Weeks 4 and 5 The Skeletal System

Objective 1: Bone Classification

Long Bones are longer than they are wide. phalanges humerus metacarpals Short bones are roughly cubical carpals

Irregular bones do not fit into the other categories. Flat bones are thin, with parallel surfaces, and usually a little curved. rib parietal bone sternum Irregular bones do not fit into the other categories. vertebra Os coxae (pelvic bone)

Sesamoid bones are a type of short bone that form in tendons patella pisiform

Objective 2: Bone Markings Bone markings are bumps, projections, openings and ridges on the surfaces of bones. They function as passageways for nerves and blood vessels, as points of muscle and ligament attachment, and as joint surfaces.

Projections that help form joints: Condyle: rounded articular projection Mandibular condyle Ramus: armlike projection of bone Mandibular ramus

Projections that help form joints: Head: a bony expansion carried on a narrow neck Head of humerus Surgical neck of humerus

Depressions associated with joints: Fossa: shallow, basin-like depression in a bone, often serving as an articular surface Coronoid fossa Facet: smooth, nearly flat articular surface Costal facet

Projections for muscle and ligament attachment Spine: sharp, slender, pointed projection Process: prominence or projection Spine of scapula Zygomatic process

Projections for muscle and ligament attachment Crest: a narrow prominent ridge of bone Line: Narrow ridge of bone; less prominent than a crest Median sacral crest Inferior nuchal line

Projections for muscle and ligament attachment Trochanter: very large, blunt, irregularly shaped process Greater Trochanter Tubercle: small, rounded projection or process Greater Tubercle Femur Humerus

Projections for muscle and ligament attachment Tuberosity: large, rounded projection which may be roughened Tibial tuberosity Epicondyle: raised area on or above a condyle Lateral epicondyle

Depressions and openings to allow passage of nerves and vessels Foramen: rounded or oval opening through a bone Foramen ovale Meatus: canal-like passageway Internal acoustic meatus

Superior orbital fissure Depressions and openings Fissure: narrow, slit-like opening Superior orbital fissure Sinus: cavity within a bone filled with air Ethmoid sinus Ethmoid bone

Intertubercular groove Depressions and openings Groove: furrow Intertubercular groove

Objective 3: Gross Anatomy of a Long Bone

Spongy Bone Trabeculae filled with Red Marrow Compact Bone Medullary Cavity Trabeculae filled with Red Marrow Trabeculae are like the honeycomb; Red marrow is like the honey Compact Bone

Objective 4: Chemical Composition of Bone

Two Components of Bone Matrix Inorganic Materials (hydroxyapatites) - 2/3 of matrix Mineral salts Calcium Phosphorus Compressional strength (hardness) Organic Ground Substance (osteoid) - 1/3 of matrix Collagen fibers Soluble proteins Tensile strength (flexibility)

In lab you will observe bone that has been treated with acid. Acid dissolves minerals. What effect do you think this will have? In lab you will observe bone that has been cooked. Heat denatures proteins. What effect do you think this will have?

Objective 5: Microscopic Structure of Compact Bone Central

The structural unit of bone is called Osteon or Haversian System

Haversian System (Osteon) Central (Haversian) canal

Human bone is primarily arranged in a ringed pattern and is called lamellar bone: concentric lamella Interstitial lamella

Lacunae (containing osteocytes) Canaliculi

Lacuna (containing an osteocyte) Canaliculi Lacuna (containing an osteocyte)

Perforating (Volkman’s) Haversian canal Perforating (Volkman’s) canal

Be able to identify these microscopic components of bone from models and slides

Objectives 6 & 7 Know the bones And their markings