A&P 7: 206 Bones Flashcards
Skeleton (skeletal system)
composed of bones, cartilages, joints, and ligaments; accounts for about 20% of body mass; bones make up most of it
Axial skeleton
structured from 80 bones segregated into 3 major regions: the skull, vertebral column, and thoracic cage; forms the longitudinal axis of the body, supports the head, neck, and trunk, & protects the brain, spinal cord, and the organs in the thorax
Skull
body’s most complex bony structure; formed by cranial and facial bones, 22 in all
Cranium
cranial bones; enclose and protect the fragile brain and furnish attachment sites for head and neck muscles
Sutures
except for the mandible, all bones of the adult skull are firmly united by these interlocking joints, the lines of which have a saw-toothed/serrated appearance
Cranial vault
AKA the calvaria; forms the superior, lateral, and posterior aspects of the skull, as well as the forehead
Cranial base
forms the skull’s inferior aspects
Frontal bone
shell-shaped; forms the anterior cranium; articulates posteriorly with the paired parietal bones via the prominent coronal suture
Supraorbital margins
the frontal squamous region ends inferiorly at these thickened superior margins of the orbits that lie under the eyebrows
Anterior cranial fossa
the frontal bone extends posteriorly from the supraorbital margins, forming the superior wall of the orbits and most of this, which supports the frontal lobes of the brain
Supraorbital foramen (notch)
each supraorbital margin is pierced by this, which allows the supraorbital artery and nerve to pass to the forehead
Glabella
smooth portion of the frontal bone between the orbits
Frontal sinuses
the areas lateral to the glabella are riddled internally with these spaces
Parietal bones
2 large, curved rectangular bones that form most of the superior and lateral aspects of the skull, hence forming the bulk of the cranial vault
Coronal suture
where the parietal bones meet the frontal bone anteriorly
Sagittal suture
where the parietal bones meet superiorly at the cranial midline
Lambdoid suture
where the parietal bones meet the occipital bone posteriorly
Squamous suture
one on each side, where a parietal and temporal bone meet on the lateral aspect of the skull
Occipital bone
forms most of the skull’s posterior wall and base; articulates anteriorly with the paired parietal and temporal bones via the lambdoid and occipitomastoid sutures; the basilar part of this bone also joins with the sphenoid bone in the cranial base
Posterior cranial fossa
internally, the occipital bone forms the walls of this depression, which supports the cerebellum of the brain
Foramen magnum
in the base of the occipital bone is this large hole though which the inferior part of the brain connects with the spinal cord; flanked laterally by 2 occipital condyles
Occipital condyles
rockerlike; articulate with the 1st vertebra of the spinal column in a way that permits a nodding (“yes”) motion of the head
Hypoglossal canal
hidden medially and superiorly to each occipital condyle is this canal through which a cranial nerve (XII) passes
External occipital protuberance
just superior to the foramen magnum is this median protrusion; you can feel this knoblike projection just below the most bulging part of your posterior skull