Musculoskeletal System


The average adult skeleton weighs about 10 kilos.

The active part of the musculoskeletal system is the musculature. The passive part of the musculoskeletal system is the skeleton.

Human body has between 208 - 210 bones. This is because each person has a different amount of sesamoid bones. The largest bone is the femur and the smallest is one of the sesamoid bones.

The skeleton is responsible for movement, support, blood production, protection and storage. Blood is produced in the bone so that the bone stays lightweight and the blood is protected. Blood production takes place in every bone.

There are 5 types of bones:

Sesamoid Long Short Flat Irregular

Sesamoid bones are small, round bones embedded in tendons. They help to form a joint, together with the underlying bone. In the joint there is synovial fluid. The sesamoid bones reduce tendon friction or rubbing. The largest sesamoid bone is the patella. Another well known sesamoid bone is the pisiform bone found in the wrist.

There are two types of long bone:

diaphysis (yellow bone marrow) epiphysis (red bone marrow)

There are at least 8 bones that make up the craniofacial bone. They include: the maxilla and mandible, a part of the temporal bone, the frontal bone, the sphenoid bone, the ethmoid bone, the lacrimal bone, the nasal bone, the malar (cheek) bone, palatine, vomer, middle and lower nasal concha and auditory ossicle.

The ethmoid bone forms as part of the orbital cavity. It is an unpaired bone which separates the nasal cavity from the brain. It is located at the roof of the nose between the two orbits. The cribriform plate, which is one part of the ethmoid bone, contains 20 holes, through which the olfactory nerve and blood vessels run to the mucous membrane in the nose.

The tongue bone is found between the mandible and larynx.

The spinal column consists of single vertebra which are connected by fibrocartilaginous intervertebral discs. The bones of the sacrum and coccyx are one.

The task of the intervertebral discs are to act as a buffer (prevent shaking of the brain) and also to enable motion and moveability.

The vertebral foramen is the opening in a vertebra, through which the spinal cord runs.

The vertebral canal is the sum of every vertebral foramen. The medulla spinalis and cauda equina (a spinal nerve bundle) run through the vertebral canal.

An intervertebral foramen or foramina is a hole in the vertebra which allows spinal nerves and spinal ganglia to pass through the vertebra and into the medulla spinalis.

There are four spinal column sections: Cervical spine (C1-7), Thoracic spine (T1-12), Lumbar spine (L1-5), Sacrum (1) and Coccyx (3-6).

The first cervical vertebra is the atlas, which carries the weight of the head and brain; the second cervical vertebra is the axis, which is responsible for the horizontal rotation of the neck; the seventh cervical vertebra is the prominens.

The coccyx consists of 3-6 vertebra which have atrophied. It is an evolutionary reminder of our supposed prehistoric origins.

The breastbone is connected to the true ribs and clavicula. We have 7 true ribs, 3 false ribs and 2 free / floating ribs.

Not every true rib is connected to the breastbone by a genuine joint. The first rib, as well as the sixth and seventh, are connected by cartilage.

The shoulder girdle is made up of the scapula and the clavicula bones.

The shoulder girdle is connected to the torso by the sterno-clavicular joint.

The arm consists of the upper and lower arms and the hand. The upper arm bone is the humerus. The lower arm bones are the radius and ulnar. The hand consists of the carpals (8), metacarpals (5) and phalanges (14).

The 8 carpal bones can be divided into distal and proximal rows. The distal row consists of trapezium, trapezoid, capitate and hamate. The proximal row consists of scaphoid, lunate, triquetrum and pisiform. They connect the hand to the forearm.

The sacrum, ischium and pubis belong to the pelvic girdle.

The female pelvis is different to a male in the following ways: it has a wider


To the spinal column, vertebra and foramina