeleton composed of 5 long bones. (Palm)

Phalanges

The bones of the fingers, consisting of proximal, middle, and distal phalanges (except the thumb/pollex, which has two). (Digits/Fingers)

Pollex

The technical term for the thumb, which has only proximal and distal phalanges.

Pelvic Girdle (Hip Girdle)

Consists of paired hip bones (coxal bones) attached to the sacrum posteriorly and to each other anteriorly, providing attachment for the lower limb to the spine and supporting pelvic organs, with little movement due to the deep acetabulum.

Coxal Bone

A paired bone of the pelvic girdle, made up of three fused bones in the adult: ilium, ischium, and pubis. (Hip Bone)

Acetabulum

A deep socket in the hip bone into which the head of the femur fits, contributing to the stability and limited movement of the lower limb compared to the pectoral girdle.

Ilium

The superior region of the hip bone, with an inferior body and a superior ala featuring the iliac crest.

Ischium

The posteroinferior region of the hip bone, with a superior body and a thinner inferior ramus.

Pubis

The anterior region of the hip bone, V-shaped, with a medial body and an anterior pubic crest. (Pubic Bone)

Femur

The single bone of the thigh, extending from hip to knee, articulating with the acetabulum proximally and forming the knee joint with the tibia distally via its medial and lateral condyles.

Fovea Capitis

A pit in the center of the rounded head of the femur.

Patella

A sesamoid bone that articulates with the patellar surface of the femur, forming part of the knee joint.