Muscle Identification

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NCLEX-PN › Muscle Identification

Questions 1 - 10
1

What are the origin and insertion of the orbicularis oris?

The maxilla and mandible; the skin of the lips

The zygomatic arch; the modiolus

The temporomandibular joint; the buccinator

The mandibular condyle; the fascia of the masseter

Explanation

The orbicularis oris, a circular muscle that compresses the lips, originates on the maxilla and mandible and inserts into the skin of the lips

2

Which of the following muscles has its origin on the mastoid process of the temporal bone?

The splenius capitis

The rectus capitis posterior minor

The rectus capitis posterior major

The semispinalis capitis

Explanation

The splenius capitis, one of the main extenders of the neck, has it's origin on the mastoid process of the temporal bone. The rectus capitis posterior minor, the rectus capitis posterior major, and the semispinalis capitis all originate on the nuchal line of the occipital bone.

3

Which of the following is not a part of the erector spinae muscle group?

The trapezius

The iliocostalis

The longissimus

The spinalis

Explanation

The main muscle groups that make up the erector spinae are the iliocostalis muscles, the longissimus muscles, and the spinalis. The trapezius is not a part of the erector spinae group.

4

What is the origin of the inferior oblique muscle of the eye?

The maxilla

The annulus of Zinn

The sphenoid bone

The infra-orbital margin

Explanation

The inferior oblique muscle of the eye, an extrinsic muscle that externally rotates and abducts the eye, has it's origin on the orbital surface of the maxilla.

5

Which of the following is a muscle of mastication?

All of these

The lateral pterygoid

The temporalis

The medial pterygoid

Explanation

Mastication relies on four major muscles: the masseter, the temporalis, the medial pterygoid, and the lateral pterygoid.

6

What is the insertion of the masseter?

The coronoid process of the mandible

The temporal bone

The submandibular fossa of the jaw

The mandibular condyle

Explanation

The masseter is a quadrilateral muscle that originates from the zygomatic arch and maxilla and inserts into the coronoid process of the mandible. It's function is to lift the mandible, closing the jaw.

7

What are the main muscles responsible for keeping an upright spinal position?

The erector spinae

The rhomboids

The latissimus dorsi

The levatores costarum

Explanation

While all of the muscles listed are part of the structure and mobility of the back, the main muscle group responsible for maintaining erect posture in the erector spinae.

8

Which of the following innervates the platysma?

The facial nerve (CN VII)

The motor accessory nerve

The vagus nerve

The mylohyoid nerve

Explanation

The platysma, a sheet-like muscle that traverses the neck from the clavicle to the mouth and jaw, is innervated by the cervical branch of the facial nerve (CN VII).

9

Which of the following muscles controls the amplitude of sound waves in the inner ear?

The stapedius

The ciliary muscles

The auriculares

The lateral rectus

Explanation

The stapedius, the smallest muscle in the human body, controls the amplitude of sound vibrations pulling on the neck of the stapes.The auriculares move the ears. The ciliary muscle and the lateral rectus are both muscles of the eye.

10

Which of the following muscles assists in frowning?

The depressor anguli oris

The auricular muscles

The temporoparietalis muscle

The depressor supercilii

Explanation

The depressor anguli oris is a small triangular muscle that originates on the mandible and inserts into the modiolus. It's main action is to lower the corners of the mouth in frowning. The auricular muscles are a part of the inner ear. The temporoparietalis muscle is a thin muscle covering the temporal bone, and the depressor supercilii is a muscle of the eye.

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