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Hand Anatomy and Biomechanics

Hand anatomy & biomechanics: intrinsic/extrinsic muscle balance, ligamentous constraints, and implications for diagnosing/treating dysfunction.

Overview

Hand biomechanics and reconstruction rely on precise measurement of individual finger forces to refine models and quantify disease impact [1]. Comprehensive management requires balancing functional restoration with aesthetic preservation [2]. Surgical timing is critical for arthrogrypotic deformities, where early bony or soft-tissue interventions yield superior outcomes [3]. Decision-making for thumb reconstruction must integrate pre-operative assessment and intraoperative findings of all thumb elements [7], while functional range of motion serves as the primary metric for surgical indications, rehabilitation planning, and outcome assessment [58].

Reconstructive strategies vary by complexity and tissue availability. Decellularized flexor tendon-bone grafts provide immediate post-reconstruction strength and excursion exceeding therapy requirements [8]. In contrast, partial hand transplantation is inferior to distal forearm transplantation due to technical, functional, and ethical challenges [31]. For extensor mechanism injuries, interventions such as relative motion flexion orthoses benefit from detailed anatomical understanding of zones III and IV [15]. Surgeons must also weigh ulnar versus radial superficialis slip resection to preserve function and strength [32].

Finger fracture management continues to evolve, with operative techniques and implants improving while outcomes remain dependent on fracture type, surgeon experience, and patient compliance [29]. Three-dimensional analysis of soft tissue footprints aids in restoring elbow biomechanics and preserving range of motion [14]. However, standardizing arthrodesis angles based on mean maximal thumb strength is unreliable due to population variation and the distinct biomechanics of fused joints [30].

Anatomy & Pathophysiology

Kinematics and Biomechanics

The metacarpophalangeal joint possesses five kinematic degrees of freedom from a mechanical perspective [20]. Kinematic analysis of the thumb CMC joint effectively differentiates surgical treatments for end-stage OA [13], though total joint arthroplasty, while restoring function, cannot fully replicate the kinematics of the healthy TMC joint [40]. Thumb motion capability remains unaffected by sex and handedness [42], yet the dominant hand demonstrates greater strength than the nondominant hand, with no differences observed among three specific hand strength measurements under identical conditions [45]. The middle finger serves as the most important contributor to grip strength [48], and measurement of individual finger forces yields more accurate biomechanical models to determine disease effects on hand function [1]. Active and passive intrinsic reconstruction methods improve basic grasp and release kinematics in experimental cadaver models [21], while index finger PIP joint fusion is associated with impairment in precision pinch kinematics [49].

Dynamic interactions during cylinder grip reveal specific patterns where DIP joints consistently initiate flexion last, with synchronization increasing significantly by the end of motion compared to the beginning [44]. Further analysis of cylinder grip dynamics is required to fully understand this motion in healthy individuals [39]. Lateral grip styles involve more whole-arm stabilizing movements, whereas dynamic grip styles require fine dexterous movements [47]. A novel instrument quantifies hand forces during jar opening to better understand associated kinetics and joint protection strategies [50]. Kinematic variability during the Jebsen-Taylor Hand Function Test informs task selection for evaluation and provides expected variability for patient comparison [51]. Biomechanical concepts including stress, strain, and moments are necessary for understanding the basic science underlying hand therapy techniques [4], and the opposite hand can serve as a reference to analyze load-distribution patterns [5].

Ligamentous and Osseous Stability

The estimated lengths of principal ligaments stabilizing the CMC joint change substantially during thumb motions in vivo [27]. A biomechanical model has successfully created a reproducible and clinically relevant palmar beak fracture [46].

Classification

OMT Classification: The OMT classification system describes hand anomalies that may present in over 1,400 diseases [24].

Thumb Hypoplasia Management: Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options [9].

Upper Limb Anomaly Classification: Authors advocate an updated classification scheme for upper limb anomalies that incorporates the current molecular perspective of limb development and the pathogenetic basis for malformations using dysmorphology terminology to improve diagnosis, treatment, and research [56].

Other Considerations: Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions [1]. Kinematic analysis of the thumb CMC joint is effective in differentiating surgical treatments used for end-stage OA [13]. The structure of the human hand is distinct in many ways from that of even our closest relatives in the primate order [16]. From a mechanical perspective, the metacarpophalangeal joint represents a joint with 5 kinematic degrees of freedom [20]. Strength of the thumb is affected in all types of triphalangeal thumb, although it is apparently sufficient in daily life for the investigated group [26]. The pulley system of the thumb is composed of 4 components, as opposed to the traditional view of only 3 [53].

Clinical Presentation

A comprehensive hand evaluation begins with a systematic physical examination encompassing vascular, sensory, and motor assessments [38]. Accurate diagnosis and management of hand and carpal fractures and dislocations are predicated on this thorough examination alongside appropriate imaging to limit joint stiffness while preserving mobility and function [18]. For load-distribution analysis, the opposite hand serves as a reference [5], while reference values for intrinsic muscle strength in adolescents and young adults guide the evaluation of therapeutic outcomes [19]. In children with hemiplegic cerebral palsy, the less affected hand must be evaluated and included in comprehensive treatment plans [22].

