Muscles Of The Trunk

The sternocleidomastoid muscle originates from the upper manubrium of the sternum and the upper border of the medial clavicle, and inserts into the mastoid process. It is responsible for unilateral rotation of the head and face to the opposite side with lateral flexion, as well as bilateral flexion of the neck. It is innervated by the accessory nerve (CN XI) and branches of C2-C3 nerves.

The scalenes muscles have a specific origin, insertion, action, and nerve innervation that differ from the incorrect options provided.

Rectus Abdominus is a muscle responsible for trunk flexion and abdomen compression. It originates from the pubis and inserts into the xiphoid process and costal cartilages of ribs 5-7. It is innervated by the 7th-12th intercostal nerves.

The Internal Oblique muscle originates at the iliac crest and inserts at the 10th-12th ribs. Its actions include trunk flexion, compression of the abdomen bilaterally, and lateral bending, rotation to the same side unilaterally. It is innervated by branches T7-T12.

The correct answer provides detailed information about the origin, insertion, action, and nerve supply of the Transversus Abdominus muscle. The incorrect answers provide different muscle names, origins, insertions, actions, and nerve supplies to confuse test takers.

The correct answer provides details about the specific anatomical features of the Serratus Anterior muscle, including its origin, insertion, action, and nerve innervation, which are crucial for understanding its function and location in the human body.

Levator Scapulae originates from the C1-C4 transverse processes and inserts into the scapula near the superior angle, allowing for scapular elevation. It is innervated by the C3-C4 nerve roots. The incorrect answers provide different origins, insertions, actions, and nerve innervations that are not associated with Levator Scapulae.

The Upper Trapezius muscle originates from the occipital bone and C1-C7 spinous processes, inserts into the outer third of the clavicle and acromion process, and is responsible for scapular elevation and upward rotation. It is innervated by the accessory nerve.

The Middle Trapezius muscle originates from the C7-T3 spinous processes, inserts on the spine of scapula (medial end), and aids in scapular adduction/retraction. The nerve associated with this muscle is the accessory nerve.

Rhomboids Minor/Major originate from C7-T5 spinous processes and insert into the vertebral border of the scapula. Their actions include scapular adduction, elevation, and downward rotation, and they are innervated by the dorsal scapular nerve.

The Trapezius - Lower muscle originates from the T1-T5 vertebrae (spinous processes) and the supraspinous ligament of T6-T12 vertebrae.