SYSTEM

3D model

Anatomy quiz of the coccyx

Quiz on the normal anatomy of the coccyx: structure, joints, ligaments, muscles, vessels, and nerves of the coccygeal spine.

1/20

1. How many vertebrae does the coccyx of an adult consist of on average?

3–4 vertebrae

The coccyx consists of 3–4 (occasionally 5) rudimentary vertebrae, designated Co1–Co4. This is the most common variant in adults.
5–6 vertebrae

The coccyx consists of 3–4 (occasionally 5) rudimentary vertebrae, designated Co1–Co4. This is the most common variant in adults.
1–2 vertebrae

The coccyx consists of 3–4 (occasionally 5) rudimentary vertebrae, designated Co1–Co4. This is the most common variant in adults.
7–8 vertebrae

The coccyx consists of 3–4 (occasionally 5) rudimentary vertebrae, designated Co1–Co4. This is the most common variant in adults.
I find it difficult to answer

The coccyx consists of 3–4 (occasionally 5) rudimentary vertebrae, designated Co1–Co4. This is the most common variant in adults.

2. What is the joint connecting the sacrum and coccyx called?

Sacrococcygeal joint

Articulatio sacrococcygea—the sacrococcygeal joint—connects the apex of the sacrum to the first coccygeal vertebra. It is a type of symphysis with an intervertebral disc.
Lumbosacral joint

Articulatio sacrococcygea—the sacrococcygeal joint—connects the apex of the sacrum to the first coccygeal vertebra. It is a type of symphysis with an intervertebral disc.
Pubic symphysis

Articulatio sacrococcygea—the sacrococcygeal joint—connects the apex of the sacrum to the first coccygeal vertebra. It is a type of symphysis with an intervertebral disc.
Sacroiliac joint

Articulatio sacrococcygea—the sacrococcygeal joint—connects the apex of the sacrum to the first coccygeal vertebra. It is a type of symphysis with an intervertebral disc.
I find it difficult to answer

Articulatio sacrococcygea—the sacrococcygeal joint—connects the apex of the sacrum to the first coccygeal vertebra. It is a type of symphysis with an intervertebral disc.

3. Which ligament passes along the posterior surface of the sacrococcygeal joint?

Superficial posterior sacrococcygeal ligament

Ligamentum sacrococcygeum posterius superficiale—the superficial posterior sacrococcygeal ligament—is a continuation of the posterior longitudinal ligament and reinforces the joint posteriorly.
Iliolumbar ligament

Ligamentum sacrococcygeum posterius superficiale—the superficial posterior sacrococcygeal ligament—is a continuation of the posterior longitudinal ligament and reinforces the joint posteriorly.
Sacrospinous ligament

Ligamentum sacrococcygeum posterius superficiale—the superficial posterior sacrococcygeal ligament—is a continuation of the posterior longitudinal ligament and reinforces the joint posteriorly.
Sacrotuberous ligament

Ligamentum sacrococcygeum posterius superficiale—the superficial posterior sacrococcygeal ligament—is a continuation of the posterior longitudinal ligament and reinforces the joint posteriorly.
I find it difficult to answer

Ligamentum sacrococcygeum posterius superficiale—the superficial posterior sacrococcygeal ligament—is a continuation of the posterior longitudinal ligament and reinforces the joint posteriorly.

4. Which nerve forms the coccygeal plexus together with branches of the sacral plexus?

Coccygeal nerve

Nervus coccygeus (Co1), together with branches of S4–S5, forms the plexus coccygeus, which innervates the skin in the coccygeal region and perineum.
Pudendal nerve

Nervus coccygeus (Co1), together with branches of S4–S5, forms the plexus coccygeus, which innervates the skin in the coccygeal region and perineum.
Obturator nerve

Nervus coccygeus (Co1), together with branches of S4–S5, forms the plexus coccygeus, which innervates the skin in the coccygeal region and perineum.
Sciatic nerve

Nervus coccygeus (Co1), together with branches of S4–S5, forms the plexus coccygeus, which innervates the skin in the coccygeal region and perineum.
I find it difficult to answer

Nervus coccygeus (Co1), together with branches of S4–S5, forms the plexus coccygeus, which innervates the skin in the coccygeal region and perineum.