Biomechanical modeling benefits from measuring individual finger forces to determine the effect of disease on hand function [1]. Understanding basic science concepts such as stress, strain, and moments is necessary for interpreting hand therapy techniques [4]. Grip strength development is influenced by Gender, Age, and Hand preference [12]. Specific anatomical factors impact outcomes in radial longitudinal deficiency; individuals with moderate to severe forms exhibit weaker grasp, fewer activities using their thumbs, and more primitive grasp patterns compared to those with milder forms [10]. The ulnar nerve regularly contributes to flexion of the middle finger [41].

Thumb hypoplasia management requires understanding Embryology, Epidemiology, Classification, Presentation, and Management options [9]. Increased forearm severity correlates with more severe thumb hypoplasia in both U.S. and Japanese cohorts [25]. While strength is affected in all types of triphalangeal thumb, it remains sufficient for daily life in the investigated group [26]. Vascular patterns, such as the palmar type of median artery serving as a source for the superficial palmar arch, are critical considerations for hand surgeons [23].

The OMT classification describes hand anomalies presenting in over 1,400 diseases [24]. Most arthrogrypotic hand deformity surgeries yield better outcomes when performed during the early years of life using Bony interventions or Soft-tissue interventions [3].

Investigations

Plain radiography: Accurate diagnosis and management of hand and carpal fractures and dislocations are predicated on thorough physical examination and appropriate imaging to limit joint stiffness while preserving mobility and function [18]. Radiographs can reliably distinguish between Blauth IIIA and IIIB thumbs, with near-normal length and width predicting IIIA and abnormally short, narrow, and tapered bases predicting IIIB [75]. A distance of more than 2 mm between the abnormal bone and the distal phalanx suggests a triphalangeal thumb [67]. Arterial calcifications on hand radiographs are independently associated with coronary artery disease [64].

Computed tomography: Radiography or computed tomography of the forearm should be performed to exclude a bony prominence on the proximal part of the ulna in patients with congenital flexion deformity with an aberrant origin of the flexor digitorum profundus [61]. Three-dimensional CT angiography is useful for preoperative planning of complex congenital hand malformations, providing detailed abnormal vascular patterns and bony malformations [71]. Volar and proximal translation of the proximal phalanx was observed on four-dimensional computed tomography after silicone implant arthroplasty in patients with rheumatoid arthritis [69].

Other Considerations: Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions [1]. To analyze a hand's load-distribution pattern, the opposite hand can be used as a reference [5]. A robust model for predicting bone age can be developed by leveraging deep learning technologies trained on over 20,000 hand radiographs across three distinct, diverse data sets [63]. Contraction of the first dorsal interosseous muscle appears to radiographically reduce subluxation of the healthy thumb carpometacarpal joint [73]. Metacarpophalangeal joint motion should be assessed under standardized wrist positions [74]. Manugraphy measures total strength of a hand and enables more precise comparisons of isolated hand regions applying dynamic measurements [77]. Vascular patterns of the palmar type of median artery as a source of the superficial palmar arch are important to hand surgeons [23].

Treatment

Non-Operative

Conservative management strategies rely on a foundational understanding of hand biomechanics, including stress, strain, and moments, to guide therapeutic techniques [4]. For non-surgical extensor mechanism injuries, the use of relative motion flexion (RMF) orthoses is supported by an in-depth analysis of extensor mechanism zone III and IV anatomy [15]. In cases of myositis ossificans, early surgical management may be considered for lesions with prominent symptoms [76]. Additionally, establishing normative values for soft-tissue redundancy over the proximal interphalangeal joint assists in determining the optimal timing for surgical intervention once soft-tissue equilibrium is achieved [37].

Operative

Indications: Surgical intervention for arthrogrypotic hand deformities yields better outcomes when performed during the early years of life using bony and/or soft-tissue interventions [3]. For thumb hypoplasia, effective management requires a comprehensive understanding of embryology, epidemiology, classification, presentation, and management options [9]. Pre-operative assessment and intraoperative findings of all thumb elements must be considered to define reconstruction methods [7]. In the context of upper extremity elbow soft tissue footprints, anatomical knowledge aids in restoring biomechanics and preserving range of motion [14]. For obstetric brachial plexus paralysis, dimensional discrepancies and functional outcomes are improved by scapula stabilization procedures [28].

Surgical Approach / Technique: Kinematic analysis of the thumb CMC joint is effective in differentiating surgical treatments for end-stage osteoarthritis [13]. When addressing extensor pollicis longus reconstruction, a new technique to determine tension results in satisfactory thumb function with significant improvements in active extension, total active motion, and DASH scores [52]. For finger stiffness, minimally invasive and percutaneous techniques can effectively release several structures with minimal damage to surrounding tissues [66]. In the management of ulnar versus radial superficialis slip resection, surgeons must consider specific findings to preserve function and strength in the injured hand [32]. For thumb interphalangeal joint issues, the consistent pattern of innervation—dorsally by two radial nerve branches and palmarly by one branch each from the ulnar and radial proper digital nerves—provides an anatomical basis for effective and safe denervation [54].

Implant Selection: At the time of repair, decellularized flexor tendon-bone grafts can exceed the strength and excursion needed for hand therapy immediately after reconstruction [8]. Regarding thumb reconstruction, recommending an arthrodesis angle based on the mean values of maximal thumb strength of normal thumbs may not be possible due to population variation and biomechanical differences in a fused joint [30]. For partial hand amputation, the partial hand transplant approach is considered inferior to the distal forearm transplant due to technical, functional, and ethical challenges [31].

