Variations of the radial recurrent artery of clinical interest

Predicting the macrovascular contribution to resting-state fMRI functional connectivity at 3 Tesla: A model-informed approach

Macrovascular biases have been a long-standing challenge for fMRI, limiting its ability to detect spatially specific neural activity. Recent experimental studies, including our own (Huck et al., 2023; Zhong et al., 2023), found substantial resting-state macrovascular BOLD fMRI contributions from large veins and arteries, extending into the perivascular tissue at 3 T and 7 T. The objective of this study is to demonstrate the feasibility of predicting, using a biophysical model, the experimental resting-state BOLD fluctuation amplitude (RSFA) and associated functional connectivity (FC) values at 3 Tesla. We investigated the feasibility of both 2D and 3D infinite-cylinder models as well as macrovascular anatomical networks (mVANs) derived from angiograms. Our results demonstrate that: 1) with the availability of mVANs, it is feasible to model macrovascular BOLD FC using both the mVAN-based model and 3D infinite-cylinder models, though the former performed better; 2) biophysical modelling can accurately predict the BOLD pairwise correlation near to large veins (with R 2 ranging from 0.53 to 0.93 across different subjects), but not near to large arteries; 3) compared with FC, biophysical modelling provided less accurate predictions for RSFA; 4) modelling of perivascular BOLD connectivity was feasible at close distances from veins (with R 2 ranging from 0.08 to 0.57), but not arteries, with performance deteriorating with increasing distance. While our current study demonstrates the feasibility of simulating macrovascular BOLD in the resting state, our methodology may also apply to understanding task-based BOLD. Furthermore, these results suggest the possibility of correcting for macrovascular bias in resting-state fMRI and other types of fMRI using biophysical modelling based on vascular anatomy.

Hypoplastic superficial brachioradial artery coexisting with atypical formation of the median and musculocutaneous nerves: a rare combination of unusual topographical relationships

The use of the term "brachioradial artery" was introduced for the high origin of the radial artery. Although the prevalence of the brachioradial artery reported by different authors varies from 4.67 to 15.6%, the presence of the hypoplastic brachial segment of the brachioradial artery is rare with an occurrence rate of 0.83%. Moreover, in just 0.6% of cases the loop of the median nerve may be placed near half of the length of the brachial artery, as in the case described in our report. A comprehensive understanding of anatomical variations of neurovascular structures in the upper limb is of great clinical significance. The presented case report illustrates a rare manifestation of persistent primitive developmental relationships in the arterial pattern of the upper limb (persistent, hypoplastic brachial segment of the superficial brachioradial artery), coexisting with atypical formation of the median and musculocutaneous nerves. Anatomical variations of vessels and nerves may coexist which should be taken into account when performing vascular, reconstructive or orthopedic surgery.

The High Origin of the Radial Artery (Brachioradial Artery): Its Anatomical Variations, Clinical Significance, and Contribution to the Blood Supply of the Hand

Background

This study thoroughly analyzes the anatomic variations of the brachioradial artery (radial artery of high origin) based on the variability of its origin, the presence and types of anastomosis with the brachial artery in the cubital fossa (“cubital crossover” or “cubital connection”), and the pattern of radial recurrent arteries, as well as the vascular territory within the hand.

Material and Methods

One hundred and twenty randomly selected, isolated upper limbs fixed in 10% formalin solution were dissected.

Results

The radial artery was found to have a high origin in 9.2% of total number of the limbs: two cases from the axillary artery; nine cases from the brachial artery. Anastomosis between the brachioradial and “normal” brachial arteries in the cubital fossa was also frequently observed (54.6%). The anastomosis (“cubital crossover”) was dominant in one case, balanced in three cases, minimal in two cases, and absent in five cases.

Conclusions

The brachioradial artery may originate from the brachial and, less frequently, from the axillary artery. Anastomosis between the brachioradial and “normal” brachial arteries in the cubital fossa may be dominant, balanced, minimal, or absent. A complete radioulnar arch was found more often when the brachioradial artery was present as a variant.

Focal brachial enhancement deficit: a normal anatomic variant?

OBJECTIVE

To identify the incidence of brachialis enhancement deficits (BEDs) on contrast-enhanced elbow MRIs and determine if there is an association between the presence of BEDs and presenting symptoms, other imaging findings, or patient positioning.

MATERIALS AND METHODS

Elbow MRIs from 138 patients (64 males, mean age 45.3 years) were reviewed. The presence, size, and degree of enhancement of BEDs as well as degree of elbow flexion, relative degree of forearm rotation, and additional finding of pathology on the MRI were recorded.

