Axial Osteology

number of bones that comprise the skull

22

dome-like roof of the cranial cavity

calvaria

depression on the side of the skull anterior and slightly superior to the ears

temporal fossa

horizontally oriented bony bridge formed between the zygomatic bone and temporal bone, located about halfway between the eye and the ear

zygomatic arch

part of skull that houses the eyeball, has 7 osseous components: maxilla, frontal, sphenoid, zygomatic, lacrimal, ethmoid, and palatine bones)

orbit

large, elongated openings in the orbit

superior and inferior orbital fissures (inferior pictured)

large median opening which accommodates the respiratory passageways

anterior nasal aperture

large passageway in the occipital bone through which the spinal cord passes

foramen magnum of the occipital bone

neurovascular passageway located a few millimeters lateral and anterior to the foramen magnum

jugular foramen

paired foramina about 2 cm anterior to the foramen magnum

left and right foramen lacerum

bony roof of the oral cavity

bony palate

unpaired flat bone which forms the anterior aspect of the skull

frontal bone

forms the superior limit of the anterior aspect of the orbit

supraorbital margin of the frontal bone

small diverticulum in the frontal bone located internally on the midline, just anterior to the ethmoid bone

blind foramen of the frontal bone

paired flat bone which lies posterior to the frontal bone

parietal bone

paired, partly flat, partly irregular bone located inferior to each parietal bone

temporal bone

3 main subdivisions of the temporal bone

petrous, tympanic, squamous parts of the temporal bone

forms the prominent opening on the posteromedial aspect of the ridge on temporal bone

internal acoustic meatus of the temporal bone

forms a palpable projection behind and below the ear

mastoid process of the temporal bone

an elongated pointed projection just anterior to the mastoid process

styloid process of the temporal bone

joins the temporal process of the zygomatic bone to the form the zygomatic arch

zygomatic process of the temporal bone

most significant landmark of the tympanic part of the temporal bone, sound-conducting passageway

external acoustic meatus of the temporal bone

where the facial nerve emerges below external acoustic meatus of the temporal bone

stylomastoid foramen of the temporal bone

paired neurovascular passageway through the temporal bone anterior to the jugular foramen and slightly medial when viewed from the cranial cavity

carotid canal of the temporal bone

on inferior aspect of the temporal bone, a depression that forms part of the temporomandibular joint

fossa mandibularis (pic is not exact)

unpaired, partly flat, partly irregular bone forming the posterior aspect of the skull

occipital bone

occipital bone articulates with the atlas via left and right...

condyles of the occipital bone

paired foramina passing through the occipital bone laterally

hypoglossal canals of the occipital bone

left and right vascular channels located posterior to the occipital condyles

condyloid canals of the occipital bone

subtle, palpable, postero-inferior projection from the occipital bone

external protuberance of the occipital bone

unpaired, partly flat, partly irregular bone which forms part of the floor and part of the wall of the cranial cavity

sphenoid bone

paired smaller named part of sphenoid bone

lesser wings of the sphenoid bone

paired larger named part of the sphenoid bone

greater wings of the sphenoid bone

major landmark on the greater wing in the inferiorly directed

pterygoid process of the sphenoid bone (has medial and lateral laminae)

floor of cranial cavity slopes up from the anterior aspect of the foramen magnum to a small depressed area in the sphenoid bone

sella turcica of the sphenoid bone

anterior to sella turcica are posterior openings of this

optic canal of the spenoid bone

paired foramina lateral to the sella turcica, transmit the mandibular nerves

oval foramina of the sphenoid bone

anterior and slightly medial to the oval foramina, transmit maxillary nerves

round foramina of the sphenoid bone

posterior and slightly later to each oval foramen

foramen spinosum of the sphenoid bone

unpaired bone, contributes to formation of both orbits

ethmoid bone

median ridge on internal base of the skull on ethmoid bone

crista galli of the ethmoid bone

on each side of crista galli, openings on a small plate

cribriform foramina of the ethmoid bone, cribriform plate of the ethmoid bone

vertically-oriented inferior extension of ethmoid bone

perpendicular plate of the ethmoid bone

14 bones of the face are collectively called

viscerocranium

paired bone which forms the inferior bony "scroll" of the nasal cavity

inferior nasal concha

paired flat bone which forms a small part of the medial wall of the orbit

lacrimal bone

small paired flat bone which forms the osseous portion of the bridge of the nose

nasal bone

unpaired flat bone that forms the inferior part of the nasal septum

vomer

paired, has about 35 named landmarks, superior teeth here

maxilla

portion termed alveolar process of the maxilla supports all superior teeth in sockets called

dental alveoli of the maxilla

the opening under each orbit that transmits the infraorbital nerve and vessels

infraorbital foramen of the maxilla

horizontal part of maxilla, projects back toward the palatine bone

palatine process of the maxilla

paired flat bone, lies posterior to the maxillae

palatine bone

part of the palatine bone that contributes to the bony palate

Horizontal plate of the palatine bone

vertically-oriented part of the palatine bone that projects superiorly from the lateral aspect of the horizontal plate

