Describe the skeleton and list its mechanical and physiological functions:
Sturdy, flexible framework
- Movement (skeleton provides anchoring points for muscles and act as levers for joints)
- Haemopoiesis (red marrow)
- Mineral storage (bone matrix: calcium and phosphate)
- Lipid storage (yellow marrow)
What is the Axial skeleton and Appendicular skeleton?
The divisions of the skeleton:
Axial skeleton forms the longitudinal axis of the body (protection and support; skull - brain, vertebral column - cord, rib cage - heart and lungs)
Appendicular Skeleton is made up of the upper and lower extremities including the pectoral girdle and the pelvic girdle that attach the extremities to the axial skeleton (mobility)
What are the bone shapes and give an example for each
Long bone e.g. Femur
Short bone e.g. Calcaneus
Flat bone e.g. Parietal bone (of the skull)
Sesamoid bone e.g. Patella (kneecap)
Irregular bone e.g. Sphenoid bone (of the skull)
What can irregular bones be?
Pneumatic - sinuses/mastoids (bones have air spaces within them making them lighter than solid bone and are only found in the skull)
Accessory - rare, secondary ossification centre develop separately to the main bone ('extra bone')
Give the structure of a long bone
*Apophysis: bony outgrowth
Define Facet, Sinus, Meatus, Fissure and Notch (bone anatomy terms)
Facet: flattened surface for joint/muscle attachment
Sinus: hollow space
Meatus: tunnel or canal
Fissure: cleft/narrow slit
Notch: a large groove
What is a joint?
The articulation between 2 or more bones (anywhere where 2 bones join)
How are joints classified?
Classified structurally according to the tissues that lie between the bones and therefore:
Describe Fibrous joints
Sutures (tight union between bones of the skull)
Syndesmoses (between distal fibula and tibia - interosseous membrane)
Gomphosis (teeth - gums)
Describe Cartilaginous Joints
Synchondroses, Primary Cartilaginous: connecting medium is hyaline e.g. hyaline cartilage epiphyseal growth plate in long bones
Symphyses, Secondary Cartilaginous: a fibrocartilaginous fusion -disc of fibrocartilage in the joint cavity - pubic symphysis, intervertebral joint
Describe Synovial Joints (Diarthrosis)
Articular capsule (synovium/synovial membrane)
Articular cartilage - hyaline
NB: not all joints allow movement but the synovial joints all for the greatest range of movements and have structural features that permit this movement to occur freely.
Demonstrate Joint Movements: Flexion and Extension, Abduction and Adduction, Internal and External Rotation, Circumduction
(NB: joint between the scaphoid and hamate is a gliding joint a 'rotate and twist')
See Lecture 1.1 and 1.2 if unsure!
What are the types of Synovial Joint?
Ball and socket
Describe a Hinge joint
Permits flexion and extension only (e.g. Elbow)
Describe a Saddle joint
Concave and convex joint surfaces eg. 1st metacarpophalangeal joint
Describe a Plane joint
Permits gliding or sliding movements (e.g. Acromioclavicular joint)
Describe a Pivot Joint
Allows rotation; a round bony process fits into a bony ligamentous socket (e.g. atlantaxial joint and proximal radio-ulnar joint)
Describe a Condyloid joint
Permit flexion and extension, adduction, abduction and circumduction (e.g. metacarpophalangeal joint)
Describe a ball and socket joint
Permits movement in several axes; a rounded head fits into a concavity (shoulder and hip joints)
What does the stability of the joints depend on?
Size, shape and arrangement of the articular surfaces
Muscles/muscle tone around the joint
- Ligaments and bursae (fluid filled sacs) commonly found in association with joints are prone to damage.
Ligaments (by excessive stretching, tearing and even rupture) due to joint injuries and the bursae may become inflamed due to excessive friction between the two structures that move relative to each other.
Describe the Subclavius
Lies almost horizontally when the arm is in the anatomical position.
Located inferior to the clavicle and affords some protection to the subclavian vessels and the superior trunk of the brachial plexus if the clavicle fractures.
Subclavius anchors and depresses the clavicle and stabilizes it during movements of the upper limb.
It also helps resist the tendency for the clavicle to dislocate at the sternoclavicular joint e.g. When pulling hard during a tug-of-war game.
Nerve innervation: nerve to Subclavius (C5, C6)
What is Poland Syndrome?
Both the Pectoralis major and minor are absent; breast hypoplasia and absence of two to four rib segments are also seen
What happens when the long thoracic nerve is injured?
Serratus anterior is paralysed.
The medial border of the scapula moves laterally and posteriorly away from the thoracic wall - winged scapula.
The upper limb may not be able to be abducted above the horizontal position because the Serratus anterior is unable to rotate the Glenoid cavity superiorly to allow complete abduction of the limb.
Describe how a joint may be functionally classified
A joint may be:
- immovable (synarthrosis)
- slightly movable (amphiarthrosis)
- freely movable (diarthrosis)
How may a deficiency of Vitamin A affect bone?
May cause an imbalance in the ratio of osteoblasts and osteoclasts, thereby slowing the growth rate.
How do bisphosphonates and calcitonin provide therapy to those with osteoporosis?
- They both inhibit osteoclast activity.
- Calcitonin can also stimulate osteoblast activity and favours calcium uptake into bone
What is Paget's Disease?
Progressive bone disease in which a pattern of excessive bone destruction is followed by bone formation contributing to thickening of bones.
This deformity usually involves the skull, pelvis and lower extremities and occurs affter the age of 40 and is typical in the 60s