Alignment / Balancing Strategy: Metacarpal shortening of up to 5 mm should result in minimal loss of finger flexion force [17]. Fractures of the fingers are better understood with clearly defined indications for surgical treatment, though operative techniques and implants for osteosynthesis continue to evolve with results varying according to fracture type, surgeon experience, and patient compliance [29].

Pain Management: Published clinical results confirm the safety and efficacy of the contralateral C7 transfer procedure for upper limb function, noting that donor site morbidity is typically mild and transient [43].

Adjuncts: Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions [1]. Reference values for intrinsic muscle strength in adolescents and young adults suggest factors to be considered when evaluating hand function and therapeutic outcomes [19]. For children with hemiplegic cerebral palsy, the less affected hand should be evaluated and included in comprehensive treatment plans [22].

Other Considerations: Treatment principles for various hand disorders emphasize the balance between restoring function and maintaining aesthetic appearance [2]. Hand surgeons must maintain an understanding of diagnostic and management considerations for osteoporosis and osteopenia as they encounter patients with poor bone health [68]. Handle position 2 is recommended as the standard position for measuring grip strength with the Jamar Plus hand dynamometer [59]. In the appropriate context, the use of numbers for digits or fingers may be acceptable [55].

Complications

Timing of Intervention: Surgical reconstruction for arthrogrypotic hand deformities yields superior outcomes when performed during the early years of life utilizing bony and/or soft-tissue interventions [3]. Conversely, surgical reconstruction for radial longitudinal deficiency carries a high risk of recurrent deformity [65].

Thumb Function and Anatomy: Individuals with moderate to severe radial longitudinal deficiency exhibit unique anatomical factors affecting outcomes after pollicization, including fewer activities of use, weaker grasp, and retention of more primitive grasp patterns compared to those with milder forms [10]. Increased forearm severity correlates with more severe thumb hypoplasia in both U.S. and Japanese cohorts [25]. The components of radial longitudinal deficiency represent a progressive spectrum of upper extremity abnormalities where distal structures are likely more involved than proximal structures [34]. Regarding motor units, loss of the abductor pollicis longus and extensor pollicis brevis has no functional effect on thumb pinch-strength or hand grip, and only a minimal adverse effect on thumb movement [33].

Vascular and Neurologic Considerations: A persistent median artery can maintain blood flow to a nearly amputated hand following complete transection of the radial and ulnar arteries, thereby preserving hand viability [35]. In brachial plexus cases, spontaneous recovery occurs in 60% to 90% of patients [65].

Other Considerations: Naming congenital upper limb anomalies remains an ongoing challenge influenced by surgeon subjectivity and experience [70]. In distal radius fracture surgery, range of motion, grip strength, and radiographic outcomes are similar between groups, with complication and revision rates being very low and comparable [60].

Recovery

Light activity (weeks): Evidence does not specify a discrete week range for light activity initiation; however, immediate post-reconstruction therapy is feasible as decellularized flexor tendon-bone grafts can exceed the strength and excursion needed for hand therapy immediately after reconstruction [8].

Full activity (months): The evidence does not define a specific month range for full activity return. However, joint replacement and soft tissue reconstruction of the hand remain the most common initial procedures within the first two years following diagnosis [6], and most arthrogrypotic hand deformity surgeries result in better outcomes if performed during the early years of life using bony and/or soft-tissue interventions [3].

Complete recovery / outcome plateau (months): No specific month range for outcome plateau is provided in the evidence base. However, establishment of normative values may enable surgeons to determine progress with hand therapy and choose the optimal timing of surgical intervention once soft-tissue equilibrium is achieved [37].

Rehabilitation protocol: Active and passive intrinsic reconstruction methods improved basic grasp and release kinematics in experimental cadaver hand models [21]. Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions [1]. Metacarpal shortening of up to 5 mm should give minimal loss of finger flexion force [17].

Functional milestones: Individuals with moderate to severe radial longitudinal deficiency have unique anatomical factors that affect outcomes after pollicization, using their thumbs for fewer activities, having weaker grasp, and retaining more primitive grasp patterns compared with those who have milder forms of radial longitudinal deficiency [10]. Gender, age, and hand preference can all have an impact on how strong a handgrip develops [12]. Loss of the abductor pollicis longus and extensor pollicis brevis motor units had no functional effect upon thumb pinch-strength or hand grip, and only a minimal adverse effect upon thumb movement [33]. There is no universal or typical load distribution pattern of the hand but only an individual pattern [78].

Other Considerations: The estimated lengths of principal ligaments stabilizing the CMC joint change substantially during thumb motions in vivo [27]. A persistent median artery helped maintain blood flow to a nearly amputated hand after complete transection of the radial and ulnar arteries, preserving hand viability [35]. The study confirms the presence of a significant dorsal branch of the ulnar digital nerve of the little finger arising at the level of the MCP joint, which remains relatively palmar compared to previous descriptions [36].

