QS Study

The orbits (eye sockets) are bilateral and symmetrical cavities in the head. It is a feature of the face and contains the globe and it’s supporting structures, as well as many nerves and vessels. They surround the eyeball and its related structures.

Boundaries of orbit

The orbit can be thought of as a pyramidal structure, with the apex pointing posteriorly and the base situated anteriorly.

(A) Orbital margin: formed by –

  • Above – frontal bone.
  • Lateral margin – Process of frontal & Zygomatic bone.
  • Inferior margin – Zygomatic bone & maxilla.
  • Medial margin – Processes of maxilla & frontal bone.

(B) Roof: Formed by – Orbital plate of frontal bone. It formed by the frontal bone and the lesser wing of the sphenoid. The frontal bone separates the orbit from the anterior cranial fossa.

(C) Lateral wall: Formed by –

  • Zygomatic bone.
  • Greater wing of sphenoid bone.

(D) Floor: by orbital plate of the maxilla. It formed by the maxilla, Palatine and zygomatic bones. The maxilla separates the orbit from the underlying maxillary sinus.

(E) Medial wall: by –

  • Frontal process of the maxilla.
  • Lacrimal bone.
  • An orbital plate of ethmoid bone.
  • A body of the sphenoid bone.

Boundary of the Orbit 1

Fig: Boundary of the Orbit

Contents of the orbit –

(A) Eyeball.

(B) Fascia:

  • Orbital.
  • Bulbar.

(C) Muscles: Extraocular muscles. These muscles are separate from the eye. They are responsible for the movement of the eyeball and superior eyelid.

(D) Vessels: The eye receives blood primarily from the ophthalmic artery. Venous drainage is via the superior and inferior ophthalmic veins.

  • Ophthalmic artery.
  • Superior ophthalmic
  • Inferior ophthalmic veins.

(E) Lymphatics.

(F) Nerves:

  • Optic nerve.
  • Oculomotor nerve.
  • Trochlear nerve.
  • Abducent nerve.
  • Branch of ophthalmic nerve.
  • Sympathetic nerve.

(G) Lacrimal gland.

(H) Orbital fat.

Contents of the Orbit 1

Fig: Contents of the Orbit

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