Pisohamate Ligament Research Articles

The ulnar nerve is surrounded by the tendon expansion of the flexor carpi ulnaris muscle at the wrist: an anatomical study of Guyon's canal.

The ulnar tunnel (Guyon's canal) is an osseofibrous tunnel for the ulnar nerve and artery. With regard to the proximal palmar wall (palmar carpal ligament) of the ulnar tunnel, detailed anatomical data such as attachment sites, fibrous continuity to surroundings, and variations have not been clearly described. In this study, topology of Guyon's canal was examined, especially to the palmar side of the ulnar nerve, focusing on the continuity of tendinous structures to reveal a more detailed constitution of Guyon's canal. The palmar wall of Guyon's canal was investigated in 113 forearms of 57 cadavers. The dorsal wall of the canal was also investigated in 25 subjects. The ulnar nerve passed lateral to the pisiform and the flexor carpi ulnaris tendon. At the level of the pisiform, except for one, the ulnar nerve passed dorsal to the aponeurosis expanding from the flexor carpi ulnaris tendon and the periosteum of the pisiform, and this aponeurosis laterally merged with the palmar aspect of the flexor retinaculum. Moreover, the ulnar nerve ran palmar to the pisohamate ligament and the flexor retinaculum extended from the same tendon. The present study suggests that the aponeurosis of palmar side to the ulnar nerve connected with the flexor carpi ulnaris tendon, the periosteum of the pisiform, and the palmar surface of the flexor retinaculum. These findings indicate that the ulnar nerve is surrounded by the aponeurotic portion expanding from the flexor carpi ulnaris tendon at the wrist, which is a new insight of Guyon's canal.

Assessment of pisotriquetral misalignment with magnetic resonance imaging: Is it associated with trauma?

Our objective was to determine whether there is an association between pisotriquetral (PT) malalignment and acute distal radius fracture by using magnetic resonance imaging (MRI). We evaluated 138 patients who underwent 3-T MRI of the wrists. Group A comprised 85 patients with acute distal radius fracture, and group B comprised 53 patients without trauma. PT interval and angle and pisiform excursion were measured on oblique axial and sagittal multiplanar reformats. The presence of abnormalities in the flexor carpi ulnaris tendon (FCU), pisometacarpal ligament (PML), and pisohamate ligament (PHL) were evaluated. PT interval was wider in group A on both the axial and sagittal planes (P < 0.001). Axial PT angle opened more radially in group A (P < 0.001), and the absolute value of the sagittal PT angle in group A was wider than that in group B (P = 0.006). Abnormalities in FCU, PML, and PHL were more frequently observed in group A (P < 0.001). On multiple linear regression, distal radius fracture remained significant after adjusting for the patient's age and PT osteoarthritis. Acute distal radius fracture can affect normal alignment of the PT joint, resulting in associated injuries to the primary PT joint stabilizers. • Acute distal radius fracture is associated with malalignment of PT joints. • Acute distal radius fracture is associated with abnormalities of PT stabilizers. • PT joint alignment can be evaluated with MRI with 3D sequences. • Wrist MRI is useful for evaluating primary PT stabilizer injuries.

Feasibility and limitations of endoscopy in Guyon's canal.

IntroductionThis retrospective report summarizes observations from eight operations where the endoscopically assisted approach was used to explore Guyon's canal syndromes of idiopathic aetiology.AimTo evaluate the feasibility and limitations of endoscopic Guyon's canal release performed from a distal forearm incision.Material and methodsEight charts and video records of eight ulnar tunnel syndrome patients presenting concomitant idiopathic Guyon's canal syndromes were retrospectively reviewed. In all cases endoscopically assisted explorations in Guyon's canals with simultaneous cubital tunnel releases were performed.ResultsIn all of the patients the multiple tight bands of the superficial volar carpal ligament forming the canal roof were divided. Some of these bands crossing the nerve in its direct vicinity could have been responsible for the constriction. We were also able to divide the proximal segment of the canal floor. We have observed, however, that the proximal to distal endoscopic dissection jeopardizes the motor branch of the ulnar nerve; therefore, it should not be used to release the pisohamate ligament, or the hypothenar fascia.ConclusionsAlthough all of the patients showed improvement, we cannot recommend this method in its current form. We are of the opinion that safe endoscopic Guyon's canal operations may require a different approach.

