Gross Anatomy

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Anatomy Tables for Today's Topic


Bones
Muscles
Nerves
Arteries
Veins
Viscera

Bones

Bone/Cartilage Structure Description Notes
frontal the anterior bone of the skull which underlies the forehead articulates with the parietal bone posteriorly; zygomatic, ethmoid and sphenoid bones inferiorly; maxilla, nasal and lacrimal bones anteriorly; it is formed from two ossifications centers which normally fuse in the midline - if they do not fuse, a midline "metopic suture" is the result
orbital plate flat portion of frontal that forms the roof of the orbit a very thin portion of the frontal bone which is like an egg shell in thickness
superior orbital margin arch of bone above the orbital opening skin over this region is supplied by branches of the frontal nerve (supraorbital and supratrochlear nn.)
superciliary arch the ridge of bone above the orbital margin located deep to the eyebrow, blunt trauma to this region often results in cuts within the eyebrow
supraorbital notch notch in the superior orbital margin occasionally present as a foramen; opening for the passage of the for supraorbital neurovascular bundle
ethmoid delicate bone located between the two orbits highly pneumatized bone that contains the ethmoid air cells; forms the fragile medial wall of the orbit
crista galli superior midline projection of the ethmoid bone into the anterior cranial fossa; it arises between the cribriform plates "cock's comb"; anterior anchor point of the falx cerebri
ethmoidal foramen, anterior opening in the medial wall of the orbit transmits anterior ethmoidal vessels and nerve
ethmoidal foramen, posterior opening in the medial wall of the orbit transmits posterior ethmoidal vessels and nerve
lacrimal small bone forming part of the medial wall of the orbit articulates: anteriorly with frontal process of maxilla, superiorly with frontal bone, posteriorly with ethmoid, inferiorly with orbital process of maxilla; forms part of the canal for the nasolacrimal duct
sphenoid an irregularly shaped bone forming the central portion of the skull it has many parts, including a body, greater wing, lesser wing and pterygoid plates
lesser wing of the sphenoid thin rim of bone projecting laterally from the anterior clinoid process bilateral; it forms the posterior margin of anterior cranial fossa; it articulates anteriorly with the orbital plate of the frontal bone
greater wing of the sphenoid broad plate of bone swinging laterally from the body of the sphenoid bone bilateral; it forms the medial part of the floor of the middle cranial fossa, part of temporal fossae laterally, and the posterior part of the lateral wall of orbit; it articulates anteriorly with the zygomatic bone, superiorly with the frontal & parietal bones (at the pterion), posteriorly with the squamous & petrous portions of the temporal bone
superior orbital fissure slit-like opening between the lesser & greater wings of the sphenoid bone it transmits the oculomotor nerve, the trochlear nerve, the abducens nerve, branches of ophthalmic division of the trigeminal nerve, the superior ophthalmic vein and lymphatics from the cranial cavity into the orbit
maxilla bone forming the midface it forms the inferior orbital margin and contains the teeth and maxillary sinus
orbital process the part of the maxilla that forms the floor of the orbit also known as the orbital surface of the maxilla; it contains the infraorbital groove and canal; it forms the roof of the maxillary sinus
zygomatic process the lateral projection of the maxilla it articulates with the zygomatic bone
infraorbital groove groove in orbital process of the maxilla located in the posterior part of the orbit transmits the infraorbital neurovascular bundle from the infraorbital fissure to the infraorbital canal
infraorbital canal canal in orbital process of the maxilla located in the anterior part of the orbit the direct continuation of the infraorbital groove; transmits the infraorbital neurovascular bundle from the infraorbital groove to the infraorbital foramen
infraorbital foramen opening at the anterior end of the infraorbital canal located inferior to the orbit it transmits the infraorbital neurovascular bundle
palatine the bone that forms the posterior part of the hard palate paired; failure of the perpendicular plates to fuse during development leads to a midline defect (cleft palate)
orbital process a small, superior projection from the perpendicular plate of the palatine bone it forms a small part of the floor of the orbit located posteroinferiorly near the apex

