Chapter 18 - Muscular System

Question 1

The extrinsic eye muscles develop from
which of the following?

(A) Cervical somites
(B) Epimere
(C) Hypomere
(D) Occipital somites
(E) Preotic somites

Answer 1

E. Preotic Somites

The extrinsic eye muscles arise from the preotic somites (myotomes) found near the
prochordal plate. Recent research indicates that the extrinsic eye muscles are derived from
somitomeres 1–3, and 5.

Question 2

The tongue muscles develop from which
of the following?

(A) Cervical somites
(B) Epimere
(C) Hypomere
(D) Occipital somites
(E) Preotic somites

Answer 2

D. Occipital Somites

The tongue muscles (intrinsic and extrinsic) arise from the occipital somites
(myotomes).

Question 3

The biceps brachii muscle develops from
which of the following?

(A) Hypomere
(B) Epimere
(C) Anterior condensation
(D) Posterior condensation
(E) Preotic somites

Answer 3

C. Anterior Condensation

Because the biceps brachii muscle is a flexor of the antebrachium (forearm), it develops
from the anterior condensation of myotomic mesoderm.

Question 4

The biceps femoris muscle develops from
which of the following?

(A) Hypomere
(B) Epimere
(C) Anterior condensation
(D) Posterior condensation
(E) Preotic somites

Answer 4

C. Anterior Condensation

Because the biceps femoris muscle is a flexor of the leg, it develops from the anterior
condensation of myotomic mesoderm.