Author: Justine Smith

  • Hand in Hand: Structure, Function, and Carpal Tunnel Syndrome

    The human hand is a marvel of biological engineering—finely tuned for both strength and precision. It enables everything from forceful grips to delicate manipulations, thanks to its complex interplay of bones, joints, muscles, tendons, nerves, and blood vessels. Understanding this intricate structure is essential, especially when exploring conditions like carpal tunnel syndrome, which can severely impact hand function.

    Figure 1 Nail anatomy (Lane et al., 2023)

    Bones: The Framework of Dexterity

    The skeletal architecture of the hand begins with the carpal bones, a cluster of eight small bones forming the wrist. These bones are arranged in two rows and act as the foundation for hand movement. The proximal row includes the scaphoid, lunate, triquetrum, and pisiform, articulating with the radius and ulna of the forearm. The distal row connects to the five metacarpal bones, which extend into the palm and link to the phalanges, or finger bones.

    Each finger—except the thumb—has three phalanges (proximal, middle, and distal), while the thumb has only two. These bones not only support movement but are integral to hand stability and function.

    Figure 2 Carpal anatomy (Lane et al., 2023)

    Figure 3 Osseous anatomy of the hand (Lane et al., 2023)

    Joints: Points of Precision

    The hand’s range of motion depends on numerous joints. Intercarpal joints allow slight gliding between carpal bones, while carpometacarpal (CMC) joints connect the wrist to the metacarpals. Notably, the thumb’s saddle-shaped CMC joint enables its unique oppositional movement, which is critical for gripping and pinching.

    Further along the digits, interphalangeal (IP) joints—including proximal (PIP) and distal (DIP) joints—enable finger flexion and extension. The thumb contains a single IP joint due to its two-phalange structure.

    Figure 4 Carpometacarpal, metacarpophalangeal, and interphalangeal joint anatomy (Lane et al., 2023)

    Muscles and Tendons: The Engines of Movement

    Two major groups of muscles power hand movement: extrinsic muscles, which originate in the forearm, and intrinsic muscles, which reside within the hand itself.

    • Extrinsic flexors like the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) enable finger bending.
    • Extensors help straighten the fingers and are housed in compartments under the extensor retinaculum, a stabilizing band at the wrist.
    • Intrinsic muscles include the thenar and hypothenar muscleslumbricals, and interossei, which fine-tune finger movements, especially for grasping and manipulating objects.

    Tendons run through pulley systems in fibrous sheaths that allow for smooth gliding during movement. In the carpal tunnel—a narrow passageway at the wrist—these tendons share space with the median nerve, making the area vulnerable to compression.

    Figure 5 Digital extensor mechanism (Lane et al., 2023)

    Nerve Supply: The Control Center

    Three main nerves power the hand:

    • The ulnar nerve governs fine motor control in the ring and small fingers.
    • The median nerve supplies sensation to the thumb, index, middle, and part of the ring finger. It also innervates the thenar muscles—crucial for thumb movement.
    • The radial nerve primarily controls wrist and finger extension.

    Compression of the median nerve within the carpal tunnel can lead to carpal tunnel syndrome, a condition marked by numbness, tingling, and weakness in the hand—especially affecting thumb function.

    Blood Supply: Keeping the Hand Alive

    The hand’s rich vascular network is supported by the radial and ulnar arteries, which form both dorsal and palmar arches. These arches distribute blood to the fingers through digital arteries, ensuring that the hand’s many tissues receive necessary oxygen and nutrients.

    Figure 6 Schematic drawing of the vascular supply of the hand (Abzug et al., 2023)

    Bone Development and Growth Plates

    In children, the hand bones undergo a process known as endochondral ossification, where cartilage gradually transforms into bone. This occurs in growth zones called physes, or growth plates, which are susceptible to injury. Damage to these areas can lead to long-term issues like growth arrest or deformity if not managed promptly.

    Fractures involving the growth plate (physeal fractures) are particularly common in children and must be treated with urgency and precision. Fortunately, younger bones have a high capacity for remodeling, especially when diagnosed early.

    Functional Development: More Than Just Mechanics

    Beyond structure, the hand is both an executive tool and a sensory organ. Even before birth, fetuses begin using their hands to explore their environment. In infancy, reflexive grasping evolves into intentional, skilled hand use. Over time, children develop prehension—the ability to grasp objects—followed by refined haptic perception, allowing them to identify textures, shapes, and sizes purely through touch.