Key Evidence

  • [L4] Measurement of individual finger forces can provide more accurate biomechanical models of the hand and determine the effect of disease on hand functions. (10.1016/j.jht.2020.04.002)
  • [L5] Most arthrogrypotic hand deformity surgeries result in better outcomes if performed during the early years of life using bony and/or soft-tissue interventions. (10.1016/j.jhsa.2021.10.027)
  • [Paper] This introductory article lays the foundation of biomechanical concepts such as stress, strain, and moments, which are necessary for understanding the basic science underlying hand therapy treatment techniques. (10.1016/j.jht.2011.12.006)
  • [L4] To analyze a hand's load-distribution pattern, the opposite hand can be used as a reference. (10.1016/j.jhsa.2018.02.016)
  • [L3] Joint replacement and soft tissue reconstruction of the hand remain the most common initial procedures within the first two years following diagnosis. (10.1016/j.jhsa.2014.06.060)
  • [L5] The pre-operative assessment and intraoperative findings of all thumb elements should be considered in surgical decision-making to define the methods of reconstruction. (10.1177/1753193418793579)
  • [L5] At the time of repair, decellularized flexor tendon-bone grafts can exceed the strength and excursion needed for hand therapy immediately after reconstruction. (10.1016/j.jhsa.2013.08.092)
  • [L5] Effective management of thumb hypoplasia requires an understanding of the embryology, epidemiology, classification, presentation, and management options. (10.5435/00124635-200606000-00005)
  • [L4] Individuals with moderate to severe radial longitudinal deficiency have unique anatomical factors that affect outcomes after pollicization, using their thumbs for fewer activities, having weaker grasp, and retaining more primitive grasp patterns compared with those who have milder forms of radial longitudinal deficiency. (10.1016/j.jhsa.2024.02.010)
  • [L4] The outcomes of this study also demonstrated that gender, age, and hand preference can all have an impact on how strong a handgrip develops. (10.1186/s12891-023-06197-0)
  • [L5] Kinematic analysis of the thumb CMC joint is effective in differentiating surgical treatments used for end-stage OA. (10.1016/j.jhsa.2007.02.009)
  • [L5] This study provides the upper extremity surgeon with information that may aid in restoring elbow biomechanics and preserving range of motion in these patients. (10.1016/j.jse.2014.05.003)
  • [L5] Hand surgery and hand therapy practice interventions, including use of RMF orthoses for management of non-surgical and surgical EM injuries may benefit from an in-depth look at the EM zone III and IV anatomy and biomechanics. (10.1016/j.jht.2023.01.002)
  • [L5] The structure of the human hand is distinct in many ways from that of even our closest relatives in the primate order. (10.1016/j.jhsa.2021.07.006)
  • [L5] Metacarpal shortening of up to 5 mm should give minimal loss of finger flexion force. (10.1177/1753193412461589)
  • [L4] The results provide reference values and suggest factors to be considered when evaluating hand function and therapeutic outcomes in both clinical and research settings. (10.1016/j.jht.2017.05.012)
  • [L5] From a mechanical perspective, the metacarpophalangeal joint represents a joint with 5 kinematic degrees of freedom. (10.1016/j.jhsa.2008.10.004)
  • [L5] Active and passive intrinsic reconstruction methods improved basic grasp and release kinematics in experimental cadaver hand models. (10.1016/j.jhsa.2014.09.031)
  • [L3] The less affected hand should be evaluated and included in comprehensive treatment plans for these children. (10.1177/1558944721990803)
  • [L4] These vascular patterns are important to hand surgeons. (10.1007/s11552-009-9197-4)
  • [L4] The OMT classification can be used to describe hand anomalies that may present in over 1,400 diseases. (10.1016/j.jhsa.2017.03.043)
  • [L3] Both cohorts showed that increased forearm severity was associated with more severe thumb hypoplasia. (10.1016/j.jhsa.2019.12.004)
  • [L4] Strength of the thumb is affected in all types of triphalangeal thumb, although it is apparently sufficient in daily life for the investigated group. (10.1177/1753193412438195)
  • [L4] The estimated lengths of principal ligaments stabilizing the CMC joint change substantially during thumb motions in vivo. (10.1016/j.jhsa.2010.11.007)
  • [L4] Dimensional discrepancies and functional outcomes are improved by scapula stabilization procedures. (10.1007/s11552-014-9640-z)
  • [L5] Fractures of the fingers are better understood, indications for surgical treatment are more clearly defined, and operative techniques and implants for osteosynthesis are continuing to evolve and improve, though results vary according to fracture type, surgeon experience, and patient compliance. (10.1054/jhsb.2002.0889)
  • [L4] Recommending an arthrodesis angle based on the mean values of maximal thumb strength of normal thumbs may not be possible because of the variation in the population and the difference in biomechanics in a fused joint. (10.1177/17531934231184821)
  • [L4] The partial hand transplant approach in the evaluated candidate was concluded to be inferior to the distal forearm transplant due to technical, functional, and ethical challenges. (10.1016/j.jhsa.2018.04.031)
  • [L5] Our findings show this is not an arbitrary choice; hand surgeons should keep our findings in mind when deciding which slip to sacrifice, in effort to preserve function and strength in the injured hand. (10.1177/15589447211060416)
  • [L4] Loss of the abductor pollicis longus and extensor pollicis brevis motor units had no functional effect upon thumb pinch-strength or hand grip, and only a minimal adverse effect upon thumb movement. (10.1054/jhsb.2001.0744)
  • [L2] This study supports the growing body of evidence that the components of radial longitudinal deficiency represent a progressive spectrum of upper extremity abnormalities, with distal structures likely to be more involved than proximal structures. (10.2106/00004623-200410000-00010)
  • [Case_report] A persistent median artery helped maintain blood flow to a nearly amputated hand after complete transection of the radial and ulnar arteries, preserving hand viability. (10.1016/j.jhsa.2011.01.020)
  • [L4] The study confirms the presence of a significant dorsal branch of the ulnar digital nerve of the little finger arising at the level of the MCP joint, which remains relatively palmar compared to previous descriptions. (10.1177/1753193408101468)
  • [L3] Establishment of normative values may enable surgeons to explain the lack of progress after surgical joint release, determine progress with hand therapy, and choose the optimal timing of surgical intervention once soft-tissue equilibrium is achieved. (10.1016/j.jhsg.2025.100748)
  • [L5] This current concepts review presents a systematic process of performing a comprehensive physical examination of the hand including vascular, sensory, and motor assessments, which is essential for appropriate treatment and providing the patient the opportunity for the best outcome. (10.1016/j.jhsa.2014.04.026)