5. Which muscle attaches to the lateral border and apex of the coccyx?

Coccygeus muscle

Musculus coccygeus (m. ischiococcygeus) originates from the spina ischiadica and attaches to the lateral border of the coccyx and the inferior part of the sacrum, forming part of the pelvic floor.
Piriformis muscle

Musculus coccygeus (m. ischiococcygeus) originates from the spina ischiadica and attaches to the lateral border of the coccyx and the inferior part of the sacrum, forming part of the pelvic floor.
Obturator internus muscle

Musculus coccygeus (m. ischiococcygeus) originates from the spina ischiadica and attaches to the lateral border of the coccyx and the inferior part of the sacrum, forming part of the pelvic floor.
Iliococcygeus muscle

Musculus coccygeus (m. ischiococcygeus) originates from the spina ischiadica and attaches to the lateral border of the coccyx and the inferior part of the sacrum, forming part of the pelvic floor.
I find it difficult to answer

Musculus coccygeus (m. ischiococcygeus) originates from the spina ischiadica and attaches to the lateral border of the coccyx and the inferior part of the sacrum, forming part of the pelvic floor.

6. The first coccygeal vertebra (Co1) differs from the other coccygeal vertebrae by the presence of:

Rudimentary transverse processes and coccygeal cornua

Co1 retains rudimentary transverse processes (processus transversi) and coccygeal cornua (cornua coccygea), which articulate with the sacral cornua, forming the articulatio sacrococcygea.
A body and complete arches

Co1 retains rudimentary transverse processes (processus transversi) and coccygeal cornua (cornua coccygea), which articulate with the sacral cornua, forming the articulatio sacrococcygea.
A spinous process

Co1 retains rudimentary transverse processes (processus transversi) and coccygeal cornua (cornua coccygea), which articulate with the sacral cornua, forming the articulatio sacrococcygea.
Articular processes forming a synovial joint

Co1 retains rudimentary transverse processes (processus transversi) and coccygeal cornua (cornua coccygea), which articulate with the sacral cornua, forming the articulatio sacrococcygea.
I find it difficult to answer

Co1 retains rudimentary transverse processes (processus transversi) and coccygeal cornua (cornua coccygea), which articulate with the sacral cornua, forming the articulatio sacrococcygea.

7. Which ligament connects the sacral cornua to the coccygeal cornua?

Lateral sacrococcygeal ligament

Ligamentum sacrococcygeum laterale is stretched between the processus transversus of Co1 and the lateral border of the hiatus sacralis, stabilizing the joint laterally.
Deep posterior sacrococcygeal ligament

Ligamentum sacrococcygeum laterale is stretched between the processus transversus of Co1 and the lateral border of the hiatus sacralis, stabilizing the joint laterally.
Anterior sacrococcygeal ligament

Ligamentum sacrococcygeum laterale is stretched between the processus transversus of Co1 and the lateral border of the hiatus sacralis, stabilizing the joint laterally.
Iliolumbar ligament

Ligamentum sacrococcygeum laterale is stretched between the processus transversus of Co1 and the lateral border of the hiatus sacralis, stabilizing the joint laterally.
I find it difficult to answer

Ligamentum sacrococcygeum laterale is stretched between the processus transversus of Co1 and the lateral border of the hiatus sacralis, stabilizing the joint laterally.

8. The coccyx is a vestige of which structure?

The caudal spine

During evolution, the coccyx was reduced from the caudal spine of tailed ancestors. It represents rudimentary caudal vertebrae.
Sacral vertebrae

During evolution, the coccyx was reduced from the caudal spine of tailed ancestors. It represents rudimentary caudal vertebrae.
Lumbar vertebrae

During evolution, the coccyx was reduced from the caudal spine of tailed ancestors. It represents rudimentary caudal vertebrae.
Thoracic vertebrae

During evolution, the coccyx was reduced from the caudal spine of tailed ancestors. It represents rudimentary caudal vertebrae.
I find it difficult to answer

During evolution, the coccyx was reduced from the caudal spine of tailed ancestors. It represents rudimentary caudal vertebrae.

