Ocular Anatomy V S 111 UAB School of

Ocular Anatomy V. S. 111 UAB School of Optometry Timothy W. Kraft, Ph. D. 975 -2885 twkraft@uab. edu

Goals for the Term • Solid base of knowledge • Comfort with Ocular terminology • Basics of tissue structure & function – At the end of the course you can give yourself a 3 D guided tour of the eye and orbit within your mind’s eye.

Exam Schedule & Grading • Midterm 45% • Lab work sheets & hw (5%) • Quizzes: Six, pick your best 5 for 10% • and Final Exam 40% • some of Final is review There will be 4 or 5 Lab sessions, attendance is mandatory

Sources of information • The Human Eye structure and Function by Clyde Oyster • Hand-outs, outlines including additional figures. • CD’s of power point presentations for out of class review Come to Class

Texts and Supplements • Oyster (you buy this one) The Human Eye • Williams & Warwick Functional Neuroanatomy of Man (copy provided) • Snell & Lemp: Clinical Anatomy of the Eye (copy of selected figures provided)

Broad-based learning • Power point presentations – Almost all lectures available on CD • Hand outline the lecture • Study Guides • When all else fails: RTB Go to Class

Overview • When the structure seems complicated , think FUNCTION – Imaging : OPTICAL CLARITY – Information processing: pathways, adaptation – Mobility: balance, strength, speed, MECHANICS – Biological System: respiration, pain, protection

Terminology • Rostral (toward top of head - rooster) • Caudal (toward tail) cauda equina - horses tail • Anterior - front - ventral • Posterior- back - dorsal (dorsal fin) • Medial (midline) {Nasal} • Lateral away from midline (Temporal) • Central • Peripheral- away from center

Basic components of eyeball Scleral outer Vitreal Inner

Eyeball: Optical Pathway • Cornea • Anterior Chamber • Iris/Pupil • Posterior Chamber • Lens • Vitreous • Retina Figure by Snell & Lemp

Eyeball: Layered tissues • Protective epithelium • Cornea/Sclera • Choroid • RPE – All to protect/nourish the nervous tissue of retina/optic nerve • Scleral/Vitreal

Figure by Snell & Lemp

The Orbit: Bone structures Bones: Those Latin names Protecting the eye while serving its needs. • VS 111 • Aug 11, 2008 • Lect 1 -2

Reasonable Goals • Overall function is simple, but the details. . – Name the bones, – Know the construction of the orbit walls, – Know the strong and weak points, – What is in the orbit, what holds it there? – What comes into, goes out of the orbit? – What are holes (fissures, foramina) used for?

Skull has 22+ bones • Cranium – Parietal (2) – Occipital – Temporal (2) • Face – Maxillary (2) – Nasal (2) – Inferior chonchae (2) – Lacrimal (2) – Sphenoid – Palatine (2) – Ethmoid – Zygomatic (2) – Mandible – Vomer • Frontal bone is part of both cranium & face

11 bones make up the orbits • Single Bones • Paired Bones – Frontal Bone – Maxillary – Ethmoid Bone – Zygomatic – Sphenoid Bone – Lacrimal – Palatine

Bones of the skull

Lateral View of Skull • Frontal • Zygomatic • Note temoral aspect of Sphenoid • Maxillary • Lacrimal • Ethmoid

Sinuses exist in 4 Orbital Bones • Air filled • Mucosa lined • Lighten bone • Acustic • Possible infection site

The basic shape of the orbit is a pyramid: • The medial walls are parallel • The depth is 1. 5 x base

• The margin of the orbit {VERY STRONG} – 4 cm wide – 3. 5 cm high – 3 BONES • Frontal • Zygomatic • Maxillary • 4. 5 cm deep

Terminology • Fossa: shallow depression in bone • Foramen (pl. foramina): hole(s) in bone • Fissure: hole between adjacent bones • Tubercle: bump attachment site • Groove, canal, notch (as they sound)

A key figure of Chap 3 Let me help you get a 3 D understanding of the structures summarized by this figure • Naso

The orbital ceiling • Frontal • Bits of. Sphenoid Lacrimal Fossa Trochlear Fossa Supraorbital Notch

The Lateral Wall • Not shown are: • Zygomatic foramen • Whitnall’s Tubercle • Zygomatic • Sphenoid

Bones of the skull Now look at the Sphenoid

The Sphenoid Bone • Butterfly • (Owl like) – Greater Wing – Lesser Wing – Pterygoid process • Many Foramina – Optic Foramen – Sup. Optic Fissure

Lateral View of Skull • Frontal • Zygomatic • Note temoral aspect of Sphenoid • Maxillary • Lacrimal • Ethmoid

The Sphenoid Bone & Occipital (at back) Ethmoid (yellow) Palatine (small red) Maxillary (straight on view of structure shown on hand out - page 42) • Now go back to lateral wall slide

The Lateral Wall • Not shown are: • Zygomatic foramen • Whitenalls Tubercle • Zygomatic • Sphenoid

The Medial Wall • Ethmoid • Lacrimal • Sphenoid • Maxillary

The Orbit Floor • Maxillary • Zygomatic • Palatine

Main components of fissures

Let me help you get a 3 D understanding of the structures summarized by this figure • Fig 3. 2

Weakest bones are in the floor and medial wall of the orbit. • Transmitted pressure through the tissues(? ) or the sturdier bones causes blowout fractures. • Lamina papyracia

$Blowout fracture of the floor of maxillary bone.$

Blowout fracture of the floor of maxillary bone.

$Blowout fracture of the floor of maxillary bone. CT image$

Blowout fracture of the floor of maxillary bone. CT image

$Blowout fracture of the ethmoid bone. CT image. • esf ethmoid sinus fracture •$

Blowout fracture of the ethmoid bone. CT image. • esf ethmoid sinus fracture • mwf medial wall fracture

Connective tissues in the orbit • All of the structures within the orbit have a connective tissue sheath – Around the Globe & muscles it’s call Tenon’s capsule • If the globe is the palm and EOM fingers, then Tenon’s capsule is the glove. – Lining the bones, it’s the periosteum • periorbita- a special name for orbit bone lining – nerves, blood vessels have them too • And they are interconnected making for a web of sheaths.

Two Views • Tenon’s capsule • Periorbita

A better view

Terminology • Fossa: shallow depression in bone • Foramen (pl. foramina): hole(s) in bone • Fissure: hole between adjacent bones • Tubercle: bump attachment site • Groove, canal, notch (as they sound)

Soft tissue covering • Surrounding the sclera is the episclera – Connective tissue and blood vessels. • Surrounding the episclera is Tenon’s capsule – Another layer of connective tissue protecting the globe and making it slippery for movement within the orbit.

Soft tissue covering • Check ligaments – medial and lateral are most prominent but the inferior rectus and levator have them too. • Superior transverse ligament – Supports levator muscle (Whitnall’s Ligament) • Suspensory ligament (of Lockwood) – Connective tissue underneath the globe

Orbital infection • Orbital cellulitis: infection of the tissues and fat pads behind/surrounding the eye, but not the eye itself – 60% of orbital cellulitus is a secondary infection due to a sinus infection

Bone development • Dermal Bones, most of orbit – Foci of osteoblasts differentiated from with the mesoderm • Cartilage pre-formed bones: ethmoid and part of sphenoid. (Endochondral bone) – Chondrocytes form cartilagenous template of the final bone – Osteoblasts invade and differentiate into osteocytes • Bone can restructure/repair itself – Osteoclast cell can breakdown boney matrix • Permits growth of the skull and orbits