Morphometric study of the extraocular muscles in Thai population

Morphology of the extraocular muscles plays an important role in many ophthalmological surgeries and diagnostic imaging studies. Detailed understanding of length, width, point of insertion and the relationships between these muscles could be of significance for successful surgical outcomes. Forty-six orbital contents were extracted from formaldehyde-embalmed cadavers. Dissection was performed to reveal the extraocular muscles from their origins to insertions on the sclera. Muscle length, muscle width, distance from point of insertion to the sclerocorneal limbus, relationship between the superior oblique and superior rectus and between the inferior oblique and lateral rectus were measured. The lateral rectus and superior rectus were the longest muscles. The insertion of the medial rectus muscle was closest to the sclerocorneal limbus while the inferior rectus, lateral rectus and superior rectus insertions were progressively further apart. Only the length of the inferior rectus and medial rectus were significantly different between males and females. The distances between the superior oblique and superior rectus and between the inferior oblique and lateral rectus were slightly greater than in previous study. A direct comparison of these parameters between ethnic groups is still needed for an improvement of the procedural outcomes

Co-existence of the double inferior vena cava with complex interiliac venous communication and aberrant common hepatic artery arising from superior mesenteric artery: a case report

Variations of the arterial and venous system of the abdomen and pelvis have important clinical significance in hepatobiliary surgery, abdominal laparoscopy, and radiological intervention. A case of double inferior vena cava (IVC) with complex interiliac communication and variation of the common hepatic artery (CHA) arising from superior mesenteric artery (SMA) in a 79-year-old male cadaver is presented. Both IVCs ascended on either side of the abdominal aorta. The left-sided IVC crossed anterior to the aorta at the level of the left renal vein. The union of both IVCs was at the level just above the right renal vein. The diameter of right-sided IVC, left-sided IVC and the common IVC were 16.73 mm, 21.57 mm and 28.75 mm, respectively. In the pelvic cavity, the right common iliac vein was formed by a union of right external and internal iliac veins while the formation of left common iliac vein was from the external iliac vein and two internal iliac veins. An interiliac vein ran from right internal iliac vein to left common iliac vein with an additional communicating vein running from the middle of this interiliac vein to the right common iliac vein. Another co-existence variation in this case was the origin of the CHA arising from the SMA with a suprapancreatic retroportal course. Clinical importance of double IVC are observed in retroperitoneal surgery, whole organ transplantation or radical nephrectomy, surgical ligation of the IVC or the placement of an IVC filter for thromboembolic disease. The variation of CHA has an important clinical significance in liver transplantation, abdominal laparoscopy and radiological abdominal intervention. (Folia Morphol 2018; 77, 1: 151–155

Morphometric study of the left atrial appendage related to closure device deployment: a cadaveric study in Thai population

Background: This study aims to investigate the left atrial appendage (LAA) regarding external morphology, positional relation of the ostium of LAA to the left superior pulmonary vein (LSPV), ostium shape, ostium diameter and functional depth. Materials and methods: Left atrial appendages of 65 cadaveric hearts were examined. Results: The prevalence of Cauliflower, Windsock, Cactus and Chicken wing type of LAA were 27.7%, 27.7%, 26.1%, and 18.5%, respectively. LAA with two lobes was the most common. All specimens showed no accessory LAA. The relation of the ostium to the LSPV was found in two types which were mid-type (LAA ostium was at the same level as LSPV) in 29 (44.6%) cases and inferior type (LAA ostium was below the level of LSPV) in 36 (55.4%) cases. The shapes of LAA ostium were oval and round with a prevalence of 55.4% and 44.6%, respectively. The diameter of round type ranged from 9.53 to 21.51 mm with a mean of 14.56 ± 2.6 mm. While in oval type, the long and short diameters ranged from 11.61 to 31.71 mm with a mean of 14.23 ± 4.2 mm and from 6.70 to 23.90 mm with a mean of 11.66 ± 3.5 mm, respectively. The Surface area of the ostium was calculated from the ostium diameter, range from 71.29 to 594.92 mm2 with a mean of 169.56 ± 84.73 mm2. There was no statistically significant difference of the surface area between LAA types. The mean functional depth of LAA was 11.57 ± 4.43 mm. The functional depth of the Windsock-type appeared to be statistically significant from the others. However, there was no correlation between the functional depth and the ostium surface area. Conclusions: This morphometric data might be beneficial for deployment of LAA closure device in the Thai population

Morphometric study of the ciliary ganglion and its pertinent intraorbital procedure

