Lumber vertebrae
The lumber vertebrae are found in the upper abdomen region. In rabbit, they are seven in number.
Characteristics of the Lumber Vertebrae
(i) It has a large flattened transverse process.
(ii) It has broad and flat neural spine.
(iii) It has large and thick centrum
(iv) It has well developed pre and post zygapophyses.
(v) It also has two extra paired projections ( anapophysis and metapophysis) for attachment of abdomen muscles.
Functions of the Lumber Vetebrae
(i) The lumber vertebrae provides attachment muscles.
(ii) They bear considerable weight of the body.
Sacral vertebrae
The sacral vertebrae are found in the lower abdominal region. In rabbit, they are four in number. They fused together to form a structure called sacrum.
Characteristics of the Sacral Vertebra
(i) It has a narrow neural canal.
(ii) It has a neural spine which is reduced to a small notch.
(iii) It has a large centrum.
(iv) The first sacral vertebra has a pair of
transverse process which is large and
wing-like, but the others are attached to
the muscles of the back.
(v) The first sacral vertebra has a small neural alay canal which gradually becomes narrower in other vertebrae.
They are joined to the pelvic girdles to provide support, rigidity and strength.
Caudal Vertebrae

The caudal vertebrae are found in the tail region. They decrease in size from the sacrum backwards. In rabbit, they are sixteen in numbers. They are fused together to form a structure called coccyx which project from the body.
Characteristics of Caudal Vertebrae
(I) It has no neural spine.
(ii) It has no neural canal.
(iii) It appears as a solid, rectangular mass of bone.
(iv) It has no transverse process.
Functions of the Caudal Vertebra
(I) They support the tail.
(B) The Appendicular Skeleton
The appendicular skeleton is made up of the girdles, i.e., pectoral and pelvic girdles as well as the bones of the limbs, i.e., fore limbs and hind limbs.
The Pectoral Girdle
The pectoral girdle is found around the shoulder in mammals. It is made of two halves which are held by muscles. Each half of the girdle is made of three bones. These bones are: i) scapula or shoulder blade (ii) the clavicle or collar bone and (iii) coracoid.
In mammals, the scapula and coracoid are fused to form what is called scapula-coracoid. The scapula is a flat triangular bone. At the apex is a hollow or cavity called glenoid cavity into which the head of the humerus fits to form the shoulder joints. Above the glenoid cavity is a small hook-shaped bone called coracoid bone.
On the outer surface of the scapula, there is ridge or spine called the scapular spine. It runs towards the glenoid cavity. The scapula spine ends in two projections which are acromion and metacromion. Acromion is shorter than the metacromion which is larger. The clavicle is a small rod of bone attached to a ligament joining the sternum to the acromion of the scapular.
The pectoral girdle especially the surface of the scapula, the two processes and the spine are important for the attachment of muscles and ligaments. Pectoral girdles also provide firm support for the fore limbs (arms).
The Pelvic Girdle
The pelvic girdle is found around the waist in mammals. It consists of two halves which are joined to each other ventrally and to the sacrum dorsally. The line of fusion of the two halves is called pubis symphysis. Each half is called innominate bone. Each half is made up of three bones which are (i) ilium (ii) ischium and (iii) pubis. They are fused together. At the top is the ilium which is the largest and the longest of the three bones. At the lower end are the fused bones-ischium and pubis. The ischium and pubis enclose an opening or a hole called obturator foramen. It is through this hole that nerves, blood vessels and muscles pass. On the other surface of each half of the girdle where the three bones meet, there is a deep hollow or depression called acetabulum where the head of the femur of the hind limb fits to form the hip joint, an example of ball and socket joint.

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