Éminence hypothénar

The hypothenar eminence is of great surgical interest yet its complex anatomy is yet to be fully discovered. This review focuses on: the osteoligamentous floor and topography of the Guyon's canal and the carpal ulnar neurovascular space. The canal under the Pisohamate ligament must be individualized. It corresponds to the zone 2 of Shea and McClain where the deep branch of the ulnar nerve is particularly vulnerable. Usually described as a hole, it is a real canal that circumvents the hamulus; the hypothenar muscles are extremely variable. The short abductor of the little finger may be harvested for opposition transfer but its absence penalizes abduction of the little finger if an independent flexor digiti minimi brevis inserts on the head of the fifth metacarpal; the termination of the ulnar nerve distribution to the hypothenar muscles and medio-ulnar anastomoses. The ulnar artery, its close relationship with the hook of the hamate and its variable course that may put it at risk during endoscopic carpal tunnel release. Finally, blood supply of fat pads and skin and their use as flaps to cover the palm and fingers.

Delayed onset ulnar nerve neuropathy following hand injury: a case report

We present a 40-year-old man, manual worker, who sustained a right hand injury, after a fall on his outstretched hand. Initial diagnosis was isolated pisiform fracture, documented with the conventional carpal views and a conservative treatment was applied by using a cast. Three months after the trauma episode, the patient presented at hospital outpatient’s clinic with symptoms of ulnar neuropathy. The fracture had been already united, according to the signs of callus formation in plane radiographs. Nerve conduction studies confirmed the ulnar nerve’s neuropathy and a decision of surgical exploration of Guyon’s canal was made. Intraoperatively, we found that pisohamate ligament was ruptured and an acquired aberrant fibrous band was the main cause of ulnar nerve compression. The patients’ symptoms were promptly receded after the resection of the pisohamate ligament band. At one-year follow-up, no recurrence of symptoms was reported and the patient was successfully returned to his priory to injury occupation.

An immunohistochemical study of the extracellular matrix of entheses associated with the human pisiform bone

The immunohistochemical labelling patterns of the extracellular matrix at the insertion of the flexor carpi ulnaris tendon and the entheses at both ends of the pisometacarpal and pisohamate ligaments were compared in order to relate the molecular composition of the attachment sites to their mechanical environment. Tissue was obtained from elderly dissecting room cadavers and labelled with a panel of monoclonal antibodies directed against collagens, glycosaminoglycans, proteoglycans and matrix proteins. All entheses were fibrocartilaginous and labelled positively for molecules typically associated with articular cartilage (type II collagen, chondroitin 6 sulphate, aggrecan and link protein). Labelling for type II collagen was most conspicuous at the attachment of the flexor carpi ulnaris tendon. In the ligaments, type II collagen labelling was always greater at the pisiform end. Matrilin 1 was universally present at all five entheses examined and fibromodulin labelling was most intense around the tidemark. Fibromodulin may thus be involved in anchorage and/or the control of mineralization at the hard-soft tissue interface of entheses. The greater prominence of fibrocartilage at the pisiform enthesis of the flexor carpi ulnaris tendon than at any ligament attachment may relate to the marked change in the tendon insertional angle that occurs with wrist movements. We also suggest that the more fibrocartilaginous character of the proximal compared with the distal ends of the ligaments relates to the fact that the pisiform is anchored in position and is thus at the centre of rotation of any movement of ligaments attached to it.

