The investigation of cranial fossae in the intracranial cavity of fixed cadaveric skull bases: associations with sex, laterality, and clinical significance.

PURPOSE: Our study aims to investigate three parts of the intracranial cavity, their distances to essential anatomical landmarks, and the correlations between these distances with sex, laterality, and surgical significance. METHODS: The cranial nerve foraminae and essential surgical landmarks of each fossa were investigated bilaterally in 30 adult formalin-fixed cadaveric heads. Measurements, including lengths, depths, diameters, and horizontal distances to each other, to the midline of the skull, and to the outer lateral margin of the skull, were recorded on both sides. RESULTS: The optic canal (OC) depth, internal auditory meatus (IAM) width, CNVII and CNIX diameters, and accessory hypoglossal canal (HC) distance were significantly greater on the left side (p < 0.05). CNVI length, CNV diameter, CNXI length, and the distances of the HC and accessory HC from the skull were significantly greater on the right side (p < 0.05). In males, correlations were found between the length of the left CNVIII and the right IAM diameter (r = 0.864, p = 0.001), right CNVIII length (r = 0.709, p = 0.022), right accessory HC length (r = 0.847, p = 0.016), and right-sided skull distance (r = 0.829, p = 0.042). In females, correlations were noted between IAM depth and length, right IAM location relative to the skull, left CNIX and CNX lengths, left CNXII length, left accessory HC location relative to the skull, and accessory HC length. CONCLUSIONS: The findings of the current study indicate inherent asymmetry, sexual dimorphism, and variability in certain cranial nerves among cadaveric heads, which could have implications for surgical procedures, neuroanatomical studies, and clinical assessments. The study revealed side disparities and correlations within cranial fossa formations and essential surgical landmarks in both genders.

Quantitative analysis of surgical landmarks of the face in fixed cadaveric heads: clinical and anatomical implications.

PURPOSE: This study aimed to examine and analyze the presence of sexual dimorphism and symmetry/asymmetry in fixed cadaveric heads and their contributions to clinical practice. METHODS: Measurements were conducted on 6 cadavers and 24 fixed cadaveric heads (n = 30) using a digital microcaliper to assess cranial dimensions, including surgical landmarks, facial index (FI), orbital index (OI), and the danger triangle of the face, offering crucial references for surgeons during surgical interventions. RESULTS: Analyses were conducted on cadavers consisting of 10 females (33.3%) and 20 males (66.7%). Males demonstrated significantly higher values than females in terms of Zy-Zy (Zy = Zygion), nasal body, and width/length of the columella. Hyperleptoprosop types were the most frequently observed, followed by the leptoprosop type. Females exhibited megaseme characteristics according to OI on both sides. Additionally, the danger triangle of the face was greater in males compared than in females, suggesting a higher risk of infection in this region among males. CONCLUSION: The observed sex differences in facial and nasal dimensions, along with facial indices, are crucial for customizing surgical procedures to individual patients. For example, the greater distance in the danger triangle among males highlights the importance of considering anatomical variations to avoid complications, such as septic cavernous sinus thrombosis. Integrating these measurements into preoperative planning can enhance the precision of facial reconstruction and aesthetic surgeries, thereby improving patient outcomes and safety.

Superior mesenteric artery revisited using magnetic resonance angiography.

