Download - Skeletal system
SKELETAL SYSTEMLecture #3
Skeletal organization Axial skeleton – skull, vertebral column,
ribs, sternum Appendicular skeleton – pectoral girdle,
pelvic girdle, limbs
Axial – Skull bones Cranial – flat bones enclose and protect
brain Frontal bone: forehead and upper ridges
of eye sockets Parietal bones: upper left and right sides
of skull Temporal bones: lower left and right
(ears)
Skull bones cont’d Sphenoid bone: back of the eye sockets Ethmoid bone: contributes to eye
sockets and helps to support the nose Occipital bone: curves underneath to
form the back & base of the skull Foramen magnum (L. great opening):
where vertebrae connects to skull
But wait, there’s moreSkull bones!
Facial bones - front Maxilla – forms part of eye sockets and
sockets to anchor upper row of teeth Palatine bones – hard palate (roof of
mouth) Vomer bone – behind palatine & part of
nasal septum
But wait, there’s moreSkull bones!
Zygomatic bones: cheek bones & outer portion of eye socket
Nasal bones: underlie the upper bridge of nose (space between maxilla & nasal bones is the nasal cavity)
Lacrimal bones: inner eye sockets with tear duct (drains to nasal cavity)
All skull bones joined tightly except for mandible (speak & chew)
Mandible: lower jaw w/ sockets for teeth Sinuses are air spaces which make the
skull lighter and give the human voice its tone and resonance
Each sinus is lined with tissue that secretes mucus & connects to nasal cavity by small passageways
Blocked sinuses = pain Respiratory infections cause sinus tissue
to become inflamed and block the passages to the nasal cavity
Sinusitis = sinus inflammation Fluid gets trapped causing sinus pressure
headache
Hyoid Bone – structure & function
U-shaped, superior to larynx in the neck The only bone that isn’t articulated with
another bone Suspended from styloid processes of
temporal bone Anchors the tongue & serves as
attachment for swallowing muscles
Vertebral Column Skull to pelvis - rib attachment, pelvic
girdle attachment Protects spinal cord as it passes through
vertebral canal 33 vertebrae
7 neck / cervical 12 chest / thoracic 5 lumbar / lower back 5 sacral 3-5 tailbone / coccygeal
4 curvatures Cervical & lumbar = convex Thoracic & sacral = concave
FIGURE 5.7
Thoracic (Rib) Cage 12 thoracic vertebrae = 12 ribs connect
to vertebrae posteriorly Upper 7 connect directly to sternum via
cartilage = true ribs Lower 5 = false ribs – upper 3 attach to
sternum with common cartilage & bottom 2 are not attached to sternum (floating)
FIGURE 5.9