Muscles

Muscle Origin Insertion Action Innervation Artery Notes
orbicularis oculi orbital part: medial orbital margin and the medial palpebral ligament; palpebral part: medial palpebral ligament orbital part: skin of the lateral cheek; palpebral part: lateral palpebral raphe closes the eyelids temporal & zygomatic branches of the facial nerve (VII) supraorbital a., supratrochlear a., infraorbital a., angular branch of the facial a. activated involuntarily in the blink reflex; the palpebral part is active in normal blinking and the orbital part is used to forcefully close the eye
levator palpebrae superioris apex of the orbit above the optic canal skin and fascia of upper eyelid and the superior tarsal plate elevates the upper eyelid oculomotor nerve (III) and sympathetics (to the superior tarsal portion) ophthalmic a. fibers inserting into the superior tarsal plate are called superior tarsal muscle and are smooth muscle; lesion of the sympathetic supply causes slight ptosis (drooping of the eyelid)
superior rectus common tendinous ring at the apex of the orbit sclera on the superior surface of the eyeball elevates and adducts the eyeball; rotates the superior pole of the iris medially oculomotor nerve (III), superior division ophthalmic a. because this muscle approaches the eye from a medial position, it causes the iris to rotate medially
inferior rectus common tendinous ring at the apex of the orbit sclera on the inferior surface of the eyeball depresses and adducts the corneal part of the eyeball; rotates the superior pole of the iris laterally oculomotor nerve (III), inferior division ophthalmic a. because this muscle approaches the eyeball from a medial direction, it has a rotational action on the iris
medial rectus common tendinous ring at the apex of the orbit sclera on the medial surface of the eyeball adducts the corneal part of the eyeball oculomotor nerve (III) (inferior division) ophthalmic a. this muscle directly opposes the action of the lateral rectus m.
lateral rectus common tendinous ring at the apex of the orbit sclera on the lateral surface of the eyeball abducts the corneal part of the eyeball abducens nerve (VI) ophthalmic a. loss of function of the abducens nerve will cause the eye to be adducted
superior oblique apex of the orbit above the optic canal sclera on the posterior superior surface of the eyeball depresses and abducts the eyeball; rotates the superior pole of the iris medially trochlear nerve (IV) ophthalmic a. passes through a fibrocartilagenous pulley known as the trochlea; when the eye is adducted, this muscle moves the cornea inferiorly
inferior oblique floor of the orbit lateral to the lacrimal groove sclera on the inferior surface of the eyeball elevates and abducts the corneal part of the eye; rotates the superior pole of the iris laterally; when the eye is adducted, this muscle elevates the cornea oculomotor nerve (III), inferior division ophthalmic a. clinicians examining the eye will ask the patient to look toward the bridge of the nose to test the function of this muscle
sphincter pupillae encircles iris encircles iris constricts the pupil parasympathetic fibers of oculomotor nerve (III), synapsing in ciliary ganglion ophthalmic a. none
ciliary meridional fibers: scleral spur; circular fibers: encircle the ciliary process meridional fibers: ciliary process; circular fibers: encircle the ciliary process relaxes the suspensory ligament of the lens parasympathetic fibers in the oculomotor nerve (III), synapsing in the ciliary ganglion ophthalmic a. relaxation of the suspensory ligament allows the lens to thicken for accommodation (near vision)
dilator pupillae outer margin of iris inner margin of iris dilates the pupil sympathetic fibers via short ciliary nerves, synapsing in superior cervical sympathetic ganglion ophthalmic a. none

