Anatomic description of the distal great saphenous vein to facilitate peripheral venous access during resuscitation: a cadaveric study.

The distal great saphenous vein is a popular site for venous access by means of percutaneous cannulation or venous cutdown in a hemodynamically unstable patient. The aim of this study was to precisely define the surface anatomy and dimensions of the distal part of the great saphenous vein to facilitate the aforementioned procedures. Cross-sectional anatomy of the distal saphenous vein was studied in 24 cadaveric ankles sectioned at a horizontal plane across the most prominent points of the medial and lateral malleoli. The curvilinear distance from the most prominent point of the medial malleolus to the center of the saphenous vein, its widest collapsed diameter and skin depth were obtained. The great saphenous vein was located at a mean distance of 24.4 ± 7.9 mm anterior to the medial malleolus. The mean widest collapsed diameter was 3.8 ± 1.5 mm. The mean distance from the skin surface to the vein was 4.1 ± 1.2 mm. These measurements could be used to locate the saphenous vein accurately, particularly in hemodynamically unstable patients with visually indiscernible veins.

Morphology of ejaculatory ducts: A systematic review.

The morphology of human ejaculatory ducts has not been well established. The objective of this study was to describe macroscopic and microscopic anatomy of ejaculatory ducts. We conducted a systematic review using MEDLINE, Scopus, PubMed, and Cochrane databases. Search terms were: "ejaculatory ducts," "seminal colliculus," "prostatic utricle," "anatomy," "histology," "radiology," and "embryology." We only included studies assessing adult (>18 years) humans published before November 1, 2019. We excluded studies describing pathological ducts and case reports. Independent authors extracted data using predefined criteria. Fourteen studies were included in the qualitative synthesis. Usually, the ejaculatory ducts entered the prostate by piercing the central part of its base. Most studies identified an anteromedial curve of the ducts at the outset within the prostate, their subsequent course being a straight path towards the seminal colliculus, their terminal parts diverging immediately before joining the prostatic urethra. However, the morphology of the terminal part of the ducts was inconsistent. The mean length of the ducts ranged from 1.4 to 2.2 cm. In conclusion, the luminal diameter gradually decreased as the ducts traveled towards the seminal colliculus. Ejaculatory ducts angulate anteromedially at their onset within the prostate and travel straight towards the seminal colliculus. Their terminal parts diverge immediately before joining the prostatic urethra. However, the reported dimensions of the ducts differ among studies.

Pigmented border as a new surface landmark for digital nerve blocks: a cross sectional anatomical study.

The purpose of this study was to identify surface anatomy of digital nerves in relation to the pigmented border of digits. Three-hundred and sixty digital nerves in 36 preserved adult cadaveric hands were dissected under magnification. The digital nerves were constantly located anterior to the pigmented border. The median curvilinear distance along the skin from the pigmented border to the digital nerves of the index, middle, ring and little fingers was 1.4 mm. In the thumb, this distance was 2.4 and 3.7 mm on the radial and ulnar sides, respectively. The digital nerve was located 2.4 mm deep to the skin in all fingers. The median angle to the nerve from the skin at the pigmented border was 30°. These dimensions differed in the thumb compared with the rest of the fingers. We conclude that the pigmented border of digits is a reliable anatomical landmark to locate digital nerves.

Anatomical landmarks for safer carpal tunnel decompression: an experimental cadaveric study.

BACKGROUND: Carpal tunnel syndrome is a common presentation to surgical outpatient clinics. Treatment of carpal tunnel syndrome involves surgical division of the flexor retinaculum. Palmar and recurrent branches of the median nerve as well as the superficial palmar arch are at risk of damage. METHODOLOGY: Thirteen cadavers of Sri Lankan nationality were selected. Cadavers with deformed or damaged hands were excluded. All selected cadavers were preserved with the conventional arterial method using formalin as the main preservative. Both hands of the cadavers were placed in the anatomical position and dissected carefully. We took pre- determined measurements using a vernier caliper. We hypothesized that the structures at risk during carpal tunnel decompression such as recurrent branch of the median nerve and superficial palmar arch can be protected if simple anatomical landmarks are identified. We also hypothesized that an avascular area exists in the flexor retinaculum, identification of which facilitates safe dissection with minimal intra operative bleeding. Therefore we attempted to characterize the anatomical extent of such an avascular area as well as anatomical landmarks for a safer carpal tunnel decompression.Ethical clearance was obtained for the study. RESULTS: In a majority of specimens the recurrent branch was a single trunk (n =20, 76.9%). Similarly 84.6% (n = 22) were extra ligamentous in location. Mean distance from the distal border of the TCL to the recurrent branch was 7.75 mm. Mean distance from the distal border of TCL to the superficial palmar arch was 11.48 mm. Mean length of the flexor retinaculum, as measured along the incision, was 27.00 mm. Mean proximal and distal width of the avascular area on TCL was 11.10 mm and 7.09 mm respectively. CONCLUSION: We recommend incision along the radial border of the extended ring finger for carpal tunnel decompression. Extending the incision more than 8.16 mm proximally and 7.75 mm distally from the corresponding borders of the TCL should be avoided. Incision should be kept to a mean length of 27.0 mm, which corresponds to the length of TCL along the above axis. We also propose an avascular area along the TCL, identification of which minimizes blood loss.

Anatomical relations of the superficial sensory branches of the radial nerve: a cadaveric study with clinical implications.

BACKGROUND: Anatomically, it is difficult to give a systematic description of the superficial branch of the radial nerve (SBRN). Our aim was to describe the exact relationship of the SBRN to fixed bony points of radial styloid and Lister's tubercle, and to the cephalic vein. We also compared our data with other international studies. METHODS: The study was a descriptive anatomical study. Twenty-five forearms were dissected. Measurements were made from predefined fixed reference points. RESULTS: The mean distance to the point of emergence of the nerve from the radial styloid was 8.54 cm (SD = 1.32). The nerve branched at a mean distance of 5.57 cm (SD = 1.43) from the radial styloid. The mean distance to the point where the most medial and most lateral branches of the nerve crossing the wrist joint, measured from the Lister's tubercle were 2.51 cm (SD = 0.53) and 3.90 cm (SD = 0.64). In 17 specimens(68%) cephalic vein crossed the SBRN superficially once. Mean distance from the radial styloid to the most distal point where the vein crossed the nerve was 5.10 cm. Diffefrence between mean distance to the point of emergence and branching point, when compared with other international studies were not statistically significant. (P value > 0.05) CONCLUSIONS: We recommend avoiding transverse incisions in the snuffbox region between 2.51 cm and 3.90 cm from the Listers tubercle. We also recommend avoiding cannulation of the cephalic vein in the distal forearm.