Rhomboid Fossa
Question 1. Discuss the features of the rhomboid fossa in brief.
Answer.
The features of the rhomboid fossa are as follows:
Stria medullaris
- It is rhomboidal in shape and has four angles: rostral, caudal and two lateral.
- The floor is divided into two halves by a median sulcus. Each half of the floor is further divided into two parts (pontine and medullary) by fibres of the stria medullaris, which run from the median sulcus to the lateral boundary.
Facial colliculus
Features Above The Medullary Striae (I.E., In The Pontine Part)
- Presence of facial colliculus, on either side of the median sulcus. It is an oval elevation produced by the fibres of the motor nucleus of the facial nerve hooking around the abducent nucleus (internal genu of the facial nerve).
- A depression at the upper end of the sulcus limitans is called the superior fovea.
- A bluish-grey area (locus coeruleus), above the superior fovea. The bluish colour is imparted by the underlying group of nerve cells containing melanin pigment.
Features Below The Stria Medullaris (I.E., In The Medullary Part)
- Inferior fovea, a triangular depression
- Hypoglossal triangle, medial to the inferior fovea
- Vestibular triangle, lateral to inferior fovea
- Vagal triangle, inferior to the inferior fovea
- Funiculus separates, a fine translucent ridge crossing the vagal triangle
- Area postrema, a small area below the funiculus, separates
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