PURPOSE: We aimed to examine the superior mesenteric artery in detail by magnetic resonance angiography to provide an alternative to other imaging methods, to reduce the exposure time of patients and physicians to X-rays and the time spent in catheter angiography, to determine the variations, positions, and locations of the celiac trunk, and to provide detailed information for surgeons and interventional radiologists using this method. METHODS: The procedures were approved by the Kocaeli University Medical School Non-Interventional Clinical Research Ethics Committee (10.04.2023, approval number: 2021/51). MR angiography images of 185 patients with abdominal imaging in PACS (Picture Archiving Communication Systems) were retrospectively registered. The level of origin of the superior mesenteric artery according to the vertebral column, angle of origin, distance between the superior mesenteric artery and branches of the abdominal aorta, and branching pattern of the superior mesenteric artery were evaluated. Parameters were evaluated according to gender and age using SPSS version 25. RESULTS: The distance between superior mesenteric artery-inferior mesenteric artery and superior mesenteric artery-aortic bifurcation in males was higher than in females, and the difference was statistically significant. In females and the whole study group, a low, positive and significant relationship was found between age and superior mesenteric artery-sagittal angle. The most common origin site for the superior mesenteric artery, according to the vertebral column was found to be at L1 middle for males and L1 upper for females. The most common superior mesenteric artery branching pattern was classical type in both genders. CONCLUSION: Individual evaluation of the superior mesenteric artery could reduce the risks during surgical interventions, considering the relationship of the superior mesenteric artery, especially with distally located vessels, and the gender differences for the angle of origin. Furthermore, considering that interventional radiologists choose the catheter according to the angle of origin of the artery during catheter angiography procedures, individual evaluation of patients taking into account gender and age is of utmost importance.

A case report of bilateral atypical origin of pectoralis minor.

PURPOSE: In the existing literature, various insertion variations and classifications for the Pectoralis Minor (PMi) muscle have been reported. However, there is limited information on inferior origin variations of the PMi muscles and a certain classification is lacking. CASE PRESENTATION: During routine cadaver dissection of an adult male, variations in the origin of the bilateral PMi muscles were identified. Morphometric measurements of the PMi were conducted using ImageJ software, and the unusual origin patterns of the PMi were categorized into specific types. The PMi muscle demonstrated a bilateral variations. On the right side, the PMi displays a bifid structure comprising medial and lateral fibers. The left PMi originate from the superolateral margins of the 4th to 6th costae and terminate at the anterosuperior surface of the coracoid process. The length of the right medial fiber before merging was 5.67 ± 0.04 cm, while that of the right lateral fiber was 6.68 ± 0.05 cm. The distance between the two fibers was measured as 0.43 cm, with a length of 3.33 ± 0.02 cm. The length and diameter of the muscle fibers extending to the 6th costa were 2.63 ± 0.01 cm and 0.46 cm, respectively. CONCLUSIONS: Potential variations in PMi arising from impairment during development may occasionally manifest as asymptomatic conditions or predispose individuals to shoulder impingement, rotator cuff dysfunction, shoulder-related disorders, and functional impairments. Therefore, careful attention to this variation is considered in surgical planning.

Trifurcation of the facial artery at the inferior border of the mandible: a case report.

PURPOSE: The facial artery is known to show variations in its origin, course, termination, and branching pattern. This study aimed to present a case with trifurcation of the facial artery at the inferior border of the mandible accompanied by variable branches. METHODS: During our routine head dissection, it was observed that a 67-year-old male cadaver had a trifurcation of the facial artery at the level of the lower border of the mandible on the left. The skin was reflected, and the subcutaneous fatty tissue and subcutaneous layers were dissected to reveal the triple facial artery. RESULTS: The left facial artery arising from the external carotid artery entered the face with three branches as it crossed the lower border of the mandible. The three branches are the anterior, intermediate, and posterior branches. The posterior branch passed in front of the anterior border of the masseter muscle along with the facial vein and gave off muscular branches with a straight course, whereas the anterior thickest curved branch terminated by the inferior labial artery, and a tortuous intermediate branch initially gave off the superior labial artery and then terminated by the angular artery. CONCLUSION: Understanding these variational branches of the triple facial artery and their relationships is crucial for avoiding complications in reconstructive and reparative maxillofacial, craniofacial and plastic surgery in order to mitigate the risk of damage to the facial artery during flap surgery.

Reappraisal of the types of trigeminal porus and importance in surgical applications.

