PURPOSE : This study was designed to examine the anatomical relationship between Horner's muscle and the lacrimal sac at 3 representative levels of the lacrimal sac and to verify the contribution of Horner's muscle to lacrimal sac drainage. METHODS : Seven ocular specimens from 7 elderly Japanese cadavers, fixed in 10% buffered formalin, were analyzed. Axial sections were made parallel to the eyelid margin at 1 mm above the upper eyelid margin, 1 mm below the lower eyelid margin, and 3 mm below the lower eyelid margin. The vertical common fascial length, length of the lateral lacrimal sac wall, and the proportion between the 2 were measured for each specimen at the 3 levels. RESULTS : The vertical common fascial length and its proportion to the length of the lateral lacrimal sac wall were statistically the same at all 3 levels of the lacrimal sac. CONCLUSIONS : Based on the present anatomical findings, the activity of Horner's muscle may be the same for all sac levels, although this hypothesis should be examined by further experimental research, such as manometric studies of the sac at different levels along its length.

It has been postulated that physical immobilization is an essential factor in developing chronic pain after trauma or surgery in an extremity. However, the mechanisms of sustained immobilization-induced chronic pain remain poorly understood. The present study, therefore, aimed to develop a rat model for chronic post-cast pain (CPCP) and to clarify the mechanism(s) underlying CPCP. To investigate the effects of cast immobilization on pain behaviours in rats, one hindlimb was immobilized for 2 weeks with a cast and remobilization was conducted for 10 weeks. Cast immobilization induced muscle atrophy and inflammatory changes in the immobilized hindlimb that began 2 h after cast removal and continued for 1 week. Spontaneous pain-related behaviours (licking and reduction in weight bearing) in the immobilized hindlimb were observed for 2 weeks, and widespread mechanical hyperalgesia in bilateral calves, hindpaws and tail all continued for 5-10 weeks after cast removal. A sciatic nerve block with lidocaine 24 h after cast removal transitorily abolished bilateral mechanical hyperalgesia in CPCP rats, suggesting that sensory inputs originating in the immobilized hindlimb contribute to the mechanism of both ipsilateral and contralateral hyperalgesia. Intraperitoneal injection of the free radical scavengers 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxy1 or N-acetylcysteine 24 h after cast removal clearly inhibited mechanical hyperalgesia in bilateral calves and hindpaws in CPCP rats. These results suggest that cast immobilization induces ischaemia/reperfusion injury in the hindlimb and consequent production of oxygen free radicals, which may be involved in the mechanism of widespread hyperalgesia in CPCP rats.

We studied the horizontal location of the inferior oblique muscle (IOM) origin in relation to the ipsilateral ala nasi and compared the results between genders in 76 orbits of 38 Japanese cadavers. Consequently, the IOM origin was located 1.2 mm laterally to the vertical line through the lateral margin of the ipsilateral ala nasi. No significant difference was noted between genders (males, 1.3 mm; females, 0.9 mm; P = 0.257, Student t test) or between sides (right, 1.1 mm; left, 1.3 mm; P = 0.570, Student t test). In contrast, the mean interalae-nasi distance was 39.8 mm and was significantly greater in males than that in females (males, 40.8 mm; females, 38.6 mm; P = 0.049, Student t test). The ala nasi can be used as a reference point irrespective of gender or side for identifying the IOM origin during oculoplastic surgery.

PURPOSE:: This study was designed to examine the distance from the posterior lacrimal crest to the posterior margin of the Horner's muscle origin (the PLC-HMO distance), considering their complex anatomical relationship. METHODS:: Eight macroscopic specimens from 8 Japanese cadavers and 7 microscopic specimens from 7 Japanese cadavers, fixed in 10% buffered formalin, were analyzed. Macroscopically, the PLC-HMO distance was measured at 2 mm superior to the most posterior point of the muscle origin (Group A), directly at the most posterior point (Group B) and 2 mm inferior to the most posterior point (Group C). Microscopically, the PLC-HMO distance was measured in axial sections at 1 mm above the upper eyelid margin (Group 1), 1 mm below the lower eyelid margin (Group 2), and 3 mm below the lower eyelid margin (Group 3). RESULTS:: In the macroscopic study, the average PLC-HMO distance was 2.94, 2.57, and 2.05 mm for Groups A, B and C, respectively. The distance for Group C was significantly smaller than that of Group A (p = 0.006). In the microscopic study, the average PLC-HMO distance was 3.62, 3.74, and 3.14 mm for Groups 1, 2 and 3, respectively (no significant difference). CONCLUSIONS:: The PLC-HMO distance was approximately 2-4 mm with some specimens showing a smaller distance inferiorly.

Introduction:  The microscopic and macroscopic anatomy of the anterior and posterior Tenon's capsule is described. Methods:  An observational anatomic study of twelve orbits of 6 cadavers (mean age, 79.5 years) were examined microscopically and 8 orbits of 4 cadavers (mean age, 76.8 years) were examined macroscopically. After orbital exenteration, an X-shaped incision was made in the specimens to include the posterior part of the globe. The sections were divided into 4 parts: superomedial, inferomedial, superolateral and inferolateral. In the macroscopically examined specimens, the eyelids and globes were removed from the exenterated tissues and the appearance of Tenon's capsule was studied. Results:  In the microscopic study, Tenon's capsule covered the sclera beneath the conjunctiva and contained smooth muscle fibers in the anterior area. This anterior fascia, which had a thick appearance, reached the globe equator. From there, the capsule of the orbital fat, which contained no smooth muscle fibers, enveloped the sclera and reached the optic nerve. This was defined as the posterior capsule. In the macroscopic specimens, Tenon's capsule had a thick and fibrous white appearance in the anterior area. More posteriorly, the capsule was thinner and more translucent. This thin capsular part was generally larger in the lateral area than in the medial area. Conclusions:  Tenon's capsule is composed of an anterior thick fibrous tissue comprising the orbital smooth muscle network and the posterior thin fibrous capsule of the orbital fat.

