The origin of a skeletal muscle is usually its attachment to the more stationary bone.
Correct Answer
True
True. The origin is the attachment that stays relatively fixed during contraction, while the insertion is on the bone that moves. The insertion is pulled toward the origin when the muscle shortens.
Category: Muscle Roles and Levers
Question 2
Compared with a parallel muscle of similar size, a pennate muscle can generate greater tension.
Correct Answer
True
True. Because pennate fascicles attach obliquely to a tendon, more fibers can be packed into the muscle, which increases the force it can produce. The tradeoff is that pennate fibers cannot shorten as far as parallel fibers.
Category: Fascicle Arrangement
Question 3
In the body's lever systems, the muscle acts as the fulcrum and the joint supplies the effort.
Correct Answer
False
False. The joint is the fulcrum, the pivot point of the lever, and the contracting muscle supplies the effort. The bone is the lever arm, and the body part or object being moved is the load.
Category: Muscle Roles and Levers
Question 4
Most levers in the body are third-class levers, in which the effort is applied between the fulcrum and the load.
Correct Answer
True
True. Third-class levers, such as the biceps brachii flexing the forearm at the elbow, are the most common type in the body. They sacrifice force for speed and range of motion at the end of the limb.
Category: Muscle Roles and Levers
Question 5
The term maximus in a muscle name indicates that the muscle is the smallest of its group.
Correct Answer
False
False. Maximus means largest, as in the gluteus maximus, the largest of the gluteal muscles. The term for the smallest muscle of a group is minimus, as in the gluteus minimus.
Category: Naming Muscles
Question 6
The orbicularis oris is the circular muscle that closes the eyelids.
Correct Answer
False
False. The orbicularis oris encircles the mouth and closes and purses the lips. The circular muscle that closes the eyelids is the orbicularis oculi.
Category: Head and Neck
Question 7
The term brevis in a muscle name indicates that the muscle is short.
Correct Answer
True
True. Brevis means short, as in the adductor brevis and the extensor pollicis brevis. Its counterpart is longus, which marks the longer of two similar muscles.
Category: Naming Muscles
Question 8
The erector spinae muscles flex the vertebral column.
Correct Answer
False
False. The erector spinae extend the vertebral column and help maintain upright posture. Flexion of the trunk is produced mainly by the rectus abdominis.
Category: Back and Trunk
Question 9
The frontal belly of the occipitofrontalis raises the eyebrows and wrinkles the forehead.
Correct Answer
True
True. The frontal belly lies over the forehead and pulls the scalp and eyebrows upward, producing horizontal forehead wrinkles. The occipital belly at the back of the skull pulls the scalp posteriorly.
Category: Head and Neck
Question 10
The latissimus dorsi abducts the arm at the shoulder.
Correct Answer
False
False. The latissimus dorsi adducts, extends and medially rotates the arm, as in a swimming stroke or a pull-up. Abduction of the arm is produced mainly by the deltoid, with the supraspinatus initiating it.
Category: Back and Trunk
Question 11
The linea alba is a midline band of connective tissue running from the xiphoid process to the pubic symphysis.
Correct Answer
True
True. The linea alba is formed where the aponeuroses of the lateral abdominal muscles meet in the anterior midline. It separates the left and right rectus abdominis muscles.
Category: Abdomen and Thorax
Question 12
Contraction of the diaphragm decreases the volume of the thoracic cavity.
Correct Answer
False
False. When the diaphragm contracts it flattens and moves downward, increasing the volume of the thoracic cavity and drawing air into the lungs. Relaxation of the diaphragm decreases thoracic volume during exhalation.
Category: Abdomen and Thorax
Question 13
The rotator cuff muscles help hold the head of the humerus in the glenoid cavity.
Correct Answer
True
True. The tendons of the supraspinatus, infraspinatus, teres minor and subscapularis blend with the shoulder joint capsule and stabilize the humeral head in the shallow glenoid cavity. This compensates for the joint's weak bony fit.
Category: Upper Limb
Question 14
The biceps brachii is located in the posterior compartment of the arm.
Correct Answer
False
False. The biceps brachii lies in the anterior compartment of the arm along with the brachialis and coracobrachialis. The posterior compartment contains the triceps brachii.
Category: Upper Limb
Question 15
Most muscles that flex the wrist are located in the anterior compartment of the forearm.
Correct Answer
True
True. The wrist and finger flexors, such as the flexor carpi radialis and flexor carpi ulnaris, lie on the anterior forearm and arise largely from the medial epicondyle of the humerus. The extensors lie in the posterior compartment.
Category: Upper Limb
Question 16
The sartorius belongs to the posterior compartment of the thigh.
Correct Answer
False
False. The sartorius is in the anterior compartment of the thigh, crossing it obliquely from the anterior superior iliac spine to the medial side of the tibia. The posterior compartment contains the hamstrings.
Category: Lower Limb
Question 17
The hamstring group consists of the biceps femoris, semitendinosus and semimembranosus.
Correct Answer
True
True. These three posterior thigh muscles flex the leg at the knee, and most of them also extend the thigh at the hip. They are antagonists of the quadriceps femoris.
Category: Lower Limb
Question 18
The gastrocnemius and soleus insert on the calcaneus by way of the patellar ligament.
Correct Answer
False
False. The gastrocnemius and soleus insert on the calcaneus through the calcaneal tendon, also called the Achilles tendon. The patellar ligament connects the patella to the tibial tuberosity and carries the pull of the quadriceps.
Category: Lower Limb
Question 19
The gluteus medius abducts the thigh at the hip.
Correct Answer
True
True. The gluteus medius runs from the lateral ilium to the greater trochanter of the femur and abducts and medially rotates the thigh. During walking it keeps the pelvis level when the opposite foot is off the ground.
Category: Lower Limb
Question 20
The quadriceps femoris flexes the leg at the knee.
Correct Answer
False
False. The quadriceps femoris extends the leg at the knee through the patellar ligament. Flexion of the knee is produced mainly by the hamstrings.
Category: Lower Limb