  • [L4] However, to fully understand the cylinder grip in healthy individuals, further analysis of the dynamics of the cylinder grip is required. (10.1016/j.jhsa.2009.12.031)
  • [L4] We also showed that, whereas total joint arthroplasty is able to restore thumb function, it cannot fully replicate the kinematics of the healthy TMC joint. (10.1016/j.jhsa.2017.10.011)
  • [L4] Our clinical and neurophysiologic observations confirm that the ulnar nerve regularly contributes to flexion of the middle finger. (10.1177/1753193413505581)
  • [L3] Thumb motion capability was unaffected by sex and handedness. (10.1016/j.jhsa.2014.08.012)
  • [L5] Published clinical results have demonstrated significant improvements in upper limb function, confirming the procedure's safety and efficacy, with donor site morbidity that is typically mild and transient. (10.1177/17531934251314640)
  • [L4] The dynamic interaction of finger joints during cylinder grip shows specific patterns, with DIP joints consistently initiating flexion last and synchronization increasing significantly by the end of motion compared to the beginning. (10.1177/1753193412444399)
  • [L5] This model successfully created a reproducible and clinically relevant palmar beak fracture in a biomechanical setting. (10.1016/j.jhsa.2018.04.024)
  • [L4] Lateral grip styles involve more whole-arm, stabilizing movements while dynamic grip styles require fine dexterous movements. (10.1016/j.jht.2021.03.004)
  • [L4] The middle finger was the most important contributor to grip strength. (10.1016/j.jhsa.2014.06.121)
  • [L1] This study reports impairment in the kinematics of precision pinch associated with index finger PIP joint fusion. (10.1016/j.jhsa.2011.09.010)
  • [L4] Our findings support that we have presented a tool which can be used in future study within this population to better understand the hand kinetics associated with the highly problematic task of jar-opening and joint protection strategies intended to reduce hand loads. (10.1016/j.jht.2021.04.012)
  • [L4] Results can be used to inform selection of tasks for kinematic evaluation and provide expected variability for comparison to patient populations. (10.1016/j.jht.2018.10.002)
  • [L4] This technique resulted in satisfactory thumb function with significant improvements in active extension, total active motion, and DASH scores. (10.1177/1753193419845281)
  • [L4] The pulley system of the thumb is composed of 4 components, as opposed to the traditional view of only 3. (10.1016/j.jhsa.2012.08.005)
  • [L5] The study demonstrates a consistent pattern of innervation of the thumb interphalangeal joint, provided dorsally by two branches of the radial nerve and palmarly by one branch each from the ulnar and radial proper digital nerves, which may provide the anatomical basis for effective and safe denervation. (10.1177/1753193418771311)
  • [L5] In the appropriate context, the use of numbers for digits or fingers may be acceptable. (10.1177/1753193419841530)
  • [L5] The authors advocate an updated classification scheme for upper limb anomalies that incorporates the current molecular perspective of limb development and the pathogenetic basis for malformations using dysmorphology terminology to improve diagnosis, treatment, and research. (10.1016/j.jhsa.2010.09.031)
  • [L4] The functional range of motion is important for directing indications for surgery and rehabilitation, and assessing outcome of treatment. (10.1177/1753193414533754)
  • [L4] We therefore recommend handle position 2 as the standard position for measuring grip strength with the Jamar Plus hand dynamometer. (10.1016/j.jhsa.2012.08.014)
  • [L4] Range of motion, grip strength, and radiographic outcomes are similar between groups, and complication and revision rates were very low and comparable. (10.1016/j.jhsa.2022.12.018)
  • [L4] They recommend performing radiography or computed tomography of the forearm to exclude a bony prominence on the proximal part of the ulna in patients with this deformity. (10.1016/j.jhsa.2015.07.012)
  • [L4] Leveraging newer DL technologies trained on over 20,000 hand radiographs across 3 distinct, diverse data sets, this study developed a robust model for predicting bone age that outperforms previous state-of-the-art models when applied to validation data sets. (10.1177/03635465251359618)
  • [L3] The current data demonstrate that arterial calcifications on hand radiographs are independently associated with CAD. (10.1016/j.jhsa.2019.10.004)
  • [L5] Minimally invasive and percutaneous techniques can effectively release several structures known to cause finger stiffness with minimal damage to surrounding structures. (10.1016/j.jhsa.2019.01.006)
  • [L4] A distance of more than 2 mm between the abnormal bone and the distal phalanx suggests a triphalangeal thumb. (10.1016/j.jhsa.2019.04.013)
  • [L5] This article provides an updated review on current methods of screening and the role of the hand surgeon in the evaluation and treatment of osteoporosis and osteopenia, emphasizing that hand surgeons must maintain an understanding of diagnostic and management considerations as they encounter patients with poor bone health. (10.1016/j.jhsa.2025.05.009)
  • [L4] Volar and proximal translation of the proximal phalange was observed on 4-dimensional computed tomography. (10.1016/j.jhsa.2021.10.001)
  • [L4] This historical case note study observed an evolution of nomenclature for congenital upper limb anomalies over the last few decades and highlighted that naming these conditions remains an ongoing challenge influenced by surgeon subjectivity and experience. (10.1177/17531934231160400)
  • [L4] Three-dimensional CT angiography is useful for preoperative planning of complex congenital hand malformations, providing detailed abnormal vascular patterns and bony malformations. (10.1177/1753193420954357)
  • [L4] Contraction of the FDI appears to radiographically reduce subluxation of the healthy thumb CMC joint. (10.1016/j.jht.2015.06.002)
  • [L4] Metacarpophalangeal joint motion should be assessed under standardized wrist positions. (10.1177/1558944717736823)
  • [L3] Radiographs can reliably distinguish between Blauth IIIA and IIIB thumbs, with near-normal length and width predicting IIIA and abnormally short, narrow, and tapered bases predicting IIIB. (10.1016/j.jhsa.2024.04.005)
  • [Case_report] Their review of the literature supports the idea that early surgical management may be considered for hand lesions with prominent symptoms. (10.1016/j.jhsa.2017.03.007)
  • [L4] Both measurement techniques yielded similar results, suggesting that manugraphy is well suited for clinical research purposes because it not only takes measurements that are just as reproducible and valid as the conventional measurement technique but in doing so measures not just the total strength of a hand but also enables more precise comparisons of isolated hand regions applying dynamic measurements. (10.1186/s12891-018-1971-4)
  • [L2] There is no universal or typical load distribution pattern of the hand but only an individual pattern. (10.1016/j.jht.2016.10.009)