    As they grow, children shift from relying on feedback-driven movement to more anticipatory control. By the age of 4 to 7, most children can match objects by feel alone, and by 11 months, many begin to develop a preferred hand—a precursor to dominant-hand use in adulthood.

    Setting the Stage for Carpal Tunnel Syndrome

    With this complex yet elegant design, the human hand is vulnerable to a variety of conditions—especially where multiple systems converge. One such vulnerable site is the carpal tunnel, through which the median nerve and flexor tendons pass. When pressure builds up in this narrow space—due to swelling, repetitive motion, or anatomical anomalies—carpal tunnel syndrome (CTS) can develop.

    Next time, we’ll explore how this condition affects the finely tuned harmony of the hand, who’s at risk, and how modern medicine addresses it—especially in growing children.

    References:

    Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2023). Clinically oriented anatomy (9th ed.). Wolters Kluwer.

    Netter, F. H. (2023). Atlas of human anatomy (8th ed.). Elsevier.

  • Mastering life-saving memory-aiding techniques – an example

    Let’s look at the following task.

    You need to memorise the names of the bones in the human hand. What to do to achieve it quickly?

    The best technique depends on your learning style, but the most effective ones are usually:

    Mnemonic Acronyms or Phrases (Acronyms/Reverse Acronyms)

    These are widely used in anatomy because they’re quick, memorable, and easy to recall under exam pressure.

    Carpal Bones (wrist, proximal and distal rows):

    There are 8 carpal bones:

    • Proximal row (lateral to medial): Scaphoid, Lunate, Triquetrum, Pisiform
    • Distal row (lateral to medial): Trapezium, Trapezoid, Capitate, Hamate

    Mnemonic Example:

    “Some Lovers Try Positions That They Can’t Handle”

    Each first letter corresponds to a carpal bone:

    • Scaphoid
    • Lunate
    • Triquetrum
    • Pisiform
    • Trapezium
    • Trapezoid
    • Capitate
    • Hamate

    Make it personally vivid or funny to improve recall.

    Memory Palace (Method of Loci)

    Use this if you’re more visual-spatial and need to learn locations and relationships between bones.

    Example:

    1. Visualize a hallway with 8 rooms (or stops).
    2. Associate each room with an exaggerated image:
      • Room 1: A scarf (for Scaphoid) wrapped around a wrist
      • Room 2: A glowing moon (Lunate) on the floor
      • Room 3: A triangle shaped sculpture (Triquetrum)
      • Room 4: A cat purring loudly (Pisiform)
      • Room 5: A gymnast on a trapeze (Trapezium)
      • Room 6: A puzzle (pieces fitting perfectly like Trapezoid)
      • Room 7: A cap worn on a statue (Capitate)
      • Room 8: A hammer smashing something (Hamate)

    Then mentally walk through this “palace” when recalling.

    Peg Method (Rhyme-Based Association)

    This can be adapted if you want to learn both names and order, especially useful for numbered bones like metacarpals or phalanges.

    Example pegs:

    • 1 is a bun: imagine a bun with a scaphoid inside.
    • 2 is a shoe: shoe made of lunate, etc.

    Less common for anatomy, but good if you’re already familiar with peg systems.

    Best Pick for Most Students:

    Acronym + Spatial Diagram Sketching

    Start with mnemonic phrases like “Some Lovers Try Positions That They Can’t Handle”, then reinforce it by drawing hand diagrams repeatedly, labelling each bone. This builds both verbal and spatial memory.

    RegionElementsMnemonic
    Carpals8 named bones“Some Lovers Try Positions That They Can’t Handle”
    MetacarpalsThumb to Little (I–V)“Tall Individuals Make Real Leaders”
    Phalanges OrderProximal → Middle → Distal“Please Make Dinner”
    Thumb PhalangesProximal → Distal only“Thumbs Prefer Dessert”

    References:

    Iftikhar, N. (2019). Important Joints: Hand and Wrist Bones. [online] Healthline. Available at: https://www.healthline.com/health/wrist-bones.

    National Library of Medicine (2018). How do hands work? [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK279362/.

