Skull Radiography

Skull Radiography : Positioning Projections and Methods

Cranium

Projections / Views

Lateral Projection : Rotated Right or Left
Dorsal Decubitus Projection : Right or Left Laterals
PA (Posteroanterior) View
AP (Anteroposterior) View

Radiographic Methods of the Skull

X-ray Examination of the Cranial Base of the Skull

Radiographic Methods

Submentovertical (SMV) – Schuller Method
Verticosubmental (VSM) – Schuller Method

Anterior View

Skull Anatomy and Pathology

The skull is located on the superior part of the vertebral column. There are 22 separate bones these are divided into 8 cranial bones and 14 facial bones. The cranial bones are further divided into the calvaria and floor.

The cranial bones protects and acts as the housing of the brain. Facial bones provides structure, shape and support for the face and forms the protective housing for the upper ends of the respiratory and digestive tracts plus with several protection for the structures and organs of our sight.
The 22 primary bones of the skull should be located and recognized in the different views before they are situated in greater detail. The inner layer of the cranial vault is separate by spongy tissue (diploe) and composed of 2 plates of compact tissue, outer plate or table is thicker than the inner table. Inner layer of cranium (spongy tissue) varies considerably.

Lateral View

Cranial Bones Compositions

Calvaria
1 Frontal
1 Occipital
1 Right parietal
1 Left parietal

Floor of the Skull

1 Ethmoid
1 Sphenoid
1 Right temporal
1 Left temporal

Superior View

Facial Bones Composition

2 Nasal
2 Lactimal
2 Maxillary
2 Zygomatic
2 palatine
2 Inferior nasal conchae
1 Vomer
1 Mandible

Sutures of the skull

The sutures are fibrous joints that connects the cranium and the face.
Coronal – it is found between the frontal and parietal bones.
Sagital – it is located on the top of the head between the two parietal bones and just behind the coronal suture line
Squamosal – It is between the temporal bones and the parietal bones.
Lambdoidal – Between the occipital bone and the parietal bone.
Junction of the coronal and sagittal sutures.
Lambda – junction of the lambdoidal and sagittal sutures.
Bregma – it joints the coronal sutures and sagittal sutures.
Pterion - Junction of the Parietal Bones, Squamosal and Greater Wing of the sphenoid, and lies in the middle of meningeal artery.
Asterion - Junction of the occipital bone, parietal bone and mastoid portion of the temporal bone.

Common Radiographic Pathology of the Skull

Anterior View Landmark

Fracture – Disruption in the continuity of the bone
Basal – A fracture located at the base of the skull
Blowout – Fracture of the floor of the orbit
Contre-coup – Fracture to one side of a structure caused by trauma to the other side.
Depressed – Fracture causing a portion of the skull to be depressed into the cranial cavity.
Leforte Fracture – Bilateral horizontal fractures of the maxillae
Linear Fracture – Irregular or jagged fracture of the skull
Tripod Fracture – Fracture of the zygomatic arch and orbital floor or rim and dislocation of the frontozygomatic suture.
Mastoiditis – Inflammation of the mastoid antum and air cells.
Metastases – Transfer of a cancerous lesion from area to another.
Osteomyelitis – Inflamation of bone in the skull due to a pyogenic infection.
Osteopetrosis – Increased density of atypically soft bone.
Osteoporosis – Loss of bone density.
Paget’s Disease – Thick, soft bone marked by bowing and fractures.
Polyp – Growth or mass protruding from a mucous membrane
Sinusitis – Inflamation of one or more of the paranasal sinuses.
TMJ Syndrome – Dysfunction of the temporomandibular joint.
Tumor – New tissue growth where cell proliferation is uncontrolled.
Acoustic Neuroma – Benign tumor arising from Schwann cells of the eight cranial nerve.
Multiple Myeloma – Malignant neoplasm of plasma cells involving the bone marrow and causing destruction of the bone.
Osteoma – Tumor composed of bone tissue.

Lateral View Head Landmark

Pituitary Adenoma – Tumor arising from the pituitary gland, usually in the anterior lobe.

To make correct positioning of the skull or head it needs a complete understanding of skull landmarks, which must be studied carefully before Positioning. The planes, points, lines, and abbreviations that most often used in skull radiography are the following:

Midsagittal Plane
Interpupillary Line
Acanthion
Outer Canthus

Infraorbital Margins

External Acoustic Meatus (EAM)
Orbitomeatal Line (OML)
Infraorbitalmeatal Line (IOML)
Acanthiomeatal Line (AML)
Mentomeatal Line (MML)

The skull of adult has a normal of 7° angle difference existence between the OML and IOML, and a difference of 8° angle between the OML and the glabellomeatal line. The difference in degree of angle between the cranial lines used in positioning must be known. Often the relationship of the patient, Image receptor, and central ray is the similar, but its angulation has described differently, depending on the lines of the cranial references.
Cranium