Somatic efferent nerve

Which of the following is not a somatic efferent nerve?

A. III rd (Oculomotor Nerve)
B. IV th (Trochlear Nerve)
C. VII th (Facial Nerve)
D. XII th (Glosso Pharyngeal Nerve

Answer .C (VII th)

• All the skeletal muscles are under GSE (General somatic efferent) nerves except the muscles of branchial arch.
For example:

1. Biceps brachii is supplied by musculocutaneous nerve, which comes under GSE column.

2. Styloglossus is a muscle of tongue and is skeletal, supplied by the CN-12, hence under GSE column.

• Branchial arch muscles are the skeletal muscles under SVE (special visceral efferent) column.

For example: Facial nerve supplies the facial expression muscles, which are derivatives of 2nd branchial arch (SVE).

• Eye ball muscles are supplied by 3 nerves (LR6 SO4)3.

• Oculomotor and Trochlear nerves supply the muscles which are not a derivative of branchial arch, hence are under GSE.

• Tongue muscles, supplied by hypoglossal nerve develop from the occipital myotomes and not branchial arches; hence they are also under GSE.

Note:
• Cranial nerves containing efferents or general somatic efferents (SE/GSF)—are CN-III, IV, VI, XII

• Cranial nerves containing bronchial efferents or special visceral efferents (BE/S VE)—are CN-V, VII, IX, X, XI

• Cranial nerves containing general visceral efferents (GVE/VE)—CN III, VII, IX, X