36 research outputs found
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