OBJECTIVE: The detailed information regarding the types of trigeminal porus (TP) and related surgical approach is lacking in the literature. Therefore, we performed this study to elucidate further the types of TP and the relationships with critical surgical landmarks in the skull base. METHODS: The study was performed on 19 formalin-fixed cadavers of the cranial base (52.6% male, n = 10; 47.4% female, n = 9) on both sides. Calculations were made of the vertical dimension (VD), horizontal dimension (HD), and types of TP, the thickness of the TP, the HD and VD of the internal acoustic meatus, the distance between the TP-IAM, the thickness of the ossifying tissue that forms the TP, the trigeminal nerve (CN V) in both types and the distance between the CN V-VI. RESULTS: The elliptical (42.1% left, 36.8% right), oval (52.6% left, 36.8% right) and slit-like (5.3% right) types of TP were detected (X2 = 11.722). The HD of the TP was, on average, 8.02 mm (female) and 9.2 mm (male) on the right side, and 8.26 mm (female) and 8.81 mm (male) on the left side. The VD of the TP was, on average, 1.99 mm (female) and 2.65 mm (male) on the right side, and 2.42 mm (female) and 2.94 mm (male) on the left side. CONCLUSIONS: In our study, ellipse and slit-like types of TP are taken into account in order to plan the surgical approaches to remove or prevent the extension of tumors. A combined surgical technique is recommended to reach the TP easily without damaging the nearby surgical structures during surgery. The oval type of TP allows a wide range of movements, so it is more advantageous in skull base surgery.

Sphenoid Sinus in Relation to Age, Gender, and Cephalometric Indices.

The sphenoid sinus is located in the center of the cranial base and is surrounded by numerous neurovascular structures. The aim of this study was to determine sphenoid sinus types and subtypes, dimensions of the sinus and cranium, and the relations of these to age and gender.Computed tomography data was obtained from 144 patients to determine right sphenoidal volume (sphVOLR), left sphenoidal volume (sphVOLL), total sphenoidal volume (sphVOLT), anteroposterior length of the sphenoid sinus (sphAP), laterolateral length of the sphenoid sinus (sphLL), head circumference (crHC), fronto-occipital length (crFO), and biparietal length (crBP), with OSIRIX software. The patients' ages ranged between 9 and 83 years (mean age 38 ±â€Š15.5 years). The study included 89 males (mean age 39 ±â€Š15.5 years) and 55 females (mean age 38 ±â€Š15.6 years).Conchal (1.4%), presellar (8.3%), sellar (23.6%), and postsellar (66.7%) type sphenoid sinuses were determined based on the extension of pneumatization around the sella turcica. Each type of sphenoid sinus was classified into the following 5 types based on the direction of pneumatization: body, full lateral, pterygoid, lesser wing, and greater wing subtypes. Mean sphAP was determined as 29.72 mm and mean sphLL as 37.73 mm. In 5 patients only (3.4%), the sphenoid sinus was not divided into right and left by the intersphenoidal septum.The variations in the extensions of pneumatization of the sphenoid sinus and its dimensions might be used to estimate the selection of a surgical approach to lesions bordering the sinus.

Evaluation of Eyeball and Orbit in Relation to Gender and Age.

