Muscle that contributes to both hip and knee extension originates from which of the following structures?& x2… - INI-CET EXAM -2025

INI-CET EXAM -2025

Applied Anatomy

Medium

Appeared in: INI-CET EXAM -2025

Explanation

The pointer 'B' indicates the posterior gluteal surface of the ilium, which is a primary origin for the gluteus maximus muscle.
The gluteus maximus is the chief extensor of the thigh at the hip joint.
It contributes to knee extension by stabilizing the extended knee joint through its insertion on the iliotibial (IT) tract.
No other muscle originating from the labeled points performs both hip extension and contributes to knee extension.

Option A: Pointer 'A' is the iliac crest. Muscles originating here, like the tensor fasciae latae and gluteus medius, are primarily involved in hip abduction and flexion, not extension.
Option C: Pointer 'C' is the ischial spine. It serves as an attachment for muscles like the superior gemellus and ligaments that are not primary movers for hip or knee extension.
Option D: Pointer 'D' is the ischial tuberosity, the origin of the hamstring muscles. While hamstrings extend the hip, they are primary flexors of the knee, which is the opposite of what the question requires.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and function of the muscles of the gluteal region and thigh as background academic context rather than a clinical decision trigger.
The gluteus maximus is crucial for functional movements such as rising from a chair, climbing stairs, and running. Its strength is essential for maintaining an erect posture.
Weakness of the gluteus maximus can lead to compensatory movement patterns, resulting in lower back pain, hip pain, and knee injuries (e.g., patellofemoral pain syndrome) due to poor stabilization.
What if? - If a patient has an injury to the inferior gluteal nerve (which supplies the gluteus maximus), they will have significant difficulty extending their hip from a flexed position. This is observed as a 'gluteus maximus lurch,' where the patient thrusts their thorax backward at heel-strike to maintain hip extension.

How to Approach the Question

First, carefully analyze the image to identify the anatomical structures indicated by the pointers A, B, C, and D on the hip bone.
Identify A as the iliac crest, B as the posterior ilium, C as the ischial spine, and D as the ischial tuberosity.
Next, break down the question. The key requirements are a muscle that 'contributes to both hip extension and knee extension' and finding its 'origin'.
Evaluate the muscles originating from each labeled structure. B (posterior ilium) is the origin of the gluteus maximus (hip extensor, knee stabilizer). D (ischial tuberosity) is the origin of the hamstrings (hip extensor, knee flexor).
Compare the muscle actions with the question's requirements. The gluteus maximus is the only muscle originating from the given options that fulfills both criteria.
Select the option corresponding to the origin of the gluteus maximus, which is B.

Concept Tested & Keywords

Concept Tested: Anatomy and function of the muscles of the gluteal region and thigh.
Stem keywords: muscle, hip extension, knee extension, origin
Lead-in keywords: originates from
Clinical cues: The question requires identifying a bony landmark from a posterior view of the pelvis.
Clinical cues: The muscle in question must perform two specific actions: hip extension and contributing to knee extension.

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E6 Anatomy BDChaurasia V2 10e Part 1 pp. 30-32, 29-31, 92-94