Shoulder

Brachium

Antebrachium

Facial and Masticatory Muscles

Thorax and Heart

Brain

Body Wall

Hip and Thigh

Shank and Foot

Digestive System

Urinary and Reproductive Systems

Hip and Tail

Deep Hip and Tail of the Rabbit (Oryctolagus cuniculus)

Photos and text by Alexandra Sardi and Janelle Cooper

Dissection Notes:

The dissection of the pelvis and tail was quick and easy because we had already dissected a lot of the area around it.  In order to expose the deep hip muscles we had to cut and reflect the gluteus maximus, minimus and medius muscles.  The muscles that insert on to the tail are extensions of longissimus dorsi.  The muscle bodies are found mostly on the lateral sides and on the ventral side of the tail and progress towards the dorsal side as they move caudally.   The tail musculature was not segmented.

Discussion:

The rabbit is a cursorial mammal but has a very unique style of locomotion: half-bounding (3).  In half-bounding, the two hind feet touch the ground almost in unison but the forefeet alternate (1).  The time the forefeet spend on the ground is shorter at all speeds.  In this gait, the hind limbs provide the propulsive force and the rabbit increases its speed by flexing and extending its vertebral column until maximizing its stride length(1).   Therefore, it is extremely important that the rabbit has strong muscles to flex the spinal column.  Therefore, we would expect the rabbit to have relatively large quadratus lumborum and iliopsoas muscles compared to cursorial mammals that do not use the half-bound.  This is indeed what we discovered in the rabbit.

The rabbit has two primary functions for its tail.  It slightly aids in balance and it serves as a means of communication (1). There is not a lot of musculature on the tail, nor does the rabbit have any real means of moving it side to side so it is unlikely it helps too much for balance as it does in large cats, for example.  However, the rabbit does have four muscles that aid in lifting the tail straight up in the air.  The muscles are extensor caudae medialis, abductor caudae posterior, abductor caudae anterior and flexor caudae. This movement is a signal of danger or a sign of anger (2).  The underside of the rabbit’s tail is always a much lighter color than the dorsal side and is clearly visible when the rabbit erects its tail.  The “cotton tail” we find so endearing is actually a sign of warning and anger for potential predators.

Adapted from (3).

References:

1. Kent, George C. and Carr, Robert K., Comparative Anatomy of the Vertebrates. McGraw-Hill, New York: 2001.

2. Kardong, Kenneth V., Vertebrates: Comparative Anatomy, Function, Evolution. McGraw Hill, New York: 2002.

3. McLaughlin C.A., Chiasson R.B., Laboratory Anatomy of the Rabbit, McGraw-Hill, New York: 1990.