The orbital aperture is the entrance to the orbit in which most important visual structures such as the eyeball and the optic nerve are found. It is vital not only for the visual system but also for the evaluation and recognition of the face. Eyeball volume is essential for diagnosing microphthalmos or buphthalmos in several eye disorders. Knowing the length of the optic nerve is necessary in selecting the right instruments for enucleation. Therefore, the aim of this study was to evaluate eyeball volume, orbital aperture, and optic nerve dimensions for a morphological description in a Turkish population sample according to gender and body side.Paranasal sinus computed tomography (CT) scans of 198 individuals (83 females, 115 males) aged between 5 and 74 years were evaluated retrospectively. The dimensions of orbital aperture, axial length and volume of eyeball, and diameter and length of the intraorbital part of the optic nerve were measured. Computed tomography examinations were performed on an Activion 16 CT Scanner (Toshiba Medical Systems, 2008 Japan). The CT measurements were calculated by using OsiriX software on a personal computer. All parameters were evaluated according to gender and right/left sides. A statistically significant difference between genders was found with respect to axial length of eyeball, optic nerve diameter, dimensions of orbital aperture on both sides, and right optic nerve length. Furthermore, certain statistically significant side differences were also found. There were statistically significant correlations between age and the axial length of the eyeball, optic nerve diameter, and the transverse length of the orbital aperture on both sides for the whole study group.In this study we determined certain morphometric parameters of the orbit. These outcomes may be helpful in developing a database to determine normal orbit values for the Turkish population so that quantitative assessment of orbital disease and orbital deformities will be evaluated both for preoperative planning and for assessing postoperative outcomes.

Anatomical variations of foramen of the diaphragma sellae and neighboring structures: a cadaveric study.

The aim of our study was to examine the variations and types of foramen of diaphragma sellae (FDS) and their relationship with nearby surgical landmarks on cadavers.Twenty adult (9 male, 11 female) formalin-fixed cadaveric heads were bilaterally used to analyze the anatomical relationships around the supradiaphragmatic region of sella turcica. Lengths and distances of nearby surgical landmarks were measured by a digital microcaliper. SPSS version 25 was used to analyze the comparison between genders and body sides. Dorsum sellae distances to tuberculum sellae and the optic chiasm(OC) were higher in males than females (p < 0.05). Type 8 infundibulum passage was the most common variation with 50%. There was no finding related to types 1-4 of infundibulum passage. Thus, the present study has indicated that the infundibulum passes mostly from the posterior half of the foramen. The shape of the foramen was irregular in 45%, circular in 20%, sagittally oval in 20%, and horizontally oval in 15% of the cases. The OC was noted normal in 60%, prefixed in 35%, and postfixed in 5% of the cases. Comprehensive anatomical knowledge about the types of the FDS and their neighboring structures is crucial for preoperative planning of sellar region diseases in terms of navigating the region when accessing the foramen. Discrimination of variations of FDS, OC, and pituitary stalk, their relationships, and differences between genders is useful to minimize potential surgical complications.

Evaluation of the celiac trunk and its branching pattern by magnetic resonance angiography.

OBJECTIVE: The study aimed to examine the celiac trunk (CT) in detail by magnetic resonance angiography, to determine the locations, positions and variations of the CT, to provide detailed information for surgeons and interventional radiologists, and to reduce the time spent in the catheter angiography. MATERIAL AND METHODS: MR angiography images of 185 patients with abdominal imaging in PACS (Picture Archiving Communication Systems) were retrospectively analyzed. The level of origin of CT, according to the vertebral column, angle of origin, distance between CT and branches of the abdominal aorta (AA), and the branching pattern of CT were evaluated. Parameters were evaluated according to gender and age. RESULTS: The most common origin site for CT, according to the vertebral column, was found to be at T12-L1 in both genders. There was a low, positive correlation between age and CT-Sagittal angle (SA) in the whole study group (p<0.05). The most common CT branching pattern was the hepatogastrosplenic trunk in both genders, according to Adachi and Uflkacker's classification. The distance between CT and the inferior mesenteric artery (IMA) and CT and the aortic bifurcation (AB) of males was greater than in females, and the differences were statistically significant (p<0.05). CONCLUSION: Knowledge of the locations, positions, and variations of CT is essential in the diagnosis, differential diagnosis and decision-making mechanisms regarding the type of intervention to be performed for this vessel and related structures. In addition, the fact that data on these vessels can be obtained by MR angiography due to the improved image quality will prevent patients and physicians from the problems caused by the ionizing radiation of computed tomography. The data presented will constitute a basis for detailed and individualized interpretation and evaluation of each patient, as they provide important details about the configuration of the CT concerning gender and age using MRA.

