Axial Skeleton & Associated Joints – Key Vocabulary

86 vocabulary flashcards covering bones, bone markings, spinal curvatures, thoracic cage, vertebrae, joint types, and key foramina found in the axial skeleton lecture.

Axial Skeleton

The central skeleton consisting of the skull, vertebral column, and thoracic cage.

Skull

Bony structure of the head composed of the cranium and facial bones.

Cranium

Portion of the skull that encloses and protects the brain.

Frontal Bone

Anterior bone of the cranium forming the forehead and superior orbit.

Parietal Bone

Paired bones forming the superior and lateral walls of the cranium.

Temporal Bone

Paired bones housing the ear structures and forming part of the cranial base and side.

Occipital Bone

Posterior and inferior bone of the cranium containing the foramen magnum.

Sphenoid Bone

Butterfly-shaped bone forming part of the cranial floor; houses the sella turcica.

Ethmoid Bone

Deep cranial bone containing the cribriform plate and crista galli; forms nasal septum.

Lacrimal Bone

Small medial orbital bone that contains the lacrimal fossa for the tear duct.

Nasal Bone

Small paired bones forming the bridge of the nose.

Zygomatic Bone

Cheekbone; forms part of the zygomatic arch and lateral orbit.

Maxilla

Paired upper-jaw bones containing upper teeth and forming most of hard palate.

Mandible

Lower jawbone; only movable skull bone; holds lower teeth.

Vomer

Plow-shaped bone forming the inferior part of the nasal septum.

Inferior Nasal Concha

Scroll-like bone forming part of the lateral wall of the nasal cavity and aiding airflow.

Fontanel

Soft membranous gap between fetal skull bones that allows skull flexion during birth.

Anterior Fontanel

Largest fontanel located at junction of frontal, coronal, and sagittal sutures.

Occipital (Posterior) Fontanel

Fontanel at intersection of lambdoid and sagittal sutures.

Sphenoidal Fontanel

Soft spot at junction of squamous and coronal sutures in fetal skull.

Mastoid Fontanel

Fontanel located between squamous and lambdoid sutures near the temporal bone.

Wormian (Intrasutural) Bones

Small extra bone pieces that occur within cranial sutures.

Coronal Suture

Fibrous joint between frontal and parietal bones.

Sagittal Suture

Midline fibrous joint between the two parietal bones.

Lambdoid Suture

Fibrous joint between parietal bones and occipital bone.

Squamous Suture

Joint between parietal and temporal bones.

Occipitomastoid Suture

Suture between occipital and temporal bones.

Supraorbital Foramen

Opening in frontal bone for passage of supraorbital nerve and vessels.

Infraorbital Foramen

Opening in maxilla transmitting infraorbital nerve and vessels.

Mental Foramen

Opening in anterior mandible for the mental nerve and vessels.

Foramen Magnum

Large opening in occipital bone for spinal cord passage.

Sella Turcica

Depression in sphenoid bone housing the pituitary gland.

Crista Galli

Vertical projection of ethmoid bone for falx cerebri attachment.

Cribriform Plate

Ethmoid bone region perforated by olfactory foramina.

Optic Canal

Opening in sphenoid bone transmitting the optic nerve.

Superior Orbital Fissure

Gap between sphenoid wings transmitting cranial nerves III, IV, V1, VI.

Inferior Orbital Fissure

Fissure between sphenoid and maxilla for infraorbital vessels and nerve.

Dens (Odontoid Process)

Peg-like projection of C2 (axis) that acts as pivot for head rotation.

Atlas (C1)

First cervical vertebra; lacks a body and supports the skull.

Axis (C2)

Second cervical vertebra; possesses the dens for rotation with atlas.

Intervertebral Disc

Pad of fibrocartilage between vertebrae absorbing shock.

Annulus Fibrosus

Tough outer fibrocartilage ring of an intervertebral disc.

Nucleus Pulposus

Gel-like central region of an intervertebral disc.

Scoliosis

Abnormal lateral curvature of the spine.

Kyphosis

Excessive thoracic curvature producing a “hunchback.”

Lordosis

Exaggerated lumbar curvature causing a “swayback.”

Thoracic Cage

Skeleton of thorax consisting of ribs, sternum, and thoracic vertebrae.

Sternum

Flat bone of anterior thorax composed of manubrium, body, and xiphoid process.

Manubrium

Superior portion of sternum articulating with clavicles and first ribs.

Body of Sternum

Long middle portion of the sternum articulating with ribs 2–7.

Xiphoid Process

Inferior tip of sternum; cartilaginous in youth, ossifies in adulthood.

True Ribs

First seven rib pairs attaching directly to sternum via costal cartilage.

False Ribs

Rib pairs 8-12 that do not attach directly to sternum.

Floating Ribs

Ribs 11-12 lacking anterior attachment to sternum.

Synarthrosis

Immovable joint (functional classification).

Amphiarthrosis

Slightly movable joint (functional classification).

Diarthrosis

Freely movable joint; synonymous with synovial joint.

Fibrous Joint

Joint with no cavity; bones united by collagen fibers.

Cartilaginous Joint

Joint with no cavity; bones united by cartilage.

Synovial Joint

Freely movable joint enclosed by a capsule containing synovial fluid.

Suture (Joint)

Fibrous synarthrosis between bones of the skull.

Syndesmosis

Fibrous amphiarthrosis where bones are connected by a ligament (e.g., tibia-fibula).

Synchondrosis

Cartilaginous synarthrosis where bones are joined by hyaline cartilage (e.g., epiphyseal plate).

Symphysis

Cartilaginous amphiarthrosis where bones are joined by fibrocartilage (e.g., pubic symphysis, intervertebral discs).

Atlantoaxial Joint

Pivot synovial joint between atlas and axis allowing head rotation ("no" motion).

Temporomandibular Joint (TMJ)

Modified hinge synovial joint between the mandible and temporal bone.

Transverse Foramen

Opening in cervical vertebrae transmitting vertebral arteries.

Sacrum

Triangular bone of five fused vertebrae forming posterior pelvic wall.

Coccyx

Terminal vertebral column of three to five fused vertebrae; tailbone.

Sacral Promontory

Anterior projecting edge of the first sacral vertebra.

Jugular Foramen

Opening between temporal and occipital bones transmitting internal jugular vein and cranial nerves IX–XI.

Carotid Canal

Passage in temporal bone for internal carotid artery.

Foramen Ovale

Sphenoid opening transmitting mandibular branch of trigeminal nerve (V3).

Foramen Rotundum

Sphenoid opening for maxillary division of trigeminal nerve (V2).

Foramen Spinosum

Sphenoid opening transmitting middle meningeal artery.

Foramen Lacerum

Irregular opening at skull base filled with cartilage in life.

Hypoglossal Canal

Opening in occipital bone transmitting cranial nerve XII.

Zygomatic Arch

Bridge formed by temporal process of zygomatic bone and zygomatic process of temporal bone.

Pterygoid Process

Downward projections of sphenoid bone serving as muscle attachment.

Alveolar Margin

Ridge of maxilla or mandible containing tooth sockets (alveoli).