7 Main Ligaments and Muscles in a Snake | Reptiles

The following points highlight the seven main ligaments and muscles in a snake.

1. The poison gland is held in position by ligaments, which extend from maxillolacrimal junction to pterygoquadrate.

2. Fan-shaped ligaments present along the sides of the poison gland.

3. Associated muscles are anterior and posterior temporalis (masseter), digastric muscles and protractor- pterygoid muscle (Fig. 8.32B) that help in biting mechanism.

4. The fan-shaped temporalis muscle (masseter) originates from the post­frontal and parietal ridges, embraces most part of the poison gland and inserts at the frontal part of the skull. Its sudden contraction helps to eject out the venom from the gland, and also controls the biting mechanism. Different authors have given different names to the muscle which helps to squeeze out the secretion from the poison glands.

Colbert (1969) refers to it as Capitomandibularis superfi­cial is muscle to the temporalis or mas­seter muscle in elapids. Masseter means one of the chewing muscles from temporal bone to lower jaw.

The muscle has been also named super­ficial adductor mandibulae muscle in Puff adder (Bitis arietans) by Boltt and Ewer (1964). Again Minton and Minton (1971) and Kardong (2002) refer to this muscle as compressor glandulae muscle in vipers (Fig. 8.30).

5. Digastric muscle:

It arises from the squamosal and quadrate junction and is attached to the articular of the lower jaw (Fig. 8.32B). Contraction of these muscles help in opening the mouth by depressing the lower jaw.

6. Sphenopterygoid or protractor- pterygoid muscle:

It arises from the anterior region of the basal orbitosphenoid region and inserts to the dorsal side of the pterygoid (Fig. 8.32B). It assists in pulling the ptery­goid forward, resulting in pushing the ectopterygoid which rotates the maxilla and erects the fang.

7. Anterior temporalis muscle: It is the closing muscle of the mouth. It arises from the pterygoid bones of the upper jaw and is inserted to the particular region of the mandible (Fig. 8.32B).