Background: Ciliary ganglion (CG) can be easily injured without notice in many intraorbital procedures. Surgical procedures approaching the lateral side of the orbit are at risk of CG injury which results in transient mydriasis and tonic pupil. This study aims to focus on the morphometric study of the CG which is pertinent to intraoperative procedure. Materials and methods: Forty embalmed cadaveric globes were dissected to observe the location, shape and size of CG, characteristics and number of roots reaching CG, number of short ciliary nerve in the orbit. Distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were measured. Results: Ciliary ganglion was located between optic nerve and lateral rectus in every case. Its shape could be oval, round and irregular. Mean width of CG was 2.24 mm and mean length was 3.50 mm. Concerning the roots, all 3 roots were present in 29 (72.5%) cases. Absence of motor root was found in 7 (17.5%) cases. Absence of sympathetic root was found in 4 (5%) cases. The number of motor root could be 1, 2 and also 3 roots. Three motor roots were found in 1 case which originated from nerve to inferior oblique muscle. Only one sensory root was found in every specimen. One sympathetic root could be observed in most of the specimens and 6–14 short ciliary nerves were found. Mean distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were 16.04 mm, 1.47 mm, 2.88 mm, and 31.53 mm, respectively. Conclusions: This study described the characteristic of CG, number of its nerve root and some measurements relevant to intraorbital procedures in Asian population. Moreover, a new parameter was the distance between CG and scleral insertion of the lateral rectus muscle. This parameter should be considered when performing operation involved the lateral rectus muscle and BTX-A injection to lateral rectus muscle to reduce CG injury

Morphometric study of inferior peroneal retinaculum and contents of inferior peroneal tunnel

Background: The aims of this study are to investigate the inferior peroneal retinaculum (IPR) regarding morphometric parameters, and contents in the inferior peroneal tunnel (IPT). Materials and methods: One hundred and nine embalmed cadaveric legs were dissected in prone position. Results: The extension band of the IPR was found in 31.19% of cases. The mean of length, width at the origin, width at the middle part, width at the insertion, and thickness of the IPR [mm] were 23.42 ± 3.54 (17.05–33.68), 13.29 ± 2.56 (5.83–20.92), 14.50 ± 2.37 (6.68–21.34), 10.10 ± 2.63 (4.59–19.17) and 0.48 ± 0.16 (0.20–0.87), respectively. The angle of the IPR to the horizontal axis was 38.51 ± 7.07 (11.67–54.00) degrees. The IPT was divided into the upper and lower tunnels. The normal contents were the tendons of peroneus brevis and peroneus longus in the upper and lower tunnels, respectively. However, additional contents were found in the upper tunnel in 2 cases. One was the tendon of peroneus digiti quinti, and peroneus quartus in the other one. Moreover, an unusual accessory peroneal muscle coursed into the lower tunnel and inserted on the peroneal tubercle. Tears of the peroneus brevis tendon were observed in 2 cases. Conclusions: These morphometric data might be beneficial in surgical repair for IPR injury.

Evaluation of the sciatic nerve location regarding its relationship to the piriformis muscle

Background: The localisation of sciatic nerve (SN) is essential for the achievement of several procedures performed in the gluteal region. This study proposed to investigate the location of SN regarding its relationship to the piriformis (PM) by the line joining the posterior superior iliac spine (PSIS), ischial tuberosity (IT) and greater trochanter (GT).Materials and methods: SN-PM relationship was examined in 204 specimens from 102 embalmed cadavers (55 males, 47 females). Distances between PSIS, IT and GT were measured. Midpoints of SN at the lower edge of PM (S1) and IT-GT line (S2) were marked. Perpendicular line from S1 to PSIS-GT (S1-R) and to PSIS-IT (S1-Q), were created and measured. Distances of PSIS-R, PSIS-Q (S1) and IT-S2 were measured and calculated into percentage of PSIS-GT, PSIS-IT and IT-GT lengths, respectively.Results: Regarding the classification of Beaton and Anson, three types of SN-PM relationship (a, b and c) were obtained. The percentage of type a, b and c was 74.02, 22.55 and 3.43, respectively. Symmetrical SN-PM relationship was found in 75.49%. The mean length of PSIS-IT, PSIS-GT and IT-GT in all types was 129.63 ± 11.89 mm, 151.34 ± 14.78 mm and 73.02 ± 10.20 mm, respectively. A statistically significant difference was found between types a and b (p = 0.013) in PSIS-IT length, whereas mean length of IT-GT and PSIS-GT showed no statistically significant difference between SN-PM types. PSIS-IT line passed SN at the lower edge of PM (S1) in 112 specimens (54.90%). In these cases, S1 and Q were the same point. A statistically significant difference was also found between types a and b (p = 0.023) in PSIS-Q (S1) length. The mean lengths of PSIS-Q (S1), PSIS-R and IT-S2 in term of percentage of PSIS-IT, PSIS-GT and IT-GT line in all types were 60.06 ± 5.90%, 54.19 ± 6.10%, and 37.87 ± 8.27%, respectively. The mean lengths of S1-R and S1-Q were 30.07 ± 8.30 mm and 6.54 ± 7.99 mm. Therefore, SN at S1 could be located at the point of 54.19 ± 6.10% of PSIS-GT length (R) with a distance of 30.07 ± 8.30 mm perpendicular to PSIS-GT line (S1-R). Since the PSIS-IT line did not pass SN at S1 in every case, it might not be suitable for localizing SN at S1. SN at S2 could be located at the point of 37.87 ± 8.27% of IT-GT line. No significant difference was found between types.Conclusions: Sciatic nerve can be localised by PSIS-GT and IT-GT lines without statistically significant difference between types (a, b, and c) of SN-PM relationship

