Orbit

Orbit refers to the cavity or socket of the skull in which the eye and its appendages are situated. The orbit is conical or four-sided pyramid-like in shape, with its apex pointed back into the head. There are seven bones that make up the human orbit.

Anatomy

The seven bones that constitute the orbit are the frontal bone, the sphenoid bone, the zygomatic bone, the maxillary bone, the palatine bone, the lacrimal bone, and the ethmoid bone.

Frontal Bone

The frontal bone forms the upper boundary of the orbit. Its lower margin is smooth and rounded, and presents, laterally, under cover of the zygomatic process, a shallow depression, the lacrimal fossa, for the lacrimal gland.

Sphenoid Bone

The sphenoid bone contributes to the apex of the orbit, which points back into the head.

Zygomatic Bone

The zygomatic bone forms the lateral high point of the face, and is generally considered the 'point' of the cheek.

Maxillary Bone

The maxillary bone forms the lower boundary of the orbit, the floor of the orbit.

Palatine Bone

The palatine bone forms the back of the bottom part of the orbit.

Lacrimal Bone

The lacrimal bone is the smallest and most fragile bone of the face; it is roughly the size of the little finger nail. It is situated at the front part of the medial wall of the orbit.

Ethmoid Bone

The ethmoid bone is a singular porous bone that makes up the middle area of the viscerocranium and forms the midfacial region of the skull.

Images

• 
  Animation of C/2018 Y1 orbit
• 
  Ptolemaic Planisphere
• 
  Moon Apsidal Precession
• 
  Newton's Cannon

See Also

• Eye socket
• Human skull
• Human skeleton