SciCombinator

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Concept: Suprascapular nerve

171

A unique anatomical variation of the suprascapular notch was discovered in one scapula from 610 analyzed by three-dimensional CT reconstruction. Two bony bridges were found, converting it into a double suprascapular foramen, in the left upper extremity of an 56-year-old Caucasian female. This variation might be a risk factor for suprascapular nerve entrapment. Suprascapular nerve running through inferior suprascapular foramen was discovered. Suprascapular vessels passed through superior suprascapular foramen (artery lay medially and vein laterally). A new hypothesis of double suprascapular foramen formation (mechanism of creation) is presented based on recent anatomical findings (e.g., the discovery in 2002 of the anterior coracoscapular ligament). Knowledge of the anatomical variations described in this study should be helpful in arthroscopic and open procedures at the suprascapular region and also confirms the safety of operative decompression for the suprascapular nerve.

Concepts: Blood vessel, Observation, Anatomy, Supraspinatus muscle, Suprascapular nerve, Suprascapular notch, The Double, Double variation

168

The suprascapular notch is the most common site of suprascapular nerve entrapment, which can manifest in disability and pain of the upper limb. Here, we present three cases of a very rare anatomical variation in the suprascapular region: the coexistence of the suprascapular notch and the suprascapular foramen. The variation was found during radiological and anatomical investigations. The suprascapular foramen was situated inferior to the suprascapular notch. A bony bridge lay between them, likely created by an ossified anterior coracoscapular ligament (ACSL). This anatomical variation probably increased the risk of suprascapular nerve entrapment by nerve irritation of the bony margins during passsage through the foramen and by a lack of the elasticity that the ACSL normally demonstrates. Also, a bony bridge passing through the middle part of the suprascapular notch reduces the space available for nerve passage (bony bridge decreases the space by about 36.5-38.6 %). One patient who underwent the radiological study had typical symptoms of suprascapular nerve entrapment. Based on his medical history and the presence of this rare variation of the suprascapular notch at the suprascapular region we suspect this neuropathy.

Concepts: Pain, Radiology, Anatomy, Upper limb, Limb, Supraspinatus muscle, Suprascapular nerve, Suprascapular notch

167

BACKGROUND: Better knowledge of the suprascapular notch anatomy may help to prevent and to assess more accurately suprascapular nerve entrapment syndrome. Our purposes were to verify the reliability of the existing data, to assess the differences between the two genders, to verify the correlation between the dimensions of the scapula and the suprascapular notch, and to investigate the relationship between the suprascapular notch and the postero-superior limit of the safe zone for the suprascapular nerve. METHODS: We examined 500 dried scapulae, measuring seven distances related to the scapular body and suprascapular notch; they were also catalogued according to gender, age and side. Suprascapular notch was classified in accordance with Rengachary’s method. For each class, we also took into consideration the width/depth ratio. Furthermore, Pearson’s correlation was calculated. RESULTS: The frequencies were: Type I 12.4%, Type II 19.8%, Type III 22.8%, Type IV 31.1%, Type V 10.2%, Type VI 3.6%. Width and depth did not demonstrate a statistical significant difference when analyzed according to gender and side; however, a significant difference was found between the depth means elaborated according to median age (73 y.o.). Correlation indexes were weak or not statistically significant. The differences among the postero-superior limits of the safe zone in the six types of notches was not statistically significant. CONCLUSIONS: Patient’s characteristics (gender, age and scapular dimensions) are not related to the characteristics of the suprascapular notch (dimensions and Type); our data suggest that the entrapment syndrome is more likely to be associated with a Type III notch because of its specific features.

Concepts: Statistics, Statistical significance, Type I and type II errors, Ronald Fisher, Statistical hypothesis testing, Pearson product-moment correlation coefficient, Suprascapular nerve, Suprascapular notch

28

Restoration of stability and movements at the shoulder joint are the 2 most important goals in the management of brachial plexus injuries. The 2 nerves that are preferentially targeted for this purpose are the suprascapular (SSN) and the axillary (AXN) nerves. These nerve transfers have conventionally been performed by the anterior approach, but recently transfers performed by posterior incisions have been gaining popularity, by virtue of being selective and located close to the target muscles. Herein, we describe the technical details of spinal accessory nerve (SAN) to SSN and triceps branch to AXN for upper plexus injuries, both performed by the posterior approach.

Concepts: Cranial nerves, Brachial plexus, Suprascapular nerve, Trapezius muscle, Axillary nerve, Radial nerve, Accessory nerve

28

Regional anesthesia has become the preferred method of anesthesia for many upper extremity operations and generally results in decreased hospital stays, postoperative opioid requirement, and postoperative nausea. Complications of regional anesthesia are rarely reported in the literature, possibly because of limited anesthesiologist-patient follow-up. Three cases of suprascapular nerve palsy after ultrasound-guided supraclavicular nerve block for routine outpatient upper extremity surgery are reported. All cases occurred in men who originally presented with shoulder pain, which resolved with time, followed by weakness in the supraspinatus and infraspinatus, which improved over time but did not resolve. One case resulted in ipsilateral phrenic nerve palsy as well. A review of the literature on the subject accompanies the report of these 3 cases.

