Skeletal system

Chapter 3 Skeletal system

The skeletal system is the ‘framework’ upon which the body is built – it provides support, protection and enables the animal to move (Fig. 3.1). The joints are considered to be an integral part of the skeleton. The skeletal system is made of the specialised connective tissues, bone and cartilage.

The functions of the skeletal system are:

Bone structure and function

Bone shape

Bones can be categorised according to their shape:

Some specialised types of bone are:

Development of bone

The process by which bone is formed is called ossification and there are two types: intramembranous and endochondral ossification. The cells responsible for laying down new bone are called osteoblasts; the cells that destroy or remodel bone are called osteoclasts.

Endochondral ossification

The process of endochondral ossification (Fig. 3.3) is as follows:

The axial skeleton

The skull

The bones of the head include the skull, nasal chambers, mandible or lower jaw and hyoid apparatus. The functions of the skull are:


The caudal part of the skull that provides the bony ‘case’ in which the brain sits is called the cranium (Figs 3.4, 3.5). The bones of the cranium include:


The mandible or lower jaw is comprised of two halves or dentaries, joined together at the chin by a cartilaginous joint called the mandibular symphysis. Each half is divided into a horizontal part, the body, and a vertical part, the ramus (Fig. 3.6). The body carries the sockets or alveoli for the teeth of the lower jaw. The ramus articulates with the rest of the skull at the temporomandibular joint via a projection called the condylar process. A rounded coronoid process, which projects from the ramus into the temporal fossa, is the point to which the temporalis muscle attaches (Fig. 3.6). There is a depression on the lateral surface of the ramus, the masseteric fossa, in which the masseter muscle lies.

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Jul 18, 2016 | Posted by in PHARMACOLOGY, TOXICOLOGY & THERAPEUTICS | Comments Off on Skeletal system

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