Avulsion Fracture of the Hamulus From Clay Gunshot Sport: A Case Report

We report a case of hamulus (hook of hamate) fracture nonunion and secondary flexor digitorum profundus tendon rupture caused by repetitive wrist hyperextension sustained during clay shotgun shooting. The hyperextension caused avulsion of the hamulus by the pisohamate ligament. The hamulus was excised and a flexor digitorum profundus tendon transfer of the ring to small finger side to side was performed with satisfactory outcome.

The Pisotriquetral Joint: Anatomic, Biomechanical, and Radiographic Analysis

To examine anatomically and radiographically the ligaments stabilizing the pisotriquetral (PT) joint and to determine the contribution of each ligament to the stability of this joint. Twelve cadaver arms were used. The study had 3 components: (1) anatomic dissection of the PT joint ligaments and patterns of degenerative changes, (2) biomechanical sequential sectioning of the supporting ligaments, and (3) radiographic assessment of PT joint motion in several planes both before and after ligament sectioning. The ligaments that attached to the pisiform were the pisometacarpal (PM), pisohamate (PH), radial PT, ulnar PT, and transverse carpal ligament. The PH ligament was shorter, wider, and thicker than the PM ligament. The transverse carpal ligament attachment in the pisiform was insubstantial. In 10 limbs degenerative changes were present, most of them peripheral. Biomechanical testing showed that the primary stabilizers of the PT joint were the PM, PH, and ulnar PT ligaments and that these were responsible for resisting proximal, ulnar, and radial forces, respectively. The PH distance increased along with the pisiform sagittal motion during wrist flexion on oblique x-rays after transection of the PM and ulnar PT ligaments. Concomitantly this distance decreased on the anteroposterior x-rays during radial deviation. The PH distance increased along with the pisiform frontal motion after transection of the PH and radial PT ligaments. The pisiform ligament complex has primary and secondary stabilizers to the PT joint. The primary stabilizers are the PH, PM, and ulnar PT ligaments. The transverse carpal and radial PT ligaments are secondary stabilizers. Injuries of the primary stabilizers of the PT joint may lead to instability that predisposes to degenerative joint disease.

Anatomic study of the pisotriquetral joint: Ligament anatomy and cartilagenous change

Eighty embalmed cadaver wrists (40 right and 40 left, 55 male and 25 female, aged 36 to 93 years [average age, 72.5 years]) were dissected to assess the anatomy of the pisotriquetral joint and the location of degenerative changes. The patterns of degenerative changes were classified into five types: type 1, central (8.8%); type 2, peripheral (38.8%); type 3, fan-shaped (13.8%); type 4, mixed (combination of > or =1 of types 1, 2, and/or 3; 10.0%); and type 5, total (12.5%). There was no cartilagenous change in 16.2% of the pisoform and 13.7% of the triquetrum. Degenerative changes (exposed subchondral bone and chondromalacia) on the articular surface of the pisiform were present in 83.3% of the wrists and on the triquetrum in 86.3% of the wrists. Degenerative changes were most commonly of the type 2 pattern (peripheral), with change located most commonly in the distal, distal-radial, and radial aspects of the pisiform and triquetrum. The ligamentous anatomy was categorized into 3 different types: type A, pisohamate and pisometacarpal ligaments inserted on the palmar distal aspect of the pisiform (52.5%); type B, pisohamate ligament inserted on the radial side of the pisiform and pisometacarpal ligament inserted on the palmar side of the pisiform (41.3%); and type C, type B anatomy with an additional ligamentous slip between the pisometacarpal ligament and the distal aspect of the hook of the hamate (6.2%).

The proximal end of the palmar aponeurosis

The proximal end of the palmar aponeurosis receives two important contingents of fibres from the flexor carpi ulnaris tendon. The superficial contingent blends with the fibres of palmaris longus; the deep contingent runs on the surface of the pisohamate ligament and connects the flexor retinaculum to the palmar aponeurosis. In congenital absences of the palmaris longus, flexor carpi ulnaris completely takes over as the longitudinal tensor of the palmar aponeurosis.