Redesign and treatment planning orbital floor reconstruction using computer analysis anatomical landmarks.

Orbital floor fractures are one of the most commonly encountered maxillofacial fractures due to their weak anatomical structure. Restoration of the orbital floor following a traumatic injury or a tumor surgery is often difficult due to inadequate visibility and lack of knowledge on its anatomical details. The aim of this study is to investigate the locations of the inferior orbital fissure (IOF), infraorbital groove (G), and infraorbital foramen (Fo) and their relationship with the orbital floor using a software. Measurements from the inferior orbital rim (IOR) using the Fo, the IOF, G, and the optic canal (OC) were calculated in 268 orbits as reference points. The surgical landmarks from the G and the OC, the G and the IOF, the G and the intersection point were measured as 31.6 ± 6, 12.9 ± 4, and 12 ± 5 mm, respectively. The mean distances between the G and the IOR, the Fo and the IOF, and the Fo and the OC were found as 8.3 ± 2.1, 28.7 ± 3.5, and 53.6 ± 5.9 mm, respectively. The mean angles were calculated as OC-IOF-G 68.1° ± 16.4°; intersection-G-IOF as 61.4° ± 15.8°; IOF-OC-G as 19° ± 5.5°; OC-G-intersection as 31.5° ± 11.9°, G-intersection-OC as 129.5°, IOF-intersection-G as 50.5°. Furthermore, variable bony changes on the orbital floor which may lead to the differences at intersection point of the G and Fo were determined. In 28 specimens (20.9 %), unilateral accessory Fo (AcFo) was present. In 27 specimens, AcFo was situated supermaedially (96.4 %) on the main aperture. In one specimen, two intraorbital canals and Fo emerged from different points and coursed into different apertures. The measured mean distances of the AcFo-IOR and the AcFo-Fo were as 7 ± 2 and 7.3 ± 3.2 mm, respectively. The primary principle in the oculoplastic treatment of orbital floor reconstructions must be repositioning the herniated orbital aperture by maintaining the infraorbital artery and the nerve in the orbital floor. The IOF and the G were recommended as the more reliable oculoplastic surgical landmarks for identifying the orbital floor. To avoid pinching of the orbital floor structures, the triangle (IS-G-IOF) should be equilateral with an exigence of a 70° angle within it. Among each distance of the intersection-IOF, IOF-G, G-intersection should be equal. With the help of certain software, this study made possible to investigate the variability of the orbital floor structures, observe the variety in measurements and calculate the parameters which are crucial in implementing personalized reconstruction and implanting support.

The importance of the supratrochlear foramen of the humerus in humans: an anatomical study.

BACKGROUND: The supratrochlear foramen (STF) is an important and relatively common anatomic variation in the lower end of the humerus in humans. Its structure has received increased attention in recent years. Anatomical knowledge of STF is useful for anatomists, anthropologists, orthopedic surgeons, and radiologists. This aperture is of great interest to anthropologists who claim it as one of the points in establishing a relationship between humans and lower animals. The goal of this study was to describe the features of STF of the humerus in the Turkish population. MATERIAL AND METHODS: All bones were obtained from the Department of Anatomy, Faculty of Medicine and Department of Antrophology, University of Mustafa Kemal, Hatay. A total of 166 dried humeri (83 right side and 83 left side), of which 78 belonged to males and 88 to females, were examined to determine the presence of supratrochlear foramen. Digital vernier calipers were used to measure the maximum width (transverse) and height (vertical) of the STF. RESULTS: Out of 166 bones, the foramen was present in 18 humeri (4 right side and 14 left side), showing the incidence as 10.8% with unpaired humeri. We observed 4 types of shape: oval, round, triangular, and sieve-like. The average diameter of the long (transverse) axis was 5.93±1.68 mm and the short (vertical) axis was 4.06±0.89 mm. Some of the bones showed translucency of the bony septum, found in 17 (20.5%) on both sides of the humeri. CONCLUSIONS: There are few studies about STF in the Turkish population. Knowledge of supratrochlear foramen in the distal humerus in humans is important in diagnostic orthopedics, in intramedullary nailing of the humerus, and in possibly increasing the risk of future low-energy fractures. In addition, STF is a radiolucent area in radiographs and may be misinterpreted as an osteolytic or cystic lesion.

