Muscles of chest, shoulder and brachium SELF TEST- MUSCLES OF THE CHEST, SHOULDER AND BRACHIUM Modified True False. Indicate if each of the following statements is true. Make each incorrect statement correct by replacing the underlined words with the correct word or phrase:
1. CardMuscles of chest, shoulder and brachium SELF TEST- MUSCLES OF THE CHEST, SHOULDER AND BRACHIUM Modified True Falseiac muscle tissue has branching fibers.
2. Smooth muscle has spindle-shaped cells with single nuclei in each cell.
3. The organs of the muscular system are composed of skeletal muscle tissue.
4. Skeletal muscle is voluntary and has prominent striations.
5. Cardiac muscle tissue is found in the walls of most visceral organs.
6. Intercalated discs are found only in smooth muscle tissue.
7. The proximal part of the upper limb is called the arm or brachium. Between the skin and the muscle mass is a layer of connective tissue called the deep fascia.
8. The tendon of a muscle attached to the more movable of two bones is called the tendon of insertion.
9. Distinct tendons are always present on muscles.
10. The biceps brachii is an antagonist to the triceps brachii.
11. Muscles with their origins on the axial skeleton and their insertions on the appendicular skeleton are called intrinsic muscles.
12. The brachialis anticus (-brachialis) muscle inserts on the radius.
13. The trapezius muscle, in the human, inserts on the ulna.
14. Three muscles in the cat represent the single trapezius muscle of humans. Major muscles inserting on the vertebral border of the scapula include the serratus anterior and levator scapulae.
15. The supraspinatus, infraspinatus, teres minor and the coracobrachialis are rotator cuff muscles.
16. The triceps brachii has its insertion on the olecranon process of the ulna.
17. The layer of dense connective tissue covering the muscle mass of the forearm is the antebrachial fascia.
18. The action of adduction of the arm at the shoulder is caused by action of the pectoralis minor.
19. The antagonist of the brachialis muscle is the triceps brachii.
20. The trapezius muscle in humans originates on the acromion process, spine of scapula, and clavicle.
21. A muscle that flexes the elbow and supinates the hand is the biceps brachii.
22. The biceps brachii flexes the shoulder and extends the elbow.
23. 24.
The Correct Answer and Explanation is:
Here are the corrected Modified True/False answers along with a 300-word explanation at the end:
Modified True/False Answers:
- True – Cardiac muscle tissue has branching fibers.
- True – Smooth muscle has spindle-shaped cells with single nuclei in each cell.
- True – The organs of the muscular system are composed of skeletal muscle tissue.
- True – Skeletal muscle is voluntary and has prominent striations.
- False – Replace “cardiac muscle tissue” with smooth muscle tissue.
➤ Smooth muscle tissue is found in the walls of most visceral organs. - False – Replace “smooth muscle tissue” with cardiac muscle tissue.
➤ Intercalated discs are found only in cardiac muscle tissue. - True – The proximal part of the upper limb is called the arm or brachium. Between the skin and the muscle mass is a layer of connective tissue called the deep fascia.
- True – The tendon of a muscle attached to the more movable of two bones is called the tendon of insertion.
- False – Replace “always” with not always.
➤ Distinct tendons are not always present on muscles. - True – The biceps brachii is an antagonist to the triceps brachii.
- False – Replace “intrinsic muscles” with extrinsic muscles.
➤ Muscles with origins on the axial skeleton and insertions on the appendicular skeleton are called extrinsic muscles. - False – Replace “radius” with ulna.
➤ The brachialis muscle inserts on the ulna. - False – Replace “ulna” with clavicle and scapula.
➤ The trapezius muscle inserts on the clavicle and scapula, not the ulna. - True – Three muscles in the cat represent the single trapezius muscle of humans. Major muscles inserting on the vertebral border of the scapula include the serratus anterior and levator scapulae.
- False – Replace “coracobrachialis” with subscapularis.
➤ The rotator cuff muscles are supraspinatus, infraspinatus, teres minor, and subscapularis. - True – The triceps brachii has its insertion on the olecranon process of the ulna.
- True – The layer of dense connective tissue covering the muscle mass of the forearm is the antebrachial fascia.
- False – Replace “pectoralis minor” with pectoralis major.
➤ Adduction of the arm at the shoulder is primarily caused by the pectoralis major. - True – The antagonist of the brachialis muscle is the triceps brachii.
- False – Replace “originates on” with inserts on.
➤ The trapezius inserts on the acromion process, spine of scapula, and clavicle; it originates from the skull and vertebrae. - True – A muscle that flexes the elbow and supinates the hand is the biceps brachii.
- False – Replace “extends” with flexes.
➤ The biceps brachii flexes the shoulder and the elbow.
Explanation
Understanding the muscles of the chest, shoulder, and brachium is critical in anatomy and physiology due to their importance in daily movements and clinical implications. These muscles include a mixture of skeletal, cardiac, and smooth muscle tissue types. Skeletal muscle, which comprises most muscles responsible for voluntary motion, features striations and multiple nuclei per cell. In contrast, cardiac muscle, found exclusively in the heart, has branching fibers and intercalated discs that facilitate synchronized contraction. Smooth muscle, present in internal organ walls, features non-striated, spindle-shaped cells with single nuclei.
The shoulder and upper arm (brachium) muscles function as a coordinated unit to produce complex movements. Muscles like the deltoid, pectoralis major, biceps brachii, and triceps brachii are integral to motions such as flexion, extension, abduction, and rotation. Origin and insertion points help identify how muscles move joints; for instance, the insertion (movable end) of the biceps brachii on the radius allows it to supinate the forearm.
Rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis) stabilize the shoulder joint, a critical function for preventing dislocations. Incorrect statements in anatomy often arise from confusing similar terms (e.g., intrinsic vs. extrinsic) or incorrect locations (like confusing the trapezius’s insertion with that of a limb muscle). Recognizing muscle antagonists (like biceps and triceps) helps understand joint control and rehabilitation.
This exercise reinforces foundational muscle anatomy, clarifies common misconceptions, and prepares students for more advanced understanding in physiology, kinesiology, and clinical assessments.
