REFERENCES

1.Mohs FE (1948). Chemosurgical treatment of cancer of the eyelid. Arch. Ophthalmol., 39: 43–59.

2.Robins P (1978). Mohs’ chemosurgery for tumors in the periorbital area. In: Ocular and Adnexal Tumors, FA Jakobiec (ed). Aesculapius, Birmingham, pp. 525–531.

3.Robins P (1979). Chemosurgery in cancer of the eyelids (the Mohs procedure). In: Tumors of the Ocular Adnexa and Orbit, A Hornblass (ed). Mosby, St. Louis, pp. 153–155.

4.Mohs FE (1978). Chemosurgery: Microscopically controlled surgery for skin cancer – past, present, and future. J. Dermatol. Surg. Oncol., 41(1): 41–54.

5.Chalfin J, Putterman AM (1979). Frozen section control in the surgery of basal cell carcinoma of the eyelid. Am. J. Ophthalmol., 87: 802–809.

6.Older JJ, Fier RH (1982). Spontaneous repair of the medial canthus after removal of basal cell carcinoma.

Ophthalmic Surg., 13(9): 737–740.

7.Domonkos AN (1979). X-ray therapy of eyelid cancer. In: Tumors of the Ocular Adnexa and Orbit, A Hornblass (ed). Mosby, St. Louis, pp. 142–146.

8.Fitzpatrick PJ, Thompson GA, Esterbrook WM, Gallie BL, Payne DG (1984). Basal and squamous cell carcinoma of the eyelids and their treatment by radiotherapy. Int. J. Radiat. Oncol. Biol. Phys., 10: 449–454.

9.Gladstein AH (1978). Radiotherapy of eyelid tumors. In:

Ocular and Adnexal Tumors, FA Jakobiec (ed). Aesculapius, Birmingham, pp. 509–516.

10.Beard C (1979). Cryosurgery in the treatment of eyelid lesions. In: Tumors of the Ocular Adnexa and Orbit, A Hornblass (ed). Mosby, St. Louis, pp. 147–152.

11.Torre D (1978). Cryosurgical treatment of eyelid tumors. In: Ocular and Adnexal Tumors, FA Jakobiec (ed). Aesculapius, Birmingham, pp. 517–524.

12.Fraunfelder FT, Zacarian SA, Wingfield DL, Limmer BL (1984). Results of cryotherapy for eyelid malignancies.

Am. J. Ophthalmol., 97: 184–188.

Knowledge of eyelid anatomy is essential for the surgeon who performs reconstruction following eyelid tumor surgery. Although it is best to learn anatomical relationships through cadaver dissection and observation during surgery, the drawings and text in this chapter are presented to assist the surgeon in reviewing the relationships among the numerous structures that are contained within the very thin eyelid. For those who have the opportunity for cadaver dissection, Beard and Quickert’s Anatomy of the Orbit is an excellent manual, and also provides multiple color photographs depicting a step-by-step dissection of the eyelid, orbit, and related structures.1

SKIN

A basic understanding of eyelid skin is important when studying eyelid tumors and their reconstruction. Most of the eyelid tumors, whether benign or malignant, arise from the skin elements, and eyelid reconstruction relies heavily on use of the skin component of the eyelid. Two of the features of skin, which are very relevant to eyelid reconstruction, are thinness and elasticity, which allow it to be used for skin grafting as well as advancement and rotation flaps.

The epidermis is made up of stratified epithelium composed of six or seven layers of cells. The stratum corneum is the surface layer consisting of squamous nonnucleated cells, the cytoplasm of which contains keratin. The stratum granulosum is a thin layer of nucleated cells. Below this layer is the stratum spinosum, which has three or four layers of polyhedral cells (prickle cells). The next layer is the stratum germinativum that contains the basal cells. The more superficial layers of the epidermis are derived from this layer of basal cells. The basement membrane underlies the basal layer.

