Supination and Pronation

Supination - In semiflexed elbow, the palm is turned upward. It is more powerful than pronation because it is an antigravity movement.
Movements- all screwing movements of hand, e.g. As in tightening nuts and bolts.
It is brought by supinator & biceps brachii.


Pronation - In semiflexed elbow, the palm is turned downward. It is brought about chiefly by pronator quadratus. Aided by pronator teres while rapid movement and against resistance




These are the rotatory movements of the forearm around vertical axis
The axis is not stationary because the lower end of ulna is not fixed - it moves backward & laterally during pronation and forwards & medially during supination.
As a result the axis is displaced laterally in pronation, and medially in supination.

THE ANASTOMOSES AROUND THE SCAPULA

The anastomoses around scapula is an arterial anastomosis around both surfaces of scapula bone between the branches of subclavian and axillary arteries. The arteries taking part in this anastomoses are‐
1. The suprascapular artery from thyrocervical trunk of first part of subclavian artery. The artery reaches upper border of scapula and passes above suprascapular ligament to reach supraspinous fossa, then it curves around spinoglenoid notch to reach infraspinous fossa.
2. The deep branch of transverse cervical artery‐also from thyrocervical trunk. The artery descends along medial border of scapula deep to levator scapulae and rhomboids (sometimes the artery arises from third part of subclavian artery and is known as dorsal scapular artery).
3. The subscapular artery from third part of axillary. Its circumflex scapular branch passes between the two origins of teres minor, enters infraspinous fossa. Another branch accompanies the thoraco‐dorsal nerve. Functional importance
a. The anastomoses provides sufficient amount of blood to scapular muscles and upper extremity during movements of shoulder joint from lateral border of scapula on its dorsal surface.
b. In case of blockage of main arterial trunk‐distal to the origin of thyrocervical trunk and proximal to the origin of subscapular artery, this anastomoses provides an alternative route for the supply of blood to upper extremity.

Enumerate the boundaries, contents of axilla, name the various branches of axillary artery

(i)                 THE AXILLA

 The axilla is the space between upper part of medial side of arm and lateral side of thorax. Shape is pyramidal

Boundaries The walls are anterior, posterior, medial and lateral. It has an apex and a base. a. The anterior wall is formed by Pectoralis major Clavipectoral fascia Pectoralis minor b. The posterior wall is formed by‐ Subscapularis Latissimus dorsi Teres major c. The medial wall is formed by Serratus anterior covering upper part of lateral thoracic wall. d. The lateral wall is narrow and formed by Shaft of humerus Coracobrachialis

Short head of biceps brachii

The apex is triangular and directed upwards and medially towards root of neck. It is bounded by Clavicle anteriorly First rib medially Upper border of scapula posteriorly The base of axilla is formed by axillary fascia. Contents of the axilla are:

 a. The axillary artery and its branches

 b. The axillary vein and its tributaries

 c. The three cords of brachial plexus and their branches.

 d. The axillary lymph nodes

e. Fibrofatty tissue

f. The axillary tail of Spence of mammary gland in females.

THE AXILLARY ARTERY

The axillary artery is the main arterial trunk of the upper extremity.∙

 Beginning

The axillary artery begins at the outer border of first rib as continuation of third part of subclavian artery.

Course

 The artery passes laterally and downwards.

 a. First part extends from outer border of first rib to medial border of pectoralis minor.

 b. Second part is the short segment of artery that lies behind pectoralis minor.

 c. Third part is the longest part that extends from lateral border of pectoralis minor to lower border of teres major.

Branches

The artery gives six branches.

From first part:

one branch

 1.The superior thoracic artery is a small branch supplying first intercostal space.

From second part:

two branches

 2. The thoracoacromial artery pierces clavipectoral fascia and divides into four branches. a. The deltoid branch lies in deltopectoral groove.

b. The clavicular branch supplies sternoclavicular joint and subclavius muscle.

c. The pectoral branch for the pectoral muscles.

d. The acromion branch takes part in anastomosis over acromion process.

 3. The lateral thoracic artery runs along the lateral border of pectoralis minor

In females, it is large and supplies the mammary gland.

From third part:

three branches

 4. The anterior circumflex humeral curves around the surgical neck of humerus from front.

 5. The posterior circumflex humeral is a larger branch that accompanies axillary nerve through quadrangular space.

 6. The subscapular artery is large artery that follows lateral border of scapula.

Upper Limb

Important Topics

 

Upper Limb

1. Course of Radial , Ulnar & Median Nerve (with clinical)

2. Lymphatic Drainage of Breast
3. Flexor & Extensor Retinaculum
4. Shoulder Joint
5. Intrinsic Muscles of  Hand with Nerve Supply
6. Muscles of Thenar Spcaes of hand
7. Cubital Fossa
8. Deep Palmer Arch
9. Muscular Space of Scapular region
10. Wrist Joint
11. Palmer Fascial Spaces
12. Dorsal Digital Expension
13. Region of Axilla
14. Anastmosis Around Elbow and Scapula
15. Brachial Plexus
16. Supination & Pronation
**** All of the topics above are important and must be learned with their Diagrams & Applied Aspect.