Biomech unit 4 Upper limb & Spine - deck 1 Flashcards
What 5 parts make up the upper limb?
- Shoulder girdle
- Arm
- Forearm
- Wrist
- Hand
What bones form the shoulder girdle ?
The clavicle and the scapula
What bone forms the arm ?
The humerus
What bones form the forearm ?
The ulna and radius
What bones form the wrist ?
The 8 carpal bones
What bones form the hand ?
The metacarpals and the phalanges
What are the 3 major joints of the upper limb which give the upper limb its wide range of motion?
Shoulder, elbow and wrist joints
What is the major function of the upper limb ?
To position the hand in space
What is the upper limb designed to achieve ?
A wide range of movement rather than for weight bearing. To position the hand in space
What bones make up the spine (also called vertebral column)?
24 vertebrae and the sacrum and the coccyx
What about the spines structure gives it a remarkable amount of flexibility as well as the strength required to support the upper body?
Its segmented structure
What joint is the most intricate joint complex in the human body?
The shoulder joint
What forms the shoulder joint ?
The humerus, the shoulder girdle (clavicle and scapula) and the thorax
Name the articulations which form the shoulder joint
- The glenohumeral
- The acromioclavicular
- The sternoclavicular
- The scapulothoracic
State what type of articulation each of the 4 articulations of the shoulder joint are
hint one of them is different from the others
- The glenohumeral, the acromioclavicular and the sternoclavicular, are synovial articulations
- The scapulothoracic, is a bone on-muscle-on-bone articulation
Specifically what type of joint is the glenohumeral joint ?
A ball-and-socket shaped synovial joint
What forms the glenohumeral joint
The humeral head and the glenoid fossa of the scapula
What about the glenoid fossa allows for a wide range of motion of the glenohumeral joint ?
The glenoid fossa is particularly shallow
What is the disadvantage of the shallow glenoid fossa in the glenohumeral joint ?
The articulation is less stable than it would be with a more developed socket therefore dislocations of the glenohumeral articulation are not infrequent
What 3 things help provide stability to the glenohumeral articulation?
- A thick cartilaginous rim called the glenoid labrum.
- The articulation is surrounded by a capsule
- The rotator cuff
What is the rotator cuff formed by?
A group of four muscles and their tendons:
- Subscapularis
- Infraspinatus
- Supraspinatus
- Teres minor
Think - SITS
Describe how the rotator cuff provides stability to the glenohumeral articulation
- They form a cuff of tissue, like the fingers of a hand cupping a ball, around the glenohumeral articulation.
- They provide dynamic restraints to anterior, posterior and inferior displacement. This is illustrated in Figure 4(B)
- The rotator cuff pushes on the humeral head, preventing any anterior-posterior movement, thereby stabilising the joint.
What type of joint is the acromioclavicular joint and what is the joint formed by ?
- It is a small synovial joint
- It is formed by the proximal acromion of the scapula and the distal clavicle
What provides stability to the acromioclavicular joint
The superior and inferior acromioclavicular ligaments which prevent the joint being pulled apart.
Further stability is provided by the two parts of the coracoclavicular ligament between the clavicle and coracoid process of the scapula which limit the upward movement of the clavicle
