The New York Times Mini crossword on March 23, 2025 featured a five-letter clue at 7-Across that stopped solvers mid-grid: “Component of muscle tissue.” The answer was SINEW, a term that sits at the intersection of everyday language and medical anatomy.
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Why Solvers Got Stuck
Most people reached for the obvious answers first. FIBER seemed logical but belonged to a different March 23 clue in the same puzzle. TENDON made anatomical sense except for the six-letter problem. The five-letter constraint eliminated the most technically accurate options, leaving solvers to recall a more archaic term from their vocabulary.
Crossword veteran solvers recognized the pattern immediately. When a puzzle asks for body parts or medical terms with tight letter counts, constructors often pull from older or broader terminology rather than precise scientific language.
What Sinew Means in Medical Terms
Sinew refers to tendons, the fibrous cords connecting muscles to bones throughout the body. Cleveland Clinic defines these structures as tough, flexible tissue similar to rope. Every voluntary movement requires tendons to transmit mechanical force from contracting muscles to the skeletal system.
The body contains thousands of these connective tissue structures. Your Achilles tendon, running from calf muscle to heel bone, represents the largest and strongest. Smaller tendons control finger movements, eye motion, and facial expressions.
Primary functions include:
- Transferring muscle contraction force to bones
- Enabling controlled movement at joints
- Absorbing impact during physical activity to protect muscle tissue
The term “sinew” technically covers both tendons (muscle to bone) and ligaments (bone to bone), though modern medical texts separate these categories. This broader historical definition actually makes sinew more appropriate for crossword use than the specific anatomical terms.
Structural Composition and Strength
Tendons consist of 95 to 99 percent type I collagen in their dry mass, according to research published by the National Institutes of Health. This protein forms into fibers, which bundle into fascicles, which group together to create the complete tendon structure.
The architectural layers break down as follows:
- Epitenon surrounds the entire tendon with thin connective tissue
- Endotenon separates internal fiber bundles and allows them to slide past each other
- Paratenon creates a loose outer layer permitting movement against surrounding tissue
- Sharpey fibers anchor the tendon directly into bone through collagen strands
This organization gives tendons remarkable durability. Studies measuring flexor tendons in human feet found they withstand forces exceeding eight times body weight during normal activity. Athletes and manual laborers can generate even higher loads without tissue failure under healthy conditions.
Common Tendon Problems and Injuries
Tendonitis affects millions annually, causing pain and restricted movement. Cleveland Clinic data shows the condition develops from:
- Repetitive motions in work or sports
- Sudden forceful movements beyond normal range
- Inflammatory diseases like rheumatoid arthritis
- Natural degeneration with aging
The most frequently injured tendons include the rotator cuff (shoulder), Achilles (heel), patellar (knee), and flexor tendons in hands and wrists. Treatment typically requires rest, ice, physical therapy, and anti-inflammatory medication. Severe cases involving partial or complete ruptures may need surgical repair.
Recovery timelines vary widely. Minor tendonitis can resolve in weeks with proper care, while major ruptures may require six to twelve months of rehabilitation. The limited blood supply to tendon tissue slows the healing process compared to highly vascular structures like muscle.
Why Constructors Choose This Word
Crossword constructors select words based on letter patterns and solver familiarity. SINEW scores well on both metrics. The combination of common consonants (S, N, W) with versatile vowels (I, E) creates numerous crossing possibilities without forcing obscure intersections.
The word also carries cultural weight beyond medical contexts. Writers have used sinew metaphorically for centuries to represent strength, power, and resilience. Phrases like “the sinews of war” appear in historical texts describing military resources. This literary presence means educated solvers recognize the term even without anatomical training.
Merriam-Webster traces the word’s etymology to Old English “seonu” and Old High German “senawa,” showing its deep roots in Germanic languages. The spelling remained relatively stable through Middle English, unlike many anatomical terms borrowed later from Latin and Greek.
Historical Applications Beyond Medicine
Before synthetic materials existed, animal sinew served practical purposes across cultures. Native American tribes used dried tendon as thread for sewing leather and attaching arrowheads to shafts. The material’s natural adhesive properties meant it bonded to itself when wet, then tightened as it dried.
Inuit communities in Arctic regions relied exclusively on sinew for all cordage needs. The absence of suitable plant fibers in polar environments made animal tendons essential for constructing tools, clothing, and shelter. Caribou and seal sinews provided the strongest options.
Composite bow makers in Central Asia incorporated sinew on the back surface of wooden cores. When the bow bent, the sinew stretched and stored energy, then released it to propel arrows with greater force than wood alone could generate. This technology spread to medieval Europe and remained competitive with early firearms.
Solving Strategy for Anatomical Clues
When crossword puzzles reference body parts or biological structures, several approaches help narrow the possibilities:
Check the letter count first. Many anatomical terms share meanings but differ in length. Knowing you need exactly five letters eliminates TENDON, LIGAMENT, and MUSCLE immediately.
Look at crossing letters. Even one or two confirmed letters from intersecting answers can eliminate half the possible solutions. A confirmed N in position three makes SINEW much more likely than FIBER.
Think about register. The New York Times crossword, particularly the Mini format, favors words from general educated vocabulary over technical jargon. MYOSIN and ACTIN are too specialized; SINEW sits in the sweet spot of recognizable but not common.
Consider puzzle day difficulty. Monday through Wednesday puzzles use more accessible vocabulary than Thursday through Saturday. The Mini crossword maintains consistent moderate difficulty throughout the week.
Medical Versus Colloquial Usage
The word “sinew” has largely disappeared from everyday American speech, surviving mainly in literary contexts and crossword puzzles. Doctors and physical therapists use “tendon” almost exclusively in clinical settings. This creates an interesting linguistic split where the older term remains alive in written language while the modern term dominates spoken communication.
British English speakers use both terms more interchangeably, particularly when discussing meat. British butchers and cooks regularly remove sinew from cuts of beef or lamb, using the word to describe the tough connective tissue that requires careful trimming. American butchers more often say “gristle” or “connective tissue” instead.
The Dual Nature of the Answer
The March 2025 component of muscle tissue NYT crossword clue worked because SINEW functions simultaneously as a precise anatomical term and a flexible vocabulary word. Solvers needed to access both levels of meaning to crack the five-letter code.
This dual identity explains why the word appears repeatedly across different puzzle publishers and difficulty levels. It tests knowledge without demanding specialized expertise. Medical students know it from anatomy courses. Literature majors recognize it from poetry and classical texts. Everyone else can work it out from crossing letters and educated guessing.
The next time a crossword asks about muscle tissue components, fibrous connective tissue, or tendon-related terms, your brain will reach for SINEW first. That five-letter combination of letters now connects to both skeletal anatomy and crossword construction in equal measure.
