RA 1 Exam 1 Skull Flashcards
The skull functions as the skeleton of the head and composed of 2 sections:
cranium (8) and face (14) bones.
The head is the skull with the fleshy parts added. The skull is the bony framework of the head.
Purpose of Skull
Protect the brain
Support the jaws
Serve as an attachment for muscles
Give form to the head
The geometric form of the skull is an oval from a front, side, or top view, there are variations.
Bones of the Cranium: Occipital 1 Parietal 2 Temporal 2 Frontal 1 Ethmoid 1 Sphenoid 1
Male Skull Size - Relatively large Frontonasal angle - Sharp angular Supraorbital ridges - Prominent Forehead - Slopes backward Surface cheekbone - Rough concave Mandible tip (chin) - Squarer Foramen magnum - Large long Mastoid processes - Large
Female Skull Size - Relatively small Frontonasal angle - Smooth curve Supraorbital ridges - Poorly developed Forehead - Nearly vertical Surface cheekbone - Smooth flat Mandible tip (chin) - Pointed Foramen magnum - Small round Mastoid processes - Small
Surface Bones of the Head (6/8)
Frontal Occipital Parietal 2 Temporal 2 Ethmoid - non surface Sphenoid - non surface
Anterior 1/3 of cranium forming the forehead, part of eye socket. Most of the anterior of the cranial floor.
Frontal
Comprised of 2 planes vertical (make up the forehead) and horizontal/crown (make up superior part of the cranium.
Frontal
Frontal Bone Eminences RA significance
Frontal Eminences (2) Supraorbital Margin (2) Superciliary arches (2) Glabella (1)
Rounded prominences on either side of the median line and a little inferior to the center of the frontal bone.
Frontal Eminences (2)
Warm-color area of the face, appears asymmetry
Frontal Eminences (2)
Superior rim of the eye socket (behind eye brows)
Supraorbital Margin (2)
Inferior part of the forehead just Superior to the medial ends of the eyebrows.
Superciliary arches (2)
Elevation located between the superciliary arches on the Inferior part of the frontal bone immediately above the root of the nose.
Glabella (1)
Point at which the two nasal bones touch the frontal bone that is inferior to the glabella.
Root
Frontal bone Articulates with
Parietal bones at the Coronal Suture
The lowest most posterior part of the back and base of the cranium that acts as a Cradle for the brain.
Occipital
Occipital Bone Eminences RA significance
Occipital Protuberance
Foramen Magnum
Opening in the occipital bone through which the spinal cord, spinal arteries, and nerves pass
Foramen Magnum
Located between 2 Mastoid Processes and assist in securing the head to the body in a decapitation death
Foramen Magnum
the prominence at the center of the external surface of the occipital bone.
Occipital protuberance
Occipital bone Articulates with
Parietal bone at Lambdiodal Suture
Temporal bone at the Squamosal Suture
Forms superior portion of the sides and back of the cranium and posterior 2/3 of roof of cranium
Parietal
Parietal Bone Eminences RA significance
Parietal eminence
Vertex
Crown
Marked convex on the outer surfaces of the parietal bones. Widest part of the cranium. Located above posterior border of the ears.
Parietal eminence
Highest part of the cranium
Vertex
Area at the top/above of the cranium delineated by connecting four points together.
Crown
Where the king’s crown would rest on the 2 frontal eminences & 2 parietal eminences
Four Points
Parietal bone Articulates with
Occipital bone at Lambdiodal SutureTemporal bone at the Squamosal Suture
Frontal bone at Coronal Suture
Opposite side parietal at Sagittal Suture
Inferior portion of the sides and base of the cranium located inferior to parietal bones and anterior to occipital bone
Temporal
Parietal Bone Eminences RA significance
Squama Zygomatic arch (2) Mandibular fossa (2) External auditory meatus (2) Mastoid process (2)
like fish scale its the thin superior part of the temporal bone
Squama
Long thin arched process extending anteriorly from the squama to the zygomatic bone.
Zygomatic arch
Its immediately lateral (outside) the Squama and house the Temporalis muscle. In elderly emaciate case atrophy and dehydrate cause it to shrink as sunken temples and require tissue builder only after consulting a photograph
Temporal Cavity
Lies above the external auditory meatus and divides the length of the ear in half.
Zygomatic arch
Small oval depression or socket on the underside of the temporal bone.
Mandibular fossa
Anterior to the external auditory meatus. Condyle of the mandible articulates in this depression.
Mandibular fossa
Opening of the ear passage located in front of the mastoid process
External Auditory Meatus (2)
Temporal bone Articulates with
Parietal bone at Squamosa Suture
Occipital bone at Lambdoidal Suture
Greater wing of the Sphenoid bone
Rounded projection of the interior portion of temporal bone just media to the lobe of the ear.
Mastoid Process (2)
attaches to the mastoid process and the widest part of the neck measured by a straight line extending between the midpoint of the bellies of these 2 muscles
Sternocleidomastid Muscles
2 non-surface bones of the head
Ethmoid
Sphenoid
horizontal plate that forms the roof of the nasal cavity and closes the anterior part of the base of the cranium.
Ethmoid
located at the anterior part of the base of the skull and binds the other cranial bones together
Sphenoid
