The lateral skull X-ray is an imaging modality that shows a side view of the skull, highlighting its bony structures and other critical anatomical landmarks. Here’s a detailed description of the key features typically seen in a normal lateral skull X-ray:

1. Cranial Vault:

• The smooth contour of the frontal, parietal, and occipital bones is visible.

• Sutures, such as the coronal, sagittal, and lambdoid sutures, appear as thin radiolucent (dark) lines if the patient is young and sutures are not fully ossified.

2. Facial Bones:

• The nasal bones, zygomatic arches, maxilla, and mandible are well-defined.

• The nasal cavity and maxillary sinuses appear as radiolucent spaces (dark areas) within the facial bones.

3. Sella Turcica:

• This bony structure houses the pituitary gland and is a crucial feature. It should appear intact, with normal dimensions and no signs of enlargement or erosion.

• The dorsum sellae (posterior wall) and anterior clinoid processes are well-defined.

4. Sinuses:

• The frontal, sphenoid, and maxillary sinuses appear as radiolucent cavities. Normal sinuses are air-filled and symmetrical without any opacification.

5. Mandible:

• The body, ramus, angle, and condyle of the mandible are seen. The teeth roots are visible within the alveolar margins.

6. Temporomandibular Joint (TMJ):

• The articulation between the mandible and the temporal bone is identifiable.

7. Base of the Skull:

• Includes structures like the foramen magnum and occipital condyles, which provide a clear understanding of the skull’s inferior aspect.

8. Cervical Spine:

• The first few cervical vertebrae (C1–C3) are often visible, especially the atlas (C1) and axis (C2) vertebrae.

On a lateral skull X-ray of a patient with a pituitary adenoma, specific changes are commonly observed, particularly in the Sella turcica region. Here are the detailed imaging features:

Key Radiographic Findings:

1. Enlargement of the Sella Turcica:

   • The sella turcica, which houses the pituitary gland, appears abnormally large and ballooned. This is due to the expansion caused by the adenoma.

2. Erosion of the Sellar Floor:

   • The floor of the sella turcica may show thinning or erosion. This happens as the tumor grows and exerts pressure on the bony structures.

3. Double-Floor Sign:

   • In some cases, the sella turcica may show a layered appearance due to remodeling of the bone.

4. Smooth Cortical Outlines:

   • Despite the enlargement, the margins of the sella turcica may remain smooth, distinguishing it from destructive lesions like malignancies.

5. Suprasellar Extension:

   • If the tumor grows upward, it can compress adjacent structures such as the optic chiasm. This may not be directly visible on X-ray but can suggest a large mass effect.

6. Normal Adjacent Structures:

   • Surrounding cranial bones, nasal cavity, and sinuses typically remain normal unless the tumor is very large and invasive.