Anatomic position of the lingual nerve in the mandibular third molar region as potential risk factors for nerve palsy.

Palsy of the lingual nerve (LN) during third molar extractions, ramus osteotomies, anesthetic injections, procedures of orthognathic, preprosthetic, and periodontal surgery are important complications reported with varying frequency. The purpose of this study is to present quantitative data describing the position and shape of the LN in the third molar area. In the course of dissection, the LN was noted, as well as the furcation pattern, position, course, and anatomic relations under 2.5X loupe magnification in 21 adult male human cadavers. The distance of the junction of the LN and the chorda tympani from the foramen ovale was measured as average 15.1 +/- 5.8mm. The 4 furcation patterns of the LN and the inferior alveolar nerve (IAN) were observed based on their relative positions. Bifurcation of them above the level of the mandibular notch (type I) was observed in 66.7% of the specimens. The horizontal distance of the LN from the lingual plate of the mandible was greater in this study than in previous studies. This study provided measurable objective criteria for the relationship of LN in the third molar region. The knowledge of the relationship between the LN and third molar region is useful for the surgeon in avoiding unexpected complications.

Anatomic characteristics of the ophthalmic and posterior ciliary arteries.

BACKGROUND: There is little documentation of the course and relations of the ophthalmic artery (OA) and posterior ciliary arteries (PCAs). METHODS: The anatomic characteristics of the OA and PCAs were determined from a dissection of 19 neoprene-injected cadaver heads. RESULTS: The intraorbital OA had three segments, considering its relation to the optic nerve in the sagittal plane. The first segment extended from the point where the OA entered the orbit to its curving point. The second segment coursed superomedially from the inferolateral part of the optic nerve, crossing the optic nerve either superiorly or inferiorly. The third segment extended from the curving point of the superomedial distal portion of the second segment to the vessel's termination. The OA was deviated at the junction of its first and second segments, defined as its "angle"; and at the junction of the second and third segments, defined as its "bend." The PCAs arose from the first OA segment, the angle of the OA, the second OA segment and the OA bend. The patterns of branching of the PCAs were medial and lateral and medial, lateral, and superior. The superior PCA and the lateral PCA arose mainly from the angle of the OA, whereas the medial PCA arose from the curving point of the OA. The most frequently observed PCA pattern was a medial PCA and a lateral PCA. The average diameters of the medial PCA, the superior PCA, and the lateral PCA were 0.65, 0.48, and 0.68 mm, respectively. In all cases, pial arteries branching from the PCA and supplying the optic sheath were observed to form a vascular plexus on the optic sheath. The OA and PCAs were surrounded by a network of sympathetic nerves. CONCLUSIONS: Because the most common pattern of PCAs is a medial and lateral branch, a surgical approach to the orbit from those directions carries a higher risk of damage to those vessels than a superior or inferior approach.

Innervation features of the extraocular muscles.

Several transcranial surgical approaches such as frontoorbital, lateral, medial, central, inferolateral, and transmaxillary orbitotomy have been used for exposure of lesions within the orbit. During surgical approaches, detailed anatomic knowledge regarding neural, muscular, and neighboring structures for preservation of the neurovascular structures is important in avoiding traumatic retraction of the nerves of the extraocular muscles. For this study, a total of 22 formalin-fixed cadavers were dissected. Vascular structures were perfused with colored latex to facilitate their definition. In this study, the orbit was investigated in two divisions, superior and inferior. In the superior division, innervation features of the levator palpebrae superioris, the superior rectus, and superior oblique muscles were examined. In the inferior division, innervation features of the medial rectus, the lateral rectus, the inferior rectus, inferior oblique muscles, and ciliary ganglion were investigated. The diameter of the oculomotor nerve (CN3) within the superior orbital fissure was measured as 2.10 mm on the right and 2.09 mm on the left. The diameter of the superior division of the CN3 was on average 1.54 +/- 0.30 mm on the right and 1.65 +/- 0.30 on the left. The mean diameter of the inferior division was measured as 1.85 +/- 0.22 mm on the right and 1.94 +/- 0.20 on the left. In the lower wall of the orbit, different branching types of inferior division of CN3 were observed. The diameter of the trochlear nerve in the superior orbital fissure was on average 1.15 +/- 0.19 mm on the right and 1.21 +/- 0.21 mm on the left. The diameter of the abducens nerve in the superior orbital fissure was on average 1.54 +/- 0.24 mm on the right and 1.54 +/- 0.22 on the left. The number of small branches entering the muscle was on average three branches. Areas nervosa of the nerves were located in the middle one third of the muscles. In this study, detailed knowledge regarding the innervation features of extraocular muscles was attained. An understanding of the innervation features of extraocular muscles is important for the preservation of neural structures during intraorbital procedures.

