All of the following are sesamoid bone; EXCEPT:

Appeared in: AIIMS Delhi NO- 2019

Explanation

The Hyoid bone is the correct answer because it is not a sesamoid bone.
It is a unique U-shaped bone located in the neck, which serves as an attachment point for muscles of the tongue and neck.
Crucially, it is not embedded within a tendon or muscle, which is the defining characteristic of a sesamoid bone.
The Hyoid is the only bone in the human body that does not articulate with any other bone.

Option A: The Patella (kneecap) is the largest and most well-known sesamoid bone in the body.
Option B: The Pisiform is a small, pea-shaped carpal bone in the wrist that functions as a sesamoid bone, as it is located within the tendon of the flexor carpi ulnaris muscle.
Option D: The Fabella is a small, inconstant sesamoid bone found in the tendon of the lateral head of the gastrocnemius muscle behind the knee. Although not present in everyone, it is classified as a sesamoid bone.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Identification and classification of sesamoid bones as background academic context rather than a clinical decision trigger.
Understanding sesamoid bones is important as they can be prone to injury (sesamoiditis) or fracture, causing pain and mobility issues, particularly in the foot and hand.
The Hyoid bone is of great clinical and forensic importance. A fractured hyoid bone in a post-mortem examination is a strong indicator of strangulation or throttling.
What if? If a patient presents with anterior knee pain, knowledge of the patella as a sesamoid bone would lead a nurse to consider conditions like patellofemoral pain syndrome or chondromalacia patellae, which relate to its function and articulation.

How to Approach the Question

First, identify the keyword 'EXCEPT'. This indicates you need to find the option that does not fit the category mentioned in the stem.
Next, define the category from the stem: 'sesamoid bone'. Recall that a sesamoid bone is one that is embedded within a tendon.
Evaluate each option against this definition.
A. Patella: Yes, this is the kneecap, a classic sesamoid bone.
B. Pisiform: Yes, this is a carpal bone in the wrist, located in a tendon.
C. Hyoid: No, this is a bone in the neck that doesn't connect to other bones and isn't in a tendon.

Concept Tested & Keywords

Concept Tested: Identification and classification of sesamoid bones.
Stem keywords: sesamoid bone
Lead-in keywords: EXCEPT
Negative lead-in flag: The question asks to identify the option that is NOT a sesamoid bone.

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E6 Anatomy Applied Ashalatha 4e pp. 494-496, 272-274

E6 Physiology Ganong 27e Vol 2 Part 3 p. 33-35

Practise the full AIIMS Delhi NO- 2019

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