Spinner, Robert J.

Background We describe a patient with tardy ulnar neuropathy and cubitus valgus deformity found to have an intracapsular ulnar nerve. Methods An 89-year-old woman presented with severe neuropathic pain in the ulnar digits of the hand, advanced degenerative arthritis of the elbow, and tardy ulnar nerve palsy. Her pain was exacerbated with elbow movement, particularly flexion. She had paralysis of ulnar nerve innervated muscles, hypersensitivity with absence of two-point discrimination in her ulnar 1–1/2 digits, and a fixed ulnar claw deformity. She also had a grossly unstable elbow. Results Plain films revealed a cubitus valgus deformity (38°), an absent radial head, a dislocated proximal radioulnar joint and advanced arthritic changes. Ultrasonography revealed an indistinct ulnar nerve within the cubital tunnel which penetrated the joint. Electrophysiological studies revealed evidence of a severe ulnar neuropathy at the level of the elbow. Intraoperatively, an attenuated 2 cm length of the retrocondylar ulnar nerve was observed to be incorporated into the joint capsule tethered by a fibrous/synovial band which was released. A large effusion was drained. The ulnar nerve was transposed subcutaneously. The capsular rent was repaired in layers. She noted immediate and sustained (2 year follow-up) pain relief and regained moderate function in her interossei. Conclusions We believe that the chronic cubitus valgus deformity and secondary degenerative elbow joint changes led to an altered course of the nerve and attenuation of the medial joint capsule such that the ulnar nerve spontaneously buttonholed itself intra-articularly.

Hilton's Law, put forth 150 years ago, is well known and frequently taught in anatomy courses. We critically analyzed the complex description of associated muscular, cutaneous, and articular innervations in order to assess the general applicability of Hilton's Law. We applied rules for interpretation of the Law extrapolated upon but based on Hilton's original writings, and excluded obscure supplementary clauses not considered as part of the Law. We found the Law, as originally written and as we interpreted with some latitude, to be reliable and applicable to all cranial and peripheral nerves. Hilton's Law is a powerful springboard to understand articular anatomy and pathophysiology. Clin. Anat. 548–555, 2014. © 2013 Wiley Periodicals, Inc.

Misdirection of regenerating axons is one of the factors that can explain the limited results often found after nerve injury and repair. In the repair of mixed nerves innervating different distal targets (skin and muscle), misdirection may, for example, lead to motor axons projecting toward skin, and vice versa—that is, sensory axons projecting toward muscle. In the repair of motor nerves innervating different distal targets, misdirection may result in reinnervation of the wrong target muscle, which might function antagonistically. In sensory nerve repair, misdirection might give an increased perceptual territory. After median nerve repair, for example, this might lead to a dysfunctional hand. Different factors may be involved in the misdirection of regenerating axons, and there may be various mechanisms that can later correct for misdirection. In this review the authors discuss these different factors and mechanisms that act along the pathway of the regenerating axon. The authors review recently developed evaluation methods that can be used to investigate the accuracy of regeneration after nerve injury and repair (including the use of transgenic fluorescent mice, retrograde tracing techniques, and motion analysis). In addition, the authors discuss new strategies that can improve in vivo guidance of regenerating axons (including physical guidance with multichannel nerve tubes and biological guidance accomplished using gene therapy).

The human cutaneous sensory map has been a work in progress over the past century, depicting sensory territories supplied by both the spinal and cranial nerves. Two critical discoveries, which shaped our understanding of cutaneous innervation, were sensory dermatome overlap between contiguous spinal levels and axial lines across areas where no sensory overlap exists. These concepts define current dermatome maps. We wondered whether the overlap between contiguous sensory territories was even tighter: if neural communications were present in the peripheral nerve territories consistently connecting contiguous spinal levels? A literature search using peer‐reviewed articles and established anatomy texts was performed aimed at identifying the presence of communications between sensory nerves in peripheral nerve territories and their relationship to areas of adjacent and non‐adjacent spinal or cranial nerves and axial lines (lines of discontinuity) in the upper and lower limbs, trunk and perineum, and head and neck regions. Our findings demonstrate the consistent presence of sensory nerve communications between peripheral nerve territories derived from spinal nerves within areas of axial lines in the upper and lower limbs, trunk and perineum, and head and neck. We did not find examples of communications crossing axial lines in the limbs or lines of discontinuity in the face, but did find examples crossing axial lines in the trunk and perineum. Sensory nerve communications are common. They unify concepts of cutaneous innervation territories and their boundaries, and refine our understanding of the sensory map of the human skin. Clin. Anat. 27:681–690, 2014. © 2013 Wiley Periodicals, Inc.

Although the ulnar nerve is closely associated with the triceps brachii muscle, the literature does not normally describe it as supplying this muscle. However, recent research has examined the ulnar nerve in the upper arm and identified branches supplying the medial head of the triceps brachii muscle. This study aims to expand upon this research by describing the course and incidence of these branches in a larger sample size. We examined 50 specimens in 25 cadavers. Ulnar innervation of the medial head of the triceps brachii was identified in 14 specimens (28%). The mean distance of the ulnar nerve branch midpoint was 26% along a line between the surgical neck and an epicondyle line, with a range of 11–39%. Innervation of the triceps brachii muscle by the ulnar nerve has important clinical and surgical implications. Clin. Anat. 26:1028–1030, 2013. © 2013 Wiley Periodicals, Inc.

Object Patients with brachial plexus injury (BPI) present with a combination of motor weakness/paralysis, sensory deficits, and pain. Brachial plexus injury is generally not believed to be associated with headaches. However, CSF leaks may be associated with CSF volume–depletion (low-pressure) headaches and can occur in BPI secondary to nerve root avulsion. Only a few cases of headaches associated with BPI have been reported. It is unknown if headaches in patients with BPI occur so rarely, or if they are just unrecognized by physicians and/or patients in which the focus of attention is the affected limb. The aim of this study was to determine the prevalence of CSF volume–depletion headaches in patients with BPI. Methods All adult patients presenting at the Mayo brachial plexus clinic with traumatic BPI were asked to complete a questionnaire addressing the presence and quality of headaches following their injury. The patients' clinical, injury, and imaging characteristics were subsequently reviewed. Results Between December 2008 and July 2010, 145 patients completed the questionnaire. Twenty-two patients reported new onset headaches occurring after their BPI. Eight of these patients experienced positional headaches, suggestive of CSF volume depletion. One of the patients with orthostatic headaches was excluded because the headaches immediately followed a lumbar puncture for a myelogram. Six of the other 7 patients with positional headaches had a clear preganglionic BPI. The available imaging studies in these 6 patients revealed evidence of CSF leaks: pseudomeningoceles (n = 5), CSF tracking into soft tissues (n = 3), CSF tracking into the intraspinal compartment (n = 3), CSF tracking into the pleural space (n = 2), and low-positioned cerebellar tonsils (n = 2). Conclusions In this retrospective study, 15.2% of patients (22 of 145 patients) with traumatic BPI suffered from a new-onset headache. Seven of these patients (4.8%) experienced postural headaches clearly suggestive of CSF volume depletion likely secondary to a CSF leak associated with the BPI, whereas the other 15 patients (10.3%) suffered headaches that may have represented a variant of CSF depletion headaches without a postural characteristic or a headache from another cause. These data suggest that CSF volume–depletion headaches occur in a significant proportion of patients with BPI and have been underrecognized and underreported.