Session 3 - Important points

Question 1

What is amelia?

Answer 1

A complete absence of a limb or limbs

Question 2

What is meromelia?

Answer 2

Partial absence of a limb or limbs

Question 3

A complete absence of a limb or limbs?

Answer 3

Amelia

Question 4

Partial absence of a limb or limbs?

Answer 4

Meromelia

Question 5

What is polydactyly?

Answer 5

Extra fingers or toes
In the hand, the extra digit is either on the ulnar or radial side rather than central; in the foot it on the fibular side

Question 6

What is syndactyly?

Answer 6

Fusion of fingers or toes;
results from a lack of differentiation between two or more digits.
Some cases fusion of the bones, others just thinner tissue connected

Question 7

What is cutaneous synactlyly?

Answer 7

Webbing of the skin between the fingers and toes results from failure of this tissue breakdown to occur.

Question 8

What is osseous syndactyly?

Answer 8

Fusion of the bones of the digits

Question 9

What is the structural defect underlying congenital dislocation of the hip

Answer 9

Underdevelopment of acetabulum and head of femur.

Question 10

What is the function of the AER?

Answer 10

Stimulates outgrowth of limb and maintains undifferentiated state in mesenchyme immediately underlying it.

Question 11

What is subcutaneous bursitis?

Answer 11

Burs lying between the skin and the olecranon process of the ulna becomes inflamed and produces a swelling due to excessive friction. May become infected and inflamed.

Question 12

State three factors which contribute to stability of a joint

Answer 12

The tone of the rotator cuff muscles; the coracobrachialis, the short head of biceps and the long head of triceps assist the deltoid in resisting downward dislocation of the joint.
Capsular and extracapsular ligaments.
Glenoid labrum helps to deepen the glenoid fossa (cavity).

Question 13

What is the coraco acromial arch?

Answer 13

osseoligamentous structure formed by the smooth inferior aspect of the acromion and the coracoid process of the scapula with the coracoacromial ligament spanning between them.

Question 14

What does the coraco acromial arch prevent?

Answer 14

Superior dislocation of the humeral head

Question 15

Where is the anatomical neck of the humerus?

Answer 15

The anatomical neck is formed by the groove circumscribing and separating the head from the greater and lesser tubercles.

Question 16

What is the significance of the anatomical neck of the humerus?

Answer 16

The articular capsule of the joint is attached nearby.

 The anatomical neck also marks the region of the epiphyseal growth plate during the growth in length of the humerus.

Question 17

List the six movements of the scapula and the muscles associated

Answer 17

Protraction – Serratus anterior
Retraction – (Middle fibres of) trapezius, rhomboids
Elevation – (Upper fibres of) trapezius, levator scapulae
Depression – (gravity) (relaxation of elevator muscles)
Lateral rotation/upward rotation – upper and lower fibres of trapezius
Medial rotation/downward rotation – Latissimus dorsi, levator scapulae, rhomboids (tilt glenoid cavity inferiorly)

Question 18

What are the muscles involved in abduction of the arm?

Answer 18

Supraspinatus (15 – 20)
Deltoid (90)
Upper and lower fibres of the trapezius (above 90)
Serratus anterior

Question 19

Describe two effects of a torn supraspinatus tendon

Answer 19

Failure of initiation of abduction in first 15 degrees
When the person is asked to lower the fully abducted arm slowly and smoothly, from approximately 90 , the limb suddenly drops to the side in an uncontrolled manner.

Question 20

Explain painful arc syndrome

Answer 20

When the bursa is inflamed (subacromial bursitis), abduction of the arm is extremely painful during the arc of 50* to 90* (“painful arc syndrome”). The pain may radiate as far distally as the hand. Acute pain is also felt lateral to the acromion

Note that this is when the deltoid responsible for abduction, the tendon of which moves over subacromial bursa