Medial Canthal Tendon Branches Out Richard L. Anderson, MD

previously undescribed, superior supporting branch of the medial canthal tendon has been found by careful cadaver \s=b\A

dissection. This branch unites the

com-

tendon to the frontal bone; thus, it a superior support to the medial canthus. The posterior portion of the medial canthal tendon is a thin and weak structure, as compared with its anterior companion. It inserts on the posterior lacrimal crest. While most surgeons contend that the posterior limb of the medial canthal tendon maintains the position of the medial canthus after either accidental or surgical disinsertion of the anterior tendon, it is likely that this superior supporting branch maintains the canthal position in these clinical condimon

provides

tions.

(Arch Ophthalmol 95:2051-2052, 1977)

careful dissection of the medial canthal region of cadavers has revealed a previously undescribed, anatomical configuration of the medial canthal tendon. After the superior and inferior branches of the medial canthal tendon combine to form the common tendon, a large, strong supportive structure branches superiorly (Fig 1-3). It firmly attaches to the periosteum of the frontal bone. The medial canthal tendon's insertion on the frontal process of the maxillary bone also is shown (Fig 1). This configuration has been noted at surgery around the medial canthal region but is more difficult to demonstrate pictorially (Fig 4 and 5).

A

and drawings of this region label a similar structure as the "superciliaris muscle."' In other descriptions, this structure is labeled as the "superficial and deep origins of the upper part of the orbital muscle."2-5 If this represents the same structure, then it truly functions as a superior supporting branch of the medial canthal tendon. It firmly unites the medial canthal tendon to the frontal bone. The posterior portion of the medial canthal tendon is a thin and weak structure, as compared with its anterior companion (Fig 6). It inserts on the posterior lacrimal crest. Most surgeons contend that the posterior limb of the medial canthal tendon will maintain the position of the medial canthus after either accidental or

REVIEW OF LITERATURE Meticulous dissections and precise descriptions of eyelid anatomy reported by Jones1'1 and Jones et al' are a standard to which any work in this area must be compared. In some of

surgical disinsertion, eg, dacryocystorhinostomy, of the anterior tendon.

these

previous reports, photographs

Accepted

publication March 11, 1977. Oculoplastic Service, Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City. Reprint requests to Oculoplastic Service, Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242 (Dr Anderson). From the

for

'

Those surgeons who disinsert the medial canthal tendon routinely at

dacryocystorhinostomy report no canthai malpositions after surgery. Some

accidental disinsertions of the medial canthal tendon do not result in telecanthus. These facts probably cannot be attributed to the weak structure of the posterior insertion. It seems more likely that the strong superior branch, demonstrated in this report, may help maintain canthal position in these cases. If this additional attachment of the medial canthal tendon is pre-

Downloaded From: http://archopht.jamanetwork.com/ by a Karolinska Institutet University Library User on 05/31/2015

Fig 1.—Superior supporting branch of medial canthal tendon attaching to frontal bone (a). Medial levator horn (b) passing posteriorly to insert at posterior lacrimal

canthal tendon.

Fig 4.—Muscle hook under superior branch of medial canthal tendon.

Fig 5.—Exposure showing superior supporting branch.

Fig 6.—Posterior portion of medial canthal tendon (anterior portion cut away) showing posterior limb (a), posterior lacrimal crest (b), probe in lacrimal sac (c), and stump of disinserted anterior portion (d).

served, it

orly, and inferiorly.

the stresses that are placed on this structure, the difficulty in correcting

Fig 2.—Superior

attachment

(a)

of medial

Fig 3.—Superior branch of medial canthal firmly attached to frontal bone at superior medial orbital rim (a). tendon

crest. Medial canthal tendon insertion on frontal process of maxillary bone (c) and superior crus (d) and inferior crus (e) of medial canthal tendon.

surgery is In after

may avoid

performed

cases

problems when

in this

area.

COMMENT of canthal malposition

injuries, the canthus always is displaced laterally,

almost anteri-

In these cases the insertions of both the common tendon and the superior supporting branch must be disrupted. This problem can be difficult to correct. When one considers the functional and cosmetic importance of medial canthal position,

malpositions,

and the weak

superior

support that is afforded by the medial levator horn, it is gratifying to find additional architectural support for this

region.

References 1. Jones LT: The anatomy of the upper eyelid and its relation to ptosis surgery. Am J

Ophthalmol 57:943-959,

1964.

2. Jones LT: The anatomy and physiology of the ocular appendages, in Reeh MJ (ed): Treatment of Lid and Epibulbar Tumors. Springfield, Ill, Charles C Thomas Publisher, 1963, pp 16-21.

3. Jones LT: New anatomical concepts of the ocular adnexa, in Mustard\l=e'\JC, Jones LT, Callahan A (eds): Ophthalmic Plastic Surgery

Up-To-Date. Birmingham, Ala, Aesculapius lishing Co, 1970, pp 3-6.

Pub-

4. Jones LT, Reeh MJ, Wirtschafter JD: Ophthalmic Anatomy. Rochester, NY, American

Academy of Ophthalmology 1970, pp 39-48.

and

Otolaryngology,

5. Duke-Elder S (ed): The Anatomy of the Visual System. System of Ophthalmology Series, St Louis, CV Mosby Co, 1961, vol 2, pp 509-517.

Downloaded From: http://archopht.jamanetwork.com/ by a Karolinska Institutet University Library User on 05/31/2015