Question
Cranial Nerve supply of the muscle shown in the image is:
A. IX
B. X
C. XI
D. XII
Show Answer
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Correct Answer » C Explanation |
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Ans:C. XI.
In the image, the Sternocleidomastoid muscle is shown.
Sternocleidomastoid
- It is a paired muscle in the superficial layers of the side of the neck.
- Nerve supply: Spinal part of accessory nerve and Anterior rami of C-2 & 3 proprioceptive in nature.
- Arterial supply: One branch from superior thyroid artery & suprascapular artery and, two branches from the occipital artery.
- Veins follow the arteries.
- ORIGIN:
- The sternal head is tendinous & arises from the superolateral part of the front of the manubrium sterni
- The clavicular head is musculotendinous and arises from the medial one-third of the superior surface of the clavicle. It passes deep to the sternal head, and the two heads blend below the middle of neck. Between the two heads there is a small triangular depression of the lesser supraclavicular fossa, overlying the internal jugular vein.
- The function of this muscle is to rotate the head to the opposite side or obliquely rotate the head. When both sides of the muscle act together, it flexes the neck and extends the head.
- When one side acts alone, it causes the head to rotate to the opposite side and flexes laterally to the same side (ipsilaterally).
- It also acts as an accessory muscle of respiration, along with the scalene muscles of the neck.