A muscle whose action is opposite to that of the prime mover is called an antagonist.
Missing Word
antagonist
An antagonist produces the opposite movement to the agonist, such as the triceps brachii opposing the biceps brachii. Antagonists also help control and slow rapid movements.
Category: Muscle Roles and Levers
Question 2
The attachment of a muscle on the bone that moves, which is pulled toward the fixed attachment during contraction, is called its insertion.
Missing Word
insertion
The insertion is the movable end of a muscle. The origin is the more stationary attachment, and contraction draws the insertion toward it.
Category: Muscle Roles and Levers
Question 3
A parallel muscle with a spindle-shaped belly that is wide in the middle and tapers toward each end is described as fusiform.
Missing Word
fusiform
Fusiform means spindle-shaped. It describes parallel muscles such as the biceps brachii whose belly is thicker in the middle than at the tendons.
Category: Fascicle Arrangement
Question 4
A ring of skeletal muscle that surrounds a body opening and closes it when it contracts, also known as a circular muscle, is called a sphincter.
Missing Word
sphincter
A sphincter has fascicles arranged in concentric rings around an opening. Examples include the orbicularis oris around the mouth and the orbicularis oculi around the eye.
Category: Fascicle Arrangement
Question 5
The thin, sheet-like muscle covering the anterior neck that tenses the neck skin and helps depress the mandible is the platysma.
Missing Word
platysma
The platysma is a broad, superficial muscle in the subcutaneous tissue of the neck. It tenses the skin of the neck and pulls down the lower lip and mandible, as in an expression of horror.
Category: Head and Neck
Question 6
The fan-shaped muscle on the side of the skull that elevates and retracts the mandible is the temporalis.
Missing Word
temporalis
The temporalis arises from the temporal fossa and passes under the zygomatic arch to the coronoid process of the mandible. It assists the masseter in closing the jaw and pulls the mandible backward.
Category: Head and Neck
Question 7
The large, flat superficial muscle of the upper back and posterior neck that can elevate, retract and depress the scapula is the trapezius.
Missing Word
trapezius
The trapezius spans from the occipital bone and vertebrae to the clavicle and scapula. Its upper, middle and lower fibers elevate, retract and depress the scapula respectively.
Category: Back and Trunk
Question 8
The dome-shaped muscle that separates the thoracic and abdominal cavities and is the main muscle of inspiration is the diaphragm.
Missing Word
diaphragm
The diaphragm forms the floor of the thoracic cavity. When it contracts it flattens, enlarging the thoracic cavity and drawing air into the lungs.
Category: Abdomen and Thorax
Question 9
A broad, flat sheet of tendon-like tissue, such as the ones that connect the abdominal oblique muscles to the linea alba, is called an aponeurosis.
Missing Word
aponeurosis
An aponeurosis is a flattened tendon that attaches a muscle to another muscle or to a broad area of bone. The aponeuroses of the lateral abdominal muscles form the rectus sheath and meet at the linea alba.
Category: Abdomen and Thorax
Question 10
The deltoid muscle caps the shoulder and is the prime mover of abduction of the arm.
Missing Word
deltoid
The deltoid is named for its triangular shape, like the Greek letter delta. It arises from the clavicle and scapula and inserts on the deltoid tuberosity of the humerus, abducting the arm.
Category: Upper Limb
Question 11
The brachialis muscle lies deep to the biceps brachii and is a powerful flexor of the forearm at the elbow.
Missing Word
brachialis
The brachialis runs from the anterior humerus to the ulna in the anterior compartment of the arm. It flexes the elbow whatever the position of the forearm, acting as a synergist of the biceps brachii.
Category: Upper Limb
Question 12
The forearm muscle named for its action of turning the palm to face anteriorly is the supinator.
Missing Word
supinator
The supinator wraps around the proximal radius and rotates it to turn the palm forward or upward. Its antagonists are the pronator teres and pronator quadratus.
Category: Upper Limb
Question 13
The pear-shaped deep gluteal muscle that laterally rotates the thigh and lies close to the sciatic nerve is the piriformis.
Missing Word
piriformis
The piriformis runs from the anterior sacrum to the greater trochanter of the femur and laterally rotates the thigh. Its name means pear-shaped, and the sciatic nerve usually passes just below it.
Category: Lower Limb
Question 14
The broad, flat calf muscle lying deep to the gastrocnemius that plantar flexes the foot is the soleus.
Missing Word
soleus
The soleus lies beneath the gastrocnemius in the posterior compartment of the leg. It joins the gastrocnemius at the calcaneal tendon and plantar flexes the foot, which is important for standing and walking.
Category: Lower Limb
Question 15
The medial hamstring muscle named for its long, cord-like tendon is the semitendinosus.
Missing Word
semitendinosus
The semitendinosus is a hamstring of the posterior thigh with a long tendon that inserts on the medial tibia. Its name refers to this tendon, which makes up much of the lower part of the muscle.
Category: Lower Limb