An immovable joint is called:

ESIC Nursing Officer -2019 (Shift -1)

Applied Physiology

Medium

Appeared in: ESIC Nursing Officer -2019 (Shift -1)

Explanation

Synarthrosis is the correct term for an immovable joint, where bones are held tightly together by fibrous tissue.
These joints provide stability and protection for underlying organs.
Prime examples include the sutures of the skull, which protect the brain, and the gomphosis that secures a tooth in its socket.

Option B: Amphiarthrosis refers to a slightly movable joint, not an immovable one. These joints are connected by cartilage and allow for limited movement.
Option C: Polyarthritis is a medical condition, not a type of joint. It signifies inflammation affecting five or more joints.
Option D: Diarthrosis refers to a freely movable joint, which is the opposite of an immovable joint. These are also known as synovial joints.

Visual 1: Diagram - An illustration comparing the three functional classifications of joints: Synarthrosis (skull suture), Amphiarthrosis (pubic symphysis), and Diarthrosis (knee joint), highlighting the different degrees of movement.
Visual 2: Illustration - A close-up view of the sutures in the human skull to demonstrate the interlocking, immovable nature of a synarthrotic joint.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Functional classification of joints as background academic context rather than a clinical decision trigger.
A nurse's assessment of joint range of motion is a fundamental skill used to establish a patient's baseline mobility, identify limitations (e.g., contractures), and evaluate the progression of musculoskeletal diseases.
Understanding that skull sutures are synarthroses is critical in neonatal and pediatric care. Nurses assess the fontanelles (soft spots where sutures have not yet fused) to monitor infant hydration and brain development.
What if? - If a diarthrotic (freely movable) joint becomes pathologically fused and immovable due to disease like advanced arthritis or injury, the condition is called ankylosis. This functionally transforms the joint into a synarthrosis, resulting in a severe loss of mobility.

How to Approach the Question

First, identify the key term in the question: 'immovable joint'.
This is a factual recall question requiring knowledge of anatomical terminology for joint classification.
Analyze the options based on their prefixes and root words. 'Syn-' often means 'together' or 'fused', 'amphi-' suggests 'around' or 'both', 'di-' implies 'apart' or 'through', and 'poly-' means 'many'.
Evaluate each option: Synarthrosis aligns with the concept of a fused, immovable joint. Amphiarthrosis suggests slight movement. Diarthrosis implies free movement. Polyarthritis relates to a disease state ('-itis' for inflammation) involving many joints.
Based on this analysis, conclude that Synarthrosis is the correct term for an immovable joint.

Concept Tested & Keywords

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