The movable bone in the skull is?

Appeared in: HPSSC - 2015

Explanation

The mandible, commonly known as the lower jaw, is the largest and strongest bone of the face.
It is the only bone in the skull that is not fixed in place, allowing it to move.
This movement is facilitated by the temporomandibular joint (TMJ), a synovial joint formed by the articulation of the mandibular condyle with the temporal bone.
The mobility of the mandible is essential for critical functions such as mastication (chewing) and phonation (speaking).

Option A: The nasal bones are two small, oblong bones that form the bridge of the nose. They are fixed in place and articulate with the frontal bone, maxillae, and each other through immovable joints called sutures.
Option B: The maxilla, or upper jaw bone, is a major bone of the face. It is firmly fused to other skull bones and is immovable. It holds the upper teeth and forms part of the hard palate, the floor of the orbit, and the walls of the nasal cavity.
Option D: This option is incorrect because there is a correct answer among the choices. The mandible is the movable bone of the skull.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the Skull: Movable Bones as background academic context rather than a clinical decision trigger.
Disorders of the temporomandibular joint (TMD) are common and can cause significant pain, clicking or popping sounds, and limited jaw movement. Nurses should assess for these symptoms in patients complaining of jaw or facial pain.
A fractured mandible is a serious injury that can compromise the airway. Nursing priorities include maintaining a clear airway (e.g., by positioning and suctioning), managing pain, and preparing the patient for surgical intervention, which often involves wiring the jaw shut.
What if? If a patient presents with trismus (lockjaw), the inability to open the mouth fully, it could be a sign of a severe infection (like tetanus or a dental abscess) or a TMJ disorder. This requires immediate assessment of the patient's airway, vaccination history, and potential sources of infection.

How to Approach the Question

First, identify the core of the question, which is asking for the 'movable bone' in the 'skull'.
Recall the basic anatomy of the human skull. The skull consists of cranial bones and facial bones.
Mentally review the function of the bones listed in the options. Think about daily actions like talking and eating.
The nasal bone forms the nose bridge and doesn't move. The maxilla is the upper jaw and is also fixed.
The mandible is the lower jaw, which clearly moves during speaking and chewing.
Based on this functional recall, select the mandible as the correct answer.

Concept Tested & Keywords

QJtc5uZ2nk9djA0szmPFkI

E6 Physiology Ganong 27e Vol 2 Part 3 p. 42-44

E6 Anatomy Applied Ashalatha 4e p. 281-283

Practise the full HPSSC - 2015

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