See Also

References

[1] Evaluation of individual finger forces during activities of daily living in healthy individuals and those with hand arthritis. Journal of Hand Therapy. 2020. DOI: 10.1016/j.jht.2020.04.002

[2] 9. Hand Surgery. 2013.

[3] The Hand in Distal Arthrogryposis. The Journal of Hand Surgery. 2022. DOI: 10.1016/j.jhsa.2021.10.027

[4] Understanding the Biomechanical Nature of Musculoskeletal Tissue. Journal of Hand Therapy. 2012. DOI: 10.1016/j.jht.2011.12.006

[5] Influence of Maximal or Submaximal Effort on the Load Distribution of the Hand Analyzed by Manugraphy. The Journal of Hand Surgery. 2018. DOI: 10.1016/j.jhsa.2018.02.016

[6] Muscle Control of the First Carpometacarpal Joint. The Journal of Hand Surgery. 2014. DOI: 10.1016/j.jhsa.2014.06.060

[7] Surgical techniques for reconstruction of the hypoplastic thumb. Journal of Hand Surgery (European Volume). 2018. DOI: 10.1177/1753193418793579

[8] Decellularized Human Tendon–Bone Grafts for Composite Flexor Tendon Reconstruction: A Cadaveric Model of Initial Mechanical Properties. The Journal of Hand Surgery. 2013. DOI: 10.1016/j.jhsa.2013.08.092

[9] The Hypoplastic Thumb. Journal of the American Academy of Orthopaedic Surgeons. 2006. DOI: 10.5435/00124635-200606000-00005

[10] The Effects of Radial Longitudinal Deficiency on Long-Term Use of the Thumb in Pediatric Patients Following Index Pollicization. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2024.02.010

[12] Normative values for hand grip and pinch strength for 6 to 18 year-olds in Saudi Arabia. BMC Musculoskeletal Disorders. 2023. DOI: 10.1186/s12891-023-06197-0

[13] Joint Kinematics After Thumb Carpometacarpal Joint Reconstruction: An In Vitro Comparison of Various Constructs. The Journal of Hand Surgery. 2007. DOI: 10.1016/j.jhsa.2007.02.009

[14] Three-dimensional analysis of elbow soft tissue footprints and anatomy. Journal of Shoulder and Elbow Surgery. 2014. DOI: 10.1016/j.jse.2014.05.003

[15] An in-depth look at zone III and IV anatomy of the finger extensor mechanism and some clinical implications for use of the relative motion flexion orthosis. Journal of Hand Therapy. 2023. DOI: 10.1016/j.jht.2023.01.002

[16] The Evolution of the Human Hand From an Anthropologic Perspective. The Journal of Hand Surgery. 2022. DOI: 10.1016/j.jhsa.2021.07.006

[17] The effect of metacarpal shortening on digital flexion force. Journal of Hand Surgery (European Volume). 2012. DOI: 10.1177/1753193412461589

[18] Chapter 29 Hand/Carpal Fractures and Dislocations. 2021.

