The Axial Skeleton

Anatomy Chapter 7, Section 1

Facial Bones

14 bones which protect and support entrances to respiratory and digestive tracts

Crainial Bones

8 bones which protect the brain

Coronal Suture

Connects the frontal bone to the tow parietal bones

Calvaria

The skullcap

Squamous Suture

Joins the temporal bone and the parietal bone

Sagittal Suture

Connects the two parietal bones

Lambdoid suture

Separates the occipital from the two parietal bones

Nasal Bones

(facial) Connect to cartilage to support the upper bridgeof the nose

Lacrimal Bones

(facial) Form part of the medial wall of the eye sockets

Palatine Bones

(facial) Form posterior portion of hard palate, and contribute to the floor of each orbit

Zygomatic Bones

(facial) Form prominent cheekbones, and contribute tothe structure of the orbits

Maxillae

(facial) Supports upper teeth / jaw, inferior orbits, and from the hard palate

Inferior Nasal Conchae

(facial) Increase surface area to humidify / warm inhaled air

Vomer

(facial) Forms inferior portion of bony nasal septum

Mandible

(facial) Lower jaw

Frontal Bone

(cranial) Forms anterior portion of cranium and roof of orbits

Parietal Bones

(cranial) Form roof and sides of the cranium

Sphenoid 

(cranial) Unites cranium and facial bones; strengthens sides of the skull

Ethmoid

(cranial) Forms floor of the cranium; roof of the nasal cavity, and medial part of the orbital wall

Occipital Bone

(cranial) Contributes to the posterior, Lateral and inferior cranium surfaces

Temporal Bone

(cranial) Forms part of cranium lateral wall; Articulates with mandible / jaw and surrounds inner ear

Mastoid Process

Attachment site for muscles that rotate / extend the head

Styloid Process

Attached to ligaments supporting the hyoid bone, and tendons of several muscles

External Occipital Crest

Extends inferior to the external occipital protuberance; attaches ligament that helps stabilize cervical vertebrae

Superior and Inferior Temporal Lines

Curved Ridges Marking attachment sites for temporalis muscle (closes the mouth)

External Accoustic Meatus

Ends at the tymphatic memebrane (eardrum) on the lateral surface of the skull

Alveolar Processes

Projecting ridges containing spaces for upper teeth

Alveolar Portion of Mandible

Surrounds and supports lower teeth

Mental Protuberance

Attachment site for several facial muscles (chin area)

Mandibular Angle

Posterior, inferior corner of lower jaw

Frontal Sinuses

Hollow spaces in bone (vary greatly in size / time of appearance)

Hypoglossal Canal

Begins at lateral base of each occipital condyle and ends near foramen magnum; hypoglossal nerves pass through these canals

Internal Acoustic Meatus

Begins on medial surface of petrous part of temporal bone; passageway for blood vessels / facial nerves

Petrous Part 

Portion of Temporal bone, enclosing structures of the inner ear

Mandibular Fossa

Marking on inferior surface of temporal bone, where the mandible articulates

Occipital Condyles

Sites of articulation between skull and first cerival vertebra

Inferior and superior nuchal lines

ridges that intersect the occipital crest

Foramen Lacerum

Jagged slit between sphenoid and petrous part of the temporal bone; contains hyaline cartiage and small ateries

Foramen Ovale

Passage for nerves innervating teeth and jaw

Carotid Canal

Passage for internal carotid artery

Jugular Foramen

Passage for internal jugular (from brain) between occipital and temporal bones

Foramen magnum

Connects cranial cavity with vertebral canal

Olfactory foramina

Series of small openings in the cribiform plate

Optic Canals

Permit optic nerves to pass from eyes to brain

Foramen Rotundum

Permits passage of a branch of the trigemenal nerve

Foramen Spinosum

Permits passage of blood vessels to membranes that surround central nervous system

Sphenoid

Irregular shaped bone forming floor of cranium, and uniting cranium / facial bones

Lesser Wings (sphenoid)

Extend Horizontally anterior to sella turnica

Greater wings (sphenoid)

Extend laterally from body, forming part of the cranial floor

Hypophyseal fossa

Depression within the sella turcica to support the pituitary gland

Sella Turcica

Bony, saddle shaped structure on superior surface of sphenoid

pterygoid processes

Vertical projections originating on either side of the sphenoid

Ethmoid

Forms part of the floor of the anterior cranium, roof of nasal cavity, part of nasal septum and medial orbital wall

Cribiform Plate

Floor of cranium / roof of nasal cavity. Foramina for passage of olfactory nerves (sense of smell)

Crista Galli

Bony ridge projecting superior to the cribiform plate

Ethmoidal Labyrinth

Consists of ethmoidal cells and interconnected sinuses

Perpindicular Plate

Forms part of the nasal septum, along with the vomer and a piece of hyaline cartilage

palatine bones

Form posterior portion of hard palate and contribute to the floor of each orbit

Horizontal Plate

Forms posterior part of the hard palate

Orbital Process

Forms part of the floor of the orbit; Contains a small sinus

Orbital Complex

Formed by seven bones to hold the eye

Lacrima Fossa

Shallow depression in the frontal bone, marking the location of the tear gland

Supra-Orbital Margin

Thickening of frontal bone to protect the eye

Lacrimal Sulcus

Groove in the lacrimal bone to hold the lacrimal sac

Nasolacrimal Canal

Formed by Maxilla and lacrimal bone

Nasal Complex

Includes bones that enclose the nasal cavities and the paranasal sinuses

Sinusitis

Inflammation of the sinuses due to infection

Condylar Process

(Mandible) Articulates with temporal bone

Coronoid Process

Insertion point of the temporalis muscle (closes jaw)

Ramus

Ascending part of the mandible

Alveolar part

(mandible) supports lower teeth

Myohyoid line

Insertion part of muscle to support the floor of the mouth

Hyoid bone

Supports Larynx, and is attachment site for muscles of layrnx, pharynx and tounge

Auditory Ossicles

Malleus, Incus and Stapes; Enclosed in pertrous part of the temporal bone

Fontanelles

Fibrous portions between cranial bones in an infant skull

Anterior Fontanelle

A baby’s “soft spot”

Vertebral Column

Consists of 24 vertebrae, plus the sacrum and coccyx

Cervical Curve

Secondary; develops from balancing weight of head on spine

Thoracic Curve

Primary Curve to accomodate thoracic organs

Lumbar Curve

Secondary; balances weight of trunk over lower limbs

Sacral Curve

Primary; accomodates abdominopelvic organs

Articular Processes

Extend Superior and inferior; articulate with adjacent vertebrae

Vertebral Arch

Forms posterior / lateral margins of vertebral foramina

Vertebral Body

Transfers weight along axis of vertebral column

Spinous Process

Projects posteriorly from point where lamina fuse to form vertebral arch

Laminae

Form “Roof” of vertebral foramen

Transverse Process

Project laterally where lamina join pedicles; sites of muscle attachment / rib articulation

Pedicles

Form “walls” of vertebral arch

Articular Facet

Smooth, concave surface on each articular process