Skeletal System

“Skeletal”

“Dried up”

Amount of Bones

Adult Skeleton: 206 bones

Fetal Skeleton: 270 bones

Why does fetal skeleton have more bones?

Long bones have 3 separate bones separated by growth plates, eventually ossifying to create 1 bone.

Sutural (Womarian) Bones aka Extra Bones

small, irregular, extra bone fragments that develop inside the joints (sutures) between the major plates of the skull

Bone Markings

• Depressions

• Openings

• Projections

Depressions

pathways for vessels and nerves, also places where bones meet (articulate)

• Facet (convex or concave, where two bones articulate)

• Fossa (deeper depression, can fit another bone)

• Fovea (shallow pit)

• Groove

Openings

enclose delicate structuers like arteries, veins, nerves (allow them to pass thru bone)

• Canal

• Fissure

• Foramen (plural: foramina) Foramen is completely round

- Notch (incomplete foramen)

Projections

sites where bones articulate or where tendons and ligaments attach

• Condyle

• Crest

• Head

• Epicondyle

• Tubercle/Tuberosity

• Process

• Spine

• Protuberance

• Trochanter

• Line

Axial & Apendicular Skeleton

Axial Skeleton (longitudinal)

• Skull - 22 bones (divided into facial and cranial skeleton)

• Auditory ossicles - in ear, 6 of them (3 pairs)

• Hyoid - doesn’t articulate with another bone (only one in the body that doesn't)

• Vertebral column - 33 bones (24: moveable vertebrae, 9 are vertebrae fused together sacrum and coccyx immovable)

• Thoracic cage - ribs, sternum, verterbral column

Appendicular Skeleton

• Pectoral Girdle

• Upper Extremities - more mobile

• Pelvic Girdle

• Lower Extremities - more susceptible to injury

apendicular skeleton - rod that hangars hang on

girdle - clothes hangar

extremities - sweater

“Pectoral”

“relating to the chest”

“Pelvis”

“basin”

Skull

Cranium (8)

• ethmoid, sphenoid, temporal, parietal, occipital, frontal bone

- temporal and parietal are single bones, others are all in pairs

Skelton of the Face (14)

• zygomatic, maxilla, mandible, nasal, lacrimal, palatine, inferior, nasal concha, vomer

- mandible and vomer are single bones

Paranasal Sinuses

• Frontal

• Maxillary

• Sphenoid

• Ethmoid

Frontal Bone

• Frontal Sinus - 2 separate frontal bones create one flat solid one (frontal sinus), above and between eyebrows (forhead)

• Supraorbital Foramen

- Supraorbtil notch on supraorbital ridge

- Supraorbital artery vein and nerve run thru

“Glabella”

“smooth and hairless”

Parietal Bone

• Parietal Formina - paired front bones, lateral aspect of skull (cranium)

• Emissary Veins - run thru and connect between vessels internal to cranium and blood flow goes thru partial foramina then to scalp

“Pariet”

“wall”

“emissary”

“outlet”

SCALP

• Skin

• Connective Tissue

• Aponeurosis

• Loose connective tissue

• Pericranium

Temporal Bones