Waldeyer’s ring is a collection of lymphoid tissue or follicles in the upper part of digestive system. This ring is formed by: Superiorly- Pharyngeal tonsils or Adenoids. Inferiorly- Lingual tonsil. Laterally- Palatine tonsils and tubal tonsils. I. Pharyngeal Tonsil: Lie postero superiorly under the mucous membrane of the roof and adjoining posterior wall of nasopharynx. II. Lingual Tonsil: This is [...]
In this article we will discuss about the meaning, parts and surfaces of frontal bone which belongs to human skull. Meaning and Parts of Frontal Bone: This is a membrane bone, forms forehead and lodges frontal air sinus, i.e., pneumatic bone. Parts: Three parts are: 1. Squamous part 2. Orbital plates are on either side 3. Nasal part. I. Squamous [...]
In this article we will discuss about:- 1. Anatomical Structure and Surfaces of Parietal Bones 2. Angles of the Parietal Bones 3. Parts. Anatomical Structure and Surfaces of Parietal Bones: There are two parietal bones present on the top of skull, develops from membrane. Each bone comes in contact - to all the lobes of cerebral hemisphere. It has two [...]