The muscles, which move the external ear are divided into extrinsic and intrinsic groups. The muscles of the former arise from extraneous parts as cranial bones, ligamentum nuchae or parotid gland and are inserted into the cartilages of the ear. The muscles of the latter are confined to the cartilage of the ear. They are
- Extrinsic muscles
- Parotido-auricularis
- Cervico-auricularis
- Parieto-auricularis externus
- Parieto-auricularis internus
- Zygomatico-auricularis
- Temporo- auricularis (Tragicus of horse)
- Intrisic muscles
- Scuto-auricularis externus
- Scuto-auricularis internus
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.
INTRINSIC MUSCLE
Scuto-auricularis externus
- Origin: The outer face of the scutiform cartilage.
- Insertion: Medial part of the base of concha.
- Action: To prick the ear.
Scuto-auricularis internus
- Origin: Internal face of the scutiform cartilage,
- Insertion: Anterior aspect of the Concha.
- Action: To prick the ear,
- Blood supply: External carotid, superficial temporal arteries and a small branch from the occipital artery.
- Nerve supply: Facial nerve, first and second spinal nerves.