Nerves

Nerve Source Branches Motor Sensory Notes
trochlear n. trochlear nucleus of the midbrain no named branches superior oblique m. of the eye (GSE) none also known as: CN IV, 4th cranial nerve; the trochlear n. passes through the superior orbital fissure to exit the middle cranial fossa; it is the smallest cranial nerve and the only cranial nerve to arise from dorsum of brainstem
ophthalmic division of the trigeminal n. trigeminal ganglion meningeal br., lacrimal n., frontal n., nasociliary n. none (GSA) skin of the forehead, upper eyelid and nose; mucous membrane of the upper nasal cavity, frontal sinus, ethmoid air cells and sphenoid sinuses also known as: V1; the ophthalmic division of the trigeminal n. passes through the superior orbital fissure to exit the middle cranial fossa; the lacrimal n. receives postganglionic parasympathetic axons to the lacrimal gland from the zygomaticotemporal br. of the zygomatic n.
lacrimal n. ophthalmic division of the trigeminal n. (V1) no named branches carries secretomotor axons to the lacrimal gland skin of the lateral portion of the upper eye lid and its associated conjunctiva lacrimal n. carries the postganglionic parasympathetic axons from the zygomaticotemporal br. of the maxillary n. that originate in the pterygopalatine ganglion
frontal ophthalmic division of the trigeminal n. (V1) supraorbital n., supratrochlear n. none skin of the forehead and the medial part of the upper eyelid; mucous membrane of the frontal sinus the most superior linear structure within the orbit
supraorbital n. frontal n, from the ophthalmic division of the trigeminal n. (V1) medial and lateral brs. none skin of the forehead; mucous membrane of the frontal sinus supraorbital nerve passes through the supraorbital foramen (notch)
supratrochlear n. frontal n, from the ophthalmic division of the trigeminal n. (V1) no named branches none skin of the medial forehead and the medial part of the upper eyelid; associated conjunctiva supratrochlear n. passes superior to the trochlea (pulley) of the superior oblique m.
infratrochlear n. nasociliary br. of the ophthalmic division of the trigeminal n. (V1) no named branches none skin and conjunctiva of the medial upper and lower eyelids; skin of the lateral surface of the nose infratrochlear n. passes inferior to the trochlea (pulley) of the superior oblique m.
nasociliary n. ophthalmic division of the trigeminal n. (V1) communicating br. to the ciliary ganglion, long ciliary n., anterior and posterior ethmoidal nn., infratrochlear n. none eyeball, skin of the nose and medial sides of the eyelids; conjunctiva of the medial sides of the eyelids; mucous membranes of the upper nasal cavity, ethmoid and sphenoid sinuses the distribution of this nerve is indicated by its name - nasociliary
long ciliary n. nasociliary no named branches none eyeball (GSA) these nerves bypass the ciliary ganglion
anterior ethmoidal n. nasociliary n. internal & external nasal brs. none mucous membrane lining the anterior ethmoid air cells and upper anterior part of the nasal cavity; skin of the lower half of the nose anterior ethmoidal n. passes from the orbit into the anterior ethmoidal foramen, passes through the cribriform plate, passes anteriorly on cribriform plate, then exits the cranial cavity through the ethmoid fissure into the nasal cavity
posterior ethmoidal n. nasociliary n. no named branches none mucous membrane lining the posterior ethmoid air cells and sphenoid sinus posterior ethmoidal n. exits the orbit by passing through the posterior ethmoid foramen
abducens n. pons: abducens nucleus no named branches GSE: lateral rectus m. none also known as: CN VI, 6th cranial nerve; passes through the superior orbital fissure
oculomotor n. oculomotor nuclei of the midbrain (extraocular muscles); accessory oculomotor nucleus (nucleus of Edinger-Westphal - preganglionic parasympathetic) superior br., inferior br. GSE: superior br.: levator palpebrae superioris m., superior rectus m.; inferior br: medial rectus m., inferior rectus m., inferior oblique m.; GVE: ciliary m. & sphincter pupillae m. (preganglionic parasympathetic axons go to the ciliary ganglion via the parasympathetic root, postganglionic parasympathetic go from the ciliary ganglion to the eyeball via short ciliary nn.) none also known as: CN III; oculomotor n. passes through the superior orbital fissure to exit the middle cranial fossa
nerve to inferior oblique inf. br. of oculomotor parasympathetic root of ciliary gang. sphincter pupillae & ciliary m. (parasymp.), inf. oblique parasymp. root carries GVE pregang. parasymp. to ciliary gang., short ciliary ns. carry postgang. parasymp. into eyeball
ciliary ganglion preganglionic parasympathetic axons arrive via the inferior division of the oculomotor n. (III) postganglionic parasympathetic axons which distribute via short ciliary nn. sphincter pupillae m., ciliary m. of the eye none a parasympathetic ganglion; ciliary ganglion is located on the lateral side of the optic n. near the apex of the orbit; sensory and sympathetic axons pass through the ciliary ganglion without synapse - the sensory root is carried via the nasociliary n.and the sympathetic root arrives in the orbit via the internal carotid a.
short ciliary n. ciliary ganglion: sensory root - from the nasociliary n.(a branch of V1); sympathetic root - from the internal carotid plexus; parasympathetic root - from the inferior division of the oculomotor n. (III) multiple short ciliary nn. which leave the ciliary ganglion anteriorly sphincter pupillae & ciliary mm. (parasympathetic), dilator pupillae (sympathetic) eyeball (GSA) short ciliary nn. are mixed nerves which contain sensory and 2 types of autonomic nerve fibers; postganglionic parasympathetic neurons whose axons are located in these nerves have their cell bodies located in the ciliary ganglion
optic n. ganglion layer of the retina to the forebrain none none vision (SSA) also known as: CN II, 2nd cranial nerve; the course of the optic nerve is: through the optic canal to the optic chiasma, then the optic tract to the lateral geniculate body and optic radiation
zygomatic n. maxillary division of the trigeminal n. (V2) zygomaticofacial & zygomaticotemporal carries secretomotor fibers skin of the face lateral and superior to the orbit zygomatic n. carries postganglionic parasympathetic fibers from the pterygopalatine ganglion to the lacrimal gland (via the communicating br. of the zygomaticotemporal n. which joins the lacrimal n.)
zygomaticofacial n. zygomatic from the maxillary division of the trigeminal n. (V2) no named branches none skin of face lateral to the orbit zygomaticofacial n. passes through the zygomaticofacial foramen
zygomaticotemporal n. zygomatic from the maxillary division of the trigeminal n. (V2) communicating br. carries secretomotor fibers skin of face superolateral to the orbit zygomaticotemporal n. carries postganglionic parasympathetic fibers from the pterygopalatine ganglion to the lacrimal gland (via the communicating br. which joins the lacrimal n.)
sympathetic chain ganglia, cervical preganglionic sympathetic fibers arrive via white rami communicantes of ventral primary rami of spinal nerves T1-T5 postganglionic sympathetic depart via gray rami communicans to cervical spinal nn.; internal and external carotid nn.; cervical cardiac brs. dilator pupillae m.; vascular smooth muscle; arrector pili muscles and sweat glands of head and neck; heart and lungs pain from viscera located parallel to the vertebral bodies in the neck; there are no white rami communicantes at cervical levels

