Cadaveric study of division of the median nerve by the persistent median artery.

PURPOSE: The purpose of this study is to characterize the division of the median nerve by the persistent median artery (PMA) and highlight the associated clinical implications. Penetration of the median nerve by the PMA is believed to cause compression of the median nerve and affect nerve conduction velocity. This paper explored whether the origin and the pattern of PMA dictate its ability to divide the median nerve. METHODS: Origin, and relationship of the PMA to the median nerve were documented in 60 cadavers donated to the Human Anatomy Program at UT Health San Antonio. Entire path of this artery was followed in the forearm and the hand. RESULTS: Twenty-five cases of a persistent median artery (PMA) were found in the upper limbs (20.83%; 25/120) of these donated cadavers. Most of the persistent median arteries originated from the ulnar artery (48%; 12/25) and the others originated either from the anterior interosseous artery (36%; 9/25) or from the common interosseous artery (16%; 4/25). Sixty percent (15/25) of the persistent median arteries penetrated and divided the median nerve in the forearm. Interestingly, all the persistent median arteries that originated from the ulnar artery (100%; 12/12) divided the median nerve in the forearm and a palmar type of PMA was found to be more likely to divide the median nerve. CONCLUSION: Clinicians performing surgeries in the forearm and hand need to be aware of this anomaly and should screen patients for the presence of this artery prior to surgical intervention.

The relative locations of the supraorbital, infraorbital, and mental foramina: A cadaveric study.

The purpose of this study is to investigate the applicability of the current surgical guideline stating that the main facial foramina that transmit cutaneous nerves to the face (supraorbital notch/foramen, infraorbital foramen, and mental foramen) are equidistant from the midline in European and Hispanic populations. Previous studies suggest this surgical guideline is not applicable for all ethnicities; however, to our knowledge, no data have been published regarding the accuracy of this guideline pertaining to the Hispanic population. An experimental study was performed on 67 cadavers donated to the Human Anatomy Program at UT Health San Antonio. The supraorbital, infraorbital, and mental foramina were dissected and midline structures including the crista galli, internasal suture, anterior nasal spine, and mandibular symphysis were identified. The distance from each foramen to midline was recorded using a digital caliper. For all cadavers/ethnicities studied, the supraorbital, infraorbital, and mental foramina were 25.32 mm, 29.57 mm, and 25.55 mm to the midline, respectively. Thus, the infraorbital foramen is located significantly more lateral compared to the supraorbital (p < 0.0001) and mental foramina (p < 0.0001). After dividing the sample based on ethnicity, this relationship was also true for the European sample and tended to be true for the Hispanic sample. Significant anatomical variations exist in the current surgical guideline stating that the supraorbital foramen, infraorbital foramen, and mental foramen are equidistant from the midline. Clinicians may need to adjust their methodology during surgical procedures of the face in order to optimize patient care.

A cadaveric study investigating the anatomy of the medial orbital wall.

The purpose of this study is to investigate the applicability of the current surgical guideline, known as '24-12-6' surgical guideline, in the Hispanic and European populations. This guideline is used during numerous orbital surgeries and states that the distance between the anterior lacrimal crest (ALC) to the anterior ethmoidal foramen (AEF) (24 mm), the AEF to the posterior ethmoidal foramen (PEF) (12 mm), and the PEF to the optic canal (OC) (6 mm) follows a Rule of Halves. Previous studies suggest this surgical guideline is not applicable for all ethnicities; however, to our knowledge, no data has been published regarding the accuracy of this guideline pertaining to the Hispanic population. An experimental study was performed on 79 orbits (52 cadavers) donated to the Human Anatomy Program at UT Health San Antonio. The ALC, AEF, posterior ethmoidal foramen, and OC were identified; the orbit was enucleated and all remaining soft tissue removed. The distance between each landmark was recorded using a digital caliper. For all cadavers studied, the distances between the ALC, AEF, posterior ethmoidal foramen, and OC were 24.76 mm, 13.89 mm, and 7.61 mm, respectively. Thus, the '24-12-6' surgical guideline was not applicable to the sample studied. Based on ethnicity data, these relationships were also not true for the European or the Hispanic populations. Therefore, significant anatomical variations exist in the current surgical guideline. Clinicians may need to adjust their methodology during surgical procedures in order to optimize patient care.

Innervation of the Posterior Hip Capsule: A Cadaveric Study.

OBJECTIVE: Recent studies of hip anatomy have turned to the posterior hip capsule to better understand the anatomic location of the posterior capsular sensory branches and identify nerves with potential for neural blockade. Current literature has shown the posterior hip capsule is primarily supplied by branches from the sciatic nerve, nerve to quadratus femoris, and superior gluteal nerve (1, 2). This cadaveric study investigated the gross anatomy of the posterior hip, while also identifying potential targets for hip analgesia, with emphasis on the superior gluteal nerve and nerve to quadratus femoris. DESIGN: Cadaveric study. SETTING: UT Health San Antonio Anatomy Lab. METHODS: In total, 10 total cadavers (18 hips total), were posteriorly dissected identifying nerve to quadratus femoris, superior gluteal nerve, and sciatic nerve. Nerves were labeled with radio-opaque markers. Following the dissections, fluoroscopic images were obtained at sequential angles to identify neural anatomy and help expand anatomic knowledge for interventional pain procedures. RESULTS: The posterior hip capsule was supplied by the sciatic nerve in 1/16 hips, the nerve to quadratus femoris in 15/18 hips, and the superior gluteal nerve in 6/18 hips. CONCLUSIONS: The nerve to quadratus femoris reliably innervates the posterior hip joint. Both the sciatic nerve and superior gluteal nerve have small articular branches that may be involved in posterior hip innervation, but this is not seen commonly. The results of this study may elucidate novel therapeutic targets for treatment of chronic refractory hip pain (i.e., the nerve to quadratus femoris).

