Wk2: Muscles of Head, Neck and Upper Limb

Question 1

What is the function of the muscles of facial expressions?

Answer 1

Attach to bone/fascia and produce effects by pulling on the skin, showing facial expressions, as well as closing the mouth and eyes.

Question 2

List the muscles of the facial expression

Answer 2

Occipitofrontalis, orbicular oculi, orbicular oris, buccinator

Question 3

What is the function of the muscles of mastication?

Answer 3

They facilitate movement of the mandible so that it can bring the maxilla and mandibular teeth to come in contact for chewing (breaking down food)

Question 4

What are the 2 muscles involved in mastication?

Answer 4

Masseter and temporalis.

Question 5

What are the 2 heads of the sternocleidomastoid muscle located and where do they unite?

Answer 5

At the sternal and clavicular and they unite at the skull

Question 6

What happens in the bilateral and unilateral contraction of the SCM?

Answer 6

Bilateral contraction - neck is able to depress forward towards the breastbone, and move forward to push the chin out
Unilateral - When you flex your neck so its leaning towards one side of the body/rotating neck to one side

Question 7

What is the function of the pectoralis major?

Answer 7

During insertion it crosses the shoulder joint:

• Allows for arm flexion at the shoulder joint
• Rotation of the arm medially at the shoulder joint
• Abduction of arm at shoulder joint

Question 8

What is the function of the trapezius?

Answer 8

Trapezius function is to stabilise the scapula during movement

• Elevates the scapula (in the descending fibers)
• Depresses the scapula (in the ascending part)
• Retraction of the scapula towards the midline (middle part)

Question 9

What is the function of the latissimus dorsi?

Answer 9

• Adduction of arm at shoulder joint
• Prime mover of arm extension
• Rotates arm medially

Question 10

What is the function of the deltoid?

Answer 10

• Prime mover of arm abduction
• Anterior part: shoulder flexion and and medial rotation
• Posterior part: shoulder extension and lateral rotation

Question 11

What is the function of the teres major?

Answer 11

Synergist of latissimus dorsi

Question 12

What is the function of the rotator cuff group?
S - supraspinatus/p
I - infraspinatus/p
T - teres minor/p
S - subscapularis/a

Answer 12

Function to support the shoulder joint

• Initiates abduction of arm - supraspinatus
• Laterally rotates arm (SIT)
• Medially rotates - Subscapularis (anterior)

Question 13

In the anterior compartment of the arm muscles, what is the function of the biceps brachii and brachialis?

Answer 13

Biceps brachii

• Flexes the arm at the shoulder joint
• Flexes the forearm at the elbow joint and supinates the forearm (forearm flexion)

Brachialis
- Prime mover of forearm flexion

Question 14

In the posterior compartment of the arm muscles, what is the function of the triceps brachii?

Answer 14

• Prime mover of forearm extension

- Assist in arm adduction

Question 15

What is the function of the forearm flexors (anterior compartment) and the forearm extensions (posterior compartment)?

Answer 15

Forearm flexors:

• Flexors (some wrist and interphalangeal joints)
• Some assist in elbow flexion

Forearm extensors:

• Extensors (some extend wrist and interphalangeal joints)
• Assist in elbow extension

Question 16

What is the function of the intrinsic hand muscles?

Answer 16

• Arise and insert within the hand, producing fine movement in fingers