Arterial vascularization of the extraocular muscles on its importance for orbital approaches.

The anatomic description of the arterial supply of the muscles of the eyeball was studied because medial and lateral approaches to the orbit to treat various disorders might severely damage the main trunk of the ophthalmic artery. The different arterial pedicles for each muscle, as well as their origins and points of penetration into the muscle, were studied in 19 male human orbits. In all cases, the muscular branches originated from the ophthalmic artery, and generally from the inferior face of this artery, just after crossing the optic nerve. The inferomedial muscular trunk arose from the distal of the ophthalmic artery (63.16%). The inferolateral muscular trunk, the superior oblique, levator palpebrae superioris, superior rectus, lateral rectus, and medial rectus arose from the lacrimal artery (43.36%), the bend of the ophthalmic artery (36.84%), the supraorbital artery (36.84%), the distal end of the ophthalmic artery (52.6%), the lacrimal artery (89.47%), and the inferomedial muscular trunk (84.51%), respectively. Complications resulting from damaging the artery can cause inadequacy in eye position, mobility, superior oblique function, or binocular vision, which are expected to be corrected postoperatively.

The arterial anatomy of the eyelid: importance for reconstructive and aesthetic surgery.

PURPOSE: The aim of the study was to investigate the arterial distribution of the eyelids. METHODS: The location, course, length and diameter of eyelid arteries were determined in 19 preserved and latex injected adult male cadaver heads. RESULTS: The diameter of the medial palpebral artery was found to be 1.50+/-0.28mm on the right, and 0.70+/-0.12mm on the left. The diameter of the lateral palpebral artery was measured as 0.62+/-0.10mm on the right, and 0.59+/-0.12mm on the left. The medial palpebral arteries travelling in the medial part of the eyelids usually arose as separate branches for the upper and lower lids, as superior and inferior medial palpebrals. In all cases, four arterial arcades, the marginal, peripheral, superficial orbital, and the deep orbital arcades, were revealed in the upper palpebra. These arterial arcades gave off small perforating branches. The perforating branches were identified on both sides of the tarsal plate and the orbicularis muscle. In four cases (11%) visible arterial variation was found near the inferolateral end of the levator palpebrae. Although many differences in the arterial features of the eyelid have been noted, there may not be a significant difference in the basic vasculature of the palpebra among races. A better understanding of the palpebral vascularity should allow modification of reconstructive techniques and reduce postoperative complications after eyelid surgery.

Anatomy of the supraorbital region and the evaluation of it for the reconstruction of facial defects.

Damaged supraorbital neurovascular bundle during anterior orbital approach, fronto-glabellar reconstruction flap, supraorbital injection, blepharospasm, and Graves disease surgery is an important complication reported with varying frequency. The origin, calibration, and branches of the supraorbital artery and its topographical relations were investigated by injection of the arterial bed with red-dyed latex in 38 forehead regions. The supraorbital artery with the supratrochlear artery arose from the orbit as two separate vessels in 33 out of 38 forehead sides (87%). The supraorbital artery entered the frontalis muscle between 20 and 30 mm in 20 cases (52.6%), and between 30 and 40 mm in 16 cases (42.1%). This artery was located approximately the subcutaneous tissues between 40 and 50 mm in 17 cases (44.7%), between 50 and 60 mm in 18 cases (47.4%). The transverse supraorbital vein coursed at the level of the orbital rim on 22 sides (58%) and between 6.1 and 11.2 mm (mean: 9.4 mm) above the supraorbital rim on 16 sides (42%). All branches of supraorbital nerve were located between 2.0 and 3.2 cm from the midline at the level of the orbital rim. In 23 cases (60%), the lateral branch of the supraorbital nerve exited the bone as two branches, usually one large and one much smaller, which can together run into the scalp without further branching. In the present anatomical study, special attention was paid to morphological details concerning the neurovascular relationship of the supraorbital region. A better understanding of the midline forehead neurovascularity should allow modification of reconstructive techniques, afford better localization of the supraorbital nerve during blepharoplasty and ptosis surgery, and reduce the incidence of postoperative hematomas and nerve injuries.

