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Journal of Anatomy Nov 2014The human pisiform is a small, nodular, although functionally significant, bone of the wrist. In most other mammals, including apes and Australopithecus afarensis,... (Comparative Study)
Comparative Study
The human pisiform is a small, nodular, although functionally significant, bone of the wrist. In most other mammals, including apes and Australopithecus afarensis, pisiforms are elongate. An underappreciated fact is that the typical mammalian pisiform forms from two ossification centers. We hypothesize that: (i) the presence of a secondary ossification center in mammalian pisiforms indicates the existence of a growth plate; and (ii) human pisiform reduction results from growth plate loss. To address these hypotheses, we surveyed African ape pisiform ossification and confirmed the presence of a late-forming secondary ossification center in chimpanzees and gorillas. Identification of the initial ossification center occurs substantially earlier in apes relative to humans, raising questions concerning the homology of the human pisiform and the two mammalian ossification centers. Second, we conducted histological and immunohistochemical analyses of pisiform ossification in mice. We confirm the presence of two ossification centers separated by organized columnar and hypertrophic chondrocyte zones. Flattened chondrocytes were highly mitotic, indicating the presence of a growth plate. Hox genes have been proposed to play a fundamental role in growth plate patterning. The existence of a pisiform growth plate presents an interesting test case for the association between Hox expression and growth plate formation, and could explain the severe effects on the pisiform observed in Hoxa11 and Hoxd11 knockout mice. Consistent with this hypothesis, we show that Hoxd11 is expressed adjacent to the pisiform in late-stage embryonic mouse limbs supporting a role for Hox genes in growth plate specification. This raises questions concerning the mechanisms regulating Hox expression in the developing carpus.
Topics: Animals; Female; Gorilla gorilla; Growth Plate; Homeodomain Proteins; Humans; Male; Mice; Osteogenesis; Pan troglodytes; Pisiform Bone; Pregnancy; Transcription Factors
PubMed: 25279687
DOI: 10.1111/joa.12235 -
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 -
Journal of the American Veterinary... Dec 2013A 6-year-old neutered female mixed-breed dog was evaluated because of a 6-week history of left forelimb lameness that varied in severity.
CASE DESCRIPTION
A 6-year-old neutered female mixed-breed dog was evaluated because of a 6-week history of left forelimb lameness that varied in severity.
CLINICAL FINDINGS
Radiography revealed expansile and lytic changes of the left accessory carpal bone (ACB). Results of histologic evaluation of ACB core biopsy specimens indicated areas of bone necrosis. The entire left ACB was excised and submitted for histologic evaluation; results confirmed a diagnosis of idiopathic ischemic necrosis.
TREATMENT AND OUTCOME
Left pancarpal arthrodesis was performed to treat carpal hyperextension and persistent lameness. The dog had an excellent functional outcome with no other problems related to the carpus until its death 4 years later, further decreasing suspicion that the problem was attributable to an undetected neoplasm or bacterial or fungal osteomyelitis.
CLINICAL RELEVANCE
The radiographic and histologic findings for the dog of this report were similar to previously reported findings for dogs with ischemic femoral head necrosis and humans with ischemic carpal (pisiform or lunate bone) necrosis. The etiology of the ischemic ACB necrosis in this dog was not determined. To the authors' knowledge, this is the first report of a dog with idiopathic ischemic ACB necrosis. Idiopathic ischemic necrosis should be included as a differential diagnosis for dogs with lameness and destructive and expansile ACB radiographic lesions. An excellent functional outcome may be attained by means of ACB excision and pancarpal arthrodesis.
Topics: Animals; Arthrodesis; Carpal Bones; Dog Diseases; Dogs; Female; Ischemia; Osteonecrosis
PubMed: 24299546
DOI: 10.2460/javma.243.12.1746 -
Clinics in Orthopedic Surgery Jun 2013The purpose of this study was to investigate the frequency and distribution of associated carpal bone fractures (CBFs) in distal radial fractures (DRFs).
BACKGROUND
The purpose of this study was to investigate the frequency and distribution of associated carpal bone fractures (CBFs) in distal radial fractures (DRFs).