Reappraisal of the types of hypoglossal canal: endocranial approach.

This study aims to classify the endocranial variations inside the Hypoglossal Canal (HC) and evaluate the elements of the HC region in terms of sizes, diameters, and distances to the nearby surgical landmarks. The present study was done on 18 adult human fixed cadaver heads bilaterally. The internal opening of HC was examined for the presence of dural or osseos septations in the canal and was classified into five types (Type 1-5). The dimensions of hypoglossal nerve (CN XII) and the distance of intracranial openings of HC from the jugular foramen and jugular tubercle were measured. The prevalence of endocranial HC types were determined on both sides as follows: type 1 (23.53% left, 6.25% right), type 2 (37.5% right, 5.88% left), type 3 (52.94% left, 25% right), type 4 (18.75% right, 17.65% left), type 5 (12.5% right). Understanding the endocranial HC types is crucial for neurosurgeons in the differential diagnosis of various intracranial pathologies for the posterior cranial fossa approach. Knowing the anatomical relationships between the adjacent structures and symmetrical organization of the HC according to the types is crucial in determining surgical strategies and preserving adjacent structures.

Evaluation of hand asymmetry in relation to hand preference.

We evaluated the asymmetric hand measurements in right- and left-handed individuals. 343 men and 290 women aged 18-42 years (22.11 +/- 2.07) participated in the study. There were no statistically significant differences when right-left differences in hand length, third finger length, palmar length, and the digit index value were evaluated according to hand preference and sex. Statistically significant differences were found for right-left differences in hand width, hand-shape index, and the palmar length/width according to hand preference. The strong left-handers, weak left-handers, and ambidextrous individuals in the study group all exhibited asymmetry favoring the left and were considered together. Similarly, the strong and weak right-handers exhibited asymmetry favoring the right hand and were considered together. The difference between these two groups was significant. When the data were evaluated according to sex, significant differences were found between the subgroups. In particular, right-left differences in the hand-shape index and palmar length/width values of the strong left-handers, weak left-handers, and ambidextrous individuals were found to be statistically significant according to sex; in contrast, the strong and weak right-handers showed no significant differences according to sex. These results suggest a relation of hand asymmetry to hand preference in a Turkish population.

Radical vulvectomy with right gluteal and left medial thigh V-Y advancement flap reconstruction

Vulvar cancer is rare. The vulva constitutes the external female genitalia and it is associated with the perineum with the intersection of urinary, sexual and anal systems. The deep anatomy of the perineum in the urogenital and anogenital triangle should be well-known to gynecological oncologists. Radical vulvectomy is the surgical treatment of choice in gross tumors expanding over the vulvar skin. After this type of excision, reconstruction is critically important because it is not always feasible to suture the vulvar defect in a primary manner. Thus, the reconstruction options should also be known to gynecological oncologists. Here, we present a video of radical vulvar cancer surgery, which was performed on a cadaver with gluteal and medial thigh V-Y advancement flap reconstruction.

The thickness of the ligamentum flavum in relation to age and gender.

Hypertrophy of the ligamentum flavum (LF) can reduce the diameter of the spinal canal posteriorly. Such stenosis may significantly compress the dural sac and nerve roots, resulting in symptoms, even without a bulging anulus fibrosus or herniated nucleus pulposus. We conducted an anatomical study to determine the influence of age and gender on the thickness of the LF at the lower lumbar levels using magnetic resonance imaging (MRI). The thickness of 1,280 ligaments was determined at the L4-L5 and L5-S1 levels from MRIs. We screened 320 patients (152 males [47.5%] and 168 females [52.5%]) between 21 and 82 years of age. There were no significant differences in LF thickness with respect to gender (P > 0.05). Age was not correlated with the thicknesses of the LF. The left LF at the L4-L5 and L5-S1 levels was significantly thicker than on the right side (P < 0.05). Furthermore, the LF thicknesses at L5-S1 bilaterally were significantly greater than on the corresponding sides at L4-L5 (P < 0.05). The LF is an important anatomical structure, which might cause low back or leg pain. Therefore, the thickness of the LF should be measured and evaluated carefully in the case of spinal stenosis.

