Exam 2 Review:  Chapter 7:  Axial Skeleton

axial - Belonging to the axis of the body; e.g., the axial skeleton, which consists of the skull (cranial and facial bones), the vertebrae, the ribs, and the sternum.

axial skeleton - The bones which make up the central axis of the body and support the head and trunk; it consists of the skull (cranial and facial bones), the vertebrae, the ribs, and the sternum; those bones not a part of the appendicular skeleton.

cranial - Of or relating to the skull, or more specifically to the brain and braincase; cranial bones include the frontal, parietals, occipital, temporals, sphenoid, and ethmoid.

fontanel - Any of the six soft membranous gaps between the incompletely formed cranial bones of a fetus or an infant; so called because it exhibits a rhythmical pulsation and the French word "fontanelle" means a little fountain. [Nicknamed the soft spot.]

paranasal sinuses - Any of various air-filled cavities in the bones of the skull, especially one communicating via a narrow opening with the nasal cavity or pharynx; they are located in the ethmoid, sphenoid, frontal and maxillary bones.

orbit - Either of the two bony cavities in the skull containing an eye and its external structures; formed by elements of the ethmoid, frontal, maxillary and lacrimal bones; an eye socket.

vertebral column - The series of vertebrae forming the axis of the skeleton, supporting the trunk, and protecting the spinal cord; divided into five groups by location: cervical, thoracic, lumbar, sacral and coccygeal groups.  aka. spinal column, spine.

vertebra - One of the serial segments of the spinal column; a vertebra usually consists of a more or less cylindrical and solid body, or centrum, which is surmounted dorsally by an arch, composed of lateral pedicels and dorsal lamina, leaving an opening which forms a part of the canal containing the spinal cord. From this dorsal, or neural, arch spring various processes, which have received special names: a dorsal spinous process on the middle of the arch; two anterior and two posterior articular processes, or zygapophyses; and a transverse processes on each side. In those vertebr[ae] which bear well-developed ribs, a tubercle near the end of the rib articulates at a tubercular facet on the transverse process, while the head of the rib articulates at a more ventral capitular facet.

atlas - The first cervical vertebra of the neck, which supports the skull, articulating with the condyles on the occipital bone above and forming a pivot or rotary joint with the axis (C2) below; the atlas lacks a vertebral body.

axis - The second cervical vertebra of the neck, which exhibits a unique anterior extension of bone, the odontoid process or dens, which serves as the axis of rotation within a synovial pivot joint about which the skull (head) and the atlas (C1) turn as a unit.

vertebral foramen - The hole or opening through which the spinal cord passes in each vertebrae, bounded by the vertebral body and the vertebral arch (pedicels and laminae).

intervertebral foramina - The hole or opening through which the spinal nerves pass as they exit the dorsal body cavity, bounded by the inferior notch in the pedicel of the superior vertebra and the superior notch in the pedicel of the inferior vertebra.

intervertebral discs - The two part cartilaginous joints connecting any two vertebrae, consisting of an outer ring or collar, the annulus fibrosus, composed of dense fibrocartilage with an outer wrapping of dense collagen fibers, and an inner cushioning mass, the nucleus pulposus, consisting of gelatinous elastic connective tissue.

annulus fibrosus - The outer ring or collar of an intervertebral disc composed of dense fibrocartilage with an outer wrapping of dense collagen fibers.

nucleus pulposus - The inner cushioning mass of an intervertebral disc consisting of gelatinous elastic connective tissue which is derived from the remnants of the embryonic notochord; it helps absorb the compressive forces placed on the vertebral column when standing, walking, or running.

normal curves of vertebral column - Adult humans exhibit a complex curvature to the vertebral column.  Each of the four main groups of vertebrae form their own curve.  The cervical and lumbar curves are concave posteriorly while the thoracic and sacral curvatures are convex posteriorly.  This structural arrangement permits the human to balance the head on the vertebral column efficiently.  [Note:  the thoracic and sacral curvatures are referred to as primary curvatures because they can be observed in the embryo; the cervical and lumbar curves are referred to as secondary curvatures because the develop after birth.]

List:

 1. the major divisions and subdivisions of the skeletal system.
 

Axial Skeleton	Appendicular Skeleton
1.  skull:  cranium and face 2.  vertebral column:  cervical, thoracic, lumbar, and sacral regions 3.  rib cage:  ribs and sternum	1a.  pectoral girdle:  scapulas and clavicles 1b.  pectoral limb:  arm and hand bones 2a.  pelvic girdle:  coxal bones 2b.  pelvic limb:  leg and foot bones

 4. the facial bones.

          mandible, maxilla, zygomatic, nasal, lacrimal, palatine, vomer, inferior nasal conchae

 5. the cranial bones.

          frontal, parietal, occipital, temporal, sphenoid, ethmoid, ear ossicles, 

 6. the four spinal or vertebral regions.

          cervical, thoracic, lumbar, and sacral

 7. normal spinal curves in the correct order from superior to inferior.

          cervical, thoracic, lumbar, and sacral

 8. four different processes of the vertebrae.

          spinous process, transverse processes, superior articular processes, inferior articular processes

Sketch and Label

1.  The general structure of a typical vertebra in a superior view.