9. Which anatomical structure connects the external anal sphincter to the apex of the coccyx?

Lig anococcygeum (anococcygeal ligament)

Lig anococcygeum (anococcygeal ligament)—a fibrous band connecting the apex of the coccyx to the external anal sphincter.
Perineal body

Lig anococcygeum (anococcygeal ligament)—a fibrous band connecting the apex of the coccyx to the external anal sphincter.
Lig anterior sacrococcygeal

Lig anococcygeum (anococcygeal ligament)—a fibrous band connecting the apex of the coccyx to the external anal sphincter.
Lig sacrotuberous

Lig anococcygeum (anococcygeal ligament)—a fibrous band connecting the apex of the coccyx to the external anal sphincter.
I find it difficult to answer

Lig anococcygeum (anococcygeal ligament)—a fibrous band connecting the apex of the coccyx to the external anal sphincter.

10. Which artery is the primary source of blood supply to the coccyx?

Median sacral artery

A. sacralis mediana—an unpaired branch of the abdominal aorta—descends along the anterior surface of the sacrum and coccyx, providing their primary arterial blood supply.
Iliolumbar artery

A. sacralis mediana—an unpaired branch of the abdominal aorta—descends along the anterior surface of the sacrum and coccyx, providing their primary arterial blood supply.
A. glutea inferior

A. sacralis mediana—an unpaired branch of the abdominal aorta—descends along the anterior surface of the sacrum and coccyx, providing their primary arterial blood supply.
A. pudenda interna

A. sacralis mediana—an unpaired branch of the abdominal aorta—descends along the anterior surface of the sacrum and coccyx, providing their primary arterial blood supply.
I find it difficult to answer

A. sacralis mediana—an unpaired branch of the abdominal aorta—descends along the anterior surface of the sacrum and coccyx, providing their primary arterial blood supply.

11. The levator ani muscle (m. levator ani) attaches to the coccyx by means of:

Lig anococcygeal

Some fibers of m. levator ani (especially m. pubococcygeus and m. iliococcygeus) attach to the coccyx via lig. anococcygeal and the median raphe (raphe)
Direct attachment to the body of the coccyx

Some fibers of m. levator ani (especially m. pubococcygeus and m. iliococcygeus) attach to the coccyx via lig. anococcygeal and the median raphe (raphe)
Cooper's ligament

Some fibers of m. levator ani (especially m. pubococcygeus and m. iliococcygeus) attach to the coccyx via lig. anococcygeal and the median raphe (raphe)
The tendinous arch of the pelvis

Some fibers of m. levator ani (especially m. pubococcygeus and m. iliococcygeus) attach to the coccyx via lig. anococcygeal and the median raphe (raphe)
I find it difficult to answer

Some fibers of m. levator ani (especially m. pubococcygeus and m. iliococcygeus) attach to the coccyx via lig. anococcygeal and the median raphe (raphe)

12. Which of the following ligaments originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponding to the supraspinous ligament and ligamenta flava?

Superficial dorsal sacrococcygeal ligament

The superficial dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale superficiale), which originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponds to the supraspinous ligament and ligamenta flava.
Deep posterior sacrococcygeal ligament

The superficial dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale superficiale), which originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponds to the supraspinous ligament and ligamenta flava.
Sacrotuberous ligament

The superficial dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale superficiale), which originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponds to the supraspinous ligament and ligamenta flava.
Sacrospinous ligament

The superficial dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale superficiale), which originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponds to the supraspinous ligament and ligamenta flava.
I find it difficult to answer

The superficial dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale superficiale), which originates from the margins of the sacral hiatus and attaches to the posterior surface of the coccyx, corresponds to the supraspinous ligament and ligamenta flava.

13. Which of the following ligaments is located on the anterior surface of the junction between the sacrum and coccyx and is a continuation of the anterior longitudinal ligament?

