A+P Skeletal System (cranium, facial bones, vertebral column, bony thorax, pectoral/pelvic girdle, arm, leg, foot, joints)

Frontal bone

Forehead

Bony projections under eyebrows

Superior to orbits (eyesockets)

Meets parietal at coronal suture

Parietal bone (2)

Superior/lateral walls of cranium

Meet each other at sagittal suture

Articulate w/ frontal at coronal suture

Meet temporal at squamous suture

Meet occipital at lambdoid suture

Temporal bone (2)

Inferior to parietal

Form superior + lateral walls of cranium

Meet parietal at squamous suture

BM:

• External auditory meatus — allows sound to enter cranium → eardrum

• Styloid process — icicle-like projection for attachment of neck muscles

• Zygomatic process — lateral cheekbone

• Mastoid process — large roughened surface (posterior to ear) for muscle attachment

• Jugular + carotid foramina — openings for blood vessels to brain

Occipital bone

Posterior, inferior wall of cranium

BM:

• Foramen magnum — opening for spinal cord to enter cranium

• Occipital condyles — where skull rests on first vertebrae

Sphenoid bone (butterfly shaped)

Anterior floor of cranium

BM:

• Sella turcica — saddle-shaped, holds pituitary gland

Ethmoid bone

Medial walls of orbits & roof of nasal

BM:

• Cribriform plates — allow olfactory (smell) nerve to enter cranium

Mandible

Lower jaw bone

Holds lower teeth in alveolar processes

BM:

• Mental foramina — allows nerves to enter mandible

Maxilla (2)

Upper jaw bones

Hold upper teeth in alveolar processes

House paranasal sinuses

Palatine bone (2)

Posterior roof of mouth

Hard palate

Palatine processes extended from maxillae

Zygomatic bone (2)

Cheeks & lateral to orbits

Lacrimal bone (2)

Anterior medial walls of orbit

House tear ducts

Nasal bone

Nose bridge

Inferior nasal concha bone (2)

Curved bones in nasal cavity

Vomer bone

Medial wall of nasal cavity

Hyoid bone

Suspended in anterior neck (not really a facial bone)

Anchors tongue

Fetal skull

¼ length/size of entire skeleton

Same bone layout as adult skull BUT w/ Fontanels — “soft spots” composed of hyaline cartilage | allows compression of head during birth | ossify by age two

Synarthrotic joints

Fixed, immovable

Ex: cranial sutures

Amphiarthrotic joints

Minimal movement

Ex: SI joint (between pelvis & sacrum), pubic symphysis, ribs/sternum

Diarthrotic joints

Free movement

Ex: elbow, knee, shoulder

Fibrous joints

Synarthrotic joints

Held together by fibrous connective tissue

Ex: cranial sutures, syndesmoses

Cartilaginous joints

Amphiarthrotic joints

Ex: pubic symphysis, intervertebral disks, epiphyseal plates, sympheses

Synovial joints

Diarthrotic joints

All joints of limbs are synovial joints

Surrounded by articulate cartilage/capsule

• Hyaline cartilage pad, bursae sacs for cushioning, tendon sheath

• Filled w/ synovial fluid (lubricant/coolant)

Generally surrounded by ligaments which hold bones together

Types of synovial joints classified by directional movement

Ex: elbow, knee, shoulder

BM Projections — Muscle and ligament attachment sites

• Tuberosity: Large, rounded projection; may be roughened

• Crest: Narrow ridge of bone; usually prominent

• Trochanter: Very large, blunt, irregularly shaped process (only on femur)

• Line: Narrow ridge of bone; less prominent than crest

• Tubercle: Small, rounded projection or process

• Epicondyle: Raised area on or above a condyle

• Spine: Sharp, slender, often pointed projection

• Process: Any bony prominence

BM Projections — Aid joint formation

• Head: Bony expansion carried on a narrow neck

• Facet: Smooth, nearly flat articular surface

• Condyle: Rounded articular projection

• Ramus: Armlike bar of bone

BM Depressions + openings

Passage of blood vessels and nerves

• Groove: Furrow

• Fissure: Narrow, slitlike opening

• Foramen: Round or oval opening through a bone

• Notch: Indentation at edge of structure

Other

• Meatus: Canal- or tunnel-like passageway

• Sinus: Cavity within a bone, filled with air and lined with mucous membrane

• Fossa: Shallow, basin-like depression in a bone, often serving as an articular surface