Collateral circulation of the femoral and genicular systems in human lower limbs is highly uncommon.

The descending branch of the lateral circumflex artery is a septocutaneous vessel that is vital for free and pedicle thigh flap transfer surgeries when repairing tissue defects. It also forms an anastomosis with the superior lateral genicular artery to create a collateral pathway for circumventing occlusions in the superficial femoral artery (SFA). Many anatomical texts and atlases imply the persistence of this anastomosis. However, previous studies indicate variability in the source of the arteries that form the anastomosis, and have reported cases where an anastomosis does not exist. We hypothesized that variations from the conventional accepted pattern can be predicted by comparisons of arterial diameters, and that unconventional anastomoses may be present to facilitate collateral circulation to the limb. Fifty-one limbs were dissected and analyzed to establish the source of the descending branch of the lateral circumflex artery, classify the types of anastomoses, and compare the diameters of the descending branch of the lateral circumflex artery, the SFA and the profunda femoris artery to the common femoral artery (CFA). Vessel diameters were normalized to the diameter of the CFA to allow comparison of limbs from both sexes and to minimize the effects of cadaver size on correlating vessel size to the presence or absence of collateral circuits. We report that 62.7% of limbs (32/51) had typical branching patterns; however, only 27.4% of limbs (14/51) had any anastomosis to connect the proximal and distal regions of the thigh. Importantly, the SFA had a wider relative diameter in limbs without anastomoses than in limbs that had normal anastomoses, perhaps precluding the formation of a collateral pathway. Overall, collateral circulation of the lower limb was highly uncommon, in contrast to information inferred from anatomical texts. This study suggests the need for more thorough procedures for determining viable anastomoses prior to thigh flap surgeries to ensure flap survival.

Quantitative analysis of the distal, lateral, and posterior articular branches of the axillary nerve to the shoulder: implications for intervention.

INTRODUCTION: The terminal sensory branches innervating the shoulder joint are potential therapeutic targets for the treatment of shoulder pain. This cadaveric study investigated in detail the anatomic pathway of the posterior terminal sensory branch of the axillary nerve (AN) and its relationship to nearby anatomic structures for applications, such as nerve block or ablation of the shoulder joint. METHODS: For this study, nine shoulders were dissected. Following dissection, methylene blue was used to stain the pathway of the terminal sensory branches of the AN to provide a visual relationship to the nearby bony structures. A transparent grid was overlaid on the humeral head to provide further detailed information regarding the innervation to the shoulder joint. RESULTS: Eight of the nine shoulders displayed terminal sensory branches of the AN. The terminal sensory branches of the AN innervated the posterolateral head of the humerus and shoulder capsule and were deep and distal to the motor branches innervating the deltoid muscle and teres minor muscle. All terminal branches dissected innervated the shoulder capsule at the posteroinferior-lateral aspect of the greater tuberosity of the humerus. All specimens displayed innervation to the shoulder joint in the lateral most 25% and inferior most 37.5% before methylene blue staining. CONCLUSION: The terminal sensory branches of the AN consistently innervate the inferior and lateral aspects of the posterior humeral head and shoulder capsule. These nerves are easily accessible and would provide a practical target for nerve block or ablation to relieve shoulder pain without compromising motor integrity.

Incomplete superficial palmar arch and bilateral persistent median artery.

INTRODUCTION: The superficial palmar arch (SPA) is a major source of blood supply to much of the hand and is conventionally formed by the anastomosis of the ulnar artery with the superficial branch of the radial artery. The SPA has been classified into complete or incomplete based on the presence or absence of anastomosis between the arteries contributing to the formation of this palmar arch. CASE REPORT: Reported here is a unilateral presentation of incomplete superficial palmar arch. The ulnar artery (UA) gave off one proper palmar digital artery, which supplied the ulnar side of the little finger, and two common palmar digital arteries, which supplied the little, ring, and the middle finger. The superficial palmar branch of the radial artery gave off a proper palmar digital artery to the thumb, and two common palmar digital arteries, which supplied the thumb, index, and middle fingers. Apart from the presence of the incomplete SPA, persistent median arteries were also observed bilaterally in this cadaver. DISCUSSION: The prevalence of incomplete SPA has been reported to vary between 3.6-54.76%. To the best of our knowledge, this is the first case report describing an incomplete palmar arch and bilateral persistent median artery in a cadaver. CONCLUSION: Patients should be screened for the presence of complete or incomplete SPA before harvesting the radial artery either for myocardial revascularization or for radial artery forearm flap to prevent ischemic complications in the hand.

Radiofrequency-radiation exposure does not induce detectable leakage of albumin across the blood-brain barrier.

The blood-brain barrier (BBB) consists of tight junctions between the endothelial cells that line the capillaries in the central nervous system. This structure protects the brain, and neurological damage could occur if it is compromised. Several publications by researchers at Lund University have reported alterations in the BBB after exposure to low-power 915 MHz energy. These publications increased the level of concern regarding the safety of wireless communication devices such as mobile phones. We performed a confirmation study designed to determine whether the BBB is altered in rats exposed in a transverse electromagnetic (TEM) transmission line cell to 915 MHz energy at parameters similar to those in the Lund University studies. Unanesthetized rats were exposed for 30 min to either continuous-wave or modulated (16 or 217 Hz) 915 MHz energy at power levels resulting in whole-body specific absorption rates (SARs) of 0.0018-20 W/kg. Albumin immunohistochemistry was performed on perfused brain tissue sections to determine the integrity of the BBB. Chi-square analysis revealed no significant increase in albumin extravasation in any of the exposed animals compared to the sham-exposed or home cage control animals.