Concepts: Anesthesia, Opioid, Vomiting, Shoulder, Supraspinatus muscle, Infraspinatus muscle, Suprascapular nerve, Nerves of the head and neck

27

The shape and size of the suprascapular notch (SSN) is one of the most important risk factors in suprascapular nerve entrapment. The aim of the study was to perform a morphological study of SSN variations.

Concepts: Suprascapular nerve, Suprascapular notch, Carl Czerny, Frédéric Chopin

27

BACKGROUND: The suprascapular region is the most common site of suprascapular nerve entrapment. The aim of the present study was to determine the morphologic variation of the superior transverse scapular ligament (STSL) and measure the reduction in size of the suprascapular opening. Other structures that might be potentially significant during open and arthroscopic procedures in this region are also described. MATERIALS AND METHODS: The study used 86 randomized formalin-fixed human cadaveric shoulders. After dissection of the suprascapular region, the following measurements were defined and collected for every STSL: length, proximal width, distal width, and thickness at the proximal and distal ends. Measurements were also taken of the area of the suprascapular opening (aSSO) and the middle width of the suprascapular opening (mwSSO). RESULTS: Three types of STSL may be distinguished: a fan-shaped type (54.6%), a band-shaped type (41.9%), and a bifid type (3.5%). Statistically significant differences between the specimens with fan-shaped and band-shaped types of STSL were observed in aSSO and mwSSO of the suprascapular opening. Anterior coracoscapular ligaments (ACSL) were present in 44 of 86 shoulders. The aSSO and mwSSO were smaller in specimens with an ACSL than in those without; however, this difference was only significant in the band-shaped type of STSL. CONCLUSION: Knowledge of the morphologic variations of STSL presented in this study is important for better understanding the possible anatomic conditions that can promote suprascapular nerve entrapment and should be taken into particular consideration during surgical and arthroscopic procedures around the suprascapular notch.

Concepts: Biology, Statistical significance, Anterior cruciate ligament, Anatomy, Supraspinatus muscle, Suprascapular nerve, Suprascapular notch, Superior transverse scapular ligament

27

The vascular anatomy at the spinoglenoid and suprascapular notches appears to be more variable than previously thought. In patients presenting with signs of suprascapular nerve compression, vascular causes must be considered. Especially when considering percutaneous or arthroscopic treatment, awareness of these entities may help to guide treatment decisions, aid in identification of the anatomy, and prevent unwanted vascular insult.

Concepts: Causality, Concepts in metaphysics, Supraspinatus muscle, Suprascapular nerve, Suprascapular notch

24

OBJECTIVE To describe the clinical features, diagnostic procedures, management, and outcome of horses with peripheral neuropathy of a forelimb. DESIGN Retrospective case series. ANIMALS 27 horses. PROCEDURES Records from 2000 to 2013 were reviewed to identify horses with peripheral neuropathy of a forelimb. Horses were grouped as having predominant lesions of a suprascapular nerve, axillary nerve, or radial nerve (alone or in association with other brachial plexus nerves) on the basis of physical examination and diagnostic imaging findings. Treatments were primarily conservative. Signalment, history, lameness characteristics, diagnostic imaging features, case management, and outcomes were evaluated. RESULTS Predominant lesions of a suprascapular nerve, axillary nerve, and radial nerve were identified in 11, 2, and 14 horses, respectively. Eight horses with predominant suprascapular nerve injury and 9 with injury to a radial nerve alone or in association with other nerves returned to their previous activity level or intended use after mean recovery periods of 9.3 and 13.3 months, respectively; 2 horses with a predominant axillary nerve injury had this outcome after a mean 3.5-month recovery period. Ultrasonography was useful for evaluation of muscle atrophy and other injuries during the initial examination (in 27 horses) and the rehabilitation period (in 7 horses). CONCLUSIONS AND CLINICAL RELEVANCE Most horses with peripheral neuropathy of a forelimb returned to athletic soundness following an adequate period of rest. Horses with lesions of a radial nerve alone or in association with other nerves typically required longer recovery times than did those with predominant injuries of a suprascapular nerve.

Concepts: Nervous system, Muscle, Brachial plexus, Suprascapular nerve, Axillary nerve, Radial nerve, Nerves of the upper limb, Posterior cord

23

Suprascapular nerve block (SSNB) is used in the management of frozen shoulder. There are no evidences from the literature that can determine how many blocks and the interval between them.

Concepts: Shoulder, Supraspinatus muscle, Suprascapular nerve, Suprascapular notch, Block, Blocking