MUSCLES OF THE POSTERIOR TRIANGLE

Question 1

1. trapezius

Answer 1

1. Att= from the external occipital protuberance and nuchal lines to 1/3 of the clavicle
2. Spinal accessory nerve (CN XI; motor); C2 and C3 nerves (pain and proprioception)
3. MA= Elevates, retracts and rotates scapulae superiorly

Question 2

2. sternocleidomastoid

Answer 2

1. Att= from the mastoid process of the temporal bone and nuchal lines
2. IN= Spinal accessory nerve (CN XI, motor); C2 and C3 nerves (pain and proprioception)
3. MA= Unilateral contraction: tilts head to the same side

Question 3

3. platysma

Answer 3

1. Att= from the inferior border of the mandible to fascia covering pec major and deltoid muscle
2. IN= cervical branch of the facial nerve CNV2

Question 4

A. splenius capitis muscle

Answer 4

1. IN= POSTERIOR RAMI OF MIDDLE CERVICAL SPINAL NERVES.
2. MA= LATERALLY FLEXES
   AND ROTATES HEAD AND NECK TO SAME SIDE, ACTINGBILATERALLY EXTENDSHEAD AND NECK

Question 5

B. levator scapulae muscle

Answer 5

1. DORSAL SCAPULAR
   NERVE C5 AND
   CERVICAL SPINAL
   NERVES C3 AND C4

2. DOWNWARD
ROTATION OF
SCAPULA AND TILTS
ITS GLENOID CAVITY
INFERIORLY BY
ROTATING SCAPULA

Question 6

anterior scalene

Answer 6

Function: Elevation of the first rib. Ipsilateral contraction causes ipsilateral lateral flexion of the neck, and bilateral contraction causes anterior flexion of the neck.
Innervation: Anterior rami of C5-C6.

Question 7

middle scalene

Answer 7

Function: Elevation of the first rib. The ipsilateral contraction causes ipsilateral lateral flexion of the neck.
Innervation: Anterior rami of C3-C8.

Question 8

posterior scalene

Answer 8

Attachments: Originates from the posterior tubercles of the transverse processes of C5-C7, and attaches into the second rib.

Function: Elevation of the second rib, and ipsilateral lateral flexion of the neck.

Innervation: Anterior rami of C6-C8.