Perpendicular plate of the palatine bone

paired "cheek" bone

zygomatic bone

part of the zygomatic bone that projects superiorly to meet the frontal bone

frontal process of the zygomatic bone

part of the zygomatic bone that projects to meet zygomatic process of the temporal bone

temporal process of the zygomatic bone

unpaired flat bone that supports the inferior teeth

mandible

horizontally-oriented part of the mandible

body of the mandible

vertically-oriented part of the mandible

ramus of the mandible

left and right sides of mandible joined on midline here

mandibular (mental) synthesis

anterolateral aspects of the bodies of the mandible, these openings

mental foramina of the mandible

bony sockets into which roots of inferior teeth project

dental alveoli of the mandible

where ramus and body of the mandible meet

mandibular angle

neurovascular opening on the medial side of each ramus of the mandible

mandibular foramen

anterior of two major landmarks on superior aspect of each mandibular ramus

coronoid process of the mandible

posterior projection, landmark on the superior part ramus of the mandible

condyloid process of the mandible

separates projections on superior aspect of the ramus of the mandible

mandibular notch

end of condyloid process of the mandible

head of the mandible

portion just inferior to the head of the mandible

neck of the mandible

palpable U-shaped bone of the head located in the upper cervical region

hyoid bone

big ends of the hyoid bone

greater horns of the hyoid bone

smaller projections from the hyoid bone

lesser horns of the hyoid bone

solid, anterior portion of a vertebra

vertebral body (not the blue in picture)

large, vertically oriented foramen in a single vertebra posterior to vertebral body

vertebral foramen

thin plate of vone which surrounds the spinal cord and forms the vertebral foramen on the posterior aspect of vertebral body.

vertebral arch

left or right "side" of vertebral arch

pedicle of vertebral arch

left or right half of the "roof" (posterior wall) of vertebral arch

lamina of vertebral arch

single projection from the posterior aspect of the vertebral arch

spinous process of a vertebra

either of two (left and right) projections which extend laterally near junction of each pedicle and lamina of vertebral arch

transverse process of a vertebra

any one of the four processes (left/right, superior/inferior) which project inferiorly and superiorly from the vertebral arch near junction of each pedicle and ipsilateral lamina

articular process of a vertebra

defects" near the junction of the verebral body with its pedicles

superior and inferior vertebral notches

contiguous vertebral notches of adjacent vertebrae, through which spinal nerves emerge

intervertebral foramina

seven vertebrae immediately inferior to the skull

cervical vertebrae (C1-C7)

cervical vertebrae have small vertebral bodies and a hole in each transverse process termed...

transverse foramen of a cervical vertebra

vertebra in the lower cervical region with the longest spinous process

prominent vertebra

first cervical vertebra

Atlas (C1)

markedly reduced body of c1 vertebra

anterior arch of the atlas

arch" of atlas to distinguish from anterior part

posterior arch of the atlas

lateral aspects of the atlas where its two arches join

lateral masses of the atlas

second cervical vertebra

axis, c2

superior tooth-like projection from c2

dens of the axis

12 vertebrae inferior to the cervical region which bear ribs

thoracic vertebrae (T1-T12)

articular facets located on the posterolateral aspect of the vertebral bodies articulate with the heads of ribs

inferior and superior costal fovea of a thoracic vertebra

most thoracic vertebrae also have a facet of each transverse process

costal fovea of the transverse process of a thoracic vertebra

five vertebrae located just below thoracic vertebrae

lumbar vertebrae (L1-L5)

vertebrae located below the lumbar vertebrae

sacral vertebrae (S1-S5)

sacral vertebrae fuse into one definitive bone

sacral bone/bony sacrum

broad superior end of the sacrum

base of the sacral bone

anterior border of the body of its first sacral component projects into the pelvic cavity

promontory of the sacral bone

each lateral part of sacral bone has a laterally directed part that articulates with auricular surface of ipsilateral ilium to form sacroiliac joint

auricular surface of the sacral bone

anterior aspect of the bony sacrum, named as faces pelvic cavity

pelvic surface of the sacral bone

pelvic surface of sacral bone is penetrated on each side by four of these

anterior foramina of the sacral bone

posterior aspect of the bony sacrum

dorsal surface of the sacral bone

dorsal surface of sacral bone penetrated by four openings, correspond to those on other side

posterior foramina of the sacral bone

spinous processes of the sacral elements are partially fused

median crest of the sacral bone

sacral portion of vertebral canal

canal of the sacral bone

inferior, pointed end of bony sacrum

apex of the sacral bone

vertebrae that form the tailbone

coccygeal vertebrae (Cy1-Cy4) (coccyx)

human vertebral formula

C7T12L5S5Cy4

rounded portion of rib that articulates with costal fovea of the bodies of the vertebrae

head of a rib

constricted portion of a rib immediately adjacent to its head

neck of a rib

major portion of a rib

body of a rib

a subtle enlargement on the body of most ribs near junction of body and neck

tubercle of a rib

portion of the body of a rib which makes the tightest bend

angle of a rib

subtle linear depression along the internal surface of the inferior border of a rib which transmits intercostal vessels and nerves

groove of a rib

eleven spaces between ribs

intercostal spaces

each rib has this attached to anteromedial end of its body

costal cartilage

costal cartilages of 1-7 ribs join directly to the sternum, these are called...

true ribs

ribs 8-12 do not have costal cartilage that connect directly to the sternum, these are...

false ribs

costal cartilages of ribs 8-10 attach to each other and to that of rib 7 to form this

costal arch

last two false ribs on each side are called...

floating ribs

elongated flat bone 15-20 cm long costal cartilage connect here on true ribs

sternum

widest and superior portion of the sternum

manubrium of the sternum

unpaired median indentation at the top of the manubrium

jugular notch of the sternum

paired indentation on either side of jugular notch

clavicular notch of the sternum

longest segment of the sternum

body of the sternum

inferior segment of the sternum

xiphoid process of the sternum

angle formed at the junction of the body and manubrium of the sternum

sternal angle

indentations along the lateral aspects of the sternum which receive the ends of the first seven pair of costal cartilages

costal notches of the sternum

sternum, thoracic part of vertebral column, and ribs/costal cartilages collectively

thoracic cage

opening at top of thoracic cage

superior thoracic opening (thoracic inlet)

larger opening at bottom of thoracic cage

inferior thoracic opening (thoracic outlet)