Head, Neck & Spine Anatomy Quiz

Head, Neck & Spine

• This section covers the anatomy of the head, neck, and spine.

• The study material includes the divisions of the skull, specific skull bones, sutures, and the vertebral column.

Divisions of the Skull

• The skull is divided into two main parts: Cranium and Facial bones.

• Cranium:

  • 2 Parietal bones (form the superior and lateral side of the skull)
    • they fuse together at the sagittal suture.
    • fuse with the frontal bone at the coronal suture.
    • fuse with the temporal bones inferiorly at the squamous suture.
    • fuse with the occipital bone posteriorly at the lambdoid suture.
  • 2 Temporal bones (form the lower lateral side of the skull)
    • they do not fuse together.
    • fuse with the sphenoid bone at the squamous suture.
    • fuse with the occipital bone posteriorly at the lambdoid suture.
    • fuse with the zygomatic bone, forming the zygomatic process (cheek bone).
    • temporal fossa - shallow indentation above zygomatic process
    • mastoid process - major attachment point for muscles of the neck and jaw.
  • Frontal bone (forms the anterior side of the skull, the forehead)
    • fuses with the parietal bones, sphenoid and ethmoid bones at the coronal suture.
    • forms the supraorbital margin (rounded brow ridges generally larger in males).
  • Occipital bone (forms the base and posterior side of the skull)
    • fuses with the parietal and temporal bones at the lambdoid suture.
    • foramen magnum: allows passage of spinal cord exiting the skull.
    • occipital condyle: on either side of the foramen magnum; forms joints with the C1 vertebrae; allowing us to nod our heads "yes".
  • Sphenoid bone (highly complex bone of the central skull)
    • connects with nearly every bone of the cranium.
    • extends laterally to contribute to the sides of the skull (anterior to the temporal fossa).
    • resembles a flying bird or butterfly.
    • optical canal: supplies passage for the optic nerve to the orbit
  • Ethmoid bone (located at midline within the central skull)
    • crista galli: upward projection
    • perpendicular plate: downward projection
    • both the C.G and P.P form the nasal septum (division between both nostrils).
    • forms the upper part of the nasal cavity.
    • contributes to the medial wall of the orbit.

• Facial bones:

  • Zygomatic (cheek bone)
    • makes up most of the lateral and inferior margins of the orbit.
    • zygomatic process (temporal bone connection).
  • Maxilla (forms the upper jaw)
    • alveolar process - inferior margin, houses the teeth.
    • each tooth is anchored in an individual alveolus.
    • contributes to the floor of the orbit and the hard palate.
  • Mandible (forms the lower jaw)
    • the only moveable bone of the skull.
    • alveolar process - upper boundary of the mandible, attachment point for the teeth.
    • mandibular condyle - a set of condyles ("U-shaped") connects to the temporal bone, forming the temporomandibular joint.
  • Nasal bones (2 articulating bones that form the "bridge" of the nose)
    • supports the cartilage of the nose.
  • Lacrimal (small, rectangular bone contributing to the medial aspect of the orbit)
    • nasolacrimal canal: where the lacrimal fluid (tear flow) passes.

Sutures

• Sutures are immobile joints connecting adjacent skull bones.
• Interlocking joints create strength for protection.
• Dense fibrous connective tissue.

Sutures (specific types)

• Coronal (runs side-to-side at the top of the head) - joins the frontal bone to the right and left parietal bones.
• Sagittal (runs front to back at the top of the head) - unites the right and left parietal bones, connected at the bregma.
• Lambdoid (located on the posterior side of the skull) - connects the occipital bone to the parietal and temporal bones.
• Squamous (located on the lateral side of the skull) - connects the temporal bones to the parietal and sphenoid bones.

Cranial Cavity

• Houses the brain inside the skull (interior space).
• Calvaria is the "skull cap" or top half of the skull.
• Base of the skull is the cranial floor. - Cranial nerves, spinal cord, and blood vessels pass through here.
• 3 large spaces ("fossae" - trenches/ditches):
  • anterior cranial fossa
  • middle cranial fossa
  • posterior cranial fossa
  • Size of fossae depends on the size of brain region.

Skull Diagram

• Students are instructed to complete a skull diagram, labeling and coloring each bone and landmark, and drawing lines between structures.

Vertebral Column

• A sequence of vertebrae made up of 5 regions: cervical, thoracic, lumbar, sacrum, coccyx
• 24 vertebrae by adulthood, including the fused sacral and coccygeal vertebrae.

Curvature of Vertebral Column

• The vertebral column has 4 alternating curves.
• The curves support strength, flexibility, and shock absorption.
  • Thoracic and Sacrococcygeal Curves: concave anteriorly
  • Cervical and Lumbar Curves: concave posteriorly

Curvature of Vertebral Column (Disorders)

• Kyphosis: excessive posterior curvature of the thoracic spine. - Commonly caused by osteoporosis, causing the vertebrae to collapse.
• Lordosis: excessive anterior curvature of the lumbar spine. - Commonly associated with pregnancy or obesity.
• Scoliosis: abnormal lateral curvature of the spine, often accompanied by rotation. - Often unknown cause, but growth anomalies, and back braces could be a cause.