New aspect of morphometric study of the superior peroneal retinaculum: pertinent data for surgical repair and reconstruction

Background: This study was conducted to investigate characteristics, attachments and morphometric parameters of the superior peroneal retinaculum (SPR). Materials and methods: Morphology and morphometric details including width, length, thickness and angle of alignment of SPR in 109 embalmed cadaveric legs were investigated. The occurrence of peroneal tendon tear was also noted. Results: Most of SPR originated from the fibrocartilaginous ridge of the lateral malleolus. The SPR might be a single band or split into proximal and distal bands inserted on the posterior intermuscular septum and lateral wall of calcaneus, respectively. Based on the characteristics and insertion patterns, the SPR could be divided into three types: type I (double band with subtype Ia and Ib), type II (single band) and type III (single band) with the prevalence of 56.88% (12.84%, 44.04%), 1.83%, and 41.28%, respectively. The average coordinate (X, Y axis) of the midpoint of width at origin measured from the tip of fibula in all types was 7.26 ± 3.15 and 10.45 ± 4.52 mm. The average coordinate of the midpoint at insertion on the posterior intermuscular septum was 24.06 ± 4.94 and 13.35 ± 5.18, and those inserted on the lateral wall of calcaneus was 21.45 ± 7.88 and 13.59 ± 6.73 mm. Prevalence of peroneus brevis tendon tear was 12.84% (14 cases) and was associated with SPR type Ib with statistical significance. Conclusions: Precise information of the characteristics, morphometric data and coordinates of attachment sites of SPR are essential for surgical procedures and reconstruction

Multiple variations in the course and motor branching pattern of the musculocutaneous nerve with unusual communication with the median nerve

Anatomic variations in course and motor branching pattern of the musculocutaneous nerve (MCN) with unusual communication with the median nerve were determined on the left arm of a 62-year-old formalin fixed male cadaver. The MCN did not pierce the coracobrachialis muscle. It provided 4 primary motor branches. The first branch emerged 1.5 cm inferior to the coracoid process to innervate the coracobrachialis muscle. The second branch emerged 8 cm inferior to the coracoid process to innervate the biceps brachii muscle. The third branch to brachialis muscle emerged 13.9 cm inferior to the coracoid process. The last branch to the common belly of biceps brachii muscle emerged 19.6 cm inferior to the coracoid process. Two communications with the median nerve were observed. The proximal thick communicating branch had the direction from the MCN to the median nerve while the distal one was a small nerve bundle with a direction from the median nerve to the MCN. The present report provided evidence of multiple variations in one MCN which had not been reported previously. Anatomic variation in this case has clinical implications, considering that injury of the MCN in the upper part of arm would cause unexpected paralysis of flexor muscles of forearm and thenar muscle due to communications between this and median nerve

Surface localisation of master knot of Henry, in situ and ex vivo length of flexor hallucis longus tendon: pertinent data for tendon harvesting and transfer

