Orbit

ORBITالمحجر

Bony Orbit
Seven bones, arranged to form a pyramidal shaped space (orbit) which contains eye ball, EOM, Optic N., vessels, nerves and other connective tissue components. It has Base (anterior) & Apex (posterior) Medial 1. Maxillary b. + ant. Lac. CrestWall Frontal b. lacrimal2. Lacrimal  post. Lac. Crest fossa3. Ethmoidal (lamina paperacya)Ant. back* very thin, * blow out fracture, * ethmoidal sinus orbital cellulitis4. Body of sphenoid

Floor1. Maxillary bone (medially)2. Zygomatic bone(laterally)3. Palatine (posteriorly)• Infraorbital n. runs in groove, canal, foramen  lower lid• Maxillary sinus below* Blow out FractureLateral1. Frontal bone (above)Wall2. Zygomatic bone(below)3. Greater wing of sphenoid (posteriorly)It separates the orbit from: 1. Temporal fossa (anterior) 2. Middle cranial fossa & temporal lobe (posterior) * Thickest wall

Roof Frontal bone, Lesser wing of sphenoid 1. Frontal sinus (within supraorbital rim) 2. Anterior cranial fossa & frontal lobe - Trochlea / Supra orbital notch / Fossa of lacrimal gland.

The bony orbit Walls

Superior Orbital Fissure Between roof & lateral wall Transmits structures passing between middle cranial fossa and the orbit 1. Oculomotor n. 2. Trochlear n. 3. Ophthalmic n. branches 4. Abducens nerve 5. Superior & inferior ophthalmic vein Inferior Orbital Fissure Between floor & lateral wall Transmits branches of maxillary nerve (infraorbital nerve, zygomatic nerve) from pterygopalatine fossa.

The Bony Orbit

Optic Canal Transmits: 1. Optic nerve (+ CRA) 2. Ophthalmic artery Between orbit & middle cranial fossa The periosteum of the orbital wall is called: Peri orbita .. At the orbital rim (margin) It extends downward (up) within the lids until if fuse with the tarsal plate and called: Orbital Septum the orbital septum limits the orbit anteriorly..

Optic canal

Apex: Posterior part of whore the 4 walls converge.. Near the optic canal and posterior part of superior and inferior orbital fissures The 4 recti arise from a common tendinous ring at the apex & run forward along corresponding walls in the form of Cone around the optic nerve..

Orbital Apex & Tendinous Ring

Orbital Symptoms 1. Proptosis. 2. Pain. 3. Ophthalmoplagia (EOM motility disorder). 4. Periorbtal changes (swelling, redness, chemosis). Orbital Investigations: 1. Orbital examination 2. Exophthalmometry 3. U/S 4. C.T. 5. MRI

Exophthalmometry

Proptosis (Exophthalmos):Forward protrusion of the eye ball.. (normally the corneal apex does not protrude in front of the orbital margins..)Differentiate it from pseudoexophthalmosE.g.: • lid retraction• contralateral enophthalmos• large eye ball  buphthalmos

Exophthalmos

Examination:• Inspection• Ruler• Hertel exophthalmometerAetiology of the Proptosis:1. Endocrine  thyrotoxicosis2. Inflammatory  orbital cellulitis 3. Tumors  *cyst *benign or malig. 1ry tumor * metastasis4. Traumatic  retrobulbar hemorrhage 5. Vascular  * AV malformation *orbital varix *caroticocavernus fistula

Analysis of Proptosis:1. Axial  intraconal Non axial (displaced)  extraconal  …2. Bilateral proptosis  thyrotoxicosis3. Unilateral proptosis  1.Thyrotoxicosis 2.Orbital Cellulitis3.Tumours… etc4. Rapid onset proptosis  Trauma  emphysema  hemorrhage5. Intermittent exo. (positional)  orbital varicosity Commonest cause of exoph.  ThyrotoxicosisCommonest cause of exoph. In child orbital cellulitis

Unilateral Proptosis

Orbital Cellulitis Suppurative inflammation of the orbital soft tissue behind the orbital septum. It is either Extension from neighboring str. (sinuses) Trauma Comm. Micro.: *Strept. * Staph. * Pneumococci

Orbital Cellulitis

Orbital Cellulitis


Clinical features: 1. Swelling & redness of the lids. 2. Conjunctival chemosis 3. Exophthalmos 4. Pain 5. Diplopia 6. Constitutional symptoms 7. Vision may be impaired (optic neuritis)


Complications: 1. Orbital abscess 2. Panophthalmitis 3. Meningitis 4. Brain abscess 5. Cavernous sinus thrombosis


Treatment: ( Admission)1. Systemic antibiotics child  Ampicillin + Cloxacillin adult  3rd generation cephalosporin + Metronidazole2. Monitoring of optic nerve function (VA, pupils)3. Investigation *WBC count *CT of orbit, brain & sinuses *LP if suspect meningitis4. Surgical drainage, if:a. no response to antibioticsb. orbital abscess N.B. Preseptal cellulitis

Rhabdomyosarcoma The most common primary malignant orbital tumor in children Highly malignant, in its early stages may be mistaken as orbital cellulitis 7 years Present as rapidly progressive proptosis, other signs include: 1. palpable mass 2. ptosis 3. swelling & injection of overlying skin (but not hot)

Rhabdomyosarcoma

Investigations:1. Biopsy for diagnosis2. Systemic assessment for metastasis by CXR, LFT, BMA, LP, skeletal survey.. Treatment:Local radiotherapy + chemotherapy IF no response  Exentration

Blow out fracture Floor  medial wall Trauma by an object whose size is larger than the diameter of the orbital inlet. ↑ intraorbital pressure transmitted forceThese will affect weak areas..

Signs & Symptoms: 1. Surgical emphysema, edema, echymosis 2. Diplopia (tethering of orbital contents, e.g.: inferior rectus) with restricted up movement. 3. enophthalmos, orbital fat necrosis 4. Anesthesia along the infra orbital n. distribution 5. Hypotropia 6. Intraocular damage (e.g.: hyphema)

Investigations:CT of the orbit & maxillary sinusTreatment:1. Systemic antibiotics 2. Not blow the nose3. Surgery timing  indications  procedure

Blow out Fracture

Blow out Fracture



Blow out Fracture