Extrinsic muscles

EXTRINSIC MUSCLES

Parotido-auricularis

  • It is a thin and wide muscle situated on the parotid salivary gland. It is wide below and narrow above.
  • Origin: Fascia on the lower part of parotid gland.
  • Insertion: Conchal cartilage below the angle of junction of its borders.
  • Action: To incline the ear downwards and backwards

Cervico-auricularis

  • This muscle is a compound muscle with three parts, namely cervico-auricularis externus, medius and internus, named according to their position at their origin. They are arranged layer by layer.
  • Origin: Ligamentum nuchae and cervical fascia.
  • Insertion: Medial face of the base of the concha.
  • Action: Rotate the ear and draw it backward.

Parieto-auricularis externus

  • It is a wide but thin muscle covering the temporalis.
  • Origin: Frontal crest, parietal and occipital bones.
  • Insertion: Scutiform cartilage and anterior aspect of concha.
  • Action: To adduct the concha rotate it forwards to prick the ear

Parieto-auricularis internus

  • It is placed partially under the preceding muscle.
  • Origin: Parietal bone behind the frontal eminence.
  • Insertion: Medial face of the concha.
  • Action: To adduct the ear.

Zygomatico-auricularis

  • It is made up of two bundles.
  • Origin: Zygomatic process of the squamous temporal.
  • Insertion: The upper bundle to the scutiform cartilage and the lower one to the front and base of concha.
  • Action: To prick the ear.

Temporo- auricularis (Tragicus of horse)

  • It is a very thin fasciculus.
  • Origin: External auditory process and annular cartilage.
  • Insertion: Base of concha.
  • Action: To telescope the conchal and annular cartilage and shorten the external acoustic meatus.
Last modified: Saturday, 15 October 2011, 8:39 AM