The dermis is the second component of eyelid skin, and it is composed of a delicate layer of connective tissue containing many elastic fibers, blood vessels, lymphatics, and nerves. The subcutaneous areolar layer, which contains no fat, separates the dermis from the underlying muscle layer. This loose attachment allows free movement of the skin over the muscle, except in the area of the upper lid crease where fibers of the levator aponeurosis attach the skin to the underlying orbicularis muscle. The loose attachment between skin and muscle also allows for easy accumulation of edematous fluid and the formation of wrinkling with age. The subcutaneous layer contains hair follicles and sebaceous glands.

66 Surgical Anatomy

MUSCLES

The muscles of the eyelid include the orbicularis oculi, the insertion of the levator palpebrae superioris, and the palpebral muscles of Müller (169, 170).

ORBICULARIS OCULI

The orbicularis oculi can be divided into three parts, orbital, preseptal, and pretarsal. The orbital part of the muscle surrounds the orbital margin covering the region of the eyebrows, the temple, and the cheek. The fibers of the main muscle arise from the medial orbital margin on the side of the nose along the line from the supraorbital notch to the infraorbital foramen. The superficial origin is smaller and is comprised of fibers arising from the anterior part of the medial canthal tendon.2

The preseptal orbicularis muscle may be divided into an upper and a lower section. The superficial part of the upper section arises from the upper margin of the anterior part of the medial canthal tendon. The deep origin of the upper preseptal muscle is from the outer surface of the posterior part of the medial canthal tendon. The muscle passes laterally in front of the orbital septum, to which it is loosely attached. At the lateral canthus, the upper part meets the lower part of the preseptal muscle, forming a common tendon in the lateral palpebral raphé.

The lower preseptal muscle has a superficial head, which arises from the lower margin of the anterior part of the medial canthal tendon, and a deep head, which takes origin from the posterior aspect of the medial canthal tendon, and from the lateral lacrimal fascia below the level of the internal common punctum. The muscle passes laterally in front of the orbital septum to join the upper preseptal muscle at the lateral palpebral raphé.

The pretarsal orbicularis muscle is divided into an upper and lower section, each of which has a superficial and a deep head. The superficial head of the upper pretarsal muscle arises from the lateral end of the anterior part of the medial canthal tendon. The deep head arises just behind the upper half of the posterior lacrimal crest, below the origin of the deep head of the upper preseptal muscle. The fibers of the superficial and deep heads of the upper pretarsal muscle join near the medial end of the tarsus, and pass laterally along the tarsal plate of the upper lid. The fibers join the lateral canthal tendon, which is about 8 mm (0.3 in) in length, and is inserted into the lateral orbital tubercle of Whitnall.

The superficial and deep heads of the lower pretarsal muscle arise in common with the corresponding heads of the upper muscle, and pass laterally along the lower tarsal plate to join the upper pretarsal muscle in the area of the lateral canthal tendon.2 A group of fibers of the upper and lower pretarsal muscles form short, thick bands which originate at the posterior lacrimal crest, and attach to the connective tissue surrounding the upper and lower canaliculi and the medial borders of the tarsal plates. These fibers are often referred to as Horner’s tensor tarsi muscle.2, 3 One of the smallest muscles in the body, the muscle of Riolan, is an isolated fasciculus of fine muscle fibers that run along the margin of the lid behind the ciliary follicles.2,3

The orbicularis oculi is supplied by the seventh cranial nerve, and its action depends on which sections of the muscles are brought into play. The upper preseptal muscle is the main depressor of the upper lid, and the lower preseptal muscle is the main elevator of the lower lid. The upper and lower preseptal muscles pull the lacrimal diaphragm in a lateral direction, thereby expanding the lacrimal sac. The muscle of Riolan keeps the lids closely opposed to the globe in most eyelid movements. The preseptal and pretarsal portions of the muscle are active in gentle closure of the lids, such as in sleep or blinking, whereas the orbital portion is active in forced closure.2

LEVATOR PALPEBRAE SUPERIORIS

The levator palpebrae superioris originates from the periorbita overlying the lesser wing of the sphenoid bone above the annulus of Zinn. It crosses forward above the superior rectus muscle. There are numerous fascial bands connecting the sheaths of these two muscles. As the levator comes forward, it widens and passes over the superior rectus tendon and becomes tendinous (169, 170). The aponeurosis, which is the tendinous extension of the muscle, widens to about the width of the tarsus and courses downward to insert onto the anterior surface of the tarsus beginning about 3 or 4 mm (0.15 in) below its superior border. The anterior fibers of the levator aponeurosis attach to the septa between the orbicularis muscle fibers at the level of the upper tarsal border.4 These attachments are important in forming the upper lid crease.

