Muscles and Skeleton of Boa Constrictors

            The skeleton of a Boa Constrictor is not complex because they have no limbs.  Boa Constrictors have vestigial structures just like pelvic bones.  They have vertebrae, ribs, and a skull.  Their skulls allow Boa’s to eat animals larger than themselves.  Elastic ligaments connect the bones allowing the Boa to stretch its jaw.  The upper and lower parts of the jaw are in the back of the skull so that the Boa Constrictor can open its mouth very wide.  The lower part of the jaw can move around when they are eating their prey.  The Boa also has an extra loose bone called the quadrate on each side of the jaw.  It gives the snake a double hinge that helps it move its food into the Boa’s mouth.  The Boa also has backwards curve teeth that also help eat its food.  They act like hooks and angle toward the throat and prevent the prey from wiggling out of the Boa’s mouth.  The snakes teeth are attached to the bone and when they lose their teeth, they are able to grow back.  There are separate sets of teeth that a Boa has through its lifetime.  Their teeth usually come out when their eating.  A Boa Constrictor has a skull, hyoid, vertebral column, and ribs.  The skull of a Boa Constrictor has a braincase.  A Boa’s vertebral column has two hundred to four hundred vertebrae.  About twenty percent Boa’s have tail vertebrae.  A vertebrae gives a Boa strong muscle attachments allowing the snake to move faster.  A lot of Boa’s have vestiges of the hind limbs that make pelvic spurs.   

            The muscles of boa constrictors are very strong.  They have as many as 24 muscles attached to each vertebra and rib. Their muscles are also used to move they prey internally as they eat it.  Boa constrictors move by using its muscles.  There are many different ways in which they move such as slithering, rectilinear, sidewinding, and concertina.  The slithering motion is the most common form of movement.  It allows them to reach top speeds.  In the rectilinear movement, they use a caterpillar like movement to travel in a straight line.  Moving the skin of the belly forward allows them to pull the rest of their body along.   In sidewinding, the snake thrusts their body in a curling motion.   Concertina is a technique that they use when climbing trees.  Their body bunches up in horizontal loops, their head moves forward, and then they straighten out their body, very similar to an accordion or a spring.  All this movement requires their muscle strength.  This shows that the muscular systems of these snakes are very strong.

Reference: http://animal.discovery.com/guides/reptiles/snakes/anatomy_02.html