Deep posterior sacrococcygeal ligament

The ventral sacrococcygeal ligament (lig. sacrococcygeum ventrale), located on the anterior surface of the junction between the sacrum and coccyx, is a continuation of the anterior longitudinal ligament.
Ventral sacrococcygeal ligament

The ventral sacrococcygeal ligament (lig. sacrococcygeum ventrale), located on the anterior surface of the junction between the sacrum and coccyx, is a continuation of the anterior longitudinal ligament.
Sacrotuberous ligament

The ventral sacrococcygeal ligament (lig. sacrococcygeum ventrale), located on the anterior surface of the junction between the sacrum and coccyx, is a continuation of the anterior longitudinal ligament.
Sacrospinous ligament

The ventral sacrococcygeal ligament (lig. sacrococcygeum ventrale), located on the anterior surface of the junction between the sacrum and coccyx, is a continuation of the anterior longitudinal ligament.
I find it difficult to answer

The ventral sacrococcygeal ligament (lig. sacrococcygeum ventrale), located on the anterior surface of the junction between the sacrum and coccyx, is a continuation of the anterior longitudinal ligament.

14. Which of the following ligaments is located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae and is analogous to the posterior longitudinal ligament?

Deep posterior sacrococcygeal ligament

The deep dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale profundum), located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae, is analogous to the posterior longitudinal ligament.
Anterior sacrococcygeal ligament

The deep dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale profundum), located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae, is analogous to the posterior longitudinal ligament.
Sacrotuberous ligament

The deep dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale profundum), located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae, is analogous to the posterior longitudinal ligament.
Sacrospinous ligament

The deep dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale profundum), located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae, is analogous to the posterior longitudinal ligament.
I find it difficult to answer

The deep dorsal sacrococcygeal ligament (lig. sacrococcygeum dorsale profundum), located on the posterior surface of the bodies of the first coccygeal and fifth sacral vertebrae, is analogous to the posterior longitudinal ligament.

15. What is the superior surface of the first coccygeal vertebra that articulates with the sacrum called?

Base of coccyx

Basis coccygis—the base of the coccyx—is the superior surface of Co1, bearing an articular facet for articulation with the apex of the sacrum (apex ossis sacri).
Apex of coccyx

Basis coccygis—the base of the coccyx—is the superior surface of Co1, bearing an articular facet for articulation with the apex of the sacrum (apex ossis sacri).
Pelvic surface

Basis coccygis—the base of the coccyx—is the superior surface of Co1, bearing an articular facet for articulation with the apex of the sacrum (apex ossis sacri).
Transverse process

Basis coccygis—the base of the coccyx—is the superior surface of Co1, bearing an articular facet for articulation with the apex of the sacrum (apex ossis sacri).
I find it difficult to answer

Basis coccygis—the base of the coccyx—is the superior surface of Co1, bearing an articular facet for articulation with the apex of the sacrum (apex ossis sacri).

16. Which plexus is formed by the union of the anterior rami of S4, S5, and Co1?

Coccygeal plexus

Plexus coccygeus is formed by the anterior rami of S4 (partially), S5, and Co1. It innervates the skin in the coccygeal region and posterior perineum through the nn. anococcygeal.
Sacral plexus

Plexus coccygeus is formed by the anterior rami of S4 (partially), S5, and Co1. It innervates the skin in the coccygeal region and posterior perineum through the nn. anococcygeal.
Pudendal plexus

Plexus coccygeus is formed by the anterior rami of S4 (partially), S5, and Co1. It innervates the skin in the coccygeal region and posterior perineum through the nn. anococcygeal.
Inferior hypogastric plexus

Plexus coccygeus is formed by the anterior rami of S4 (partially), S5, and Co1. It innervates the skin in the coccygeal region and posterior perineum through the nn. anococcygeal.
I find it difficult to answer

Plexus coccygeus is formed by the anterior rami of S4 (partially), S5, and Co1. It innervates the skin in the coccygeal region and posterior perineum through the nn. anococcygeal.

