Chapter 7: The Skeletal System – Bones and Joints

59 vocabulary flashcards covering essential terms and concepts from the Chapter 7 lecture on bones, joints, and related disorders.

Axial skeleton

The 80 bones of the head, neck, and trunk, including skull, vertebral column, and thorax.

Appendicular skeleton

The 126 bones of the limbs and the shoulder and pelvic girdles that attach them to the axial skeleton.

Osteoblast

Bone-forming cell that produces new bone matrix during growth and repair.

Osteoclast

Large multinucleated cell that breaks down and resorbs bone tissue.

Osteocyte

Mature bone cell embedded in lacunae that maintains the bone matrix.

Osteon

Structural (Haversian) unit of compact bone made of concentric lamellae around a central canal.

Osteoporosis

Disorder characterized by significant loss of bone density, greatly increasing fracture risk.

Osteopenia

Mild to moderate reduction in bone density that can progress to osteoporosis.

Osteomyelitis

Bacterial infection and inflammation of bone and bone marrow.

Osteosarcoma

Malignant bone tumor arising from bone-forming cells.

Chondrosarcoma

Malignant tumor originating in cartilage cells.

Ossification

Process of bone tissue formation.

Diaphysis

The shaft or central part of a long bone.

Epiphysis

The enlarged end of a long bone where growth occurs.

Medullary cavity

Central hollow cavity within the diaphysis that contains bone marrow.

Periosteum

Dense fibrous membrane covering the outer surface of bone except at joints.

Endosteum

Thin membrane lining the medullary cavity of a bone.

Bone marrow

Soft connective tissue inside bones; includes red (hematopoietic) and yellow (fat-storing) varieties.

Red bone marrow

Hematopoietic tissue that produces red blood cells, white blood cells, and platelets.

Synarthrosis

Immovable joint held together by fibrous tissue, e.g., skull sutures.

Amphiarthrosis

Slightly movable joint connected by cartilage or fibrous tissue, such as the pubic symphysis.

Diarthrosis

Freely movable (synovial) joint containing a fluid-filled cavity.

Synovial joint

Diarthrotic joint with a synovial cavity, articular cartilage, and supporting ligaments.

Articular cartilage

Hyaline cartilage covering bone ends in synovial joints to reduce friction.

Ligament

Strong band of dense connective tissue that connects bones and stabilizes joints.

Bursa

Small fluid-filled sac that reduces friction where tendons or ligaments rub against bone.

Circumduction

Circular movement of a limb that traces a cone-shaped path.

Dorsiflexion

Movement that decreases the angle between the dorsum of the foot and the leg (toes up).

Plantar flexion

Movement that points the toes downward, increasing the ankle angle.

Pronation

Rotation of the forearm or foot so the palm or sole faces posteriorly/downward.

Supination

Rotation of the forearm or foot so the palm or sole faces anteriorly/upward.

Kyphosis

Abnormal exaggeration of the thoracic spinal curvature (hunchback).

Lordosis

Abnormal exaggeration of the lumbar curvature (swayback).

Scoliosis

Lateral curvature of the spine.

Sprain

Injury involving a torn or ruptured ligament, causing pain and swelling.

Herniated disk

Protrusion of the nucleus pulposus through an intervertebral disc, compressing nerves.

Osteoarthritis

Degenerative joint disease caused by wear and tear of articular cartilage.

Rheumatoid arthritis

Autoimmune inflammatory arthritis in which the immune system attacks joint synovium.

Gout

Metabolic arthritis due to deposition of uric acid crystals in joints.

Parathyroid hormone (PTH)

Hormone that raises blood calcium by stimulating bone resorption, kidneys, and intestines.

Collagen

Fibrous protein forming a major component of bone matrix and other connective tissues.

Calcium

Mineral deposited in bone matrix to harden and strengthen the skeleton.

Resorption

Process by which osteoclasts break down bone, releasing minerals into the blood.

Soft callus

Fibrocartilaginous tissue that bridges a fracture during early healing.

Hard (bony) callus

Spongy bone that replaces the soft callus in fracture repair.

Bone remodeling

Ongoing process in which old bone is resorbed and new bone is formed.

Fontanel

Membranous gap between cranial bones in an infant’s skull.

Atlas

First cervical vertebra (C1) that supports the skull and allows nodding motion.

Axis

Second cervical vertebra (C2) with the dens that enables head rotation.

Clavicle

Anterior bone of the shoulder girdle connecting sternum to scapula.

Scapula

Flat triangular bone forming the posterior part of the shoulder girdle.

Humerus

Long bone of the upper arm extending from shoulder to elbow.

Femur

Thigh bone; the longest and strongest bone in the human body.

Tibia

Medial, weight-bearing bone of the leg between the knee and ankle.

Fibula

Lateral, slender bone of the leg that stabilizes the ankle but bears little weight.

Patella

Sesamoid bone (kneecap) that protects the anterior knee joint.

Acetabulum

Cup-shaped socket in the pelvis that receives the head of the femur.

Glenoid cavity

Shallow socket in the scapula that articulates with the head of the humerus.

Intervertebral disc

Fibrocartilaginous pad between vertebral bodies that absorbs shock and permits movement.