Intraforaminal Dural Septations of the Jugular Foramen: A Cadaveric Study.

OBJECTIVE: The aim of this study was to define the types, prevalences, and diameters of dural septations (DSs) on the inner surface of the jugular foramen (JF) and to describe the distances between the JF, the glossopharyngeal nerve (cranial nerve [CN] IX), vagus nerve (CN X), and accessory nerve (CN XI), the internal acoustic meatus, and nearby surgical landmarks on cadaveric heads. METHODS: Seventeen adult (9 men and 8 women) formalin-fixed cadaveric heads were used to analyze the types and prevalence of DS bilaterally. Diameters and distances between the DS and the adjacent CNs (CN IX-XI) were measured by digital microcaliper. The multiple t test (SPSS version 25) was used to analyze the comparison between both sides via diameters, numbers, distance, length, and thickness of DS. RESULTS: The most frequent type of DS was type I (62.5%, right; 56.3%, left), followed by type II (18.8%, right; 25%, left), type III (12.5%, right; 6.3%, left), and type IV (6.3%, right; 12.5%, left). The mean diameter of the septum was 0.6-1 mm, and the mean length of the dural septa was 4.01 mm (right) and (3.83 mm) left. The difference in the length and thickness of the DS between the genders was statistically significant on both sides (P < 0.05). The DS-CN X and DS-JF distances of women were greater than those of men on the right side (P < 0.05). CONCLUSIONS: The significant differences between dural septum types on the 2 sides of the body may indicate asymmetric location or a variant emerging site of CNs in the same individual.

Influence of age and sex on lumbar vertebral morphometry determined using sagittal magnetic resonance imaging.

We evaluated age-related changes in the morphometric features of lumbar vertebrae in both sexes using magnetic resonance imaging (MRI). Midsagittal MRI scans of 366 individuals (156 males, 210 females; 25-82 years old) were evaluated retrospectively. The anterior height (H(a)), central height (H(c)), posterior height (H(p)), and anteroposterior diameter (D) of the body of each lumbar vertebra were measured. These measurements were used to calculate three indices, namely, the anterior wedge index (H(a)/H(p)), the biconcavity index (H(c)/H(p)), and the compression index (H(p)/D). The values of each of the three indices for the upper lumbar vertebrae of females were higher than those of the same vertebrae in males. The values of the compression index for all lumbar vertebrae decreased with age in females, whereas in males the compression index of the L1-L4 vertebrae decreased with age. No significant changes were observed in the value of the anterior wedge index in either sex. The biconcavity indices of the L1 and L5 vertebrae decreased with age in males. These results may be useful for evaluating age-related morphological changes that occur in the lumbar vertebrae.

Association of height and weight with second to fourth digit ratio (2D:4D) and sex differences.

Sex difference in 2D:46 digit ratio was studied in 386 right-handed students. The lengths of index (2D) and ring (4D) fingers were measured using a caliper. Height and weight of participants were recorded. Body height correlated negatively with right- and left-hand digit ratios in the total sample (N = 386); correlations were significant for the left-hand digit ratio of men and for the right-hand digit ratio of women (no significant correlations with weight). Males had a significantly lower 2D:4D ratio than females. After controlling for height, sex differences in right- and left-hand digit ratios completely disappeared. The results suggest that height of adults reflecting prenatal hormone status may play a role in differences between men and women in 2D:4D digit ratio for right-handers.

Assessment of the atlanto-occipital junction in the MRI of subjects with cervical disc herniation.

