Which one of the following muscle is called the peripheral heart?

NIA - 29 January 2023

Applied Anatomy

Easy

Appeared in: NIA - 29 January 2023

Explanation

The Soleus muscle is called the 'peripheral heart' because it is the primary muscle responsible for the calf muscle pump, which is essential for venous return from the lower limbs.
It contains large venous sinuses, and its sustained, rhythmic contractions during activities like walking and standing squeeze the deep veins of the calf.
This pumping action forces venous blood against gravity back towards the heart, preventing blood from pooling in the legs.
The Soleus is composed mainly of slow-twitch muscle fibers, making it resistant to fatigue and ideal for the continuous postural support and pumping action required during standing and walking.

Option A: This is a small, weak muscle with a long tendon, often considered vestigial in humans. Its contribution to the calf muscle pump and venous return is negligible.
Option B: While the Gastrocnemius assists in the calf pump, it is not the primary 'peripheral heart'. It consists of fast-twitch fibers used for powerful, short-duration movements like jumping and running, not the sustained pumping action for which the Soleus is known.
Option D: This muscle is located in the anterior compartment of the thigh, not the calf. It acts on the hip and knee joints (flexion, abduction, lateral rotation) and has no role in the calf muscle pump.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Identification of the muscle known as the 'peripheral heart' and its physiological role in venous return as background academic context rather than a clinical decision trigger.
Understanding the 'peripheral heart' is critical for preventing Deep Vein Thrombosis (DVT), especially in immobile, post-operative, or long-haul travel patients where venous stasis is a major risk.
Nurses must educate patients and actively encourage post-operative or bedridden individuals to perform ankle pumps (dorsiflexion and plantar flexion) to activate the soleus muscle, promote venous return, and reduce the risk of clot formation.
What if? If a patient has a cast on their lower leg that prevents ankle movement, the calf muscle pump is completely immobilized. This dramatically increases the risk of DVT, and the nurse must be vigilant for signs like calf pain, swelling, and redness, and ensure prophylactic anticoagulants are administered as ordered.

How to Approach the Question

First, identify the key phrase in the question: 'peripheral heart'.
Recognize that this is a functional nickname, not a literal anatomical term. It implies a structure outside the chest that assists in pumping blood.
Consider the options based on their anatomical location and primary function. The term 'peripheral heart' strongly suggests a role in venous return from the extremities.
Eliminate Sartorius immediately, as it is a thigh muscle and not involved in pumping blood from the lower leg.
Evaluate the calf muscles. Plantaris is known to be vestigial and weak, making it an unlikely candidate for such an important role.
Differentiate between Gastrocnemius and Soleus. While both contribute to the calf pump, the Soleus is the 'workhorse' muscle, active during standing and walking, providing sustained pumping. The Gastrocnemius is for powerful, intermittent actions. Therefore, Soleus is the best fit for the title 'peripheral heart'.

Concept Tested & Keywords

Concept Tested: Identification of the muscle known as the 'peripheral heart' and its physiological role in venous return.
Stem keywords: muscle, peripheral heart
Lead-in keywords: Which one
Negative lead-in flag: false

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E6 Physiology Ganong 27e Vol 2 Part 3 pp. 110-112, 111-113

E6 Anatomy Applied Ashalatha 4e p. 349-351