Skeletal

Appendicular skeleton

Bones making up the limbs, pelvis, and shoulder areas.

Consist of 126 Bones

Axial skeleton

The skeleton that forms the central supporting axis of the body.

Consist of 80 bones

Articulation

The site of close approximation of two or more bones.

Articular cartilage

Thin layer of hyaline cartilage covering the surface of the epiphysis.

Carpal bones

Small bones of the wrist.

Condyle

Rounded knob; usually fits into a fossa on another bone to form a joint.

Epicondyle

A bump superior to a condyle.

Crest

A moderately raised ridge.

Diaphysis

The central body/shaft-like portion of a long bone.

Epiphysis

The head of each end of a long bone.

Medullary cavity

The central hollow portion of a long bone that contains bone marrow.

Endosteum

Thinner inner lining/Thin epithelial membrane lining the inside of the medullary cavity.

Periosteum

Outer layer that covers the bone/Dense fibrous membrane covering the diaphysis.

Epiphyseal plate

Layer of cartilage separating the epiphysis from the diaphysis at each end of a long bone; site where bone growth occurs.

False pelvis

Portion of the pelvis that extends between the edges of the iliac bones.

Fontanel

Un-fused area of an infant’s skull.

Fossa

A furrow or depression.

Foramen

A round opening in a bone, usually a passageway for vessels and nerves.

Head

The prominent, expanded end of a bone.

Haversian canal

A central canal in compact bone containing blood vessels and nerves; surrounded by lamellae.

Intramembranous ossification

Process in the fetus whereby fibrous connective tissue evolves into bone.

Endochondral ossification

Bone forms within and replaces cartilage.

Kyphosis

An exaggerated thoracic curvature.

Lacunae

Tiny gaps between rings of lamellae in compact bone.

Lamellae

Concentric rings of matrix surrounding Haversian canal in compact bone.

Meatus

A tube-like opening/also known as Canal.

Osseous tissue

Bone tissue.

Ossification

The creation of new bone/Bone formation.

Osteoblast

Bone-forming cell.

Osteoclasts

Bone cells that dissolve old or unhealthy bone.

Osteocyte

Mature osteoblast.

Osteon

Basic structural unit of compact bone consisting of a Haversian canal and surrounding lamellae.

Canaliculi

Extracellular matrix of the lamellae within tiny canals.

Process

A projection or raised area.

Bone remodeling

Reshaping or reconstructing part of a bone.

Resorption

The destruction of old bone; part of the bone remodeling process.

Scoliosis

A lateral curvature of the spine.

Sinus

Cavity in the skull filled with air.

Spongy bone

Also called cancellous bone; found in the ends of long bones and the middle of most other bones.

Sutures

Immovable joints of the skull.

Trabecula

Latticework of osseous tissue that makes up the structure of spongy or cancellous bone.

Trochanter

A large process found only on the femur.

True pelvis

Portion of the pelvis that extends between the pelvic brim.

Tubercle

A small, rounded process.

Tuberosity

A rough, raised bump, usually for muscle attachment.

Extracellular matrix

Contains substances that are essential for the make-up of our bones.

Collagen

A tough and rope-like protein giving strength to tendons, ligaments and cartilages.

Hydroxyapatite

Minerals in bone in the form of calcium phosphate crystals.

Proteoglycans

Large molecules consisting of polysaccharides.

Long Bones

Bones longer than they are wide; example: arms and legs.

Short Bones

Bones equal in length and width; example: ankles and wrists.

Flat Bones

Thin bones that provide protection and surfaces for muscle attachments; example: skull bones.

Irregular bones

Bones with complex shapes; example: Vertebral Column.

Functions of Skeletal System

Support, Protection, Movement, Blood cell production, Storage.

Compact Bone

Strong and dense bone providing protection and support.

Cancellous Bone

Lightweight bone containing irregular lattices of thin bone columns called trabeculae.

Parathyroid hormone (PTH)

Stimulates osteoclasts.

Calcitonin

Stimulates formation of osteoblasts.

Human growth hormone (hGH) and Insulin-like growth factor (IGF)

Stimulates cartilage and bone growth.

Sex hormones

Influence sex-related differences in skeletal growth.

Calcium, magnesium, and phosphorus

Minerals that contribute to osseous tissues.

Vitamins A, C, and D

Vitamins that contribute to osseous tissues.

Foramen

A hole in a bone

Open fracture

A broken bone protruding through the skin.

Closed fracture

A broken bone protruding within the skin.

Canal or Meatus

An elongated opening in a bone.

Fossa

A depression in a bone.

Process

A projection from a bone.

Condyle

Smooth, rounded end of a bone forming a joint.

Body/Shaft

Main portion of a bone.

Head

Enlarged end of a bone.

Neck

Constricted area between head and body.

Facet

Small, flattened articular surface.

Frontal Bone

forms the forehead, roofs of the eye sockets, and front part of the cranial floor.

Parietal Bones

form the sides and roof of the cranium

Temporal bones

form the lower side of the cranium and part of the cranial floor.

Spinous process

Projection from the laminae; attachment point for muscles.

Mandible

Also known as the lower jawbone. The largest and strongest facial bone.

Carotid foramen

carotid artery passes through a foramen

Styloid Process

serves as a point of attachment for the tongue and neck muscles.

Zygomatic Bones

or cheekbones, form the cheek prominences and part of thewall of the eye sockets.

Lacriminal Bones

are the smallest, thinnest bones on the medial eye socket.

Coronal Suture

unites the frontal bone and two parietal bones.

Saggital Suture

Attaches two parietal bones

Lambdoid Suture

joins parietal bones to the occipital bones

Squamous Suture

seal the parietal bones to the temporal bones

Transverse processes

Lateral extensions serving as muscle attachment points.

Superior articular process

Attach to the vertebra above

Inferior articular process

Attach to the vertebra below

Cervical vertebrae

7 vertebrae in the neck region.

Thoracic vertebrae

12 vertebrae posterior to the chest cavity, serve as rib attachments.

Lumbar vertebrae

5 vertebrae forming the lower back.

Sacrum

5 fused vertebrae forming posterior wall of the pelvis.

Coccyx

4 fused vertebrae referred to as the tailbone.

Rib pairs 1-7

Called true ribs.

Rib pairs 8-12

Called false ribs.

Rib pairs 11 and 12

Referred to as floating ribs.

Clavicle

Collarbone attaching to the sternum and scapula.

Humerus

The longest bone in the upper body.

Pelvic girdle

Basin-shaped ring of bones connecting the main body to the legs.