Human Biology Terms Chapter 7

Skeleton

Bones of the body.

Axial Skeleton

Central, vertical axis of the body including the skull, vertebral column, and thoracic cage.

Skull

Bony structure that forms the head, face, and jaws and protects the brain.

Vertebral Column

Entire sequence of bones extending from the skull to the tailbone.

Thoracic Cage

Consists of 12 pairs of ribs and the sternum; protects organs in the chest.

Hyoid Bone

Small U-shaped bone in the upper neck that does not articulate with any other bone.

Ear Ossicles

Three small bones in the middle ear that transmit sound vibrations.

Vertebra

Individual bone of the vertebral column.

Sacrum

Single bone formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis.

Coccyx

Small bone at the inferior end of the vertebral column; the tailbone.

Ribs

Thin, curved bones of the chest wall.

Sternum

Flattened bone located at the center of the anterior chest.

Appendicular Skeleton

All bones of the upper and lower limbs plus the girdles that attach them to the axial skeleton.

Cranium

Skull; specifically the portion that encloses and protects the brain.

Mandible

Lower jaw bone; the only movable bone of the skull.

Orbit

Bony socket that contains the eyeball and associated muscles.

Nasal Cavity

Opening through the skull for the passage of air.

Nasal Septum

Midline structure that divides the nasal cavity into right and left halves.

Vomer Bone

Unpaired bone that forms the inferior and posterior portions of the nasal septum.

Zygomatic Arch

Arch on the side of the skull formed by parts of the zygomatic and temporal bones.

Zygomatic Bone

Cheekbone; contributes to the orbit and zygomatic arch.

Parietal Bone

Paired bones that form the upper and lateral sides of the skull.

Temporal Bone

Paired bones that form the lateral and inferior portions of the skull.

Mastoid Process

Large bony projection on the temporal bone located behind the ear.

External Acoustic Meatus

Ear canal opening on the lateral side of the skull.

Frontal Bone

Bone that forms the forehead, roof of the orbit, and floor of the anterior cranial fossa.

Occipital Bone

Bone forming the posterior portion and base of the skull.

Foramen Magnum

Large opening in the occipital bone through which the spinal cord passes.

Sphenoid Bone

Unpaired bone that forms the central base of the skull.

Cribriform Plate

Part of the ethmoid bone containing numerous small openings for olfactory nerves.

Ethmoid Bone

Unpaired bone forming parts of the nasal cavity, orbit, and anterior cranial fossa.

Suture

Fibrous joint that unites skull bones.

Maxillary Bone

Upper jaw bone; forms part of the hard palate.

Hard Palate

Bony roof of the mouth and floor of the nasal cavity.

Nasal Bone

Paired bones that form the bridge of the nose.

Nasal Conchae

Curved bony plates that project from the lateral walls of the nasal cavity and help warm and humidify air.

Paranasal Sinuses

Air-filled cavities in the skull that lighten the skull and help condition inhaled air.

Frontal Sinus

Paranasal sinus located within the frontal bone.

Maxillary Sinus

Paranasal sinus located within the maxillary bone; largest sinus.

Sphenoid Sinus

Paranasal sinus located within the sphenoid bone.

Intervertebral Disc

Structure between vertebrae that provides cushioning and allows movement.

Cervical Curve

Posteriorly concave curvature of the cervical region; a secondary spinal curve.

Lumbar Curve

Posteriorly concave curvature of the lumbar region; a secondary spinal curve.

Kyphosis

Excessive posterior curvature of the thoracic vertebral column; hunchback.

Lordosis

Excessive anterior curvature of the lumbar vertebral column; swayback.

Scoliosis

Abnormal lateral curvature of the vertebral column.

Vertebral Arch

Bony arch of a vertebra that surrounds and protects the spinal cord.

Vertebral (Spinal) Canal

Bony passageway within the vertebral column that contains the spinal cord.

Cervical Vertebrae

Seven vertebrae (C1-C7) located in the neck region.

Atlas

First cervical vertebra (C1).

Axis

Second cervical vertebra (C2).

Dens

Bony projection extending upward from the axis (C2).

Thoracic Vertebrae

Twelve vertebrae (T1-T12) located in the upper back.

Lumbar Vertebrae

Five vertebrae (L1-L5) located in the lower back.

Manubrium

Superior portion of the sternum.

Jugular Notch

Shallow notch on the superior surface of the manubrium; also called the suprasternal notch.

Xiphoid Process

Small process forming the inferior tip of the sternum.

Costal Cartilage

Hyaline cartilage that connects ribs to the sternum directly or indirectly.

True Ribs

Ribs 1-7 that attach directly to the sternum through costal cartilage.

False Ribs

Ribs 8-12 that do not attach directly to the sternum.

Floating Ribs

Ribs 11-12 that do not attach to the sternum or another rib's cartilage.

Fontanelle

Area of fibrous connective tissue between skull bones before birth and during infancy.