Ventral cervical group

VENTRAL CERVICAL GROUP

These muscles lie below and lateral to the cervical vertebrae and are for the most part found around the trachea. They are

Sterno-cephalicus

  • This muscle consists of two divisions -sterno-mandibularis and sterno-mastoideus.
  • Origin
    • The two divisions arise together from the manubrium sterni and first costal cartilage.
    • On either side the muscles are very close together at their origin and at the lower third of the neck and from the middle of the neck, they diverge.
    • The sterno-mandibularis is the superficial division and it forms the lower boundary of the jugular furrow.
    • The deep division is the sterno-mastoideus.
    • It covers the oesophagus, trachea, and carotid structures and crosses under the superficial division at the upper third of the neck.
  • Insertion: Superficial division is inserted to the anterior border of the masseter muscle and the angle of the jaw; the deep division is common with the rectus capitis ventralis major to the mastoid process, and the basilar tubercles.
  • Action: Together to flex the head and the neck and acting singly to incline head and neck laterally.
  • Blood supply: Common carotid artery.
  • Nerve supply: Spinal accessory nerve.

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Sterno-thyro-hyoideus

  • This is a long, slender muscle situated on the ventral face of the trachea.
  • Origin: Manubrium sterni.
    • The two side muscles are very close together at their origin and cover trachea at the lower third of the neck. About the middle of the neck, each muscles divide into two bands-the thyroid and hyoid bands which diverge from those of the opposite side from the upper third of the neck. Hence in the upper third of the neck, the ventral face of the trachea is not covered by any muscle. The thyroid band is the larger and the lateral of the two bands.
  • Insertion: Thyroid band is inserted to the thyroid cartilage of the larynx and the hyoid band to the body of the hyoid and lingual process.
  • Action: To depress the hyoid, larynx, and tongue during deglutition .
  • Blood supply: Carotid artery.
  • Nerve supply: First and second cervical spinal nerves .

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Omo-hyoideus

  • This is small triangular muscle extending from the neck at its ventro-lateral aspect in an oblique direction upward and forward to the hyoid bone.
  • Origin: Transverse processes of the third and fourth cervical vertebrae.
    • This muscle passes under the deep face of the brachio-cephalicus and sterno-mastoideus obliquely forwards and inwards laterally over the sterno-mastoideus or passes through the latter and passes forwards in company with the hyoid band of the sterno-thyro-hyoideus.
  • Insertion: Body of the hyoid bone.
  • Action: To retract the hyoid and root of the tongue.
  • Blood supply: Carotid artery.
  • Nerve supply Second cervical spinal nerve.

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Scalenus

  • This muscle is situated partly in the posterior part of the cervical region and partly on the antero-lateral part of the thorax. It is made up of two division-dorsal and ventral between which emerge the roots of the brachial plexus.
  • Origin:
    • The dorsal part-scalenus dorsalis arises from the transverse processes of the fourth to the seventh cervical vertebrae.
    • The ventral part- scalenus ventralis arises from the transverse processes of the fourth to the sixth cervical vertebrae.
    • The dorsal part is covered by the serratus thoracis.
    • The roots of the phrenic nerves traverse the ventral part. The brachial vessels cross its ventral edge.
  • Insertion: The dorsal part into the fourth rib; ventral part to the anterior border of the first rib.
  • Action: To flex the neck or incline it laterally. If the neck is fixed, acts as an inspiratory muscle.
  • Blood supply: Vertebral and intercostal arteries.
  • Nerve supplyCervical spinal nerves.

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Rectus capitis ventralis major (Longus capitis)

  • This muscle extends from the neck to the basi occipital.
  • OriginTransverse processes of the 2 nd to 6 th vertebrae.
  • Insertion: Basilar tubercle.
  • Action: To flex the head or incline it laterally.
  • Blood supply: Vertebral and occipital arteries.
  • Nerve supply: Cervical spinal nerves.

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Rectus capitis ventralis minor (Rectus capitis ventralis)

  • This is a small muscle placed partly above, partly below and external to the preceding (This muscle and the next should be examined in a median sagittal section of the head).
  • OriginVentral surface of the exterior of the wing of atlas.
  • Insertion: Basilar tubercle.
  • Action: To flex the occipito-atlantal joint.
  • Blood supply: Occipital artery.
  • Nerve supplyFirst cervical spinal nerve.

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Rectus capitis lateralis

  • This is smaller than the preceding and is under the cover of obliquus capitis anterior.
  • Origin: The atlas, lateral to the origin of the obliquus capitis anterior.
  • Insertion: Paramastoid process.
  • Action: To flex the occipito-atlantal joint.
  • Blood supply: Occipital artery.
  • Nerve supply: First cervical spinal nerve.

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Intertransversales colli (Intertransversari cervicis)

  • These are six in number. This occupies the space between the articular and transverse processes of the cervical vertebrae. In general, there is a muscle for each joint. Each muscle has dorsal and ventral parts. Origin and insertions are not recognized.
  • Attachment: The dorsal bundles extend from the upper part of the transverse process to the anterior articular process of the preceding vertebra. The deeper part of the ventral bundles extends between the ventral parts of the transverse process. Their superficial fibres unite to form a long muscle-intertransversarius longus-whose anterior attachment is to the lateral border of atlas.
  • Action: To flex the neck laterally.
  • Blood supply: Vertebral artery.
  • Nerve supply: Cervical spinal nerves except the first and the last.

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Longus colli

  • This is a long muscle extending from the sixth dorsal vertebra to the atlas. It is situated on the ventral aspect of the bodies closely applied against its fellow. It consists of thoracic and cervical parts.
  • Origin: Bodies of the first six dorsal vertebrae to the medial surface of transverse process of the cervical vertebrae.
  • Insertion: The thoracic part is inserted to the bodies and transverse processes of the last two cervical vertebrae. The cervical part is inserted to the bodies of the cervical vertebrae and the ventral tubercle of atlas.
  • Action: To flex the neck.
  • Blood supply: Subcostal and vertebral arteries.
  • Nerve supply: Cervical and dorsal spinal nerves.

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Last modified: Saturday, 15 October 2011, 9:19 AM