A gomphosis is a specialized type of fibrous joint. Where in the human body is this 'peg-and-socket' joint found?

Appeared in: HSSC Staff Nurse - 2015

Explanation

A gomphosis is a unique 'peg-and-socket' fibrous joint.
This joint's specific location is where the root of a tooth articulates with its socket in the alveolar process of the mandible or maxilla.
The tooth is held firmly in place by the periodontal ligament, a collection of short collagenous fibers.
Functionally, it is a synarthrosis, meaning it is an immovable joint, though it allows for microscopic movements to dissipate the force of chewing.

Option A: The joints between the flat bones of the skull are not gomphoses; they are a different type of fibrous joint called sutures.
Option B: The joint connecting the distal ends of the tibia and fibula is a syndesmosis, where bones are joined by a ligament.
Option D: The joints between vertebral bodies are classified as symphyses, which are cartilaginous joints, not fibrous joints. They are connected by intervertebral discs.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and classification of fibrous joints, specifically the location of a gomphosis as background academic context rather than a clinical decision trigger.
Understanding gomphosis is fundamental to dental and oral health. The integrity of this joint is crucial for tooth stability.
Periodontal disease involves the inflammation and breakdown of the periodontal ligament, which can loosen the gomphosis joint and lead to tooth loss.
Orthodontic treatments work by applying sustained pressure to teeth, which causes remodeling of the alveolar bone socket and allows the gomphosis joint to slowly shift to a new position.

How to Approach the Question

First, identify the key term in the question: 'gomphosis'.
Recall the definition and key characteristics of a gomphosis joint. The question itself provides a major clue: 'peg-and-socket' joint.
Systematically evaluate each option to see which anatomical location fits the 'peg-and-socket' description.
Option A (skull bones) are flat and interlocking, not peg-and-socket. These are sutures.
Option B (tibia and fibula) are long bones connected by a ligament, not a peg-and-socket. This is a syndesmosis.
Option C (tooth and socket) perfectly matches the 'peg' (tooth root) in a 'socket' (alveolar bone) description.

Concept Tested & Keywords

Concept Tested: Anatomy and classification of fibrous joints, specifically the location of a gomphosis.
Stem keywords: gomphosis, fibrous joint, peg-and-socket
Lead-in keywords: Where, found
Negative lead-in flag: false

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E6 Osteology InderbirSingh 5e pp. 22-24, 23-25

Practise the full HSSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.