Axial Skeleton

Synarthrosis Joints

Immovable joints, present only in skull

4 Types of Suture Joints

Coronal, Sagittal, Lambdoidal, Squamous

Coronal Suture

The suture between the parietal and frontal bones of the skull

Sagittal Suture

The suture uniting the two parietal bones

Lambdoidal Suture

Suture between the parietals and the occipital bone

Squamous Suture

Suture between the parietals and the temporal bone

Frontal Bone

The large cranial bone forming the front part of the cranium: includes the upper part of the orbits

Parietal Bones

Two skull bones between the frontal and occipital bones and forming the top and sides of the cranium

Temporal Bones

Thick bones forming the side of the human cranium and encasing the inner ear

Occipital Bone

A saucer-shaped membrane bone that forms the back of the skull

Sphenoid Bone

Butterfly-shaped bone at the base of the skull, holds all other bones together

Ethmoid Bone

A small bone located between the orbits in the skull, comprising part of the sinuses

Nasal Bones

Two bones on either side of the nose, of varying shape and size depending on genetics, irregularly shaped

Zygomatic Bones

Two irregularly shaped bones on either side of the skull; form the cheekbones

Maxillae

The bone that forms your upper jaw. The right and left halves are irregularly shaped bones that fuse together in the middle of the skull, below the nose, in an area known as the intermaxillary suture

Mandible

Lower jaw bone, detached & movable, irregular bone

Mental Foramen

Entry points in the mandible bone for blood vessels

Vomer

Thin trapezoidal bone of the skull forming the posterior and inferior parts of the nasal septum

Inferior Nasal Concha

Small irregularly shaped bones in the sides of the nasal canal

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; drains eyes to nasal

Foramen Magnum

The large opening at the base of the cranium through which the spinal cord passes

Styloid Process

Extends from the base of the temporal bone

Mastoid Process

A smooth conical projection of bone located at the base of the mastoid area of the temporal bone. It allows the attachment of muscles.

External Auditory Meatus

Hole in the side of the cranium which forms the ear canal

External Occipital Protuberance

Small bump on occipital bone which serves as a muscular attachment point

Palatine Bones

Two bones in upper jaw, forming roof of mouth/hard palate

Vertebral Column

26 bones in total; Cervical, Thoracic, Lumbar, Sacrum, and Coccyx

Cervical Spine

Seven bones; bifid spinous (two bumps); first bone is called Atlas, second is called Axis.

Atlas Vertebra

First cervical vertebra, holds up skull, allows for nodding motion

Axis Vertebra

Second cervical vertebra, allows for head-shaking motion, has a structure called a dens which is a bump.

Thoracic Vertebrae

Articulate with ribs, look like giraffe's face, downward spinous

Lumbar Vertebrae

Largest and strongest of the vertebrae; looks like moose's face; square spinous

Sacrum

Wedge-shaped bone consisting of five fused vertebrae forming the posterior part of the pelvis; permits articulation of two hip bones; contains many foramen for nerves

Coccyx

Tailbone; points inferiorly in those with birth canals, anteriorly in those without

Vertebral Discs

Discs of cartilage between vertebrae which absorb shock

Vertebral Fusion

The placing of a vertical rod between two vertebrae, keeping the disc in place while eliminating the ability for those two vertebrae to bend

Herniated Disc

A painful slip of the fibrocartilage of the disc between spinal vertebrae; occurs most often in the lumbar region; causes disc to put pressure on spinal cord

Scoliosis

An abnormal lateral curve to the vertebral column

Kyphosis

An abnormal backward curve to the vertebral column; observed most commonly in the elderly due to muscular atrophy

Rib Cage

12 pairs of ribs (24 in all), plus sternum

Sternum

Flat bone which connects all ribs in the anterior face of the ribcage; Manubrium (top), body (middle, part with most of the rib connections), Xiphoid Process (very bottom tip, can break off during CPR and puncture lungs)

True RIbs

7 pairs-- connect directly to sternum

False Ribs

5 pairs, including floating ribs-- connect indirectly to sternum

Floating Ribs

2 pairs-- don't connect to sternum at all, connect only to thoracic spine; technically also false ribs

Inner Ear Bones

Hammer, anvil, stirrup; malleus, incus, stapes

Malleus

Hammer ear bone

Incus

Anvil ear bone

Stapes

Stirrup ear bone

Manubrium

Top of sternum

Rib Facets

The part of the rib which articulates with the thoracic spine

Floating ribs are false ribs

Why are there 7 pairs of true ribs, 5 pairs of false ribs, and 2 pairs of floating ribs when there are only 12 pairs of ribs in all?