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PLoS Biology Sep 2014From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used...
From early dinosaurs with as many as nine wrist bones, modern birds evolved to develop only four ossifications. Their identity is uncertain, with different labels used in palaeontology and developmental biology. We examined embryos of several species and studied chicken embryos in detail through a new technique allowing whole-mount immunofluorescence of the embryonic cartilaginous skeleton. Beyond previous controversy, we establish that the proximal-anterior ossification develops from a composite radiale+intermedium cartilage, consistent with fusion of radiale and intermedium observed in some theropod dinosaurs. Despite previous claims that the development of the distal-anterior ossification does not support the dinosaur-bird link, we found its embryonic precursor shows two distinct regions of both collagen type II and collagen type IX expression, resembling the composite semilunate bone of bird-like dinosaurs (distal carpal 1+distal carpal 2). The distal-posterior ossification develops from a cartilage referred to as "element x," but its position corresponds to distal carpal 3. The proximal-posterior ossification is perhaps most controversial: It is labelled as the ulnare in palaeontology, but we confirm the embryonic ulnare is lost during development. Re-examination of the fossil evidence reveals the ulnare was actually absent in bird-like dinosaurs. We confirm the proximal-posterior bone is a pisiform in terms of embryonic position and its development as a sesamoid associated to a tendon. However, the pisiform is absent in bird-like dinosaurs, which are known from several articulated specimens. The combined data provide compelling evidence of a remarkable evolutionary reversal: A large, ossified pisiform re-evolved in the lineage leading to birds, after a period in which it was either absent, nonossified, or very small, consistently escaping fossil preservation. The bird wrist provides a modern example of how developmental and paleontological data illuminate each other. Based on all available data, we introduce a new nomenclature for bird wrist ossifications.
Topics: Animals; Biological Evolution; Carpus, Animal; Cartilage; Chick Embryo; Collagen Type II; Collagen Type IX; Dinosaurs; Fossils; Gene Expression; Paleontology; Tendons; Wings, Animal
PubMed: 25268520
DOI: 10.1371/journal.pbio.1001957 -
Plastic Surgery (Oakville, Ont.) May 2017Compression neuropathy of the ulnar nerve at the Guyon canal is commonly seen by hand surgeons. Different anatomical variations of structures related to the Guyon canal...
BACKGROUND
Compression neuropathy of the ulnar nerve at the Guyon canal is commonly seen by hand surgeons. Different anatomical variations of structures related to the Guyon canal have been reported in the literature. A thorough knowledge of the normal contents and possible variations is essential during surgery and exploration.
OBJECTIVES
To review the recognized anatomical variations within and around the Guyon canal.
METHODS
This study is a narrative review in which relevant papers, clinical studies, and anatomical studies were selected by searching electronic databases (PubMed and EMBASE). Extensive manual review of references of the included studies was performed. We also describe a case report of an aberrant muscle crossing the Guyon canal.
RESULTS
This study identified several variations in the anatomical structures of the Guyon canal reported in the literature. Variations of the ulnar nerve involved its course, branching pattern, deep motor branch, superficial sensory branch, dorsal cutaneous branch, and the communication with the median nerve. Ulnar artery variations involved its course, branching pattern, the superficial ulnar artery, and the dorsal perforating artery. Aberrant muscles crossing the Guyon canal were found to originate from the antebrachial fascia, pisiform bone, flexor retinaculum, the tendon of palmaris longus, flexor carpi ulnaris, or flexor carpi radialis; these muscles usually fuse with the hypothenar group.
CONCLUSION
The diverse variations of the contents of the Guyon canal were adequately described in the literature. Taking these variations into consideration is important in preventing clinical misinterpretation and avoiding potential surgical complications.
PubMed: 29026818
DOI: 10.1177/2292550317694851 -
Cureus Sep 2023Isolated pisiform dislocation is an uncommon condition, with a limited number of cases reported in the literature. We present a unique case of a 15-year-old male who...
Isolated pisiform dislocation is an uncommon condition, with a limited number of cases reported in the literature. We present a unique case of a 15-year-old male who experienced an atraumatic isolated dislocation of the pisiform bone in his left wrist and presented with pain, deformity, and ulnar nerve palsy in his little and ring fingers. Radiographic investigations confirmed the diagnosis of isolated pisiform dislocation, and the patient successfully underwent an open reduction, stabilization of pisiform, and exploration of the ulnar nerve.
PubMed: 37900515
DOI: 10.7759/cureus.46042 -
BMC Musculoskeletal Disorders Apr 2020Osteochondroma is a benign tumor that occurs mainly at the metaphysis of long bones and seldom arises from carpal bones. We describe an extremely rare case of... (Review)
Review
BACKGROUND
Osteochondroma is a benign tumor that occurs mainly at the metaphysis of long bones and seldom arises from carpal bones. We describe an extremely rare case of osteochondroma of the hamate without a typical cartilaginous cap and with a spiky bony protrusion in an elderly patient.
