The largest sesamoid bone of human body is?

NIA - 29 January 2023

Applied Anatomy

Easy

Appeared in: NIA - 29 January 2023

Explanation

The patella, or kneecap, is the largest sesamoid bone in the body.
Sesamoid bones are bones embedded within a tendon or muscle. They act like pulleys, providing a smooth surface for the tendon to slide over and increasing the muscle's mechanical advantage.
The patella is located in the tendon of the quadriceps femoris muscle and plays a crucial role in the extension of the knee joint.

Option B: The hamate is a carpal (wrist) bone, classified as a short bone, not a sesamoid bone. It is characterized by a distinctive hook-like process.
Option C: The pisiform is a sesamoid bone located in the wrist, embedded in the tendon of the flexor carpi ulnaris muscle. However, it is very small and pea-shaped, not the largest.
Option D: The stapes is one of the three auditory ossicles in the middle ear. It is classified as an irregular bone and is famously known as the smallest bone in the human body, not a sesamoid bone.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the skeletal system, specifically the classification and identification of sesamoid bones as background academic context rather than a clinical decision trigger.
Understanding the patella's function is vital for assessing knee injuries. A patellar fracture can severely impair a patient's ability to extend the knee and walk, often requiring surgical intervention.
Nurses frequently care for patients post-knee surgery (including patellar fractures or knee replacements). Key interventions include pain management, monitoring for neurovascular compromise, wound care, and assisting with early mobilization as prescribed.
What if? If a patient has chondromalacia patellae (runner's knee), the cartilage on the undersurface of the patella deteriorates, causing anterior knee pain. Nursing care would focus on pain management, applying the RICE (Rest, Ice, Compression, Elevation) protocol, and educating the patient on activity modification and strengthening exercises for the quadriceps.

How to Approach the Question

First, identify the key terms in the question: 'largest' and 'sesamoid bone'.
Recall the definition of a sesamoid bone: a bone that is embedded within a tendon.
Systematically evaluate each option based on this definition and its relative size.
Eliminate options that are not sesamoid bones. The Hamate is a carpal bone, and the Stapes is an irregular bone in the ear.
This leaves two sesamoid bones: Patella and Pisiform.
Compare the sizes. The Patella (kneecap) is significantly larger than the Pisiform (a small, pea-sized bone in the wrist).

Concept Tested & Keywords

Concept Tested: Anatomy of the skeletal system, specifically the classification and identification of sesamoid bones.
Stem keywords: largest sesamoid bone, human body
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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E6 Anatomy Applied Ashalatha 4e p. 272-274

E6 Osteology InderbirSingh 5e p. 137-139