  • The Unsung Hero of Learning: Why Tests and Quizzes are More Than Just Assessments

    In the realm of education, tests and quizzes are often viewed primarily as evaluative tools – instruments to measure student comprehension or gauge teaching effectiveness. However, a growing body of psychological research consistently demonstrates that testing is a powerful intervention that actively enhances learning, a phenomenon termed “the testing effect” or “test-enhanced learning”. This systematic review integrates findings from hundreds of studies, revealing the profound importance of incorporating retrieval practice into classroom settings, not merely as a means of assessment, but as a fundamental learning strategy.

    The Robust Impact of Retrieval Practice

    Over the last century, numerous studies have shown that engaging in retrieval practice – actively recalling information from memory, often through quizzes or tests – significantly boosts long-term retention of studied knowledge and facilitates the mastery of new information. Compared with passive strategies like re-reading or concept mapping, testing proves to be a more effective approach. A comprehensive meta-analysis involving data from 48,478 students across 222 independent studies concluded that overall, testing (quizzing) raises student academic achievement to a medium extent (g = 0.499). This is a noteworthy effect, considering that in educational interventions, an effect size of 0.20 standard deviations is often considered large.

    The benefits of testing are particularly evident for long-term retention, with studies consistently showing greater recall after longer intervals (e.g., a week or more) when testing is employed, compared to repeated studying. This “backward testing effect” consolidates previously studied information, making it a robust phenomenon across various educational materials and settings, from laboratory experiments to real classrooms.

    Beyond Rote Memorisation: Fostering Deeper Learning and Transfer

    A common criticism levelled against testing is that it acts as a “drill-and-kill” strategy, only promoting “inert knowledge” that cannot be applied to new problems. However, research refutes this narrow view. The findings indicate that testing is not solely beneficial for remembering facts but also promotes conceptual learning and facilitates knowledge application in problem-solving scenarios. For instance, it can enhance comprehension by encouraging knowledge organisation and integration, and support knowledge transfer to aid in solving new problems in unfamiliar contexts.

    Moreover, the “testing effect” can transfer to untested knowledge, meaning that quizzing on some material can also benefit the retention of related, untried information. This transferability is particularly relevant in classrooms where lecture content and textbook sections are often semantically coherent.

    The Critical Role of Feedback and Repetition

    The effectiveness of testing is significantly amplified by the provision of corrective feedback. Studies show that offering feedback following quizzes significantly increases learning gains compared to not providing it. This is because feedback provides additional exposure to the correct information and helps learners rectify their misunderstandings. Interestingly, delayed feedback can sometimes be even more beneficial than immediate feedback, as it prompts the learner to retrieve their original thought process, which further strengthens memory.

    Furthermore, the number of test repetitions matters: there is a positive relationship between the frequency of testing and learning gains, indicating that the more often class content is quizzed, the greater the learning benefits. Multiple retrieval opportunities, especially when spaced over time and across various contexts, lead to superior long-term retention compared to a single test.

    Tests as Catalysts for Future Learning: The Forward Testing Effect

    Beyond consolidating past learning, testing also possesses a “forward testing effect,” whereby testing on studied information can facilitate the acquisition of new, subsequent information. This occurs because interim testing can influence focused attention, reduce mind-wandering, and improve the integration of information during subsequent learning sessions. It can also prime students to activate relevant mental models and identify key concepts to focus on during instruction. This effect is noted across various educational materials and age groups, emerging early in human life.

    Flexibility in Format and Context

    The benefits of test-enhanced learning are not confined to a single format or setting. Testing generalises across a variety of test formats, including matching, fill-in-the-blank, short answer, multiple-choice, cued recall, and free recall, with different formats offering comparable benefits depending on the context. For instance, while some theories suggest more effortful recall tests should be superior, recognition tests (like multiple-choice) have been shown to be equally effective, sometimes even improving recall for untested, related information. This is practically significant, as multiple-choice questions are often quicker to administer and score, especially with technology.

    Similarly, the mode of administration (e.g., paper-and-pen, clicker response systems, online platforms) does not significantly modulate the testing effect, implying that the benefits stem from the act of retrieval itself rather than the specific technology used. The location of administration also matters: quizzes administered in the classroom tend to be more beneficial than those taken outside, likely due to instructor supervision and mandatory engagement. Furthermore, post-class quizzes are more effective at enhancing learning than pre-class quizzes.

