What is Orbit (anatomy)?

Information about Orbit (anatomy)

The seven bones which articulate to form the orbit.
yellow = Frontal bone
blue = Zygomatic bone
purple = Maxillary bone
red = Sphenoid bone
brown = Ethmoid bone
aqua = Palatine bone
green = Lacrimal bone
subject #46 188
MeSH Orbit
Dorlands/Elsevier o_05/12594914
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated.

It can also mean the skin which surrounds the eye of a bird.

In the adult human, the volume of the orbit is 30 ml, of which the eye occupies 6.5 ml. [1]

Contents

Bones

In humans, seven bones make up the bony orbit:

Foramina and openings

  1. Optic foramen
  2. Superior orbital fissure
  3. Inferior orbital fissure
  4. Anterior ethmoid foramen
  5. Posterior ethmoidal foramen
  6. Infraorbital foramen
  7. Supraorbital foramen
  8. Naso-lacrimal canal opening
  9. Zygomatic orbital foramen

Additional images


The skull from the front.

Medial wall of left orbit.

Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.

Coronal section of nasal cavities.

Lateral orbit anatomy

Lateral orbit nerves


References

1. ^ Duane's Ophthalmology, Chapter 32 Embryology and Anatomy of the Orbit and Lacrimal System . (eds Tasman W, Jaeger EA) Lippincott/Williams & Wilkins, 2007

External links

The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:
  • a vertical portion, the squama frontalis, corresponding with the region of the forehead.

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The zygomatic bone (malar bone) is a paired bone of the human skull. It articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It forms part of the orbit and is commonly referred to as the cheekbone.
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The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible, which is also a fusion of two halves at the mental symphysis.
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The sphenoid bone (from Greek sphenoeides, "wedgelike") is a bone situated at the base of the skull in front of the temporals and basilar part of the occipital bone.

The sphenoid bone somewhat resembles a butterfly or bat with its wings extended.
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The ethmoid bone (from Greek ethmos, "sieve") is a bone in the skull that separates the nasal cavity from the brain. As such, it is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction.
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The palatine bone is a bone in the palate (Latin palatum; unrelated to palatium 'palace', from which other senses of palatine derive).

Anatomy

It is situated at the back part of the nasal cavity between the maxilla and the pterygoid process of the
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The lacrimal bone, the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders.

Surfaces

Lateral or orbital surface


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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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Anatomy (from the Greek ἀνατομία anatomia, from ἀνατέμνειν
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skull is a bony structure found in many animals which serves as the general framework for the head. The skull supports the structures of the face and protects the head against injury.

The skull can be subdivided into two parts: the cranium and the mandible.
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Eyes are organs of vision that detect light. Different kinds of light-sensitive organs are found in a variety of organisms. The simplest eyes do nothing but detect whether the surroundings are light or dark, while more complex eyes can distinguish shapes and colors.
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In anatomy, adnexa refers to the appendages of an organ.

Examples of adnexa

Adnexa of eye

  • extraocular muscles
  • eyelids
  • lacrimal glands

Adnexa of uterus

  • ovaries
  • oviducts

Adnexa of skin

  • hair

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Not to be confused with Fuchsia.


Fascia (făsh'ē-ə), pl. fas·ci·ae (făsh'ē-ē), adj. fascial (făsh'ē-əl) (from latin: a band) is the soft tissue component of the connective tissue system that
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The term orbital has several meanings:

In chemistry:
  • Atomic orbital
  • Molecular orbital
In physics, astronomy, and spaceflight:
  • Orbital motion
  • Orbital resonance
  • Orbital period
  • Orbital plane (astronomy)

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The corticobulbar (or corticonuclear) tract is a white matter pathway connecting the cerebral cortex to the brainstem (the term "bulbar" referring to the brainstem).

The 'bulb' is an archaic term for the medulla oblongata.
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There are seven muscles of the orbit; one controls the movement of the upper eyelid, and six others control the movement of the eye.

Muscle Innervation Primary function Secondary function Tertiary function
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A nerve is an enclosed, cable-like bundle of axons (the long, slender projection of a neuron). Neurons are sometimes called nerve cells, though this term is technically imprecise since many neurons do not form nerves, and nerves also include the glial cells that
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Cranial nerves are nerves that emerge directly from the brain in contrast to spinal nerves which emerge from segments of the spinal cord. Although thirteen cranial nerves in humans fit this description, twelve are conventionally recognized.
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Optic Nerve may be a reference to:
  • Optic nerve, the anatomical structure;
  • Optic Nerve (comic), the comic book series;
  • Optic Nerve (1998), the seminal release from the Irish hip hop act known as Exile Eye; or

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The oculomotor nerve is the third of twelve paired cranial nerves. It controls most of the eye movements (cranial nerves IV and VI also do some), constriction of the pupil, and holding the eyelid open.
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The trochlear nerve (the fourth cranial nerve, also called the fourth nerve or simply IV) is a motor nerve (a “somatic efferent” nerve) that innervates a single muscle: the superior oblique muscle of the eye.
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The trigeminal nerve (the fifth cranial nerve, also called the fifth nerve or simply V) is responsible for sensation in the face. It is similar to the spinal nerves C2–S5, which are responsible for sensation in the rest of the body.
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The abducens nerve (the sixth cranial nerve, also called the sixth nerve or simply VI) is a motor nerve (a “somatic efferent” nerve) that controls the movement of a single muscle, the lateral rectus muscle of the eye.
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The blood vessels are part of the cardiovascular system and function to transport blood throughout the body. The most important types, arteries and veins, carry blood away from or towards the heart, respectively.
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Fat

Fat may refer to:
  • Fat, a group of compounds that are generally soluble in organic solvents and largely insoluble in water
  • Adipose tissue, an anatomical term for loose connective tissue composed of adipocytes

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The lacrimal glands are paired glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper, outer portion of each orbit.

Anatomy


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The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:
  • a vertical portion, the squama frontalis, corresponding with the region of the forehead.

..... Read more.
The orbital or horizontal part of the frontal bone (pars orbitalis) consists of two thin triangular plates, the orbital plates, which form the vaults of the orbits, and are separated from one another by a median gap, the ethmoidal notch.
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