Background: Length of flexor hallucis longus (FHL), localisation of master knot of Henry (MKH) and relationship between MKH and neurovascular bundle are essential for the achievement of FHL tendon transfer. The purpose of this study is to define the localisation of MKH in reference to bony landmarks of the foot, its relationship to plantar neurovascular bundle and to investigate in situ and ex vivo length of FHL tendon in single incision, double incision and minimally invasive techniques. Materials and methods: Foot length was examined in 62 feet of 31 soft cadavers (9 males, 22 females). Various parameters including the relationship between MKH and neurovascular bundle, the distances from MKH to medial malleolus (MM), navicular tuberosity (NT) and the first interphalangeal joint of great toe (IP) were measured. Surface localisation of MKH in relation to a line joining the medial end of plantar flexion crease at the base of great toes (MC) to NT (MC-NT line) was determined. Lengths of FHL tendon graft from three surgical techniques were examined. In situ length was measured in the plantar surface of foot and ex vivo length was measured after tendon was cut from its insertion. Results: The mean length of foot was 230.98 ± 15.35 mm with a statistically significant difference between genders in both sides (p < 0.05). No distance was found between medial plantar neurovascular bundle (MPNVB) and MKH. Mean distance of 17.13 ± 3.55 mm was found between lateral plantar neurovascular bundle (LPNVB) and MKH. MKH was located at a mean distance of 117.11 ± 1.00 mm proximal to IP, 26.28 ± 4.75 mm under NT and 59.58 ± 7.51 mm distal to MM with a statistically significant difference of MKH-IP distance between genders in both sides and MKH-NT in right side. MKH was located anterior to NT (66.1%), at NT (27.4%) and posterior to NT (6.5%) on the MC-NT line. Surface localisation of MKH was 94.75 ± 8.43% of MC-NT line from MC with a perpendicular distance of 25.11 ± 5.37 mm below MC-NT line. The in situ and ex vivo tendon lengths from MTJ to ST, to MKH and to IP were 39.05 ± 10.88 mm and 34.43 ± 10.23 mm, 73.45 ± 9.91 mm and 68.63 ± 9.43 mm, 197.98 ± 13.89 and 191.79 ± 14.00 mm, respectively. A statistically significant difference between genders was found in MTJ-IP of in situ and ex vivo length of both sides (p < 0.05). The mean length of tendon between in situ and ex vivo was significantly different in all techniques (p < 0.05). A moderate positive correlation between foot length and tendon length was found in MTJ-IP of both in situ and ex vivo tendon length. Conclusions: A statistically significant difference between in situ and ex vivo tendon length was shown in all harvesting techniques. Surface location of MKH was approximately at 95% of MC-NT line from MC with a perpendicular distance of 25 mm from MC-NT line

Evaluation of the greater occipital nerve location regarding its relation to intermastoid and external occipital protuberance to mastoid process lines

Background: Localisation of the greater occipital nerve (GON) is essential for the achievement of several procedures performed in the occipital region especially the treatment of occipital neuralgia. This study proposed to investigate the location of GON subcutaneous (Sc) and semispinalis capitis (SSC) piercing points related to the intermastoid and external occipital protuberance (EOP) to mastoid process (MP) lines.Materials and methods: The Sc piercing point, relation to SSC and obliquus capitis inferior (OCI) muscles of 100 GONs from 50 cadaveric heads (23 males, 27 females) were dissected. Distances from EOP to MP (EM line) on both sides and between MPs (MM line) were measured. Perpendicular lines from Sc and SSC piercing points to EM and MM lines were created and measured. Distances from EOP to the perpendicular lines of SSC piercing point and from MP to the perpendicular lines of Sc piercing point were measured and calculated into percentage of EM and MM length, respectively.Results: Three types of Sc piercing points (I, II and III) were obtained. The percentage of GON piercing trapezius muscle (TP) (type I), aponeurosis of TP (type II) and aponeurosis between TP and sternocleidomastoid muscle (SCM) (type III) were 2, 67 and 31, respectively. In addition, 95% of GON pierced SSC, 2% pierced its tendinous band and 3% travelled between its medial fibres and the nuchal ligament. 94% of the GON turned around the lower edge of the OCI, while 6% pierced the lower edge of this muscle. Sc piercing point was always located above the MM line, but it could be above, below or on the EM line. In contrast, all of the SSC piercing points were located below the EM line except in one specimen, but it could be above, below or on the MM line. Therefore, the MM and EM lines were used as reference lines for locating the Sc and SSC piercing points, respectively. The mean EM line length was 81.26 ± 5.26 mm with statistically significant differences between genders and sides in female. The mean MM line length was 121.77 ± 8.54 mm with a statistically significant difference between genders. Sc piercing point could be located at 44% of MM line length from ipsilateral MP with a mean vertical distance of 18 mm. No statistically significant difference was found between genders and sides in these parameters, but a statistically significant difference was found in the percentage of MB to MM line between type III and type I (p = 0.02). SSC piercing point of all types could be located at the point of 25% of EM line length from EOP with a vertical distance of 18 mm below EM line. No statistically significant difference was found between genders, sides and types of both piercing points.Conclusions: MM and EM lines are potential reference lines for locating the Sc and SSC piercing points of GON, respectively