CASE PRESENTATION
A 78-year-old right-handed female housekeeper had a multilobed osteochondroma of the hamate, which caused carpal tunnel syndrome and irritation of the flexor tendons. Radiological examinations showed a morphological abnormality of the hamate comprising a spiky bony protrusion into the carpal tunnel and a free body proximal to the pisiform. Open carpal tunnel release and resection of the spiky bony protrusion on the hook of the hamate were performed. The flexor digitorum profundus tendons of the ring and little fingers displayed synovitis and partial laceration in the carpal tunnel. Histological examination also showed atypical findings: only a few regions of cartilaginous tissue were seen in the spiky bony protrusion, whereas the free body proximal to the pisiform contained thick cartilaginous tissue such as a cartilaginous cap typical of osteochondroma. We speculated that the bony protrusion to the carpal tunnel had been eroded by mechanical irritation caused by gliding of the flexor tendon and had resulted in the protruding spiky shape with less cartilaginous tissue. The fractured cartilaginous cap had moved into the cavity within the carpal tunnel proximal to the pisiform and had become a large free body.
CONCLUSIONS
Osteochondroma of the carpal bone may take various shapes because the carpal bone is surrounded by neighboring bones and tight ligaments, which can restrict tumor growth. This type of tumor is likely to present with various symptoms because of the close proximity of important structures including nerves, tendons, and joints. The diagnosis of osteochondroma of the carpal bone may be difficult because of its rarity and atypical radiological and histological findings, such as the lack of a round cartilaginous cap. We suggest that surgeons should have a detailed understanding of this condition and should make a definitive diagnosis based on the overall findings.
Topics: Aged; Carpal Tunnel Syndrome; Female; Hamate Bone; Humans; Osteochondroma; Radiography; Tendons; Wrist
PubMed: 32284050
DOI: 10.1186/s12891-020-03272-8 -
Journal of Wrist Surgery Nov 2018Pisiform excision and pisotriquetral arthrodesis are two surgical options for the treatment of pisotriquetral joint pain when conservative methods fail. However, it...
Pisiform excision and pisotriquetral arthrodesis are two surgical options for the treatment of pisotriquetral joint pain when conservative methods fail. However, it is unclear which option is best for patients who experience substantial, repetitive loading on their wrists and wish to preserve wrist flexibility and function. We present a case of bilateral ulnar-sided wrist pain related to the pisotriquetral joint in a 19-year-old collegiate diver. The pain was exacerbated by activities specific to this sport that requires wrist hyperextension, namely full weight-bearing on the hands (handstands), and has an impact on the hands and wrists upon water entry during dives due to direct palmar pressure. There were no radiographic signs of arthritis; however, there were bone marrow changes on magnetic resonance imaging (MRI). Management with rest, splinting, and corticosteroid injection failed to relieve the pain and precluded his ability to return to full-time diving. Treatment consisted of bilateral pisiform excision. Postoperatively, the patient returned to full-time competitive diving with resolution of his painful symptoms. Pisiform excision has been shown to have successful outcomes in terms of return to play for lower impact athletes (such as badminton) but has not been reported in athletes who experience a high degree of force repetitively (such as gymnasts or divers). There is one report of pisotriquetral arthrodesis in a young gymnast with suboptimal results. This case report demonstrates that pisiform excision is a successful treatment for elite athletes who experience repetitive, palmar force on hyperextended wrists and subsequently develop ulnar-sided wrist pain.
PubMed: 30349756
DOI: 10.1055/s-0038-1642047 -
Journal of Orthopaedic Case Reports Sep 2020Chondroblastoma is a rare primary benign tumor of bone with male predominance and is typically seen in an epiphyseal location. The pisiform is a carpal bone and...
INTRODUCTION
Chondroblastoma is a rare primary benign tumor of bone with male predominance and is typically seen in an epiphyseal location. The pisiform is a carpal bone and chondroblastoma of the pisiform has not been reported in the literature to the best of our knowledge.
CASE PRESENTATION
An 18-year-old male presented with painful swelling over his right wrist with restriction of ulnar deviation. Based on magnetic resonance imaging findings, two diagnostic possibilities were entertained, namely, giant cell tumor of bone and chondroblastoma. Wide local excision was performed, and histopathology confirmed the diagnosis of chondroblastoma of the pisiform. After 2 years of follow-up, the patient has gained pain-free wrist movements post excision, and there are no signs of recurrence. The Modified Mayo Wrist Score of 75 (fair) improved to 100 (excellent).
CONCLUSION
Surgeon should always keep in mind the possibility of the tumor at the rare site and accurately diagnose the tumor with the help of imaging modalities and biopsy.
PubMed: 33489960
DOI: 10.13107/jocr.2020.v10.i06.1854 -
Archives of Rheumatology Jun 2023In this study, we aimed to investigate ulnar and median nerve cross-sectional areas (CSAs) by ultrasonography in RA patients who had no signs or symptoms of neurologic...
