Chapter 8 - The Skeletal System Flashcards
How many bones are in the adult skeletal system?
Approximately 206 bones
What are the regions of the skeleton?
- Axial skeleton - skull, auditory ossicles, hyoid bone, vertebrae, and thoracic cage.
- Appendicular skeleton - upper limb bones, pectoral girdle, lower limb bones, and pelvic girdle.
Most of the bones in the skull are connected by..?
Immovable joints called sutures which are visible as seams on the surface
What are the para nasal sinuses?
a. Named for the bones they are in - frontal, sphenoid, ethmoid, maxillary.
b. They are connected with the nasal cavity, lined with mucous membrane, and filled with air.
What are the cranial bones?
The bones that enclose the brain:
- Frontal bone - forms the forehead, part of the roof of the cranium and part of the roof of the orbit.
- Parietal bone - forms most of the cranial roof and part of its walls.
- Temporal bones - anterior to the ear.
- Occipital bone - rear of the skull.
- Sphenoid bone.
- Ethmoid bone - located behind the eye.
What are the main parts of the temporal bones?
a. External acoustic meatus - opening into the ear canal.
b. Petrous part - houses the middle and inner-ear cavities.
c. Internal acoustic meatus - an opening that allows passage of the vestibulocochlear nerve.
What are the main parts of the occipital bone?
a. Foramen magnum - hole that allows spinal cord to meet the brain.
b. Occipital condyle - where the skull rests on the vertebral column.
What is the main part of the sphenoid bone?
a. Optic foramen - permits passage of the optic nerve and an artery.
b. Sella turcica - a saddle-like surface which houses pituitary gland.
What is the main part of the ethmoid bone?
a. Cribriform plate - perforated with cribriform foramina which allow passage of olfactory nerves to the olfactory bulb.
What are the facial bones?
- The maxilla - forms the upper jaw
- Palatine bones - form posterior 1/3 of the hard palate.
- Zygomatic bones - form the angles of the cheeks.
- Lacrimal bones - house the lacrimal sacs where tears collect and drain into the nasal cavity.
- Nasal bones - form the bridge of the nose.
- Vomer - forms the interior 1/3 of the nasal septum.
- Mandible
What are the main parts of the maxilla?
a. Alveola - deep sockets for the roots of each upper tooth.
b. Palatine process - roof of mouth and the floor of the nasal cavity.
What is the main part of the mandible?
a. Alveoli - sockets for lower teeth
What are the bones associated with the skull?
- Auditory ossicles (malleus, incus, and stapes) - for hearing.
- Hyoid bone - attachment site of muscles that control the mandible, tongue, and larynx.
The skull at infancy
- The skull bones at birth are not yet fused.
2. Fontanels - spaces between the infused cranial bones.
What are the types of fontanels?
a. Anterior fontanel - between the frontal and parietal bones.
b. Posterior fontanel - between the parietal and occipital bones.
c. Sphenoid fontanels - between the frontal, parietal, temporal, and sphenoid bones.
d. Mastoid fontanel - between parietal, occipital and temporal bones.
What is the vertebral column?
The vertebral column physically supports the skull and trunk, allows their movement, protects te spinal cord, and absorbs stress