[19] Reference values of intrinsic muscle strength of the hand of adolescents and young adults. Journal of Hand Therapy. 2018. DOI: 10.1016/j.jht.2017.05.012

[20] Quantified Contours of Curvature in Female Index, Middle, Ring, and Small Metacarpophalangeal Joints. The Journal of Hand Surgery. 2009. DOI: 10.1016/j.jhsa.2008.10.004

[21] The Effect of Intrinsic Loading and Reconstruction Upon Grip Capacity and Finger Extension Kinematics. The Journal of Hand Surgery. 2015. DOI: 10.1016/j.jhsa.2014.09.031

[22] Dexterity of the Less Affected Hand in Children With Hemiplegic Cerebral Palsy. HAND. 2021. DOI: 10.1177/1558944721990803

[23] Palmar Type of Median Artery as a Source of Superficial Palmar Arch: A Cadaveric Study with its Clinical Significance. HAND. 2009. DOI: 10.1007/s11552-009-9197-4

[24] Identification of Associated Genes and Diseases in Patients With Congenital Upper-Limb Anomalies: A Novel Application of the OMT Classification. The Journal of Hand Surgery. 2017. DOI: 10.1016/j.jhsa.2017.03.043

[25] Radial Longitudinal Deficiency: Severity Differences Between U.S. and Japanese Cohorts. The Journal of Hand Surgery. 2020. DOI: 10.1016/j.jhsa.2019.12.004

[26] Thumb strength in all types of triphalangeal thumb. Journal of Hand Surgery (European Volume). 2012. DOI: 10.1177/1753193412438195

[27] In Vivo Length and Changes of Ligaments Stabilizing the Thumb Carpometacarpal Joint. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2010.11.007

[28] Morphometric Analysis of the Effect of Scapula Stabilization on Obstetric Brachial Plexus Paralysis Patients. HAND. 2014. DOI: 10.1007/s11552-014-9640-z

[29] Treatment of Fractures of the Fingers. What’s New?. Journal of Hand Surgery. 2003. DOI: 10.1054/jhsb.2002.0889

[30] Metacarpophalangeal joint angle of the thumb during maximal pinch strength: a study of healthy volunteers. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934231184821

[31] Partial Hand Transplant: Lessons Learned From Cadaveric Dissection Studies. The Journal of Hand Surgery. 2018. DOI: 10.1016/j.jhsa.2018.04.031

[32] Ulnar Superficialis Slip Resection Versus Radial Superficialis Slip Resection: A Biomechanical Pilot Study. HAND. 2021. DOI: 10.1177/15589447211060416

[33] Thumb Function without the Abductor Pollicis Longus and Extensor Pollicis Brevis. Journal of Hand Surgery. 2002. DOI: 10.1054/jhsb.2001.0744

[34] The Association of Radial Deficiency with Thumb Hypoplasia. The Journal of Bone & Joint Surgery. 2004. DOI: 10.2106/00004623-200410000-00010

[35] Persistent Median Artery in a Pediatric Trauma Patient: Case Report. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2011.01.020

[36] The anatomy of the ulnar digital nerve of the little finger: a cadaveric study. Journal of Hand Surgery (European Volume). 2009. DOI: 10.1177/1753193408101468

[37] A Novel Technique to Assess Soft-Tissue Redundancy Over the Proximal Interphalangeal Joint. Journal of Hand Surgery Global Online. 2025. DOI: 10.1016/j.jhsg.2025.100748

[38] Physical Examination of the Hand. The Journal of Hand Surgery. 2014. DOI: 10.1016/j.jhsa.2014.04.026

[39] Motion Coordination Patterns During Cylinder Grip Analyzed With a Sensor Glove. The Journal of Hand Surgery. 2010. DOI: 10.1016/j.jhsa.2009.12.031

[40] Impact of Osteoarthritis and Total Joint Arthroplasty on the Kinematics of the Trapeziometacarpal Joint: A Pilot Study. The Journal of Hand Surgery. 2018. DOI: 10.1016/j.jhsa.2017.10.011

[41] The ulnar nerve consistently drives flexion of the middle finger. Journal of Hand Surgery (European Volume). 2013. DOI: 10.1177/1753193413505581

[42] Effect of Carpometacarpal Joint Osteoarthritis, Sex, and Handedness on Thumb In Vivo Kinematics. The Journal of Hand Surgery. 2014. DOI: 10.1016/j.jhsa.2014.08.012

[43] Harnessing the uninjured hemisphere for treatment of the stroke or brain-injured patient – evolution of the contralateral C7 transfer. Journal of Hand Surgery (European Volume). 2025. DOI: 10.1177/17531934251314640

[44] Dynamic aspects during the cylinder grip — flexion sequence of the finger joints analyzed using a sensor glove. Journal of Hand Surgery (European Volume). 2012. DOI: 10.1177/1753193412444399

[45] To_Sit_or_To_Stand_Does_It_Make_a_Difference_When_One_Measures_Hand_Strength_S0894113008001233. n.d..