RESULTS

BEDs were found in 54 % (75/138) of contrast-enhanced elbow MRIs. No statistically significant difference was seen between age, gender, presenting symptoms and the presence of BEDs. The BEDs varied considerably in size and degree of diminished enhancement compared to adjacent muscle. There was a very significant correlation between degree of elbow flexion and presence of BEDs (p < 0.0001) and a significant inverse correlation between cross-sectional size of BEDs and degree of flexion (p < 0.01). There was no significant correlation between BED enhancement difference and degree of flexion and no significant correlation between degree of forearm rotation and cross-sectional area or enhancement difference of the BEDs. No correlation was found between the presence of BEDs and other pathology present on the MRI.

CONCLUSION

BEDs are a common, likely asymptomatic phenomenon seen on post contrast elbow MRIs. The etiology of BEDs is uncertain, but they may represent a vascular phenomenon related to elbow flexion causing diminished enhancement related to brachialis compression.

Low origin of the radial artery: a case study including a review of literature and proposal of an embryological explanation

A low origin of the radial artery is a rare anatomical variation, with the incidence estimated at 0.2 %. This report presents a previously unrecorded case of an unusual distal origin of the radial artery, co-occurring with a double recurrent radial artery. The radial artery arose under the pronator teres muscle, 76 mm below the intercondylar line of the humerus. After emerging from under the tendon of the pronator teres muscle, the radial artery took a typical course and terminated in the deep palmar arch. Additionally, the double radial recurrent artery branched directly off the brachial artery, near the level of the radial neck. A well-developed muscular branch of the first radial recurrent artery ran beneath the brachioradialis muscle and supplied the brachioradialis, extensor carpi radialis longus and brevis, as well as supinator muscles. The second (accessory) radial recurrent artery took origin from the posterior aspect of the brachial artery, ran deep to the distal tendon of the biceps brachii muscle and terminated by joining the articular network of elbow. According to recent theories, the plexiform appearance of the arteries at early stages of upper limb development allows for formation of alternative pathways of blood flow, which may give rise to variations in the definitive arterial pattern.

Vascular anatomy relevant to distal biceps tendon repair

BACKGROUND

Avoiding bleeding and vascular complications in open repair of distal biceps tendon rupture requires knowledge of the local vascular anatomy. This study examined the vascular anatomy relevant to distal biceps tendon repair.

METHODS

The antecubital regions of 17 cadaveric upper extremities were dissected using ×2.5 loupe magnification to identify the brachial artery, the radial artery and its recurrent branches, and venous branches crossing the distal biceps tendon. With the elbow in full extension and supination, the position of each vascular structure was measured relative to the most proximal aspect of the bicipital tuberosity.

RESULTS

The most common pattern (13 of 17 specimens) was a single radial recurrent artery (RRA) crossing volar to the tendon at a mean of 4 mm proximal to the tuberosity and positioned 15.4 mm volar to the tuberosity. The RRA bifurcated 2 to 9 mm from its origin in 6 arms and demonstrated a single bifurcation. In 8 of 17 specimens, an additional recurrent branch off the brachial artery traveled dorsal to the intact biceps tendon 16 mm proximal to the RRA. Two arms demonstrated a high brachial artery bifurcation. The crossing veins were venae comitantes of the RRAs and radial and ulnar arteries. They connected to the superficial veins by way of a perforating branch. Most often, 3 transverse veins positioned on average 0.2 mm proximal and 16 mm volar to the tuberosity were seen.

CONCLUSIONS

The vascular anatomy encountered during distal biceps repair is variable, and RRAs occasionally travel dorsal to the biceps tendon. Most often, a single RRA on average 4 mm proximal to the tuberosity will branch once.

Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog: Part One

Traditional veterinary anatomical models describe the branches of the caudal gluteal artery as the iliolumbar, cranial gluteal, lateral caudal, satellite of the ischiatic nerve and dorsal perineal arteries. However, some classical veterinary anatomy textbooks often indicate variations the general organization of the arterial tree, without giving any pattern of origin or illustrations of the different branching. The aim of this study was to investigate the presumptive variability of the caudal gluteal artery. Two hundred and thirty-two pelvic halves from 116 adult dogs were examined. Twelve anatomical variations were found, nine occurring in more than 5% of the dogs, and three in <5%. A 'long-type' internal iliac artery, which means short caudal gluteal and internal pudendal arteries, was identified, while a 'perineal trunk' was observed as an interesting arterial variation. If the caudal segment alone is taken into consideration, identical vascular patterns in both hemi-pelvises are found in 17% of the dogs. Significant statistical correlation was found for four different types of anatomic variations and gender, two types of variations and body size, one type of variation for body side and one type of variation for head shape.