Question 1

The muscles of the pelvic floor are almost entirely innervated by the pudendal nerve.

Accepted Answer

The pudendal nerve is the primary nerve that innervates the muscles of the pelvic floor, including the external anal sphincter, bulbocavernosus, and ischiocavernosus muscles. Other nerves, such as the sacral nerves and coccygeal nerves, may also provide some innervation to the pelvic floor muscles.

Question 2

Which muscles form the pelvic diaphragm?

Accepted Answer

The pelvic diaphragm is formed by the levator ani muscles and the coccygeus muscle. The levator ani muscles consist of the pubococcygeus, puborectalis, and iliococcygeus muscles.

Question 3

Which of the following muscles associated with the vertebral column is the most superior?

Accepted Answer

The splenius capitis muscle is the most superior muscle associated with the vertebral column. It originates from the spinous processes of the vertebrae in the upper thoracic and lower cervical regions and inserts onto the mastoid process and occipital bone.

Question 4

The deep muscles of the back flex the vertebral column.

Accepted Answer

The deep muscles of the back, such as the erector spinae and transversospinalis muscles, actually extend the vertebral column (bring it into a more upright position) rather than flex it. Flexion of the vertebral column is primarily performed by the abdominal muscles.

Question 5

Unilateral contraction of the muscles of the erector spinal group results in

Accepted Answer

Lateral flexion of the trunk occurs when the muscles of the erector spinae group contract unilaterally. This means that if the muscles on one side of the spine contract, the trunk will bend towards that side.

Question 6

Which muscle(s)of the pelvic floor is/are responsible for erection of the penis and clitoris?

Accepted Answer

The muscles responsible for erection of the penis and clitoris are the bulbospongiosus and ischiocavernosus muscles, which are located in the pelvic floor. The bulbospongiosus muscle is responsible for compressing the bulb of the penis or clitoris during erection, while the ischiocavernosus muscle helps to maintain and enhance the rigidity of the erect penis or clitoris. The superficial transverse perineal muscle and coccygeus muscles are not directly involved in the process of erection.

Question 7

The anterior portion of the perineum is called the

Accepted Answer

The urogenital triangle is the anterior portion of the perineum, containing the external genitalia and urinary openings. The anal triangle is the posterior portion of the perineum. The genital opening is part of the urogenital triangle. The external anal sphincter is a muscular structure that controls the opening and closing of the anus, located in the anal triangle. The pelvic diaphragm is a muscular partition that separates the pelvic cavity from the perineal region.

Question 8

Which of the abdominal wall muscles help(s)flex the vertebral column?

Accepted Answer

The rectus abdominis is a paired muscle that extends vertically along the anterior wall of the abdomen. It originates from the pubic symphysis and pubic crest and inserts into the xiphoid process and costal cartilages of the 5th to 7th ribs. Contraction of the rectus abdominis helps to flex the vertebral column.

Question 9

Which of the pelvic floor muscles inserts only on the coccyx?

Accepted Answer

The answer of Which of the pelvic floor muscles inserts...

Question 10

Which of the following muscles is NOT a muscle of the abdominal wall?

Accepted Answer

The internal intercostal muscle is not a muscle of the abdominal wall. It is found between the ribs and is involved in breathing. The other muscles listed (rectus abdominis, external oblique, and transversus abdominis) are all muscles of the abdominal wall.

Question 11

Which muscle of the pelvic floor acts as a sphincter in the vagina and anal canal?

Accepted Answer

The levator ani muscle is a group of muscles that form the floor of the pelvis. It has three parts: the pubococcygeus, the iliococcygeus, and the puborectalis. The pubococcygeus muscle acts as a sphincter in the vagina and anal canal.

Question 12

The linea alba is a muscle of the pelvic floor.

Accepted Answer

The linea alba is actually a fibrous band of connective tissue that runs from the pubic symphysis to the xiphoid process of the sternum, not a muscle of the pelvic floor.

Question 13

Which of the following correctly lists the erector spinae muscles, from lateral to medial?

Accepted Answer

The erector spinae muscles are grouped into three columns: the iliocostalis group, the longissimus group, and the spinalis group. Within each group, the muscles run from lateral to medial. Therefore, the correct order is the iliocostalis group, longissimus group, and spinalis group, as listed in option A.

Question 14

Which muscles form the outermost layer of the layered abdominal wall muscles?

Accepted Answer

The external oblique muscles form the outermost layer of the abdominal wall muscles. They run diagonally downwards and forwards, with their fibers pointing towards the midline on either side of the rectus abdominis muscle. The other muscles listed (internal oblique, transversus abdominis, rectus abdominis) are located deeper and do not form the outermost layer. The external intercostal muscles are not a part of the abdominal wall muscles, but rather the muscles between the ribs that assist with respiration.

Question 15

Which of the following muscles of the vertebral column are unique, in that they originate on the iliac crest?

Accepted Answer

The Quadratus lumborum muscle is the only muscle of the vertebral column that originates on the iliac crest. The other muscles listed originate from the vertebrae or ribs.

Question 16

The diamond-shaped area between the lower limbs is called the perineum.

Accepted Answer

The perineum is the diamond-shaped area between the thighs, extending from the pubic bone anteriorly to the coccyx posteriorly.

Quiz 24: Muscles of the Vertebral Column, Abdominal Wall, and Pelvic Floor