Arterial features of inner canthus region: confirming the safety for the flap design.

The medial canthus represents a fixed-point fulcrum that is necessary for eyelid function. The aim of the study was to investigate the arterial distribution of the inner canthus. The origin, calibration, and branches of the inner canthus arteries and their topographical relations were examined by dissecting 19 cadavers, injecting red latex to their corresponding 38 nasal sections before the dissection. The distance from the dorsal nasal artery to the inner canthus was found to be 7.2 +/- 0.3 mm. In this study, the average diameter of the dorsal nasal artery was 0.74 mm on the right side and 0.88 mm on the left. Concerning the course of dorsal nasal artery on the lateral side of the nose, 4 types were observed. In most of the examples (44.7%), dorsal nasal artery anastomosed with angular artery via thick branch and gave off supplying branches to the medial canthus and to the lateral side of the nose. Dorsal nasal artery is a vessel of satisfactory size and is potentially a good vascular source for a thin free flap. It may be an ideal flap to reconstruct the eyelid defect for texture and color similarity of the inner canthus skin. A better understanding of the inner canthus vascularity should allow modification of reconstructive techniques and reduce postoperative complications.

Topography of the posterior arteries supplying the eye and relations to the optic nerve.

PURPOSE: The aim of the study was to investigate the arterial blood supply of the intraorbital part of the optic nerve. METHODS: The location, course, length and diameter of the central retinal artery (CRA) and posterior ciliary arteries were studied in 19 adult white male preserved cadavers of between 35 and 75 years of age. RESULTS: In right eyes, the first branch of the intraorbital part of the ophthalmic artery was the CRA in 26.3% (5/19) and the CRA and medial posterior ciliary artery in 21% (4/19) of eyes. In left eyes, the first branch of the intraorbital part of the ophthalmic artery was the CRA in 47.4% (9/19) and the CRA and medial posterior ciliary artery in 26.3% (5/19) of eyes. The CRA was observed as a single branch in 57.9% and a trunk in 42.1% of right eyes, and as a single branch in 52.6% and a trunk in 47.3% of left eyes. The outer diameter of the CRA measured 0.6 +/- 0.1 mm (min-max 0.5-0.9 mm) in right eyes and 0.6 +/- 0.2 mm (min-max 0.4-0.9 mm) in left eyes. The CRA entered the optic nerve 7.5 +/- 2.2 mm (min-max 5.3-12.5 mm) behind the ocular bulb in right eyes and 7.4 +/- 2.3 mm (min-max 5.3-14.1 mm) behind it in left eyes, at its lower and medial side. The posterior ciliary arteries ran forward, divided into multiple branches and pierced the sclera close to the optic nerve medially, laterally or superiorly. The longitudinal capillaries ran between the optic nerve and the CRA antero-posteriorly, while the transverse capillaries surrounded the optic nerve. Collaterals from both the longitudinal and transverse capillaries joined to form a complicated capillary plexus. CONCLUSION: This article confirms the well known variability of the arterial circulation of the intraorbital part of the optic nerve. Better understanding of the arterial anatomy of the intraorbital part of the optic nerve should enable appropriate modification of surgical techniques.

Anatomic features of the intracranial and intracanalicular portions of ophthalmic artery: for the surgical procedures.

