Exercise 10 The Axial Skeleton

bones and landmarks
Frontal bone
the large cranial bone forming the front part of the cranium: the forehead and the upper part of the orbits
Located between the superciliary arches and the inferior part of the frontal bone at the root of the nose.
Parietal bone
either of two skull bones between the frontal and occipital bones and forming the top and sides of the cranium
sagittal suture
midline articulation point of the two parietal bones
coronal suture
articulation between parietal bones and frontal bone anteriorly
Temporal bone
located below each parietal bone forming the lower sides and the base of the skull
squamous suture
Point of articulation of the temporal bone with the parietal bone
zygomatic process
Bridgelike projection that forms the posterior zygomatic arch (cheekbone).
mandibular fossa
the depression in the temporal bone into which the condyle of the mandible fits.
external acoustic meatus
canal leading to eardrum and middle ear: tympanic region marking of the temporal bone
styloid process
Small, pencil-like shaped projection that comes off of the bottom of the temporal Bone
mastoid process
rough projection on the temporal bone, inferior and posterior to external acoustic meatus; attachment site for muscles
stylomastoid foramen
Tiny opening between the mastoid and styloid processes through which cranial nerve VII leaves the cranium
jugular foramen
located on inferior, petrous part of the temporal bone posterior to the carotid canal near the suture line of the occipital and temporal bones
carotid canal
located on petrous (bony) portion of the temporal bone, anterior to the jugular foramen which internal carotid artery passes
internal acoustic meatus
opening on the posterior aspect (petrous region) of the temporal bone allowing passage of the cranial nerves VII and VIII
Occipital bone
forms the posterior floor and walls of the cranium
lambdoid suture
Site of articulation of the occipital bone and parietal bones
foramen magnum
large opening in base of occipital allows the spinal cord to join with the brain
occipital condyle
Rounded projections lateral to the foramen magnum that articulate with the first cervical vertebra (atlas)
hypoglossal canal
This foramen has appreciable depth and is found in the occipital bone on the lateral surface of the foramen magnum. It provides a passage for cranial nerve XII.
Sphenoid bone
butterfly shaped bone that forms part of the floor and sides of the cranium
greater wing
articulate with the temporal bone on either side and anteriorly with frontal and zygomatic bones to form part of the orbit
optic canal
opening located in the lesser wing of the sphenoid, medial to the superior orbital fissure
superior orbital fissures
jagged openings in orbits providing passage for cranial nerves to enter the orbit where they serve the eye between greater and lesser wings
foramen ovale
2nd of three holes situated laterally of the sella turcica, more oval shaped
lesser wing
anterior and superior to greater wing on the inferior of the sphenoid bone
sella turcica
a saddle-shaped region in the sphenoid midline which nearly encloses the pituitary gland; feature of the sphenoid bone
foramen rotundum
1st of three holes situated laterally of the sella turcica, top one
Ethmoid bone
forms part of the posterior portion of the nose, the orbit, and the floor of the cranium
crista galli
bony ridge that projects upward into the cranial cavity
cribriform plates
(behind nose) one on either side of crista galli (projection for attachment of membranes covering brain); form roof of nasal cavity
perpendicular plate
inferior projection of the ethmoid that forms the superior part of the nasal septum
middle nasal concha
the middle thin, spongy, bony plate with curved margins, part of the ethmoidal labyrinth, projecting from the lateral wall of the nasal cavity and separating the superior meatus from the middle meatus
The horseshoe-shaped bone forming the inferior jaw.
mandibular condyle
Articulate with mandibular fossa of temporal bone. Only freely movable joint in the skull.
coronoid process
front point of semi-circle of the jaw hinge, location of attachment for jaw muscles
Back corner of mandible where body and ramus meet
mental foramen
two small openings near the front of the mandible for the passage of the mental nerve/ blood vessels.
mandibular foramen
opening in the inner surface where the alveolar nerve of the 5th trigemenial nerve passes(sensory innervation for the teeth and gums)
alveolar margin
projections on the maxilla and mandible where tooth sockets are located
Maxillary bone
upper jaw bone, there are 2 that join together, contain sinuses, has sockets that hold the teeth
palatine process
forms the anterior portion of the hard palate (roof) of the mouth also forms parts of the nasal cavity and eye orbits
infraorbital foramen
opening into anterior surface of maxilla underneath eye, carries the infraorbital nerve and artery
Palatine bone
either of two irregularly shaped bones that form the back of the hard palate and helps to form the nasal cavity and the floor of the orbits
Zygomatic bone
the arch of bone beneath the eye that forms the prominence of the cheek
Lacrimal bone
small fragile bone making up part of the front inner walls of each eye socket and providing room for the passage of the lacrimal ducts(tear ducts)
Nasal bone
an elongated rectangular bone that forms the bridge of the nose
Vomer bone
shaped like the blade of a plow, it forms part of the nasal septum along with the perpendicular plate of the ethmoid
Inferior nasal concha
shelf-like projection of bone; covered by thick mucosa; increases surface area of nasal cavity and warm inhaled air
individual segment of the backbone; encloses and protects the spinal cord
transverse process
one of two processes that extend from each vertebra and provide the point of articulation for the ribs
vertebral foramen
opening in the middle of the vertebra. the spinal cord passes through here.
spinous process
Posterior projection from the junction of the two laminae. Attachment site for muscles. Not present in the atlas.
body of vertebra
This is a relatively large portion of each vertebra. The intervertebral disc attaches to it. This portion is responsible for transfering most of the weight to the vertebra inferior to it.
cervical vertebrae
the first set of seven vertebrae that form the neck; also known as C1 through C7
has no body and articulates cranially with the occipital condyles; allows one to shake head "yes"; C1
C-2, has large, broad dorsal spinous projections and cranial projection that fits into C-1, allows one to pivot head
dens or odontoid process
tooth-like or peg-like process on C2 that projects up into C1.
Thoracic vertebrae
T1-T12; have distinctive heart-shaped bodies; long, slender spinous processes and articulations of the ribs
Lumbar vertebrae
L1-L5 no transverse foramina- no rib facets- largest body- thick spinous processes that extend horizontally, lower back area
wedge-shaped bone consisting of five fused vertebrae forming the posterior part of the pelvis
the tailbone, made up of the four fused vertebrae at the base of the spinal column
the flat bone that articulates with the clavicles and the first seven pairs of ribs
triangular shaped upper region of sternum. articulates with the clavicles and with the cartilages of the first pair of ribs.
xiphoid process
made of cartilage found at the end of the sternum, provide an attachment point for the diaphragm
body of sternum
largest portion of sternum & is found inferior of the manubrium & superior to the xiphoid process. it is where the cartilage from the 2nd through 7th ribs attach
true ribs
top 7 pairs of ribs that attach directly to the sternum by costal cartilage
false ribs
lower 5 pairs, first 3 attached to sternum of 7th ribs, lowest 2 pairs dont (floating ribs)