    Importantly, test-enhanced learning is effective across all levels of education – from elementary school to university/college – and generalises across a wide range of academic subjects. This highlights its broad applicability in diverse educational contexts.

    Addressing Concerns: Low-Stakes, Motivation, and Individual Differences

    Despite the clear advantages, testing often faces resistance due to concerns about test anxiety and the perception that it is burdensome. However, research indicates that low-stakes or no-stakes quizzes are crucial for promoting learning without inducing excessive anxiety. Such practice tests can be framed as learning opportunities, alleviating pressure and allowing students to focus on the retrieval process. Indeed, low-stake interim testing has been shown to minimally influence test anxiety, and some findings even suggest that frequent tests can reduce test anxiety over time.

    Testing also plays a vital role in motivation and metacognition. Frequent tests can motivate learners to sustain or enhance their study efforts, provide diagnostic feedback on learning gaps, and induce higher test expectancy. Crucially, testing helps students develop more accurate assessments of what they know and don’t know, improving their metacognitive awareness.

    Concerns that testing might exacerbate individual differences in academic performance are also mitigated by evidence. Studies suggest that students with lower working memory capacity or inferior learning abilities can benefit equally or even more from retrieval practice than those with high ability, potentially narrowing rather than widening achievement gaps. Furthermore, male and female students appear to benefit from testing to a comparable extent.

    The Underlying Mechanisms

    The efficacy of test-enhanced learning is supported by three main theoretical accounts:

    • Additional Exposure: Testing, especially with corrective feedback, provides re-exposure to the learned material, which aids retention.

    • Transfer-Appropriate Processing: The similarity of mental operations required during initial tests and final assessments enhances recall performance.

    • Motivation: Frequent testing motivates learners to invest more effort in subsequent learning, leading to improved outcomes.

    While the “retrieval effort” theory (suggesting that more difficult retrieval tasks lead to greater benefits) has received mixed support in classroom settings, the other three theories consistently provide a robust explanation for the observed effects.

    Practical Recommendations for a Learning-Centric Classroom

    The implications of this research are clear and offer concrete strategies for educators and students alike:

    For Course Designers:

    • Incorporate frequent, low-stakes quizzes throughout the course, using various formats (multiple-choice, short-answer, fill-in-the-blank) to provide regular retrieval practice.

    • Provide corrective feedback promptly after quizzes to enhance learning gains and clarify misconceptions.

    • Design cumulative assessments that include prior material, spacing out practice to improve long-term retention.

    • Utilise pretesting before new units to prime students’ learning and highlight key concepts.

    • Dedicate time at the end of lectures for students to recall and articulate key points (e.g., “minute papers” or the PUREMEM method).

    • Employ questioning techniques in class that allow for sufficient “wait time” (3-5 seconds) for all students to retrieve information, or use cooperative learning activities like “think-pair-share” to engage more learners.

    • Communicate the benefits of testing to students explicitly, helping them understand that tests are learning tools, not just evaluative measures.

    For Students:

    • Engage in self-testing regularly using flashcards, practice questions, or by trying to recall information without looking at notes.

    • Space out study sessions over time rather than cramming, and interleave different topics during practice.

    • Seek and utilise feedback on practice tests to identify and address knowledge gaps.

    • Actively try to retrieve information during study, even if it feels more difficult than re-reading.

    In conclusion, the evidence overwhelmingly supports the notion that testing is an indispensable learning tool. By embracing quizzes and tests as integral components of the learning process, educators can significantly enhance student attainment, foster deeper understanding, and cultivate lasting knowledge, transforming the classroom into a more effective and engaging learning environment.

    References:

    Brame, C.J. and Biel, R. (2015). Test-Enhanced Learning: The Potential for Testing to Promote Greater Learning in Undergraduate Science Courses. CBE—Life Sciences Education, [online] 14(2), p.es4. doi:https://doi.org/10.1187/cbe.14-11-0208.

    Yang, C., Luo, L., Vadillo, M.A., Yu, R. and Shanks, D.R. (2021). Testing (quizzing) boosts classroom learning: A systematic and meta-analytic review. Psychological Bulletin, [online] 147(4), pp.399–435. doi:https://doi.org/10.1037/bul0000309.