ORBIT STEVEN J. ZEHREN, PH.D.

BONY ORBIT

Frontal bone Lesser wing of sphenoid Superior orbital fissure Optic canal Greater wing of sphenoid Zygomatic bone Inferior orbital fissure Infraorbital groove & foramen Maxillary bone Orbital process of palatine bone Fossa of lacrimal sac Lacrimal bone Orbital plate of ethmoid bone (lamina papyracea) Anterior ethmoidal foramen Posterior ethmoidal foramen Supraorbital notch (foramen) RIGHT BONY ORBIT (ANTERIOR VIEW)

Brain Frontal sinus Ethmoidal cells Maxillary sinus RELATIONSHIPS OF BONY ORBIT (CORONAL SECTION)

Nasal septum Ethmoidal cells Sphenoidal sinuses Brain (in middle cranial fossa) Optic n. Medial wall of orbit Temporalis m. (in temporal fossa) RELATIONSHIPS OF BONY ORBIT (HORIZONTAL SECTION)

EYEBALL

EYEBALL (HORIZONTAL SECTION)

SHEATHS OF THE OPTIC NERVE Central a. & v. of retina Pia Arachnoid Dura Subarachnoid space (Intervaginal space)

Optic disc OPTIC DISC (PAPILLA)

MUSCLES

Cornea Iris folds Lens Sclera Sphincter m. of pupil (miosis) Dilator m. of pupil (mydriasis) Ciliary m. (accommodation) Ciliary body Fibers of ciliary zonule (suspensory lig. of lens) INTRINSIC MUSCLES OF EYEBALL

Oculomotor (parasym. root) of ciliary ganglion Short ciliary nn. Ciliary g. Ciliary m. Sphincter m.Dilator m. Lateral horn of T1 – T3 cord segments Sup. cervical ganglion Int. carotid plexus V1 Long ciliary n. Sympathetic root of ciliary g. AUTONOMIC INNERVATION OF THE EYE Pre- Post- Pre- Post- Sympathetic Parasympathetic Accessory oculomotor (Edinger-Westphal) nucleus in midbrain

POSITION OF CILIARY GANGLION Ciliary ganglion Lateral rectus Optic nerve Short ciliary nerves

Trochlea (pulley) Inferior oblique m. Inferior rectus m. Lateral rectus m. (cut) Common annular tendon Medial rectus m. Superior rectus m. Levator palpebrae superioris m. Superior oblique m. EXTRINSIC EYE MUSCLES (RIGHT LATERAL VIEW)

ORBITAL AXIS NOT THE SAME AS VISUAL AXIS ORBITAL AXIS VISUAL AXIS

MOVEMENTS AROUND THE VERTICAL AXIS ADDUCTORS ABDUCTORS Medial rectus Superior rectus Inferior rectus Inferior oblique Superior oblique Lateral rectus

MOVEMENTS AROUND THE LATEROMEDIAL (TRANSVERSE) AXIS ELEVATORSDEPRESSORS Superior rectus Inferior oblique Inferior rectus Superior oblique

MOVEMENTS AROUND THE A-P AXIS INTORSION EXTORSION Superior rectus Superior oblique Inferior rectus Inferior oblique

INNERVATION OF EXTRINSIC EYE MUSCLES (SO4, LR6, R3)

MUSCLES OF THE UPPER EYELID Levator palpebrae superioris (striated muscle/oculomotor n.) Superior tarsal muscle (smooth muscle/sympathetic) Superior tarsal plate

PERIORBITA & FASCIA

Medial check ligament Lateral check ligament Periorbita Medial rectus muscle and sheath Bulbar sheath (Tenon’s capsule) Lateral rectus muscle and sheath Orbital fat PERIORBITA AND FASCIA (HORIZONTAL SECTION)

NERVES

Trigeminal ganglion Ophthalmic n. (V1) N asociliary n. Supratrochlear n. F rontal n. L acrimal n. Medial branch Lateral branch Supraorbital n. NFL (3 BRANCHES OF V1) OPHTHALMIC NERVE (V1)

Nasociliary n. Posterior ethmoidal n. Anterior ethmoidal n. Infratrochlear n. Ophthalmic n. (V1) Frontal n. (cut) Lacrimal n. Long ciliary nn. OPHTHALMIC NERVE (V1) (DEEP DISSECTION)

VESSELS

Internal carotid a. Ophthalmic a. Muscular branch Continuation of ophthalmic a. Posterior ethmoidal a. Anterior ethmoidal a. Dorsal nasal a. Supratrochlear a. Medial palpebral a. Lateral palpebral a. Supraorbital a. Posterior ciliary aa. Lacrimal a. Central a. of retina OPHTHALMIC ARTERY

Supratrochlear v. Supraorbital v. Angular v. Facial v. Vorticose vv. Superior ophthalmic v. Inferior ophthalmic v. Cavernous sinus Pterygoid plexus OPHTHALMIC VEINS

END OF LECTURE