Hammer (anatomy)
The hammer (lat. Malleus ) is a small bone of the middle ear that connects the eardrum with the anvil (lat. Incus ) and is thus part of the auditory ossicles or the sound conduction apparatus. Embryonally, the hammer arises from the lower part of the first gill arch , comparatively anatomically from the original articular bone and is related to Meckel's cartilage .
Anatomically, the hammer consists of the caput (head), collum (neck), manubrium (hammer handle) and two small processes at the upper end of the hammer handle, the lateral malleus process (lateral hammer process) and the anterior mallei process (anterior hammer process). The length of the entire ossicle varies between 7.6 and 9.1 mm, that of the hammer handle between 4.3 and 5.7 mm. The mass of the hammer is about 25 mg. The tendon of the tensor tympani muscle starts at the transition from the hammer handle to the hammer neck . In addition to the adhesion of the hammer to the eardrum and the articulated connection with the anvil , the hammer is held in its position by an upper, anterior and lateral ligament ( ligament ) from the hammer head to the middle ear walls.
During otoscopy , the hammer handle with the lateral hammer process can be seen through the eardrum. At the tip of the hammer handle, the eardrum reaches its deepest indentation ( umbo membranae tympani , eardrum navel).
Individual evidence
- ↑ Graphic on the development of the temporomandibular joints and their derivatives ( Memento of the original from February 25, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Barry J. Anson, James A. Donaldson: Surgical Anatomy of the Temporal Bone . Saunders, Philadelphia 1981, ISBN 0-7216-1292-X .
- ^ Stanley A. Gelfand: Essentials of Audiology . Thieme, New York and Stuttgart 1997, ISBN 3-13-103631-1 , pp. 46 .
