Cervical Muscles Flashcards
Where are the origin and insertion of the rectus capitis anterior? Which nerves innervate it? What movements does it contribute to?
The rectus capitis originates from the anterior surface of the lateral mass of the atlas (C1), and from the root of its transverse process, and is inserted into the inferior surface of the basilar part of the occipital bone immediately in front of the foramen magnum. It is innervated by the ventral primary rami of spinal nerves C1-2 and contributes to flexion of the neck at the atlanto-occipital joint.
Where are the origin and insertion of the longus capitis (sometimes referred to as rectus capitus anticus major)? Which nerves innervate it? What movements does it contribute to?
The longus capitus muscle arises from four tendinous slips originating from the anterior tubercles of the transverse processes of the third, fourth, fifth and sixth cervical vertebrae and converges as it ascends to insert into the inferior surface of the basilar part of the occipital bone. It is innervated by a branch of cervical plexus. When acting unilaterally, it can contribute to flexing the head and neck laterally or rotating the head ipsilaterally. When acting bilaterally, it can contribute to neck flexion.
Where are the origins and insertions of the three portions of the longus colli? Which nerves innervate it? What movements does it contribute to?
The superior oblique portion arises from the anterior tubercles of the transverse processes of the third, fourth and fifth cervical vertebrae and is inserted by a narrow tendon into the tubercle on the anterior arch of the atlas. The inferior oblique portion arises from the front of the bodies of the first two or three thoracic vertebrae and is inserted into the anterior tubercles of the transverse processes of the fifth and sixth cervical vertebrae. The vertical portion arises from the front of the bodies of the upper three thoracic and lower three cervical vertebrae and is inserted into the front of the bodies of the second, third and fourth cervical vertebrae.
It is innervated by spinal nerves C2-C6. The longus colli contributes to neck flexion.
What are the origins of the sternocleidomastoid? Where does it insert? Which nerve innervates it? What movements does it contribute to?
The sternal head arises from the upper part of the front of the manubrium sternum, while the clavicular head arises from the upper, frontal surface of the medial third of the clavicle. It inserts at the mastoid process of the temporal bone of the skull.
The accessory nerve innervates the muscle, while the cervical plexus supplies sensation, including proprioception, from the ventral primary rami of C2 and C7. (Need to double-check; some contradictory info)
The sternocleidomastoid contributes to neck flexion and contralateral rotation.
Where do the scalene muscles originate and insert? What movements do they contribute to?
The scalenes originate from the transverse processes of C2-C7 and insert onto the first and second rib.
The anterior and middle scalenes elevate the first rib and bend the neck to the same side; the posterior scalenes lift the second rib and tilt the neck to the same side.
Where does the splenius capitis muscle originate and insert? Which nerves innervate the muscle? Which movements does it contribute to?
The splenius capitis arises from the lower half of the nuchal ligament, the spinous process of C7, and the spinous process of the upper three or four thoracic vertebrae. It inserts into the mastoid process of the temporal zone (deep to the sternocleidomastoid) and into the rough surface on the occipital bone just below the lateral third of the superior nuchal line.
The splenius capitis is innervated by the posterior ramus on spinal nerves C3 and C4.
The splenius capitis is a prime mover for neck extension and can also allow lateral flexion and rotation of the cervical spine.
What are the three functional parts of the trapezius?
The upper (descending) part supports the weight of the arm, the middle (transverse) region retracts the scapula, and the lower (ascending) part medially rotates and depresses the scapula.
Where do the fibers of the upper part of the trapezius originate and insert?
The upper fibers originate from the spinous process of C7, the external occipital protuberance, the medial third of the superior nuchal line of the occipital bone, and the ligamentum nuchae. They proceed downward and laterally to insert into the posterior border of the lateral third of the clavicle.
Where do the fibers of the middle part of the trapezius originate and insert?
The middle fibers arise from the spinous process of C7 and the spinous processes of the first, second and third thoracic vertebrae. They are inserted into the medial margin of the acromion, and into the superior lip of the posterior border of the spine of the scapula.
Where do the fibers of the lower part of the trapezius originate and insert?
The lower fibers arise from the spinous process of T4-12 and proceed upward and laterally to converge near the scapula and end in an aponeurosis, which glides over the smooth triangular surface on the medial end of the spine, to be inserted into a tubercle at the apex of this smooth, triangular surface.