[46] Bennett Fractures: A Biomechanical Model and Relevant Ligamentous Anatomy. The Journal of Hand Surgery. 2019. DOI: 10.1016/j.jhsa.2018.04.024

[47] The relationship between muscle activation and handwriting quality with non-native grip styles. Journal of Hand Therapy. 2022. DOI: 10.1016/j.jht.2021.03.004

[48] Comparison of Grip Strength Among 6 Grip Methods. The Journal of Hand Surgery. 2014. DOI: 10.1016/j.jhsa.2014.06.121

[49] Influence of Index Finger Proximal Interphalangeal Joint Arthrodesis on Precision Pinch Kinematics. The Journal of Hand Surgery. 2011. DOI: 10.1016/j.jhsa.2011.09.010

[50] Reliability and validity of a novel instrument for the quantification of hand forces during a jar opening task. Journal of Hand Therapy. 2022. DOI: 10.1016/j.jht.2021.04.012

[51] Assessing kinematic variability during performance of Jebsen-Taylor Hand Function Test. Journal of Hand Therapy. 2020. DOI: 10.1016/j.jht.2018.10.002

[52] A new technique to determine the tension in extensor pollicis longus reconstruction. Journal of Hand Surgery (European Volume). 2019. DOI: 10.1177/1753193419845281

[53] Varied Anatomy of the Thumb Pulley System: Implications for Successful Trigger Thumb Release. The Journal of Hand Surgery. 2012. DOI: 10.1016/j.jhsa.2012.08.005

[54] Innervation of the interphalangeal joint of the thumb: anatomical study. Journal of Hand Surgery (European Volume). 2018. DOI: 10.1177/1753193418771311

[55] Terminology for hand surgery: digits, thumb, fingers, names and numbers. Journal of Hand Surgery (European Volume). 2019. DOI: 10.1177/1753193419841530

[56] Developmental Biology and Classification of Congenital Anomalies of the Hand and Upper Extremity. The Journal of Hand Surgery. 2010. DOI: 10.1016/j.jhsa.2010.09.031

[58] The functional range of motion of the finger joints. Journal of Hand Surgery (European Volume). 2014. DOI: 10.1177/1753193414533754

[59] Optimal Jamar Dynamometer Handle Position to Assess Maximal Isometric Hand Grip Strength in Epidemiological Studies. The Journal of Hand Surgery. 2012. DOI: 10.1016/j.jhsa.2012.08.014

[60] Effect of Time-To-Surgery on Distal Radius Fracture Outcomes: A Systematic Review. The Journal of Hand Surgery. 2023. DOI: 10.1016/j.jhsa.2022.12.018

[61] Congenital Flexion Deformity With an Aberrant Origin of the Flexor Digitorum Profundus: A Potentially Ignored Disease. The Journal of Hand Surgery. 2015. DOI: 10.1016/j.jhsa.2015.07.012

[63] Determination of Skeletal Age From Hand Radiographs Using Deep Learning. The American Journal of Sports Medicine. 2025. DOI: 10.1177/03635465251359618

[64] Coronary Artery Disease Association With Arterial Calcifications on Routine Hand Radiographs. The Journal of Hand Surgery. 2019. DOI: 10.1016/j.jhsa.2019.10.004

[65] Chapter 26 Congenital Hand and Wrist Differences and Brachial Plexus Birth Injury. 2019.

[66] Percutaneous Release of the Finger Joints and Mini-Open Intrinsic Release With Tenolysis: A Cadaveric Study. The Journal of Hand Surgery. 2019. DOI: 10.1016/j.jhsa.2019.01.006

[67] Analysis of Causes for Congenital Ulnar Deviated Thumbs at the Distal Phalanx Level in 157 Thumbs. The Journal of Hand Surgery. 2019. DOI: 10.1016/j.jhsa.2019.04.013

[68] An Update on Osteoporosis Screening: Advances, Applications, and the Role of Hand Surgeons and Allied Health Providers. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2025.05.009

[69] In Vivo Metacarpophalangeal Joint Kinematics After Silicone Implant Arthroplasty in Patients With Rheumatoid Arthritis. The Journal of Hand Surgery. 2023. DOI: 10.1016/j.jhsa.2021.10.001

[70] Re-examining the nomenclature of congenital failure of formation in the upper limb: a historical perspective. Journal of Hand Surgery (European Volume). 2023. DOI: 10.1177/17531934231160400

[71] Three-dimensional CT angiography for surgical planning in congenital hand malformations: a case series presentation. Journal of Hand Surgery (European Volume). 2020. DOI: 10.1177/1753193420954357

[73] First dorsal interosseous muscle contraction results in radiographic reduction of healthy thumb carpometacarpal joint. Journal of Hand Therapy. 2015. DOI: 10.1016/j.jht.2015.06.002

[74] Influence of Wrist Position on the Metacarpophalangeal Joint Motion of the Index Through Small Finger. HAND. 2017. DOI: 10.1177/1558944717736823

[75] Radiographic Features of the Metacarpal in Blauth Type III Thumb Hypoplasia. The Journal of Hand Surgery. 2025. DOI: 10.1016/j.jhsa.2024.04.005

[76] Management of Myositis Ossificans of the Hand: A Case Report and a Review of the Literature. The Journal of Hand Surgery. 2017. DOI: 10.1016/j.jhsa.2017.03.007

[77] Parameters influencing hand grip strength measured with the manugraphy system. BMC Musculoskeletal Disorders. 2018. DOI: 10.1186/s12891-018-1971-4

[78] Load distribution of the hand during cylinder grip analyzed by Manugraphy. Journal of Hand Therapy. 2017. DOI: 10.1016/j.jht.2016.10.009

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