Next we’ll go round to the front to see the longus muscles, and the scalene muscles. Here are the longus muscles: longus cervicis here, merging with longus capitis higher up.
Longus capitis arises from the base of the occiput, and inserts on the transverse processes of C3,4, and 5. Longus cervicis arises from the bodies of C1 to 4, and inserts on the bodies of the vertebrae from C5, all the way down to T4. Longus capitis and cervicis are weak flexors of the head and cervical spine.
Next we’ll add the three scalene muscles to the picture, the anterior scalene, middle scalene, and posterior scalene. They arise from the transverse processes of the lower five cervical vertebrae, the anterior scalene from the anterior tubercles, the middle and posterior scalene from the posterior tubercles. The anterior, and middle scalene muscles insert on the first rib, the posterior scalene inserts on the first and second ribs.
The scalene muscles are involved not in movements of the neck, but in elevating the upper ribs in deep inspiration. The scalene muscles have important relationships to the subclavian artery and the brachial plexus, shown in Volume 1 of this atlas.