Key Skeletal Landmarks of the Periorbital Region

(fig. 29-1)

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  Superior orbital rim: Fixed landmark to assess brow position

  
  
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  Inferior orbital rim: Position relative to anterior surface of globe; important in determining positive versus negative vector of orbit

  
  
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  Temporal ridge: Delineates lateral border of forehead from temporal fossa

  
  
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  Supraorbital notch: Delineates location of supraorbital neurovascular bundle

Upper Forehead Arranged in Well-Defined Layers

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  Skin

  
  
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  Subcutaneous tissue

  
  
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  Galea aponeurosis

  
  
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  Loose areolar tissue

  
  
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  Periosteum

  
  
  
  
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    At origin of frontalis muscle, the galea splits into a superficial and deep layer to encase the muscle.

    
    
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    The deep layer splits again at the midforehead level to surround the galeal fat pad, and again caudal to the fat pad to form the glide plane space of the brow.

    
    
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    The subgaleal space, deep layer of the galea, and periosteum fuse in the lower forehead and are firmly attached to the frontal bone.

    
    
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    Movement of the brow is produced through the action of brow elevators and depressors and is enhanced by the presence of the galeal fat pad, glide plane space and subgaleal space.

    
    
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    The periosteum of the frontal bones is reflected at the arcus marginalis to become the periorbita of the periorbital bones. The arcus marginalis is a thick condensation of periorbita as it enters the orbit.

Skin

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  Eyelid skin is the thinnest on the body.

  
  
  
  
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    Minimal subcutaneous fat

  
  
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  Adjacent brow and malar skin are notably thicker.

  
  
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  Surgical incisions within the skin of the eyelid generally heal with almost imperceptible scarring.

  
  
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  Age-related changes in the skin include decreased type I collagen and increased dermal collagenase activity.

Muscles

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  Frontalis

  
  
  
  
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    Originates from the galea aponeurosis and inserts into the dermis of the lower forehead

    
    
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    Interdigitates with procerus and orbicularis at its insertion

    
    
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    Elevates brow, produces transverse forehead rhytids

  
  
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  Corrugator supercilii (Fig. 29-4)

  
  
  
  
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    Corrugators start 3 mm lateral to midline and end about 85% of distance to lateral orbital rim. ³

    
    
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    Oblique head: Originates from the superomedial orbit and inserts into the dermis of the medial brow

    
    
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    Transverse head: Originates from superomedial orbit and inserts into dermis superior to the medial third of the medial brow

    
    
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    Depresses and medializes the medial brow, produces vertical glabellar rhytids

    
    
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    Lies deep to frontalis muscle

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  Depressor supercilii

  
  
  
  
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    Originates from superomedial orbit and inserts into the dermis of the medial brow, medial to the insertion of the orbicularis

    
    
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    Lies superficial to the corrugator

    
    
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    Depresses the medial brow

  
  
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  Procerus muscle

  
  
  
  
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    Originates from fascia covering lower part of nasal bone

    
    
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    Inserts onto glabellar dermis

    
    
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    Depresses the glabella

  
  
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  Orbicularis oculi (Fig. 29-5)

  
  
  
  
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    Encircles the periorbital region

    
    
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    Primary constrictor of the lids

    
    
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    Innervated by the facial nerve (CN VII)

    
    
    
    
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      Runs on the deep surface of the muscle

    
    
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    Pretarsal fibers lie over the region of the tarsal plate.

    
    
    
    
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      Responsible for involuntary blink

    
    
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    Preseptal fibers overlie the orbital septum.

    
    
    
    
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      Assist with blink

      
      
      
      
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        Both voluntary and involuntary fibers

    
    
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    Orbital fibers overlie the orbital rims.

    
    
    
    
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      Produce voluntary, forceful closure

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  Muscle of Riolan: Portion of the pretarsal orbicularis comprising the “gray line” in the eyelid margin. Promotes secretion from the meibomian glands.

  
  
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  Horner tensor tarsi muscle: Portion of the pretarsal orbicularis attaching to the posterior lacrimal crest. Encircles the canaliculi and promotes lacrimal drainage.

  
  
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  Jones muscle: Posterior preseptal orbicularis muscle fibers that insert on the posterior lacrimal crest and promote tear drainage.

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  Eyelid retractors

  
  
  
  
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    Upper lid (Fig. 29-6)

    
    
    
    
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      Levator muscle

      
      
      
      
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        Origin at the posterior orbit on the annulus of Zinn

        
        
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        Insertion onto the superior tarsal border

        
        
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        Insertion through the orbicularis onto the subdermal skin at the lid crease (in whites, lower insertion or none at all onto subdermal pretarsal skin in Asians)

      
      
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      Müller muscle (Fig. 29-7)

      
      
      
      
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        Innervated by the sympathetic nervous system

        
        
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        Arises from the inferior surface of the levator approximately 10-12 mm above the upper border of the tarsal plate and inserts onto the superior edge of the tarsus

        
        
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        Loss of function results in 2-3 mm of ptosis.

      
      
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      Levator palpebrae superioris

      
      
      
      
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        Innervated by the superior division of CN III

        
        
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        Originates from the lesser wing of the sphenoid above the optic foramen at the annulus of Zinn and extends forward to insert onto the superior edge of the tarsus; also, attaches to the posterior lacrimal crest through the medial horn of the levator tendon, the lateral orbital tubercle, and the pretarsal skin forming the eyelid crease

    
    
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    Lower lid

    
    
    
    
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      Inferior tarsal muscle is analogous to Müller muscle in the upper eyelid (Fig. 29-8).

      
      
      
      
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        Innervated sympathetically and may result in 1 mm of lower eyelid retraction when sympathetic defects are present

        
        
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        Arises from posterior border of capsulopalpebral fascia and inserts onto the inferior border of the lower eyelid tarsal plate