OBJECTIVES
In this study, we aimed to investigate ulnar and median nerve cross-sectional areas (CSAs) by ultrasonography in RA patients who had no signs or symptoms of neurologic involvement.
PATIENTS AND METHODS
This case-control study was conducted with 76 participants (72 females, 4 males; mean age: 53.2+10.9 years; range, 18 to 65 years) between April 2011 and April 2013. Of the participants, 38 were RA patients without any signs or symptoms of ulnar or median nerve involvement, and 38 were healthy subjects. All participants were evaluated with ultrasound. The median and ulnar nerve CSAs were measured at the proximal inlet of the carpal tunnel using the pisiform bone as a landmark.
RESULTS
There were no statistically significant differences between patients and controls in terms of median and ulnar CSAs (p>0.05). There were no correlations between median and ulnar CSAs of the dominant hand and age, height, weight, and disease duration. The median nerve CSA was >10 mm in 24% of the RA patients and 14% of controls, but the difference was not statistically significant (p=0.20).
CONCLUSION
Similar median and ulnar CSAs were detected in RA patients and healthy controls. These findings cannot rule out a subclinical neurologic involvement.
PubMed: 37680523
DOI: 10.46497/ArchRheumatol.2023.9027 -
Journal of Clinical Neurology (Seoul,... Jul 2016We determined the reliability of ultrasonography (US) measurements for diagnosing carpal tunnel syndrome (CTS) and their correlation with symptom duration and...
BACKGROUND AND PURPOSE
We determined the reliability of ultrasonography (US) measurements for diagnosing carpal tunnel syndrome (CTS) and their correlation with symptom duration and electrophysiology findings. We determined whether the ratio of the median-to-ulnar cross-sectional areas (CSAs) can support CTS diagnoses.
METHODS
The pisiform CSA (CSA(pisiform)), swelling ratio (SR), palmar bowing, and CSA(pisiform)/ulnar CSA (CSA(ulnar)) measurements made in two subgroups of CTS patients (having sensory affection alone or having both sensory and motor affection) were compared with controls. CSA(ulnar) was measured in Guyon's canal at the level of most-protuberant portion of the pisiform bone.
RESULTS
The values of all of the measured US parameters were higher in patients with CTS (n=50) than in controls (n=62). CSA(pisiform) could be used to diagnose CTS of mild severity. All of the parameters were positively correlated with the distal latency of the compound muscle action potential, and all of them except for SR were negatively correlated with the sensory nerve conduction velocity. A CSA(pisiform)/CSA(ulnar) ratio of ≥1.79 had a sensitivity of 70% and a specificity of 76% for diagnosing CTS.
CONCLUSIONS
Only CSA(pisiform) measurements were reliable for diagnosing early stages of CTS, and CSA(pisiform)/CSA(ulnar) had a lower diagnostic value for diagnosing CTS.
PubMed: 27095524
DOI: 10.3988/jcn.2016.12.3.289 -
Journal of Hand and Microsurgery Dec 2016
PubMed: 27999466
DOI: 10.1055/s-0036-1588022 -
The Archives of Bone and Joint Surgery 2023A retrospective study was conducted to evaluate the diagnostic accuracy of a novel examination technique, the 'Pisiform Boost Test,' in diagnosing a triangular...
BACKGROUND
A retrospective study was conducted to evaluate the diagnostic accuracy of a novel examination technique, the 'Pisiform Boost Test,' in diagnosing a triangular fibrocartilage complex (TFCC) tear.
METHODS
Wrist arthroscopies performed between 2011-2021 were retrospectively reviewed. Patients' clinical records were evaluated to determine the result of the Pisiform Boost Test during clinical examination and TFCC tear within the body of the TFCC as seen at wrist arthroscopy. The Pisiform Boost Test is performed by first assessing for ulna fovea pain on passive ulna deviation of the wrist and then assessing pain while the clinician applies digital pressure over the pisiform and passive ulna deviation.
RESULTS
The pisiform Boost test was found to have a Sensitivity of 91% (95% CI, 81 - 97%) and a Specificity of 33% (95% CI, 14-59%) for the diagnosis of TFCC tears. Positive predictive value of 83%, a negative predictive value of 50%, and an accuracy of 78%. A chi-square test of independence was performed to examine the relation between a Positive Pisiform Boost Test and an arthroscopy-confirmed TFCC tear. The relation between these two variables was statistically significant, x2 (1, N = 82) = 6.4551, .
CONCLUSION
The Pisiform Boost Test demonstrates high sensitivity for TFCC tears (0.91). Specificity (0.33) is similar to that in the ulnar grinding test. Therefore, we propose this test be utilized with additional special tests for ulna-side wrist pain to allow clinicians to build a diagnostic picture, aiding decision-making and patient information.
PubMed: 37168823
DOI: 10.22038/ABJS.2022.67029.3188