An unusual muscle of the wrist with potential compression of the ulnar nerve

During routine cadaveric dissection of the upper extremity an unusual muscle was discovered arising from the tendon of the flexor carpi ulnaris and inserting into the muscle belly of the flexor digiti minimi. The muscle’s course was superficial to the ulnar nerve and artery in Guyon’s canal. We review the literature regarding such muscle variations and discuss the potential for compression of the ulnar nerve by such muscles

An unusual muscular variation of the infratemporal fossa

The infratemporal fossa is often the site of pathology or surgical intervention. We describe an unusual muscle found during the routine dissection of the right infratemporal fossa. The literature germane to this variable muscle, best described as a variant of the pterygoideus proprius, is reviewed. The clinician may contemplate the wide array of muscular anomalies within the infratemporal fossa when considering unexplained neurological symptoms attributed to branches of V3 and pursue appropriate diagnostic testing

Bilateral accessory middle cerebral arteries associated with an aneurysm of the anterior circulation

An accessory middle cerebral artery is one variation of the intracranial vasculature that may be a source of misinterpretation by clinicians dealing with cerebrovascular diseases. We report a case of an elderly female found to have bilateral accessory middle cerebral arteries, who presented with the rupture of an aneurysm of the anterior part of the circle of Willis. Accessory middle cerebral arteries are rare anatomical findings and the bilateral occurrence is exceedingly rare. We believe this to be the first report of bilateral accessory middle cerebral arteries associated with an aneurysm of the anterior cerebral-anterior communicating arteries. The anatomical and clinical relevance of this variation is described

The morphology and function of the quadrate ligament

There is a paucity of information in the literature regarding the quadrate ligament and the information that does exist is extremely conflicting. We dissected 30 cadavers (60 sides) to determine the morphology and function of this enigmatic ligament. A quadrate ligament (thickening of the elbow joint capsule) was found in all specimens. In all specimens this band was distinct from the circumferential fibres of the annular ligament. The length, width, and thickness of the quadrate ligament were found to be 11 mm, 8 mm, and 1 mm respectively. This ligament not only aided in securing the neck of the radius to the ulna but also resisted excessive supination and, to a lesser degree, pronation of the forearm. Following transection of the quadrate ligament, the head of the radius was secured to the ulna considerably less firmly and supination and pronation increased by 10 to 20 degrees and 5 to 8 degrees respectively. The quadrate ligament contributes to proximal radioulnar stability, limits the "spin" of this joint, and should be considered in manipulation, surgery, or imaging of the proximal forearm

Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release