scholarly journals Mechanical loading of primate fingers on vertical rock surfaces

2021 ◽  
Vol 117 (11/12) ◽  
Author(s):  
Michael C. Everett ◽  
Marina C. Elliott ◽  
David Gaynor ◽  
Austin C. Hill ◽  
Jesse Casana ◽  
...  
Keyword(s):  
South Africa ◽  
Mechanical Loading ◽  
Nature Reserve ◽  
Flexor Tendon ◽  
Three Dimensional ◽  
Vertical Surface ◽  
Rock Climbing ◽  
Rock Surface ◽  
Induce Stress ◽  
Pulley System

Mechanical loading of finger bones (phalanges) can induce angular curvature, which benefits arboreal primates by dissipating forces and economising the recruitment of muscles during climbing. The recent discovery of extremely curved phalanges in a hominin, Homo naledi, is puzzling, for it suggests life in an arboreal milieu, or, alternatively, habitual climbing on vertical rock surfaces. The importance of climbing rock walls is attested by several populations of baboons, one of which uses a 7-m vertical surface to enter and exit Dronkvlei Cave, De Hoop Nature Reserve, South Africa. This rock surface is an attractive model for estimating the probability of extreme mechanical loading on the phalanges of rock-climbing primates. Here we use three-dimensional photogrammetry to show that 82–91% of the climbable surface would generate high forces on the flexor tendon pulley system and severely load the phalanges of baboons and H. naledi. If such proportions are representative of vertical rock surfaces elsewhere, it may be sufficient to induce stress-mitigating curvature in the phalanges of primates.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

Soft tissue abnormalities in Wassel Type VI radial polydactyly: a detailed anatomical study

2021 ◽  
Vol 46 (4) ◽  
pp. 352-359
Author(s):  
Susumu Saito ◽  
Itaru Tsuge ◽  
Hiroki Yamanaka ◽  
Naoki Morimoto
Keyword(s):  
Soft Tissue ◽  
Three Dimensional ◽  
Anatomical Study ◽  
Metacarpophalangeal Joint ◽  
Abductor Pollicis Brevis ◽  
Level Of Evidence ◽  
Thenar Muscle ◽  
Pulley System ◽  
Radial Deviation ◽  
Tissue Abnormalities

Wassel VI radial polydactyly is associated with metacarpal adduction and radial deviation of the metacarpophalangeal joint of the ulnar duplicate. The soft tissue abnormalities responsible for these deformities were characterized using preoperative multi-planar three-dimensional ultrasound and intraoperative observation in four patients. In all patients, the abductor pollicis brevis and superficial head of the flexor pollicis brevis inserted into the radial first metacarpal, whereas the adductor pollicis and deep head of the flexor pollicis brevis inserted into the ulnar thumb. Aberrant location of the flexor pollicis longus and absence of the A1 pulley system was associated with severe radial deviation. An additional superficial thenar muscle along the ulnar metacarpal was associated with minimal metacarpal adduction. Uneven forces on the ulnar duplicate could be associated with these characteristic deformities and joint instability. Knowledge of these abnormalities allows better planning of surgery and further insight into this rare radial polydactyly configuration. Level of evidence: II

The Effect of Body Position and Number of Supports on Wall Reaction Forces in Rock Climbing

1997 ◽  
Vol 13 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Franck Quaine ◽  
Luc Martin ◽  
Jean-Pierre Blanchi
Keyword(s):  
Body Weight ◽  
Contact Force ◽  
Body Position ◽  
Three Dimensional ◽  
Rock Climbing ◽  
Contact Forces ◽  
Vertical Posture ◽  
Reaction Forces ◽  
Force Data ◽  
Lower Contact

This manuscript describes three-dimensional force data collected during postural shifts performed by individuals simulating rock-climbing skills. Starting from a quadrupedal vertical posture, 6 expert climbers had to release their right-hand holds and maintain the tripedal posture for a few seconds. The vertical and contact forces (lateral and anteroposterior forces) applied on the holds were analyzed in two positions: an “imposed” position (the trunk far from the supporting wall) and an “optimized” position (the trunk close to the wall and lower contact forces at the holds). The tripedal postures performed in the two positions were achieved by the same pattern of vertical and contact forces exerted by the limbs on the holds. In the optimized position, the transfer of the forces was less extensive than in the imposed position, so that the forces were exerted primarily on the ipsilateral hold. Moreover, a link between the contact force values and the couple due to body weight with respect to the feet was shown.

Predictors of outcome after primary flexor tendon repair in zone 1, 2 and 3

2016 ◽  
Vol 41 (8) ◽  
pp. 793-801 ◽  
Author(s):  
I. Z. Rigo ◽  
M. Røkkum
Keyword(s):  
Flexor Tendon ◽  
Linear Regression Analysis ◽  
Tendon Repair ◽  
Tendon Sheath ◽  
Multiple Linear Regression Analysis ◽  
Level Of Evidence ◽  
Pulley System ◽  
Skeletal Injury ◽  
Active Mobilization

We retrospectively reviewed the outcomes of flexor tendon repairs in zones 1, 2 and 3 in 356 fingers in 291 patients between 2005 and 2010. The mean (standard deviation) active ranges of motion of two interphalangeal joints of the fingers were 98° (40) and 114° (45) at 8 weeks postoperatively and at the last follow-up (mean 7 months, range 3–98), respectively. Using the Strickland criteria, ‘excellent’ or ‘good’ function was obtained in 95 (30%) out of 322 fingers at 8 weeks and 107 (48%) out of 225 fingers at the last follow-up. A total of 48 (13%) fingers required reoperation because of rupture, adhesion, contracture or other complications. The prevalence of rupture was 4%. We carried out multiple linear regression analysis to identify the predictors of the active digital motion. The following variables were found as negative predictors: age; smoking; injury localization between subzones 1C and 2C; injury to the little finger; the extent of soft tissue damage; concomitant skeletal injury; delay to surgery; use of a 2-strand Kessler repair technique; attempted suture or preservation of the tendon sheath–pulley system; and resecting or leaving the concomitant superficial flexor tendon cuts untreated. Analysing the 8 weeks results of tendon repairs in zones 1 and 2, early active mobilization was found to be superior to Kleinert’s regime. Level of evidence: III

An encapsulated haemogregarine from the evileye pufferfish in South Africa

2001 ◽  
Vol 81 (5) ◽  
pp. 751-754 ◽  
Author(s):  
N.J. Smit ◽  
A.J. Davies
Keyword(s):  
South Africa ◽  
Nature Reserve ◽  
Developmental Stages ◽  
The Third ◽  
Blood Smears

Developmental stages of a haemogregarine were found within polychromatocytes and erythrocytes in Giemsa-stained blood smears from six evileye pufferfish (Amblyrhynchotes honckenii) caught at Koppie Alleen in the De Hoop Nature Reserve, South Africa. This unusual haemogregarine, Haemogregarina (sensu lato) koppiensis sp. nov., was characterized by encapsulated gamonts with recurved tails, features more common in haemogregarines infecting amphibian and reptilian erythrocytes than in those from fish. Haemogregarina koppiensis is only the third species of fish haemogregarine to have been described from South Africa.

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