METHODS
Three hundred and thirteen patients who underwent surgical treatment for DRFs between March 2007 and January 2010 were reviewed retrospectively. In this study, 223 patients who had preoperative computed tomography (CT) were included. We investigated the frequency and distribution of associated CBFs on CT scans. The relationship between the frequency of associated CBFs and patient factors such as age, gender, body mass index, and the mechanism of injury was assessed.
RESULTS
CBFs were complicated in 46 of 223 DRFs (20.9%). The distribution of CBFs was 23 cases in the triquetrum, 16 in the lunate, 12 in the scaphoid, five in the hamate, and four in the pisiform. Among the 46 cases, a fracture of one carpal bone occurred in 36 cases, two in seven cases, three in two cases, and four in one case. In 10 of the 46 cases, associated CBFs occurred in more than two carpal bones. No significant differences were observed for age, sex, body mass index, or the mechanism of injury between patients with DRFs and CBFs and those without CBFs.
CONCLUSIONS
Because CBFs that mainly occur in the proximal carpal row are complicated in DRFs at a relatively high frequency, assessment of carpal bones using CT scans is beneficial.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Carpal Bones; Female; Fractures, Bone; Hand Injuries; Humans; Male; Middle Aged; Radius Fractures; Retrospective Studies; Tomography, X-Ray Computed
PubMed: 23730472
DOI: 10.4055/cios.2013.5.2.98 -
BMJ Case Reports Jan 2013A 53-year-old man presented with an open fracture of the pisiform after a fall on his left wrist. Treatment of the patient presented a dilemma between excision of the...
A 53-year-old man presented with an open fracture of the pisiform after a fall on his left wrist. Treatment of the patient presented a dilemma between excision of the proximal fragment and internal fixation. The patient underwent internal fixation with a 2.5 cortical screw. At 6 months follow-up the fracture appeared fully consolidated with full functional recovery of the wrist.
Topics: Bone Screws; Decision Making; Fracture Fixation, Internal; Fractures, Open; Humans; Male; Middle Aged; Osteotomy; Pisiform Bone; Radiography; Wrist Injuries
PubMed: 23307459
DOI: 10.1136/bcr-2012-007621 -
Advances in Orthopedics 2011We report a case of isolated paralysis of the right adductor pollicis in a 30-year-old woman. Electromyographic study showed involvement of the deep motor branch of the...
We report a case of isolated paralysis of the right adductor pollicis in a 30-year-old woman. Electromyographic study showed involvement of the deep motor branch of the ulnar nerve. A ganglion and an anomalous muscle were both ruled out clinically and by MRI as a possible cause of the paralysis. At surgical exploration, we found a fibrous band joining the pisiform and the hook of the hamate bone that compressed the deep motor branch of the ulnar nerve. The fibrous band was excised, and a neurolysis of the motor branch of the ulnar nerve was performed. At followup, eight months later, the patient had fully recovered strength of the adductor muscle.
PubMed: 21991410
DOI: 10.4061/2011/321020 -
Anatomy & Cell Biology Jun 2011Muscular variations of the flexor compartment of forearm are usual and can result in multiple clinical conditions limiting the functions of forearm and hand. The...
Muscular variations of the flexor compartment of forearm are usual and can result in multiple clinical conditions limiting the functions of forearm and hand. The variations of the muscles, especially accessory muscles may simulate soft tissue tumors and can result in nerve compressions. During a routine dissection of the anterior region of the forearm and hand, an unusual muscle was observed on the left side of a 65-year-old male cadaver. The anomalous muscle belly arose from the medial epicondyle approxiamately 1 cm posterolateral to origin of normal flexor carpi ulnaris muscle (FCU), and from proximal part of the flexor digitorum superficialis muscle. It inserted to the triquetral, hamate bones and flexor retinaculum. Passive traction on the tendon of accessory muscle resulted in flexion of radiocarpal junction. The FCU which had one head, inserted to the pisiform bone hook of hamate and palmar aponeurosis. Its contiguous muscles displayed normal morphology. Knowledge of the existence of muscle anomalies as well as the location of compression is useful in determining the pathology and appropriate treatment for compressive neuropathies. In this study, a rare accessory muscle has been described.
