Musculoskeletal System: Muscles

Flashcards covering properties, naming criteria, major muscle groups, functions, and clinical applications from the NURS 1403 Musculoskeletal System: Muscles lecture.

What are the four primary properties of muscle tissue?

Excitability, contractility, extensibility, and elasticity.

What are the four main functions of skeletal muscles listed in the lecture?

Give movement, maintain posture and stabilize joints, produce heat, and protect fragile internal organs by enclosing them.

What is the difference between a muscle's origin and its insertion?

The origin is attached to the stationary bone, while the insertion is attached to the movable bone during contraction.

What are the origin and insertion points of the biceps brachii muscle?

Origin: Humerus & Scapula; Insertion: Radial tuberosity.

What are the origin and insertion points of the triceps brachii muscle?

Origin: Humerus & Scapula; Insertion: Olecranon of ulna.

What are the seven criteria used for naming skeletal muscles?

Action, Location of muscle, Location of attachments, Size, Shape, Direction of muscle fibers, and Number of Origin.

Which naming criteria apply to the muscle pair Gluteus maximus and Gluteus minimus?

Size (maximus vs. minimus).

Which naming criteria apply to the Sternocleidomastoid muscle?

Location of attachments (Sternum, clavicle, mastoid process).

Which naming criterion distinguishes straight muscles like rectus femoris from angled muscles like obliques?

Direction of muscle fibers.

Based on the provided anatomical diagram, what are the specified origins and insertion of the sternocleidomastoid muscle?

Origins: manubrium of the sternum and medial clavicle; Insertion: mastoid process.

What are the primary functions of the orbicularis oculi and orbicularis oris muscles?

Orbicularis oculi closes the eyes, and orbicularis oris closes the lips.

What is the function of the buccinator muscle, especially in infants?

It compresses the cheek and assists in chewing, providing powerful suckling skills to receive milk.

Which muscles are responsible for jaw closure and biting during mastication?

Temporalis and Masseter.

What specific jaw movement is produced by the lateral and medial pterygoid muscles?

Grinding (lateral excursion).

What are the functions of the neck muscles, specifically the sternocleidomastoid?

Rotation of the neck, flexion of the head (not extension), serving as an auxiliary muscle for breathing by raising the first 2 ribs, and aiding in swallowing.

What are the actions of the pectoralis major muscle?

Arm flexion, adduction, and medial rotation of the arm.

What are the functions of the serratus anterior muscle?

Protraction of the scapula, stabilizing the scapula on the posterior thoracic cage, abduction and raising of the arm, and horizontal arm movements (like playing Boxing).

What are the actions of the latissimus dorsi muscle?

Extension of the arm, adduction, and medial rotation of the arm.

Which four muscles comprise the rotator cuff group?

Supraspinatus, infraspinatus, subscapularis, and teres minor muscle.

What actions does the deltoid muscle perform?

Abduction of the arm, extension and lateral rotation of the arm, and flexion and medial rotation of the arm.

How do external intercostal muscles and internal intercostal muscles differ during breathing?

External intercostals pull ribs toward one another and elevate the rib cage to aid inspiration, whereas internal intercostals depress the rib cage to aid forced expiration.

What changes occur in the shape of the diaphragm during relaxation versus contraction?

The diaphragm is dome-shaped in its relaxed state and flattens on contraction during inspiration.

What is the primary function of the erector spinae muscles?

They act as powerful back extensors to maintain the erect position of the vertebral column.

What are the outer, middle, and inner muscle layers of the abdomen?

Outer layer: External oblique muscle; Middle layer: Rectus abdominis and Internal oblique muscle; Inner layer: Transversus abdominis.

What is the function of the levator ani muscle in the pelvic diaphragm?

It supports the pelvic organs and seals the opening of the body.

What are the actions of the biceps brachii and triceps brachii muscles?

Biceps brachii performs flexion of the elbow joint and supinates the forearm; triceps brachii performs extension of the forearm.

What functions do the thenar and hypothenar muscles serve?

Thenar muscles (in the ball of the thumb) perform opposition of the thumb, while hypothenar muscles (in the ball of the little finger) perform opposition of the little finger.

What muscles make up the quadriceps femoris group?

Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius, and Tensor of the vastus intermedius (newly discovered in 2016).

What actions are performed by the sartorius muscle?

Flexion, abduction, and lateral rotation of the thigh, helping in maintaining a cross-legged position.

Which three muscles compose the hamstrings group, and what are their actions?

Biceps femoris, Semitendinosus, and Semimembranosus; they perform extension of the thigh and flexion of the knee.

What are the functions of the tibialis anterior muscle?

Dorsiflexion (as the prime mover) and foot inversion.

Which lower leg muscles perform plantar flexion?

Fibularis muscles, Gastrocnemius, and Soleus.

Which muscle sites are used for intramuscular (IM) injections, and which site is specifically used in infants?

Deltoid, Gluteus maximus (Dorsogluteal), Gluteus medius (Ventrogluteal), and Vastus lateralis (in infants).