17. Which of the following muscles does NOT attach to the coccyx?

Piriformis muscle

M. piriformis originates from the anterior surface of the sacrum (S2–S4) and attaches to the trochanter major of the femur, with no attachment to the coccyx. The other three muscles are part of m. levator ani or m. coccygeus and attach to the coccyx.
Coccygeus muscle

M. piriformis originates from the anterior surface of the sacrum (S2–S4) and attaches to the trochanter major of the femur, with no attachment to the coccyx. The other three muscles are part of m. levator ani or m. coccygeus and attach to the coccyx.
Iliococcygeus muscle

M. piriformis originates from the anterior surface of the sacrum (S2–S4) and attaches to the trochanter major of the femur, with no attachment to the coccyx. The other three muscles are part of m. levator ani or m. coccygeus and attach to the coccyx.
Pubococcygeus muscle

M. piriformis originates from the anterior surface of the sacrum (S2–S4) and attaches to the trochanter major of the femur, with no attachment to the coccyx. The other three muscles are part of m. levator ani or m. coccygeus and attach to the coccyx.
I find it difficult to answer

M. piriformis originates from the anterior surface of the sacrum (S2–S4) and attaches to the trochanter major of the femur, with no attachment to the coccyx. The other three muscles are part of m. levator ani or m. coccygeus and attach to the coccyx.

18. The apex of the coccyx (apex coccygis) is directed:

Inferiorly and anteriorly

Apex coccygis—the inferior pointed part of the coccyx—is directed inferiorly and slightly anteriorly. The lig. attaches to it. anococcygeal.
Inferiorly and posteriorly

Apex coccygis—the inferior pointed part of the coccyx—is directed inferiorly and slightly anteriorly. The lig. attaches to it. anococcygeal.
Superiorly and anteriorly

Apex coccygis—the inferior pointed part of the coccyx—is directed inferiorly and slightly anteriorly. The lig. attaches to it. anococcygeal.
Laterally

Apex coccygis—the inferior pointed part of the coccyx—is directed inferiorly and slightly anteriorly. The lig. attaches to it. anococcygeal.
I find it difficult to answer

Apex coccygis—the inferior pointed part of the coccyx—is directed inferiorly and slightly anteriorly. The lig. attaches to it. anococcygeal.

19. Venous drainage from the coccyx occurs predominantly into:

Plexus venosus vertebralis internus and v. median sacral

Venous blood from the coccyx is drained through the plexus venosus sacralis and v. sacralis mediana into the plexus venosus vertebralis internus, as well as into the internal iliac veins.
External iliac vein

Venous blood from the coccyx is drained through the plexus venosus sacralis and v. sacralis mediana into the plexus venosus vertebralis internus, as well as into the internal iliac veins.
V. portae

Venous blood from the coccyx is drained through the plexus venosus sacralis and v. sacralis mediana into the plexus venosus vertebralis internus, as well as into the internal iliac veins.
Superior vena cava

Venous blood from the coccyx is drained through the plexus venosus sacralis and v. sacralis mediana into the plexus venosus vertebralis internus, as well as into the internal iliac veins.
I find it difficult to answer

Venous blood from the coccyx is drained through the plexus venosus sacralis and v. sacralis mediana into the plexus venosus vertebralis internus, as well as into the internal iliac veins.

20. Which term denotes complete osseous fusion of all coccygeal vertebrae with one another, as observed in adults?

Coccygeal synostosis

Synostosis coccygea—the physiological osseous fusion of the rudimentary coccygeal vertebrae with one another. It occurs with age and is a normal anatomical variant observed more frequently in men.
Ankylosis

Synostosis coccygea—the physiological osseous fusion of the rudimentary coccygeal vertebrae with one another. It occurs with age and is a normal anatomical variant observed more frequently in men.
Syndesmosis

Synostosis coccygea—the physiological osseous fusion of the rudimentary coccygeal vertebrae with one another. It occurs with age and is a normal anatomical variant observed more frequently in men.
Synchondrosis

Synostosis coccygea—the physiological osseous fusion of the rudimentary coccygeal vertebrae with one another. It occurs with age and is a normal anatomical variant observed more frequently in men.
I find it difficult to answer

Synostosis coccygea—the physiological osseous fusion of the rudimentary coccygeal vertebrae with one another. It occurs with age and is a normal anatomical variant observed more frequently in men.