PubMed: 21829760
DOI: 10.5115/acb.2011.44.2.160 -
Journal of Orthopaedic Research :... Nov 2011This study investigated the effects of loading and posture on mechanical properties of the transverse carpal ligament (TCL). Ten fresh-frozen cadaver arms were dissected...
This study investigated the effects of loading and posture on mechanical properties of the transverse carpal ligament (TCL). Ten fresh-frozen cadaver arms were dissected to expose the TCL and positioned in the load frame of a servo-hydraulic testing machine, equipped with a load cell and custom made indenters. Four cylindrical indenters (5, 10, 20, and 35 mm) loaded the TCL in three wrist postures (30° extension, neutral and 30° flexion). Three loading cycles with a peak force of 50 N were applied at 5 N/s for each condition. The flexed wrist posture had significantly greater TCL stiffness (40.0 ± 3.3 N/mm) than the neutral (35.9 ± 3.5 N/mm, p = 0.045) and extended postures (34.9 ± 2.8 N/mm, p = 0.025). TCL stiffness using the 10 and 20 mm indenters was larger than the 5 mm indenter. Stiffness was greatest with the 20 mm indenter, which had the greatest indenter contact area on the TCL. The 35 mm indenter covered the carpal bones, compressed the carpal tunnel and produced the lowest stiffness. The complexity of the TCL makes it an important part of the carpal tunnel and the mechanical properties found are essential to understanding mechanisms of carpal tunnel syndrome.
Topics: Aged; Biomechanical Phenomena; Bone Nails; Cadaver; Carpal Tunnel Syndrome; Female; Humans; Ligaments; Male; Middle Aged; Models, Biological; Pisiform Bone; Posture; Radiography; Scaphoid Bone; Weight-Bearing; Wrist Joint
PubMed: 21520261
DOI: 10.1002/jor.21442 -
Journal of Orthopaedic Surgery (Hong... Dec 2010Isolated pisiform dislocation is rare. We present one such case in a 20-year-old man occurring after a direct injury to the wrist. After an initial delay in diagnosis...
Isolated pisiform dislocation is rare. We present one such case in a 20-year-old man occurring after a direct injury to the wrist. After an initial delay in diagnosis and unsuccessful closed reduction, he underwent resection of the pisiform. At 12-month follow-up, he had full range of movement of the wrist and no residual pain.
Topics: Humans; Joint Dislocations; Male; Pisiform Bone; Wrist Injuries; Young Adult
PubMed: 21187560
DOI: 10.1177/230949901001800329 -
Eplasty Sep 2010Stenosing tenosynovitis of the thumb flexor tendon sheath is also known as trigger thumb. It is an inflammatory process that involves the flexor tendon sheath at the A1...
OBJECTIVE
Stenosing tenosynovitis of the thumb flexor tendon sheath is also known as trigger thumb. It is an inflammatory process that involves the flexor tendon sheath at the A1 pulley. Successful percutaneous or open treatment of trigger thumb depends on the ability of the clinician to properly predict the location of the A1 pulley. Longitudinal anatomic landmarks can facilitate safe treatment for the trigger thumb while circumventing injury to the neurovascular bundles.
METHODS
Fourteen fresh cadaveric hands were dissected to identify surface landmarks corresponding to the oblique course of the flexor pollicis longus tendon at the level of the A1 pulley.
RESULTS
The longitudinal landmarks for the A1 pulley of the thumb are the palpable hook of the hamate and the midline of the thumb interphalangeal (IP) crease. Other bony prominences, such as the pisiform bone did not serve as effective landmarks while the thumb was in an abducted position.
CONCLUSION
we encourage the use longitudinal anatomic landmarks to predict the location of the thumb A1 pulley. The hook of the hamate and the midline at the palmar interphalangeal crease are reliable landmarks for safe release of the A1 pulley while avoiding inadvertent injury to adjacent structures.
PubMed: 20862293
DOI: No ID Found