OBJECTIVE: To demonstrate the normal limits of Powers ratio and basion dens interval in patients with disc herniations. METHODS: The MRI of patients were retrospectively evaluated by 2 radiologists. Four hundred and forty-five patients who were admitted to Duzce University Hospital with neck pain without history of trauma were chosen between January 2004 and July 2006 in this retrospective study. The patients were between the ages of 14-80 years. RESULTS: Four groups were identified according to the number of disc herniations. The normal limits of Powers ratio and basion dens interval were 0.77+/-0.15 and 0.80+/-0.66 in group 0, 0.76+/-0.14 and 0.81+/-0.76 in group one, 0.75+/-0.13 and 0.80+/-0.71 in group 2, 0.76+/-0.14 and 0.81+/-0.74 in group 3, and 0.77+/-0.16 and 0.81+/-0.66 in group 4. The relationship between the number of disc herniations and Powers ratio and basion dens interval was not statistically significant. CONCLUSION: Our results were in concordance with the previous studies concerning the Powers ratio and basion dens interval. These 2 methods can be used in the MRI of atlantooccipital dislocation suspected patients with disc herniations.

Sagittal alignment of the lumbar spine in a Turkish population.

OBJECTIVE: To understand the normal lumbar spine in the sagittal plane, and the range of lumbar lordosis. METHODS: This study was carried out in the Department of Anatomy, School of Medicine, Duzce University, Duzce, Turkey in the year 2005. We retrospectively reviewed T1-weighed sagittal spin-echo MRIs of the lumbar spine in 413 individuals (188 male, 225 female) aged between 13-82 years, and evaluated the angle of lumbar lordosis (ALL), sacrohorizontal angle (SHA), and lumbosacral angle (LSA). RESULTS: The ALL and SHA were significantly greater in females than in males (p<0.05). Weak, but significant correlations were detected between age and ALL, SHA, and LSA for females (p<0.05). The LSA was significantly greater for individuals over 41 years (p<0.05) when the entire study group was considered, and it was also significantly greater for individuals over 51 years in females (p<0.05). The LSA was significantly greater in the 7th decade than in the 3rd decade (p<0.05). CONCLUSION: The results of this study provide insight into the sagittal alignment of the lumbar region for a Turkish population, and can serve as a reference for further clinical studies to improve the planning of spinal surgery.

Evaluation of muscle activities during locking-unlocking movements.

OBJECTIVE: To investigate muscle activities during locking-unlocking movements. METHODS: Thirty right-handed healthy volunteers, aged between 18-23 years, without any orthopedic or neurological disorders participated in the study. We choose the clavicular part of the deltoid muscle, biceps brachii, pronator teres, extensor digitorum, pronator quadratus, first dorsal interosseous muscles and muscles of the thenar eminence for the study. We adjusted the height of the lock at 80 cm, 100 cm and 120 cm from the ground surface. We recorded the activities of the chosen muscles electromyographically using surface electrodes. We obtained the electromyography recordings between September 2000-January 2001 in the Electrophysiology Laboratory of Gazi University School of Medicine, Department of Physical Medicine and Rehabilitation. RESULTS: There was a statistically significant increase in area (mVms) and amplitude (uV) values obtained from the EMG recordings of the clavicular part of the deltoid muscle and biceps brachii during locking and unlocking movements as the height of the lock increased (p<0.05). There was no statistically significant difference in the activities of the other muscles chosen for the study during locking and unlocking movements with the increase in height of the lock (p>0.05). When we considered the total activity recorded from the muscles chosen for this study, there was a statistically significant difference in the area values with the increase in height of the lock during locking and unlocking movements (p<0.05). This means that the activity recorded from the entire upper limb increased with the increase of the height. CONCLUSION: The recorded muscle activity obtained with the lock at 80 cm from the ground surface was lower compared with the activities recorded at 100 cm and 120 cm. For this reason, we suggest that it could be better to locate the lock at 80 cm from the ground surface.