Kinesiology of the wrist and the hand

Ayhan, Çiğdem; Ayhan, Egemen

doi:10.1016/b978-0-12-812162-7.00013-8

Cited by 8 publications

(8 citation statements)

References 230 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The region of thick cortical bone proximal to the trochlea coincides with the attachment site of the collateral ligaments of the PIP joint. The collateral ligaments arise from the radial and ulnar sides of the distal end of the proximal phalanx and run obliquely to the palmar radial and ulnar surfaces of the intermediate phalanx (Figure1f), providing lateral stability to the phalangeal joints during flexion and extension(Ayhan & Ayhan, 2020). This stability isF I G U R E 6 PC1 and PC2 for cortical bone distribution of proximal phalanges of (a) PP2, (b) PP3, (c) PP4 and (d) PP5 of Homo sapiens, Pan sp., Gorilla and Pongo sp.…”

mentioning

confidence: 99%

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours

et al. 2023

View full text Add to dashboard Cite

Primate fingers are typically in direct contact with the environment during both locomotion and manipulation, and aspects of external phalangeal morphology are known to reflect differences in hand use. Since bone is a living tissue that can adapt in response to loading through life, the internal bone architecture of the manual phalanges should also reflect differences in manual behaviours. Here, we use the R package Morphomap to analyse high‐resolution microCT scans of hominid proximal phalanges of digits 2–5 to determine whether cortical bone structure reflects variation in manual behaviours between bipedal (Homo), knuckle‐walking (Gorilla, Pan) and suspensory (Pongo) taxa. We test the hypothesis that relative cortical bone distribution patterns and cross‐sectional geometric properties will differ both among extant great apes and across the four digits due to locomotor and postural differences. Results indicate that cortical bone structure reflects the varied hand postures employed by each taxon. The phalangeal cortices of Pongo are significantly thinner and have weaker cross‐sectional properties relative to the African apes, yet thick cortical bone under their flexor sheath ridges corresponds with predicted loading during flexed finger grips. Knuckle‐walking African apes have even thicker cortical bone under the flexor sheath ridges, as well as in the region proximal to the trochlea, but Pan also has thicker diaphyseal cortices than Gorilla. Humans display a distinct pattern of distodorsal thickening, as well as relatively thin cortices, which may reflect the lack of phalangeal curvature combined with frequent use of flexed fingered hand grips during manipulation. Within each taxon, digits 2–5 have a similar cortical distribution in Pongo, Gorilla and, unexpectedly, Homo, which suggest similar loading of all fingers during habitual locomotion or hand use. In Pan, however, cortical thickness differs between the fingers, potentially reflecting differential loading during knuckle‐walking. Inter‐ and intra‐generic variation in phalangeal cortical bone structure reflects differences in manual behaviours, offering a comparative framework for reconstructing hand use in fossil hominins.

show abstract

mentioning

confidence: 99%

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours

et al. 2023

View full text Add to dashboard Cite

show abstract

“…This mismatch between the actual and theoretical compensation torque could be explained by the effects of passive joint impedance. Each joint in the human body demonstrates resistance against passive motion, especially near the end range of motion, resulting from muscles, ligaments, nerves, blood vessels, and skin (Chleboun et al, 1997 ; Ayhan and Ayhan, 2020 ). Formica et al ( 2012 ) measured the passive joint impedance of the wrist joint in healthy subjects.…”

Section: Discussionmentioning

confidence: 99%

The efficacy of different torque profiles for weight compensation of the hand

van der Burgh,

Filius,

Radaelli

et al. 2024

Wearable Technol.

View full text Add to dashboard Cite

Orthotic wrist supports will be beneficial for people with muscular weakness to keep their hand in a neutral rest position and prevent potential wrist contractures. Compensating the weight of the hands is complex since the level of support depends on both wrist and forearm orientations. To explore simplified approaches, two different weight compensation strategies (constant and linear) were compared to the theoretical ideal sinusoidal profile and no compensation in eight healthy subjects using a mechanical wrist support system. All three compensation strategies showed a significant reduction of 47–53% surface electromyography activity in the anti-gravity m. extensor carpi radialis. However, for the higher palmar flexion region, a significant increase of 44–61% in the m. flexor carpi radialis was found for all compensation strategies. No significant differences were observed between the various compensation strategies. Two conclusions can be drawn: (1) a simplified torque profile (e.g., constant or linear) for weight compensation can be considered as equally effective as the theoretically ideal sinusoidal profile and (2) even the theoretically ideal profile provides no perfect support as other factors than weight, such as passive joint impedance, most likely influence the required compensation torque for the wrist joint.

show abstract

“…However, a recent experimental study has shown stress is concentrated on pulleys, which hold the flexor tendon close to the bone during interphalangeal joint flexion (Leijnse et al, 2021). These pulleys arise from the radial and ulnar edges of the palmar surface, with annular pulleys A2 and A4 being the main pulleys within the fingers (Ayhan & Ayhan, 2020). The A4 pulley is located on the intermediate phalanges and Leijnse et al (2021) have shown that stress is concentrated proximally on the A4 pulley, which coincides with the location of the FSRs.…”

Section: Extant Great Ape Intermediate Phalangeal Cortical Distributi...mentioning

confidence: 99%

Cortical bone architecture of hominid intermediate phalanges reveals functional signals of locomotion and manipulation

Syeda,

Tsegai,

Cazenave

et al. 2024

American Journal of Biological Anthropology

View full text Add to dashboard Cite

ObjectivesReconstruction of fossil hominin manual behaviors often relies on comparative analyses of extant hominid hands to understand the relationship between hand use and skeletal morphology. In this context, the intermediate phalanges remain understudied. Thus, here we investigate cortical bone morphology of the intermediate phalanges of extant hominids and compare it to the cortical structure of the proximal phalanges, to investigate the relationship between cortical bone structure and inferred loading during manual behaviors.Materials and MethodsUsing micro‐CT data, we analyze cortical bone structure of the intermediate phalangeal shaft of digits 2–5 in Pongo pygmaeus (n = 6 individuals), Gorilla gorilla (n = 22), Pan spp. (n = 23), and Homo sapiens (n = 23). The R package morphomap is used to study cortical bone distribution, cortical thickness and cross‐sectional properties within and across taxa.ResultsNon‐human great apes generally have thick cortical bone on the palmar shaft, with Pongo only having thick cortex on the peaks of the flexor sheath ridges, while African apes have thick cortex along the entire flexor sheath ridge and proximal to the trochlea. Humans are distinct in having thicker dorsal shaft cortex as well as thick cortex at the disto‐palmar region of the shaft.DiscussionVariation in cortical bone distribution and properties of the intermediate phalanges is consistent with differences in locomotor and manipulative behaviors in extant great apes. Comparisons between the intermediate and proximal phalanges reveals similar patterns of cortical bone distribution within each taxon but with potentially greater load experienced by the proximal phalanges, even in knuckle‐walking African apes. This study provides a comparative context for the reconstruction of habitual hand use in fossil hominins and hominids.

show abstract

Kinesiology of the wrist and the hand

Cited by 8 publications

References 230 publications

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours

The efficacy of different torque profiles for weight compensation of the hand

Cortical bone architecture of hominid intermediate phalanges reveals functional signals of locomotion and manipulation

Contact Info

Product

Resources

About