Arteries

Artery Source Branches Supply to Notes
ophthalmic internal carotid a. central retinal a., lacrimal a., muscular brs., anterior ethmoidal a., posterior ethmoidal a., medial palpebral a., supraorbital a., supratrochlear a., dorsal nasal a. optic nerve, optic chiasm optic tract, retina, extraocular mm., eyelids, forehead, ethmoidal air cells, lateral nasal wall, dorsum of the nose ophthalmic a. provides the only artery to the retina (central retinal a.)
central, of retina ophthalmic a. superior nasal br., inferior nasal br., superior temporal br., inferior temporal br. retina central a. of the retina is the sole blood supply to the retina; it has no significant collateral circulation and blockage of this vessel leads to blindness; its branches are viewed in a funduscopic exam
ethmoidal, anterior ophthalmic a. anterior meningeal a., anterior septal br., anterior lateral nasal br. anterior ethmoidal air cells, frontal paranasal sinus, dura mater in the anterior cranial fossa, nasal mucosa, olfactory nerves anterior ethmoidal a. leaves the orbit through the anterior ethmoidal foramen, then runs forward on the cribriform plate
ethmoidal, posterior ophthalmic a. no named branches posterior ethmoidal air cells; olfactory nerves posterior ethmoidal a. leaves the orbit through the posterior ethmoidal foramen
lacrimal ophthalmic a. lateral palpebral aa. (2) lacrimal gland, lateral sides of the eyelids lacrimal a. accompanies the lacrimal n.
supraorbital ophthalmic a. no named branches muscles, skin and fascia of the forehead supraorbital a. accompanies the supraorbital n.
supratrochlear ophthalmic a. no named branches muscles, skin and fascia of the medial forehead supratrochlear a. accompanies the supratrochlear n.

Veins

Vein Tributaries Drains Into Regions Drained Notes
angular v. supraorbital v., supratrochlear v. facial vein at the inferior margin of the orbit forehead; upper eyelid; root of the nose angular v. is valveless; it connects with the superior and inferior ophthalmic vv. and can be a source of superficial infectious materials entering the cavernous sinus by this route
cavernous sinus superior ophthalmic v., cerebral vv., sphenoparietal sinus superior petrosal sinus, inferior petrosal sinus orbit, brain cavernous sinus lies between the cranial and meningeal layers of the dura mater beside the body of the sphenoid bone; cranial nn. III, IV and V1 are in its lateral wall; the internal carotid a. and cranial n. VI are in its lumen
ophthalmic, inferior ciliary vv., veins from the muscles of the inferior part of the orbit superior ophthalmic v. inferior portion of the orbit valveless; inferior ophthalmic v. connects with the pterygoid plexus through the inferior orbital fissure
ophthalmic, superior nasofrontal v., anterior ethmoidal v., posterior ethmoidal v., ciliary vv., central retinal v., lacrimal v., inferior ophthalmic v. cavernous sinus eyeball, superior portion of the orbit, ethmoidal air cells, forehead valveless; superior ophthalmic v. communicates with the angular v.

Viscera

Organ Location/Description Notes
lacrimal gland tear gland; located in superolateral orbit beneath the orbital plate of the frontal bone lacrimal gland is innervated by postganglionic parasympathetic fibers from the pterygopalatine ganglion via the communicating br. from the zygomaticotemporal br. of the zygomatic n. to the to lacrimal n.
lacrimal papilla a projection located on the edge of the upper or lower eyelid at the medial angle of the eye a lacrimal punctum is located at the apex of each lacrimal papilla
lacrimal punctum an opening located on the edge of the medial end of the upper or lower eyelid a lacrimal punctum is located at the apex of each lacrimal papilla; there are two puncta, one on each eyelid, that drain tears into the lacrimal canaliculi
lacrimal sac a sac located within the medial wall of orbit, between the orbit and the nasal cavity lacrimal sac receives the lacrimal canaliculi; it drains tears into the nasolacrimal duct

Other Tables of Interest:

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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2007, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.