skel

Intramembranous ossification

Bone development directly from connective tissue, forming most flat bones such as the skull and clavicle.

Endochondral ossification

Bone development by replacing a hyaline cartilage model, forming most bones of the body including long bones.

Epiphyseal plate

The growth plate region where long bones increase in length through cartilage cell division and subsequent replacement by bone.

Appositional growth

The process where bone increases in diameter as osteoblasts add bone to the outer surface while osteoclasts resorb bone from the inner surface.

Hormones involved in bone length growth

Growth hormone (GH), thyroid hormones, insulin, and sex hormones (estrogen and testosterone).

Parathyroid hormone (PTH) role in bone

Regulates blood calcium levels and stimulates bone resorption when blood calcium is low.

Structural classifications of joints

Fibrous, cartilaginous, and synovial joints.

Fibrous joint types

Sutures (skull), syndesmoses (e.g., tibia-fibula link), and gomphoses (tooth sockets).

Cartilaginous joint types

Synchondrosis (connected by hyaline cartilage) and symphysis (connected by fibrocartilage).

Synovial joint components

Articular cartilage, joint cavity with synovial fluid, articular capsule, synovial membrane, and stabilizing ligaments.

Functional classifications of joints

Synarthrosis (immovable), amphiarthrosis (slightly movable), and diarthrosis (freely movable).

Flexion, Extension, and Hyperextension

Flexion decreases the joint angle; extension increases the joint angle; hyperextension extends beyond the anatomical position.

Abduction and Adduction

Abduction moves a structure away from the midline; adduction moves it toward the midline.

Rotation and Circumduction

Rotation turns a bone around its own longitudinal axis; circumduction is a circular movement combining flexion, extension, abduction, and adduction.

Supination and Pronation

Supination rotates the forearm so the palm faces anteriorly/upward; pronation rotates it so the palm faces posteriorly/downward.

Hormones involved in bone length growth

Growth hormone (GH), thyroid hormones, insulin, and sex hormones (estrogen and testosterone).

Parathyroid hormone (PTH) role in bone

Regulates blood calcium levels and stimulates bone resorption when blood calcium is low.

Structural classifications of joints

Fibrous, cartilaginous, and synovial joints.

Fibrous joint types

Sutures (skull), syndesmoses (e.g., tibia-fibula link), and gomphoses (tooth sockets).

Cartilaginous joint types

Synchondrosis (connected by hyaline cartilage) and symphysis (connected by fibrocartilage).

Synovial joint components

Articular cartilage, joint cavity with synovial fluid, articular capsule, synovial membrane, and stabilizing ligaments.

Functional classifications of joints

Synarthrosis (immovable), amphiarthrosis (slightly movable), and diarthrosis (freely movable).

Flexion, Extension, and Hyperextension

Flexion decreases the joint angle; extension increases the joint angle; hyperextension extends beyond the anatomical position.

Abduction and Adduction

Abduction moves a structure away from the midline; adduction moves it toward the midline.

Rotation and Circumduction

Rotation turns a bone around its own longitudinal axis; circumduction is a circular movement combining flexion, extension, abduction, and adduction.

Supination and Pronation

Supination rotates the forearm so the palm faces anteriorly/upward; pronation rotates it so the palm faces posteriorly/downward.

Inversion and Eversion

Inversion turns the bottom of the foot inward toward the midline; eversion turns it outward away from the midline.

Protraction and Retraction

Protraction moves a body part forward; retraction moves a body part backward.

Dorsiflexion and Plantar flexion

Dorsiflexion moves toes upward toward the shin; plantar flexion points toes downward.

Elevation and Depression

Elevation moves a body part upward; depression moves a body part downward.

Six types of synovial joints and examples

Plane (wrist intercarpals), hinge (elbow), pivot (cervical vertebrae C1-C2), condyloid (wrist), saddle (thumb joint), and ball-and-socket (shoulder and hip).

Vitamin D skeleton role & deficiency

Helps absorb calcium and phosphorus for bone strength; deficiency causes rickets in children and osteomalacia in adults.

Vitamin C skeleton role & deficiency

Required to produce collagen for bone strength; deficiency leads to poor bone formation and slow healing.

Vitamin A skeleton role & deficiency

Supports normal bone growth and remodeling; deficiency causes abnormal bone growth and development.