4.4 Joint, Ligament, and Tendon Terms
Key Takeaways
- Arthr/o is the main root for joints, while ten/o, tend/o, and tendin/o refer to tendons and ligament/o refers to ligaments.
- A sprain involves ligament injury, while a strain involves muscle or tendon injury.
- Range-of-motion terms describe direction and position, not the diagnosis by themselves.
- Arthroscopy, arthrocentesis, arthroplasty, and arthrodesis are different procedure terms that should not be interchanged.
Joint Terms Are Not Muscle Terms
Joint, ligament, and tendon vocabulary is one of the easiest places to lose points because the words sound related. They are related anatomically, but the terminology is precise. A joint is where bones meet. A ligament connects bone to bone and supports joint stability. A tendon connects muscle to bone and transmits force for movement. A muscle produces contraction. When a question asks whether an injury is a sprain or a strain, the structure decides the answer. Ligament injury is a sprain. Muscle or tendon injury is a strain.
Core Word Parts
| Word part | Meaning | Example | Decode |
|---|---|---|---|
| arthr/o | joint | arthritis | inflammation of a joint |
| articul/o | joint | articular cartilage | cartilage at a joint surface |
| ligament/o | ligament | ligamentous | pertaining to ligaments |
| ten/o, tend/o, tendin/o | tendon | tendinitis | inflammation of a tendon |
| burs/o | bursa | bursitis | inflammation of a bursa |
| synov/o | synovial membrane or fluid | synovitis | inflammation of synovial membrane |
| ankyl/o | stiff, bent, fused | ankylosis | abnormal stiffening or fusion |
| chondr/o | cartilage | chondral defect | cartilage-related defect |
Arthr/o appears in many procedure terms. Arthroscopy means visual examination of a joint using a scope. Arthrocentesis means surgical puncture of a joint to remove fluid. Arthroplasty means surgical repair or replacement of a joint. Arthrodesis means surgical fusion of a joint. Arthrotomy means incision into a joint. These are not interchangeable. The suffix tells the action: -scopy is viewing, -centesis is puncture to remove fluid, -plasty is repair, -desis is binding or fusion, and -tomy is cutting into.
Sprain, Strain, Dislocation, Subluxation
| Term | Structure or event | Plain meaning |
|---|---|---|
| Sprain | Ligament | Stretched or torn ligament |
| Strain | Muscle or tendon | Stretched or torn muscle or tendon |
| Dislocation | Joint alignment | Bone displaced from normal joint position |
| Subluxation | Joint alignment | Partial dislocation |
| Tendinitis or tendonitis | Tendon | Tendon inflammation |
| Tenosynovitis | Tendon sheath | Inflammation of tendon sheath |
| Bursitis | Bursa | Inflammation of fluid-filled cushion |
| Synovitis | Synovial membrane | Inflammation of joint lining |
The distinction between sprain and strain is high yield. A patient twists an ankle and injures a ligament: sprain. A patient overstretches a hamstring muscle or Achilles tendon: strain. A shoulder bone comes out of the joint: dislocation. It partially shifts but remains partly aligned: subluxation. The exam may not require grading severity; it may only test which structure is involved.
Movement and Position Terms
| Term | Direction or action | Example clue |
|---|---|---|
| Flexion | Decreases joint angle | Bending elbow or knee |
| Extension | Increases joint angle | Straightening elbow or knee |
| Hyperextension | Extension beyond normal range | Knee bends backward wording |
| Abduction | Away from midline | Arm moves out to side |
| Adduction | Toward midline | Arm returns toward body |
| Rotation | Turns around an axis | Head turns left or right |
| Circumduction | Circular movement | Shoulder makes a cone-like motion |
| Pronation | Palm turns down or posterior | Forearm rotation |
| Supination | Palm turns up or anterior | Holding soup mnemonic |
| Dorsiflexion | Foot moves upward | Toes toward shin |
| Plantar flexion | Foot points downward | Pressing gas pedal |
| Inversion | Sole turns inward | Ankle rolls inward |
| Eversion | Sole turns outward | Sole faces laterally |
Use the midline rule for abduction and adduction. Abduction moves away from the body midline; adduction adds the limb back toward the body. For the foot, dorsiflexion and plantar flexion are common test items because they do not use the words flexion and extension in the usual arm example. Dorsiflexion lifts the foot toward the shin. Plantar flexion points the toes downward.
Joint Disease Terms
| Term | Key idea | Terminology note |
|---|---|---|
| Arthritis | Joint inflammation | Broad term, not one disease only |
| Osteoarthritis | Degenerative joint disease wording | Often cartilage wear context |
| Rheumatoid arthritis | Autoimmune inflammatory arthritis term | Systemic immune context in many courses |
| Arthralgia | Joint pain | -algia means pain |
| Ankylosis | Abnormal stiffening or fusion | Can reduce movement |
| Contracture | Shortening and tightening | Limits joint motion |
| Crepitus | Crackling or grating sensation | Often joint or tissue movement wording |
Terminology questions often ask you to decode arthralgia, arthritis, and arthrodesis side by side. Arthralgia is pain in a joint. Arthritis is inflammation of a joint. Arthrodesis is surgical fusion of a joint. Those endings are more important than the shared root. If you only see arthr/o and stop reading, you will miss the procedure, symptom, or disease process.
Documentation Logic
In a chart phrase such as "decreased active range of motion after ankle sprain," the injury word tells you ligament involvement, while the range-of-motion phrase tells you function. In "tendinitis with pain on resisted extension," the tendon term and motion term work together. Do not infer a fracture unless the word fracture or a bone-break descriptor appears. Do not infer a ligament tear from every joint pain term. Read each word as its own contribution: structure, movement, symptom, and procedure.
Which structure is injured in a sprain?
What does arthrocentesis mean?
Which movement term means moving a limb away from the midline?