Anatomy of the Skull and Vertebral Column

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Study Notes

The skeleton of the head and neck includes the skull, middle ear ossicles, hyoid bone, and cervical vertebrae.
The skull is composed of several separate bones united at immobile joints called sutures.
Only the Temporomandibular Joints (TMJ) is a synovial joint (mobile).
The bones of the skull are 22 bones, organized into a cranial skeleton (8 bones) that surrounds the brain and a facial skeleton (14 bones).
The Cranium includes Frontal, Ethmoid, Sphenoid, Occipital, Parietal, and Temporal bones.
The Facial Skeleton includes Zygomatic, Maxillae, Nasal, Lacrimal, Palatine, Inferior Conchae, Mandible, and Vomer bones.

The vertebral column is divided into five regions: Cervical, Thoracic, Lumbar, Sacral, and Coccygeal.
The Cervical region consists of 7 vertebrae (C1-C7).
The Thoracic region consists of 12 vertebrae (T1-T12).
The Lumbar region consists of 5 vertebrae (L1-L5).
The Sacral region consists of 5 fused vertebrae (S1-S5).
The Coccygeal region consists of 3-5 fused vertebrae.

Each vertebra consists of a vertebral body (centrum), vertebral arch, articular processes, and Intervertebral Foramina.
The vertebral body transfers weight down the spine.
The vertebral arch is the posterior margin of the vertebral foramen.
The articular processes, which are lateral projections, are located between the laminae and pedicles.
The pedicles are the walls of the vertebral arch, while the laminae are the roof of the vertebral arch.
The Spinous Process is the projection where the vertebral laminae fuse.
The Transverse Process is the projection where the laminae join the pedicles.
The Superior and Inferior Articular Processes have articular facets on their articular faces.
The Intervertebral Foramina are gaps located between the pedicles of adjacent vertebrae.
The Vertebral Canal, formed by the vertebral foramina, encloses the spinal cord.
Intervertebral Discs, pads of fibrous cartilage, separate the vertebral bodies and absorb shocks.

The processes of the Cervical Vertebrae are fused to costal processes, which encircle transverse foramina (protecting arteries and veins).
C1 is called the Atlas and articulates with the occipital condyles of the skull.
C1 has no body or spinous process and has a large, round foramen within the anterior and posterior arches.
C2 is called the Axis and supports the Atlas.
C2 has a heavy spinous process that attaches muscles of the head and neck.
During development, the Axis and Atlas bodies fuse to form the Dens.
C7, also known as Vertebra Prominens, is the transitional vertebra to the Thoracic vertebrae.
C7 has a long spinous process with a broad tubercle and large transverse processes.

The Thoracic Vertebrae have heart-shaped bodies and larger bodies than C1-C7.
They have smaller vertebral foramen than C1-C7 and long, slender spinous processes.
T1-T12 have costal facets on their dorsolateral surface for articulation with the heads of ribs.
T1-T10 have transverse costal facets on thick transverse processes for rib articulation.
Ribs at T1 - T10 contact the costal and transverse costal facets.
T1-T8 articulate with two pairs of ribs at the superior and inferior costal facets.
T9-T11 each articulate with one pair of ribs.
T10-T12transition to the Lumbar Vertebrae.

The Lumbar Vertebrae have the largest vertebrae, oval-shaped bodies, thicker bodies than T1-T12, and a triangular vertebral foramen.
They have no costal or transverse costal facets.
The superior articular processes face up and in, while the inferior articular processes face down and out.
The transverse processes are slender and project dorsolaterally.
The Spinous processes are short, heavy, and provide attachment for the lower back muscles.

The Sacrum is curved, more so in males than females.
It protects the reproductive, urinary, and digestive organs, and attaches the axial skeleton to the pelvic girdle.
It attaches to the broader muscles that move the thigh.
The adult sacrum consists of five fused sacral vertebrae, which fuse between puberty and ages 25-30.

The Coccyx is attached to ligaments and a constricting muscle of the anus.
The mature coccyx consists of 3-5 fused coccygeal vertebrae.
The first two coccygeal vertebrae have transverse processes and unfused vertebral arches.
The Coccygeal cornua are formed by the laminae of the first coccygeal vertebra.