Muscles - Axial and Appendicular

These flashcards cover key concepts about the axial and appendicular muscles, their functions, structures, and naming conventions to help with exam preparation.

What are axial muscles responsible for?

Support and move the head and vertebral column; function in facial expression, breathing, chewing, and swallowing.

What distinguishes appendicular muscles?

They control movements of upper and lower limbs and the movements of pectoral and pelvic girdles.

What is the origin of a muscle?

The less movable attachment typically located more proximally on the body.

What is the insertion of a muscle?

The more movable attachment that is pulled towards the origin during contraction.

What type of muscle is known for having fascicles arranged concentrically?

Circular muscles, which create a sphincter.

What are the three subtypes of pennate muscles?

Unipennate, bipennate, and multipennate.

Define agonist in muscle action.

The muscle that contracts to produce a movement; e.g., the triceps brachii in forearm extension.

What is an antagonist muscle?

A muscle whose contraction opposes that of the agonist, allowing for smooth and controlled movement.

Describe the action of the diaphragm.

It is the most important muscle for breathing, partitioning the thoracic and abdominal cavities.

What is the role of the sternocleidomastoid muscle?

It facilitates ipsilateral lateral flexion and contralateral rotation of the head.

What is unique about the rectus abdominis muscle?

It is partitioned into four segments by fibrous tendinous intersections.

What is the action of the biceps brachii?\n\n

The biceps brachii primarily flexes the elbow and supinates the forearm.\n\n

Where is the origin of the pectoralis major muscle?\n\n

The pectoralis major originates from the clavicle, sternum, and the cartilages of the first six ribs.\n\n

What is the insertion point of the gastrocnemius muscle?\n\n

The gastrocnemius inserts into the Achilles tendon, attaching to the calcaneus (heel bone).\n\n

Describe the action of the quadriceps femoris.\n\n

The quadriceps femoris extends the knee and plays a role in hip flexion.\n\n

Where does the latissimus dorsi muscle originate?\n\n

The latissimus dorsi originates from the lower thoracic vertebrae, lumbar vertebrae, sacrum, and iliac crest.\n\n

What is the action of the gluteus maximus muscle?\n\n

The gluteus maximus extends and externally rotates the hip joint.\n\n

Where is the insertion of the deltoid muscle?\n\n

The deltoid inserts on the deltoid tuberosity of the humerus.\n\n

What is unique about the origin of the trapezius muscle?\n\n

The trapezius originates from the occipital bone, nuchal ligament, and spinous processes of cervical and thoracic vertebrae.