The Basics of Anatomy (1)

Question 1

What is meant by the origin of a muscle and the insertion of a muscle?

Answer 1

The origin is the muscle’s attachment site that stays still during contraction, i.e. the anchor point, and is typically more proximal, and with greater mass than the insertion. The insertion is the muscle’s attachment that moves during contraction, and is typically more distal.

Question 2

Name the three different classifications of joints.

Answer 2

Synovial. Fibrous. Cartilagenous.

Question 3

Name the six different types of synovial joint.

Answer 3

Plane.
Hinge.
Saddle.
Condyloid.
Ball and socket.
Pivot.

Question 4

Name the features of all synovial joints.

Answer 4

Joint capsule, with an outer fibrous capsule and an inner synovial membrane.
Articulating surfaces are lined with articular cartilage.
All other surfaces are lined with synovial membrane.

Question 5

Name three important fibrous joints in the body.

Answer 5

1. Syndesmosis at ulna and radius = interosseous membrane.
2. Syndesmosis at tibia and fibula = interosseous membrane.
3. Sutures between skull bones.
   Note that the following are all synovial joints:
   Proximal radio-ulnar (pivot joint)
   Distal radio-ulnar (pivot joint)
   Superior tibiofibular (plane joint)

Question 6

Name the two subtypes of cartilaginous joints, and the type of cartilage they contain.

Answer 6

1. Primary cartilaginous joints (hyaline cartilage)

2. Secondary cartilaginous joints (fibrocartilage)

Question 7

What is the most common example of primary cartilaginous joints? What is another name for these? What is another example of a primary cartilagenous joint?

Answer 7

These are epiphyses, found in the growing child’s bones. Also called synchondroses. Other examples of primary cartilagenous joints / synchondroses include the costochondral joints (where the bony rib becomes cartilagenous as it nears the sternum), and the xiphisternal joint.

Question 8

What is an example of a secondary cartilagenous joint?

Answer 8

Intervertebral discs. Manubriosternal joint.

Question 9

Give some examples of plane synovial joints.

What is the shape of the opposing surfaces?

Answer 9

Acromioclavicular joint, Superior tibiofibular joint, Costovertebral joints, Sternocostal joints of 2nd-7th ribs.
Opposing surfaces are flat, or almost flat.

Question 10

Give one example of a hinge synovial joint. What movements are permitted?

Answer 10

Elbow. Only flexion and extension.

Question 11

Give one example of a saddle synovial joint. What movements are permitted?

Answer 11

Carpometacarpal joint at the base of the thumb. Permits flexion/extension and abduction/adduction, and permits circumduction when these movements are combined.

Question 12

Give one example of a condyloid synovial joint. What is the shape of the opposing surfaces? What movements are permitted?

Answer 12

Metacarpophalangeal joints. Looks like a ball-and-socket joint but the ball is oval-shaped. Permits flexion, extension, abduction, adduction, circumduction.

Question 13

Give three examples of a pivot synovial joint.

Answer 13

Atlantoaxial joint, Proximal radio-ulnar joint, Distal radio-ulnar joint.

Question 14

Give a definition for the term “dermatome”.

Answer 14

The unilateral area of skin innervated by the fibers of a single spinal nerve.

Question 15

Give a definition for the term “myotome”.

Answer 15

The unilateral muscle mass receiving innervation from fibers of a single spinal nerve.