Part 1 The Axial Skeleton: Skull and Associated Bones

Vocabulary practice flashcards covering the components of the axial skeleton, skull bones, cranial fossae, and inferior cranial foramina and landmarks.

Axial Skeleton

The skeletal division that makes up the longitudinal axis of the body; composed of the skull, vertebral column, thoracic cage bones, hyoid bone, and ear ossicles.

Cranial Bones

A set of $8$ bones held together by sutures that encloses the cranial cavity (brain cavity).

Facial Bones

A set of $14$ bones that cradles the eyes and encloses both the nasal cavity and oral cavity.

Hyoid Bone

A single bone ($1$) that is not attached to any other bone; serves as a site of muscle attachment for the tongue, larynx, and pharynx.

Ear Ossicles

Six bones ($2 \times 3 = 6$) situated in the middle ear—consisting of the malleus, incus, and stapes—which are the smallest bones in the human body.

Cranial Cavity

The internal space formed by the cranial bones that encloses and protects the brain.

Cranial Fossae

Lobular indentations located in the base of the cranial cavity, designated as the anterior cranial fossa, middle cranial fossa, and posterior cranial fossa.

Frontal Bone

An unpaired cranial bone that forms the anterior portion of the cranium.

Parietal Bones

Paired ($2$) cranial bones that form the superior and lateral walls of the cranium.

Temporal Bones

Paired ($2$) cranial bones located on the lateral sides and base of the skull.

Occipital Bone

An unpaired cranial bone forming the posterior wall and the inferior base of the skull.

Sphenoid Bone

An unpaired cranial bone contributing to the base of the skull and floor of the cranial cavity.

Ethmoid Bone

An unpaired cranial bone located anteriorly at the base of the skull between the orbits.

Sutures

Fibrous joints that hold the cranial bones together.

Foramen Magnum

A large opening located in the occipital bone that serves as the passageway for the spinal cord and vertebral arteries.

Occipital Condyle

Smooth, rounded articular projection on the occipital bone located adjacent to the foramen magnum.

External Occipital Protuberance

A midline bony prominence found on the external posterior surface of the occipital bone.

Superior Nuchal Line

A transverse bony ridge on the external surface of the occipital bone extending laterally from the external occipital protuberance.

Mastoid Process

A prominent, rounded projection of the temporal bone located posterior to the external auditory meatus.

Styloid Process

A slender, pointed bony projection extending inferiorly from the inferior surface of the temporal bone.

External Auditory Meatus

The external ear canal opening situated in the temporal bone.

Mandibular Fossa

A depression on the inferior surface of the temporal bone located anterior to the external auditory meatus that receives the condyle of the mandible.

Stylomastoid Foramen

An opening on the inferior aspect of the temporal bone positioned between the styloid and mastoid processes.

Entrance to Carotid Canal

A circular aperture on the inferior surface of the temporal bone transmitting the internal carotid artery.

Jugular Foramen

A large aperture positioned between the temporal and occipital bones visible from the inferior view of the skull.

Foramen Ovale

An oval-shaped opening situated in the greater wing of the sphenoid bone.

Foramen Spinosum

A small circular opening in the sphenoid bone located posterolateral to the foramen ovale.

Foramen Lacerum

An irregularly shaped opening situated at the base of the skull bounded by the sphenoid, temporal, and occipital bones.

Medial and Lateral Pterygoid Plates

Paired, vertical inferior extensions of the sphenoid bone visible on the inferior skull surface.

Palatine Process of the Maxilla

The horizontal anterior projection of the maxilla forming the anterior portion of the hard palate.

Horizontal Plate of the Palatine Bone

The horizontal posterior plate that contributes to the hard palate posterior to the palatine process of the maxilla.

Vomer

An unpaired thin bone visible on the inferior and anterior aspects of the skull forming part of the nasal septum.