Chapter 7 Axial Skeleton

206 bones

the skull, vertebral column, rib cage

upper & lower limbs and shoulder & pelvic girdle

-The skull contains cranial bones that protect the brain joined at sutures. The rest of the skull is made up of facial bones.

-The skull is composed of many cavities and openings, which allow nerves, blood vessels, and organs to function

• composed of eight bones, two are paired
• parietal (2), frontal, ethmoid, temporal (2), occipital, and sphenoid

14 facial bones - mandible, maxilla (2), palantine (2), nasal (2), vomer, inferior nasal conchae (2), palantine, zygomatics (2), nasal (2), lacrimal (2)

cavities that hold the eye and all tissues related to the eye formed by the union of seven bones which also form the lacrimal fossa, optic foramen, and orbital fissures.

-made up of bone and cartilage with the topo made by cribiform plate and the bottom made by palantine.

-There are 3 conchaes (shelfs) with 2 made by ethmoid bone and one by the inferior conchae bone.

-Nasal septum divides the nose down the middle

26 (33 techniccally but 9 are fused)

forms the body's axis, protects spinal cord, articulates with ribs & provides attachment for dorsal muscles & rib muscles

anterior & posterior longitudinal ligaments, supraspinous & interspinous ligaments, & the ligamentum flavum

composed of fribrocartilage enduring compression & shock absorption. (2 regions: annulus fibrosus & nucleus pulpuses that make up 25% of the height of the column & flatten throughout the day)

cervical (7), thoracic (12), lumbar (5), sacrum (5 fused), coccyx (4 fused)........fused means connected

• - each region has a curve:
• * cervical & lumbar-concave
• *thoracic & sacral-convex

all vertebrae except first 2 (atlas & axis) share common characteristics that differ slightly according to region. All vertebrae have a centrum (body), vertebral arch, vertebral foramen, pedicles, laminae, spinous process, transverse process, & inferior/superior articulating facets

* cervical vertebrae - retangle like containing bifid spinous process, triangular vertebral foramen, has transverse foramen, superior/anterior facets located in slightly opposite positions

* thoracic vertebrae - body is slightly heart shape, has demifacets (for ribs), long spinous process, circular vertebral foramen, transverse processes articulate with ribs, provides most of the rotation

* lumbar vertebrae - bears most of the weight so it has a massive body, short thick pedicles & laminae, triangular vertebral foramen, articulating facets prevent rotation, and short think spinous process

* sacrum - five fused vertebrae that articulates with the bones of the pelvis

* coccyx - 4 (or 3-5) fused vertebrae, also known as the tail bone

lateral curvature that happens most often in thoracic region with the cause sometimes unknown. It can be due to muscle balances (vertebrae deformed and/or other side of muscles is stronger pulling vertebral column to that side) and it can also cause compression of the lung.

a bent on a saggital plane along the thoracic region causing a hunchback that happens most often in women as a result of vertebral fractures do to osteoporosis

over curvature of the lumbar region causing a swayed back often occuring in people carrying a large long in front or spinal tuberculosis or osteomalacia (bone softening)

rib cage - assist in breathing as well as protecting internal organs

contains the sternum that have 3 sections: manubrium, body, xyphoid process (cartilage) and ribs that have 12 pairs of ribs with the first 7 being true (attach to sternum) and the last 5 floating (false ribs)