muscles related to post triangle

Question 1

trapezius

Answer 1

Nerve Supply ..
* The spinal part of the accessory nerve (motor supply).
* The ventral rami of C3 and C4 (proprioceptive sensations).
* Clinical Testing ..
* Palpate the trapezius while the shoulder is shrugged against the resistance.
Actions ..
* The upper fibres +levator scapulae -elevate the scapula as in shrugging the shoulder.
* The middle fibres +rhomboids -retract the scapula as in bracing back the shoulder.
* The lower fibres- depress the medial part of the spine of scapula.
* serratus anterior+trapezius -rotates the scapula for overhead abduction

Question 2

SCM

Answer 2

• Nerve Supply ..
• The spinal part of the accessory nerve (provides motor supply).
• The ventral rami of C2 and C3 (carry proprioceptive sensations).
• Clinical Testing ..
• To test one side, place the hand on subject chin on one side and ask the subject to turn the head towards same side shoulder against resistance.
• To test both muscles simultaneously place your hand on the point of the subject chin and ask him to press down against resistance.

Actions
* When muscle contracts, it tilts the head towards the shoulder on the same side and rotates the head so that chin turns to the opposite side. This movement occurs during an upward sideways glance.
* When muscles of both sides contract together, lifting and bending the head (nodding)
* If the head is fixed by prevertebral muscles, the two sternocleidomastoid muscles act as accessory muscles of respiration during forced inspiration.

Question 3

platysma

Answer 3

Origin: pectoral fascia (deep fascia).
* Insertion: base of the mandible and skin of the face.
* Nerve supply: Facial nerve (cervical branch).
* Action: Depresses the mandible and pulls down the angle of mouth in horror or surprise.