The levator aponeurosis broadens to form medial and lateral horns. The medial horn passes over the sheath of the reflection of the tendon of the superior oblique muscle, and then fuses with the upper border of the posterior limb of the medial canthal tendon. The lateral horn of the levator aponeurosis partially divides the lacrimal gland into an orbital and palpebral portion, and inserts into the superior edge of the lateral canthal tendon at the lateral retinaculum.

The superior transverse ligament of Whitnall, the check ligament of the levator, is formed by condensation of the superior sheath of the levator muscle at the level of the equator of the globe. It attaches medially to the fascia of the superior oblique muscle’s pulley, and temporally to the capsule of the orbital lobe of the lacrimal gland.

The muscular section of the levator is approximately 40 mm (1.6 in) long. The aponeurosis is approximately 15 mm (0.6 in) long, fanning out to an approximate width of 30 mm (1.2 in).

The levator muscle is innervated by the superior ramus of the third cranial nerve. The branch to the levator muscle passes around the medial edge of the superior rectus muscle to enter the undersurface of the levator muscle at the junction of its middle and posterior thirds.

CAPSULOPALPEBRAL FASCIA

The capsulopalpebral fascia consists of a fiber sheath that extends from the inferior rectus muscle, and runs forward beneath the inferior oblique muscle and posterior to the orbital septum until it attaches to the inferior aspect of the tarsus. This structure is analogous to the levator aponeurosis of the upper lid. It derives its force from the inferior rectus muscle, and combines with the inferior palpebral muscle to form the lower lid retractors (169, 170).

MÜLLER’S MUSCLES

The palpebral muscles of Müller constitute two small sheaths of plain fibers, one in each lid (170, 171). The superior palpebral muscle is a thick band, approximately 10 mm (0.4 in) in breadth, that arises from the undersurface of the levator palpebrae superioris. It runs downwards and forwards between the levator and the conjunctiva, to be inserted into the upper margin of the tarsal plate. The muscle is thought to assist in regulating the position of the eyelid when the eye is open. It may also assist the levator muscle in elevation of the upper lid.

The inferior palpebral muscle arises from the fascial sheath of the inferior rectus muscle and from its expansion to the inferior oblique. It runs upwards to insert into the inferior aspect of the tarsal plate. The nerve supplies to the palpebral muscles are via the sympathetic fibers, and are thought to run along with the fibers of the oculomotor nerve.2

Muscles 67

169

10

11

9 8 12

7 13

1

170

170 Schematic cross-section of the eyelids. 1 orbital septum;

2 orbicularis muscle; 3 orbital fat; 4 levator aponeurosis; 5 superior Müller’s muscle; 6 superior tarsus; 7 conjunctiva; 8 superior marginal artery; 9 superior palpebral artery; 10 inferior marginal artery;

11 inferior tarsus; 12 capsulopalpebral fascia; 13 inferior Müller’s muscle; 14 inferior oblique muscle; 15 inferior rectus muscle.

169 Schematic multilayered anterior view of the eyelids. 1 medial canthal tendon; 2 lacrimal sac; 3 orbital fat; 4 capsulopalpebral fascia; 5 inferior oblique muscle; 6 inferior tarsus; 7 superior tarsus; 8 levator aponeurosis; 9 superior oblique muscle; 10 frontalis muscle; 11 orbital orbicularis muscle; 12 preseptal orbicularis muscle; 13 pretarsal orbicularis muscle.

171

1

2

3

4

171 Suspensory ligament of the superior fornix. 1, 4 Müller’s muscle; 2 suspensory ligament of the superior fornix; 3 conjunctiva.