Axial Skeleton Bones and Bony Markings

Axial skeleton

Division of the skeleton including the skull, vertebral column, and thoracic cage

Long bones

Bones longer than they are wide, with a shaft and two ends (e.g., femur)

Short bones

Roughly cube-shaped bones (e.g., carpals, tarsals)

Flat bone

Thin, flattened bones often serving protective functions (e.g., skull bones)

Irregular bone

Bones with complex shapes that don't fit other categories (e.g., vertebrae)

Sutural/Wormian bones

Small extra bones found within the sutures of the skull

Condyle

A rounded articulating surface at the end of a bone

Facet

A small, smooth flat articulating surface

Head

A rounded articulating projection at the end of a bone, often on a narrow neck

Trochlea

A pulley-shaped articulating surface

Alveolus

A deep pit or socket, especially for a tooth

Fossa

A shallow depression in a bone

Sulcus

A groove or furrow in a bone, often for a vessel, nerve, or tendon

Canal

A tunnel-like passage through a bone

Fissure

A narrow slit-like opening in a bone

Foramen

A rounded opening through a bone for vessels or nerves

Meatus

A canal-like opening or passageway

Sinus

An air-filled cavity within a bone

Crest

A narrow ridge of bone

Epicondyle

A projection above or on a condyle

Line

A low ridge of bone, less prominent than a crest

Process

Any bony projection

Ramus

An arm-like branch off the body of a bone

Spine

A sharp, slender bony projection

Tubercle

A small rounded bony projection

Frontal bone

Single cranial bone forming the forehead

Orbital surface of frontal bone

Portion of the frontal bone forming the roof of the eye orbit

Glabella

Smooth area on the frontal bone between the eyebrows

Supraorbital margin

The upper rim of the eye orbit on the frontal bone

Supraorbital notch (or foramen)

Opening in the supraorbital margin for nerves and vessels

Parietal bone

Paired cranial bones forming the roof and upper sides of the skull

Temporal bone

Paired cranial bones forming the lower sides of the skull

Carotid canal

Opening in the temporal bone through which the internal carotid artery passes

Internal and external auditory (acoustic) meatus

Canals in the temporal bone leading to the middle/inner ear (internal) and ear canal (external)

Jugular fossa

Depression in the temporal bone that houses the jugular vein

Mandibular fossa

Depression on the temporal bone where the mandible articulates

Mastoid part of temporal bone

Region of the temporal bone behind the ear containing air cells

Mastoid process

Bony projection on the temporal bone behind the ear

Styloid process

Slender pointed projection from the temporal bone

Squamous part of temporal bone

Thin, flat, scale-like portion of the temporal bone

Petrous part of temporal bone

Dense, pyramid-shaped portion of the temporal bone housing the inner ear

Tympanic part of temporal bone

Portion of the temporal bone surrounding the ear canal

Zygomatic process of temporal bone

Projection of the temporal bone that joins the zygomatic bone

Occipital bone

Single cranial bone forming the posterior and base of the skull

Basilar part of occipital bone

Anterior portion of the occipital bone that joins the sphenoid

Cerebellar fossa

Depression on the internal occipital bone

External occipital protuberance

Bump on the posterior occipital bone at the midline

Foramen magnum

Large opening in the occipital bone for passage of the spinal cord

Grooves for superior sagittal sinus

Internal groove on the occipital bone

Groove for transverse sinus

Internal groove on the occipital bone

Internal occipital crest

Ridge on the internal occipital bone along the midline

Internal occipital protuberance

Internal bump on the occipital bone where sinus grooves converge

Occipital condyle

Rounded projection on the occipital bone that articulates with the atlas (C1)

Sphenoid bone

Single butterfly-shaped bone forming part of the central cranial floor

Anterior and posterior clinoid process

Projections on the sphenoid bone surrounding the pituitary gland

Body of sphenoid

Central portion of the sphenoid bone

Dorsum sellae

Posterior wall of the sella turcica on the sphenoid bone

Foramen ovale

Opening in the sphenoid bone for the mandibular nerve

Foramen rotundum

Opening in the sphenoid bone for the maxillary nerve

Foramen spinosum

Opening in the sphenoid bone for the middle meningeal artery

Greater wing

Lateral projection of the sphenoid bone forming part of the orbit and cranial floor

Hypophysial fossa

Depression in the sella turcica that holds the pituitary gland

Lateral pterygoid plate

bony plate extending from the sphenoid, muscle attachment

Medial pterygoid plate

Medial bony plate extending from the sphenoid, muscle attachment

Optic canal

Opening in the sphenoid bone for the optic nerve

Sella turcica

Saddle-shaped depression on the sphenoid bone holding the pituitary gland

Superior orbital fissure

Opening in the sphenoid bone for nerves and vessels entering the orbit

Ethmoid bone

Single irregular bone forming part of the nasal cavity and orbit walls

Cribriform plate and cribriform foramina

Perforated portion of the ethmoid bone allowing olfactory nerve fibers to pass

Crista galli

Upward projection of the ethmoid bone for dura mater attachment

Ethmoidal sinus (cells)

Air-filled spaces within the ethmoid bone

Middle nasal concha

Curved bony shelf of the ethmoid bone projecting into the nasal cavity

Orbital plate

Portion of the ethmoid bone forming part of the medial orbit wall

Perpendicular plate

Portion of the ethmoid bone forming the upper nasal septum

Coronal suture

Joins the frontal bone to the parietal bones

Sagittal suture

Joins the two parietal bones at the midline

Squamous suture

Joins the parietal bone to the temporal bone

Sphenosquamous suture

Joins the sphenoid bone to the squamous part of the temporal bone

Occipitomastoid suture

Joins the occipital bone to the mastoid part of the temporal bone

Lambdoidal suture

Joins the parietal bones to the occipital bone

Pterion

H-shaped junction of the frontal, parietal, temporal, and sphenoid bones

Mandible

Single bone forming the lower jaw, the only movable skull bone

Alveolar process (mandible)

Ridge of the mandible containing the tooth sockets

Angle (mandible)

Point where the body and ramus of the mandible meet

Body (mandible)

Horizontal portion of the mandible

Condylar process

Projection of the mandible that articulates with the temporal bone

Coronoid process (mandible)

Projection of the mandible for temporalis muscle attachment

Head (mandible)

Rounded end of the condylar process that forms the jaw joint

Mandibular foramen

Opening on the inner mandible for nerves and vessels

Mandibular notch

Depression on the mandible between the condylar and coronoid processes

Mental foramen

Opening on the mandible below the premolars for nerves and vessels

Maxilla

Paired bones forming the upper jaw

Alveolar process (maxilla)

Ridge of the maxilla containing the tooth sockets

Anterior nasal spine

Pointed projection of the maxilla at the base of the nasal cavity

Maxillary sinus

Air-filled cavity within the maxilla

Orbital surface of maxilla

Portion of the maxilla forming the floor of the eye orbit

Palatine process

Portion of the maxilla forming part of the hard palate

Infraorbital foramen

Opening below the orbit on the maxilla for nerves and vessels

Palatine bone

Paired bones forming the posterior hard palate and part of the nasal cavity

Zygomatic bone

Paired bones forming the cheekbones