Anatomy & Physiology Master Review: Bone Tissue, Axial Skeleton, and Joints

Vocabulary practice flashcards covering high-yield osseous tissue, cartilage mechanics, bone cells, axial skeleton features, cranial sutures, vertebrae, joint classifications, and clinical joint pathologies.

Perichondrium

A layer of dense irregular connective tissue surrounding cartilage that resists outward expansion and delivers nutrients via diffusion.

Hyaline Cartilage

The most abundant cartilage type containing fine collagen fibers; found in articular (joint) surfaces, costal (rib) cartilages, respiratory rings, and nasal cartilage.

Elastic Cartilage

Cartilage with abundant elastic fibers suited for repeated bending; located in the external ear and epiglottis.

Fibrocartilage

Cartilage composed of parallel collagen stacks that is highly compressible with extreme tensile strength; found in knee menisci, intervertebral discs, and the pubic symphysis.

Appositional Growth

Cartilage growth mechanism characterized by the secretion of new matrix onto the external surface.

Interstitial Growth

Cartilage growth mechanism where chondrocytes divide and secrete new matrix from within lacunae.

Organic Bone Matrix (Osteoid)

Constitutes $\frac{1}{3}$ of bone matrix (composed of collagen and ground substance) and provides tensile strength and flexibility.

Inorganic Bone Matrix

Constitutes $\frac{2}{3}$ of bone matrix (composed of hydroxyapatites / calcium phosphate crystals) and provides hardness and compression resistance.

Osteoprogenitor Cells

Mitotic stem cells that reside in the periosteum and endosteum.

Osteoblasts

Bone-forming cells that secrete unmineralized osteoid matrix.

Osteocytes

Mature bone cells trapped in lacunae that monitor physical strain and communicate stress.

Osteoclasts

Multinucleated giant cells derived from macrophage lineage that secrete acid and enzymes to resorb (break down) bone.

Osteon (Haversian System)

The structural and functional unit of compact bone.

Central Canal

Longitudinal channel running through the core of an osteon that carries blood vessels and nerves.

Perforating (Volkmann's) Canals

Transverse channels that connect the periosteum to the medullary cavity in compact bone.

Canaliculi

Hair-like canals connecting lacunae to each other and the central canal via gap junctions for cellular nourishment.

Intramembranous Ossification

Bone formation process where bone develops directly from fibrous mesenchymal membranes without a cartilage template (e.g., flat bones of skull, clavicles).

Endochondral Ossification

Bone formation process that replaces a hyaline cartilage model, featuring a primary ossification center in the diaphysis and secondary centers in the epiphyses (e.g., long bones such as the femur and humerus).

Fracture Repair Sequence

The 4-stage sequence of bone healing: 1. Hematoma Formation $\rightarrow$ 2. Fibrocartilaginous Callus $\rightarrow$ 3. Bony Callus $\rightarrow$ 4. Remodeling.

Parathyroid Hormone (PTH)

Hormone released by the parathyroid gland during hypocalcemia (low blood $\text{Ca}^{2+}$) that activates osteoclasts to dissolve bone and release calcium into the bloodstream.

Calcitonin

Hormone released by the thyroid during hypercalcemia (high blood $\text{Ca}^{2+}$) that inhibits osteoclasts and promotes bone deposit.

Sphenoid Bone

Cranial 'keystone' bone that features the sella turcica, a structure that encloses and protects the pituitary gland.

Ethmoid Bone

Cranial bone featuring the crista galli (attachment site for the dura mater) and the cribriform plate (passageway for olfactory nerves).

Temporal Bone

Cranial bone featuring the styloid process (a needle-like spike) and the mastoid process (an ear bump).

Coronal Suture

Cranial suture that joins the frontal bone with the parietal bones across the crown.

Sagittal Suture

Cranial suture that connects the right and left parietal bones along the midline.

Lambdoid Suture

Cranial suture that articulates the parietal bones with the occipital bone posteriorly.

Squamous Suture

Cranial suture connecting the parietal and temporal bones laterally.

Hyoid Bone

U-shaped neck bone distinguished by the unique characteristic that it articulates directly with no other bone.

Cervical Vertebrae

Group of 7 vertebrae uniquely identified by transverse foramina, which serve as passageways for the vertebral arteries.

Atlas ($C_1$)

The first cervical vertebra, which lacks a body and spinous process and articulates with the occipital condyles to enable the head to nod 'YES'.

Axis ($C_2$)

The second cervical vertebra, characterized by a vertical dens (odontoid process) that serves as a pivot pin allowing the head to rotate side-to-side to shake 'NO'.

Thoracic Vertebrae

Group of 12 vertebrae that articulate with the ribs via costal facets and feature long, downward-pointing spinous processes ('giraffe shape').

Lumbar Vertebrae

Group of 5 vertebrae characterized by massive, thick block-like bodies designed for supporting body weight ('moose/llama shape').

Scoliosis

An abnormal lateral 'S-shaped' spinal curvature, most commonly occurring in the thoracic region.

Kyphosis

An excessive thoracic curvature of the vertebral column producing a 'hunchback' appearance.

Lordosis

An excessive lumbar curvature of the vertebral column producing a 'swayback' appearance.

True Ribs

Rib pairs 1–7 that attach directly to the sternum through individual costal cartilages.

False Ribs

Rib pairs 8–10 that attach indirectly to the sternum by fusing their costal cartilages to the cartilage of Rib 7.

Floating Ribs

Rib pairs 11–12 that lack anterior attachments and have no costal cartilages.

Synarthrosis

A functional joint category denoting immovable joints; structurally classified as fibrous (sutures, gomphoses) such as skull sutures and tooth sockets.

Amphiarthrosis

A functional joint category denoting slightly movable joints; structurally classified as cartilaginous (symphyses) such as intervertebral discs and the pubic symphysis.

Diarthrosis

A functional joint category denoting freely movable joints; structurally classified as synovial joints such as the shoulder, hip, knee, and elbow.

Osteoarthritis (OA)

A non-inflammatory 'wear-and-tear' pathology involving the progressive degeneration of articular cartilage.

Rheumatoid Arthritis (RA)

An autoimmune inflammatory disorder targeting the synovial membranes, leading to the formation of a destructive pannus.

Gouty Arthritis

A form of arthritis caused by the deposition of uric acid crystals within soft joint tissues, most commonly affecting the big toe.

Unhappy Triad

A traumatic knee injury characterized by the simultaneous rupture of the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and medial meniscus.