1. Antagonistic muscle action chart · Shoulder girdle Complete the antagonistic

Question

1.      Antagonistic muscle action chart · Shoulder girdle

Complete the antagonistic muscle action chart by listing the muscle(s) or parts of muscles that are antagonist in their actions to the muscles in the left column.

Agonist

Antagonist

Serratus anterior

Trapezius (upper fibers)

Trapezius (middle fibers)

Trapezius (lower fibers)

Rhomboid

Levator scapulae

Pectoralis minor

1.      Antagonistic muscle action chart · Shoulder girdle

Complete the antagonistic muscle action chart by listing the muscle(s) or parts of muscles that are antagonist in their actions to the muscles in the left column.

Agonist

Antagonist

Serratus anterior

Trapezius (upper fibers)

Trapezius (middle fibers)

Trapezius (lower fibers)

Rhomboid

Levator scapulae

Pectoralis minor

Explanation / Answer

Before beginning with the answer, I'd like to clarify a major doubt which the formation of answer might pull you into. Antagonists and agonists are not of muscle but of actions. If we want to tell about the antagonists of a muscle we first need to identify the action of the muscle and then think about the antagonist muscles.
I have framed the answer in a way, to help you conceptually rather than merely listing the antagonist muscles.

1) Serratus anterior has following functions and thus the antagonists-
A) Upward rotation of scapula - Antagonists here being Levator scapulae, Rhomboidis major and minor, Pectoralis minor.
B) Protraction of scapula and thus upper limb - Antagonists here are Trapezius, Rhomboidis major and minor
C) Elevation of ribs thus forced inspiration
D) Depression of scapulae- Antagonists here being Trapezius and Levator scapulae.

2) Upper Trapezius has following functions and thus the antagonists-
A) Upward rotation of scapula- Antagonists here being Levator scapulae, Rhomboidis major and minor, Pectoralis minor.
B) Elevation of scapula - Antagonists are lower part of Serratus anterior, lower part of trapezius, pectoralis minor.

3) Middle trapezius has following actions and thus the antagonists-
A) Retraction of scapula - Antagonists being Serratus anterior and pectoralis minor.

4) Lower trapezius has following actions and thus the antagonists-
A) Retraction of scapula- Antagonists being Serratus anterior and pectoralis minor.
B) Depression of scapula- Antagonists being Upper part of trapezius and levator scapulae.

4) Rhomboid major and minor have following common actions and thus the antagonists-
A) Retraction of scapula- Antagonists being Serratus anterior and pectoralis minor
B) Downward rotation of scapula- Antagonists being Trapezius and lower fibres of serratus anterior.

5) Levator scapulae has following functions and thus the antagonists-
A) Elevation of scapula - Antagonists being Lower part of trapezius and serratus anterior, pectoralis minor

6) Pectoralis minor has following functions and thus the antagonists-
A) Protraction of scapula - Antagonists being Middle fibres of trapezius and both Rhomboidis
B) Assists in downward rotation of scapula- Antagonists being Lower fibres of Serratus anterior and upper, lower fibres of trapezius

Hope I helped.
Please feel free to ask any doubt.
Thank you. :)

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