The Orbit & its Contents

6 May 2010

Bones of Orbit

· Margins

– frontal

– zygomatic

– maxillary

· Interior walls

– sphenoid

– ethmoid

– lacrimal

· Foramina

– Superior orbital fissure

– Optic canal

– Inferior orbital fissure

– Inferior orbital groove

– Lacrimal canal

– Ethmoidal foramen

– Frontal(supraorbital) foramen

Netter, 2003 pl. 2; Netter, 2006 pl. 2

Attachments of Eyelid

· Orbital septum

· Superior tarsal plate

· Insertion of Levator palpabrae superioris m.

· Inferior tarsal plate

Orbital structures in parasagittal section

· Orbital septum

· Levator palpabrae superioris

· Superior tarsal plate

· Conjunctival fornix

· Inferior tarsal plate

Netter, 2003 pl. 77; Netter, 2006 pl. 81

Lacrimal Apparatus

· Lacrimal gland

· Lacrimal puncta

· Lacrimal canalicula

· Lacrimal sac

· Nasolactimal duct

· Inferior nasal meatus

Netter, 2003 pl. 78; Netter, 2006 pl. 82

Extrinsic Ocular Muscles

· Levator palpebrae superioris

· 4 Rectus muscles

– Superior rectus

– Medial rectus

– Lateral rectus

– Inferior rectus

· 2 oblique muscles

– Superior oblique

– Inferior oblique

Netter, 2003 pl. 80; Netter, 2006 pl. 84

Nerves of Orbit

· Optic n. (II)

· Ophthalmic n. (V1) (Sensory)

– Frontal n.

§ Supratrochlear

§ Supraorbital

– Nasociliary n.

§ Long ciliary nn

§ Ethmoidal nn

– Lacrimal n.

· Oculomotor n. (III)

– Motor to all ocular mm. (except two below)

· Trochlear n. (IV)

– Motor to superior oblique m.

· Abducens n. (VI)

– Motor to lateral rectus m.

Ciliary ganglion - site of synapse of parasympathetic innervation to pupillary constrictor muscle

Netter, 2003 pl. 82; Netter, 2006 pl. 86

Blood Supply of Orbit

· Ophthalmic a.

– Central artery of Retina

· Lacrimal a.

· Ciliary aa.

· Ethmoidal aa.

· Supraorbital a.

· Supratrochlear a.

Netter, 2003 pl. 81; Netter, 2006 pl. 85