PURPOSE: To characterize the microscopic anatomy of the lacrimal punctum and canaliculi in relation to the tarsal plate, muscle of Riolan, and Horner muscle; and to report a novel technique to excise the horizontal canaliculus in severe dry eye patients. DESIGN: Observational anatomic study and a retrospective case series. METHODS: The microscopic anatomy was studied in 86 eyelids of 25 cadavers (age range: 45-96 years, mean: 79.5 years). Surgery was performed on 18 canaliculi of 7 patients with dry eyes (age range: 37-69 years, mean: 59.9 years). In the microscopic study, 32 eyelids were incised sagittally, 38 eyelids were incised horizontally (1 mm from the eyelid margin), and 16 eyelids were incised parallel to the tarsal plate. All specimens were stained with Masson trichrome. In the surgical group, probe-guided horizontal canalicular excision with incision of the Horner muscle to the lateral edge of the lacrimal caruncle was performed. Both canalicular stumps were cauterized. RESULTS: In the microscopic anatomic study, the punctum and the vertical canaliculus were part of the tarsal plate with the muscle of Riolan, whereas the horizontal canaliculus was surrounded by the Horner muscle. In the surgical group, all the operated canaliculi were completely occluded without recanalization 12 months postoperatively. No complications were recorded. CONCLUSIONS: Based on microscopic anatomic findings that the lacrimal punctum and the vertical canaliculus are part of the tarsal plate, and that the horizontal canaliculus is surrounded by the Horner muscle, excision of the horizontal canaliculus may be an effective technique to treat patients with severe dry eyes.

PURPOSE To examine the positional relationship between the ethmoidal foramina and the frontoethmoidal suture. METHODS Eighty-four orbits of 42 Japanese cadavers (24 male and 18 female cadavers; average age at death, 81.0 years; range, 61-101 years), fixed in 10% buffered formalin, were used for investigation. The most anterior or posterior ethmoidal foramen was defined as the anterior or posterior ethmoidal foramen, respectively. All the intermediate foramina were determined as the accessory foramina. The vertical distances from the frontoethmoidal suture to the anterior, posterior, and accessory ethmoidal foramina were examined. RESULTS Seventeen anterior ethmoidal foramina (20.2%) were situated above the frontoethmoidal suture (mean distance, 1.8 mm), and 2 posterior ethmoidal foramina (2.3%) were situated at 1.0 mm and 1.5 mm above the suture. Although accessory ethmoidal foramina were detected in 32 orbits (38.1%), one accessory foramen (middle ethmoidal foramen) was identified in 30 orbits, and 2 foramina (additional deep-middle ethmoidal foramina), in 2 orbits. One middle ethmoidal foramen (3.1%) and 1 deep-middle ethmoidal foramen (50.0%) were located at 1.5 mm above the suture. In total, 2 of the 34 accessory ethmoidal foramina (5.9%) exhibited the extrasutural location. CONCLUSIONS Several ethmoidal foramina were situated above the frontoethmoidal suture. The anterior ethmoidal foramen most frequently showed the situation, followed by the accessory and posterior foramina, in order. Our findings help predict the anatomical variations in the location of the ethmoidal foramina in relation to the frontoethmoidal suture, thereby enhancing safety for medial orbital wall surgery.

PURPOSE To characterize the macroscopic anatomy of the vertical lacrimal canaliculus and the lacrimal punctum in relation to the tarsal plate. METHODS Twenty-eight eyelids of 7 cadavers (mean age at death, 79.1 years; range, 65-93 years) were used for the investigation. The harvested eyelids were incised vertically around the central part of the upper and lower eyelids. The whole superior border of the upper tarsal plate and the whole inferior border of the lower tarsal plate were exposed by removing the soft tissues adjacent to them. We first examined whether these tarsal plates contained a lacrimal punctum. If the lacrimal punctum was found, we inserted a lacrimal probe to the punctum and measured the length covered by the tarsal plate using a millimeter ruler. RESULTS All the tarsal plates contained the lacrimal punctum, and the mean length of the canaliculi covered by the tarsal plates was 2.82 mm (range, 2.3-3.0 mm) in the upper eyelid and 2.39 mm (range, 2.3-2.5 mm) in the lower eyelid. CONCLUSIONS Since the length of the vertical lacrimal canaliculus including the lacrimal punctum is generally 2 mm, they are considered as tarsal components in both the upper and lower eyelids.

HASH(0x363d530)

A detailed understanding of the relationship between the ethmoidal sinus and the intracranial cavity is essential to prevent intracranial penetration during orbital surgery. The authors analyzed 10 postmortem orbits with their adjacent skull bases of 5 Asian cadavers (3 males and 2 females; mean age of 80 years at death). After removing all orbital contents, skull and brain, the medial orbital wall, ethmoidal cells, and ethmoidal roof were also removed. From the intracranial cavity view, the ethmoidal roof was situated just lateral to the cribriform plate. From the orbital view, the location of the roof was close to the superior border of the medial orbital wall. These anatomical observations may be useful to prevent intracranial penetration and cerebrospinal fluid leakage during medial orbital wall decompression.