The intracranial and intracanalicular portions of the ophthalmic artery is suspectible to various diseases and injuries; therefore, knowledge of the microanatomy of the complex bony, dural, vascular, and neural relationships of this segment is necessary for proper diagnosis and preservation of the neurovascular structures during subfrontal, pterional and intracanalicular procedures. The artery was studied in 38 human adult cadaver specimens regarding origin, intracranial and intracanalicular portions for surgical approachs. The ophthalmic artery originated from the intradural portion of the internal carotid artery, except in 5% where the ophthalmic artery originated extradurally. The ophthalmic artery originated from medial of superior wall of internal carotid artery in 73.7%, from the central in 21% and the lateral in 5.3% of the specimens. The diameter of the ophthalmic artery at its origin was 2.25+/-0.3 mm on the right and 2.16+/-0.4 mm on the left. The intracranial and intracanalicular course of the artery was divided into short limb, angle "a", long limb, angle "b" and distal part to the apex of the orbit. Awareness of variations in anatomic structures is paramount importance both for diagnosis and treatment of vascular lesions of the brain.

The anatomic landmarks of ethmoidal arteries for the surgical approaches.

Knowledge of variations in the possible patterns of origins, courses, and distributions of the ethmoidal arteries are necessary for the diagnosis and important for the treatment of orbital disorders. Ethmoidal arteries are damaged in endonasal surgical interventions and in operations performed on the inner wall of the orbita.A description of the anatomic landmarks of the ethmoidal arteries and ethmoidal canals is presented, based on data from microdissection in 19 adult cadavers studied after injection of red-dyed latex into the arterial bed. In all subjects, each of ethmoidal arteries originated from ophthalmic artery. The anterior ethmoidal artery was observed in all specimens except for one case. The diameter of the artery thicker than the posterior ethmoidal artery was 0.92 +/- 0.2 mm on the right and 0.88 +/- 0.15 mm on the left. The branching of the anterior ethmoidal artery from the ophthalmic artery was determined in four different types. The diameter of the posterior ethmoidal artery was measured as 0.66 +/- 0.21 mm on the right and 0.63 +/- 0.19 mm on the left. The anterior ethmoidal canal was located between the second and third lamella in 29 of 38 cases. The mean distance between the limen nasi and anterior ethmoidal canal was 48.1 +/- 3.2 mm.The article confirms the well-known variability of the ethmoidal arteries and their topographic relation to the ethmoidal canals. Advances in surgical techniques, instrumentation, and regional arterial anatomy have resulted in functional operations of endoscopic sinus and orbital surgery with fewer complications.

Importance of the anatomic features of the lacrimal artery for orbital approaches.

Knowledge of variations in the possible patterns of origin, course, and distribution of the lacrimal artery are necessary for the diagnosis and important for the treatment of orbital disorders. The vascularization of 38 lacrimal glands was studied by orbital dissection subsequent to injection of the arterial bed with red-dyed latex. The origin, calibration, and branches of the lacrimal artery and its topographic relations were investigated. In all subjects, arteria lacrimalis originated from ophthalmic artery. On the right, the lacrimal artery sprang from the angle of the ophthalmic artery in 63.15% of the cases, from the curve of the ophthalmic artery in 26.31%, and from the first part the ophthalmic artery in 5.26%. The outer diameter of the lacrimal artery was measured as 1.02 +/- 0.17 mm on the right and 1.03 +/- 0.16 mm on the left. In 68.42 of the cases on the right and in 52.63 of the cases on the left, the lacrimal artery was present, and the lacrimal nerve was seen in a superolateral position with respect to the origin of the artery. Variability of the glandular branch in its course toward lacrimal gland was observed. Recurrent meningeal branch was seen in six cases on the right and in five on the left. On the right, of the six cases, two passed through meningoorbital foramen, and four passed through superior orbital fissure and entered middle cranial fossa. On the left, of the five cases, two passed through meningoorbital foramen, and three passed through superior orbital fissure and entered middle cranial fossa. In this case, the lacrimal gland is the site of an intraorbital anastomosis between internal and external carotid systems. This article confirms the well-known variability of the lacrimal arterial branches and their relation to the lacrimal gland. These variations have been discussed and described with respect to the embryonic development. A better understanding of the vascular anatomy of the lacrimal gland should allow modification of surgical techniques to reduce bleeding during biopsy or excision of the lacrimal gland.