The Regional Anatomy of the Upper limb

Section 1 Introduction. Boundaries and DivisionsⅠ

In response to the demand for flexibility of the upper limb. The long bones of upper limb are of slender ones and ★ more lighter than that of lower limb. The capsules of joints are loose and lack of strong ★ ligament.Division: The shoulder －－ axilla, scapular region, pectoral region.The arm －－ － anterior region, posterior region.The elbow －－ － The forarm －－ anterior region, posterior region.The hand －－ － palm, dorsum, fingers or digits.

Ⅱ. The Surface Anatomy) Surface LandmarksⅠ

1. The shoulder (1) The acromion (2) The coracoid process (3) The anterior and posterior axillary folds

2. The arm (1) The biceps brachii (2) The carrying angle (3) The deltoid tuberosity

3. The elbow (1) The medial and lateral epicondyes of humerus (2) The olecranon

4. The hand (1) The wrist creases (2) The flexor tendons (3) The anatomical snuff box (4) The styloid processes of the ulna and radius

Section 2 The superficial structures of upper limb

.The skinⅠ The thick in palm; The thin in other parts.

.The superficial fasciaⅡ ) The superficial veinsⅠ 1. The cephalic vein 2. The basilic vein 3. The median cubital vein

Ⅱ) The cutaneous nervesThe anterior surface: 1. The supraclavicular nerve 2. The superior lateral brachial cutaneous nerve 3. The inferior lateral brachial cutaneous nerve 4. The medial brachial cutaneous nerve 5. The intercostobrachial nerve 6. The lateral anterbrachial cutaneous nerve 7. The medial anterbrachial cutaneous nerve 8. The superficial branch of radial nerve 9. The median nerve 10. The superficial branch of ulnar nerve

Section 3 The deep structures of upper limb

. The deep fasciaⅠ The bicipital aponeurosis The flexor (extensor) retinaculum The intermuscular septum The neurovascular sheath The osseofibrous sheath (osteofascial compartment)

Ⅱ. The muscles ) The pectoral regionⅠ 1. The extrinsic muscles The pectoral major, The subclavius, the pectoral minor, The serratus anterior. 2. The intrinsic muscles The intercostales externi (anterior intercostal membrane), The intercostales interni (posterior intercostal membrane), The intercostales intimus

) The shoulder region The deltoid, the supraspinatus, the infraspinatus, the tere minor, the tere major, the subscapularis.

) The arm (brachium) region 1. The anterior group The biceps brachii, the coracobrachialis, the brachialis. 2. The posterior group The triceps brachii.

) The forarm (antebrachium) region

1. The anterior group 1) The superficial layer (6) The brachioradialis, the pronator tere, The flexor carpi radialis, the palmaris longus, The flexor digitorum superficialis, The flexor carpi ulnaris. 2) The deep layer (3) The flexor pollicis longus, The flexor digitorum profundus, The pronator quadratus.

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. . The vessels and nerve

1. The arteries (main trunk) axillary a. brachial a. radial a. Superficial palmar arch common palmar digitial a. deep palmar arch proper palmar digitial a. ulnar a.

2. The veins (main trunk)

Plantar v. arch dorsal v. of foot anterior tibial v. lateral plantar v. posterior tibial v. medial plantar v.

popliteal v. femoral v. external iliac v.

. The axilla

It is a pyramidal region; between the upper part of the chest wall and the medial side of the arm. the axillary fossa or armpit: a concave fossa of skin under the shoulder joint. the axillary cavity: Deep to the armpit there is a pyramidal space.

The axilla possesses a apex, a base, 4 walls. The axillary cavity contains vessels, nerves, lymph nodes and a lot of adipose tissue.

) Boundaries of the axilla

1. The apex It is directed upwards towards the root of the neck; corresponds to the interval among the outer border of the first rib,the superior border of the scapula and the posterior surface of the clavicle. the passage of the vessels and nerves between neck and the upper limb.

2. The base

is directed downwards; is broad at the chest but narrow and pointed at the arm; is formed by the skin and a thick layer of fascia (axillary fascia); the special large sweat glands are abundant in the skin of armpit, which have special odour (called bromhidrosis).

3. The anterior wall is formed by the pectoralis major, pectoralis minor and clavipectoral fascia;

4. The posterior wall consists of the subscapularis superiorly and the tere major with the latissimus dorsi iferiorly. The quadrabgular space: --- lateral; --- is formed by the subscapularis , the tere major and the long head of triceps. --- transmits the axillary nerve and the posterior humeral circumflex vessels. The triangular space: --- medial; --- is formed by the subscapularis , the tere major and the long head of triceps.

--- transmits the circumflex scapular vessels.

5. The medial wall is formed by the first four ribs with their corresponding intercostal muscles and the upper part of the serratus anterior.

6. The lateral wall is a narrow space where the anterior and posterior walls converge.

is formed by the intertubercular sulcus of the humerus, the two heads of biceps and the coracobrachialis.

) Contents of the axilla

The axillary vessels; The infraclavicular part of the brachial plexus with its branches; The lateral branches of the intercostal nerves; The large number of lymph nodes; The quantity of fat and loose areolar tissue.

1. The axillary artery It extends from the outer border of the first rib to the lower border of the tere major. The three parts by means of the pectoralis minor.

(1) The first part In front, is covered by the clavipectoral fascia; Behind, related to the long thoracic n. and the medial cord of the brachial plexus; On the medial side, related to the axillary v. and the apical lymph nodes. The branch--- The superior thoracic a. supplies the anterior part of first two intercostal spaces.

(2) The second part

lies deep to the pectoralis minor; behind, related to the subscapularis; laterally, posteriorly, medially, related to the lateral cord, posterioe cord and medial cord respectively;

The branch--- The thoracoacromial a. To pierces clavipectoral fascia and divides into 3 branches to supply the pectorals, deltoid and acromion. The lateral thoracic a.--- To follow the lateral border of the pectoralis minor to the side of the chest; To supply the serratus anterior and the pectoral m. In the female, it is large, gives lateral mammmary branches.

(3) The third part Its lower part is covered by the skin and fascia only; It is easy to be exposed clinically; Behind, related to the radial and axillary nerves; On its lateral side, musculocutaneous n. and coracobrachialis m. On its medial side, medial antebrachial n. and the ulnar n. The branch--- The thoracodoral a. The subscapular a. The circumflex scapular a. The anterior humeral circumflex scapular a. The posterior circumflex scapular a.

2. The axillary vein

From the lower border of the tere major as the continuation of the basilic v.

To is anteromedial to the axillary a.

To receive the tributaries which accompany the arteries.

3. The infraclavicular part of brachial plexus The branched of the cords of brachial plexus

Cords Main branches Other branches

Lateral

(C 5~7)

Musculocutaneous n.

Lateral root of median n.

Lateral pectoral n.

Medial

(C8,T1)

Medial root of median n.

Ulnar n.

Medial pectoral n.

Medial brachial cutaneous n.

Medial antebrachial cutaneous n.

Posterior

(C5~7,T1)

Axillary n.

Radial n.

Subscapular n.

Thoracodorsal n.

4. The axillary lymph nodes 20~30 in number; 5 groups which lie along the roots of the vessels of axilla

(1) The lateral lymph nodes (lateral group) 4 ~ 6 in number; To lie medical and posterior to the distal part of axillary vein; To receive the lymph from the whole upper limb except for the part which lymph vessels accompany the cephalic vein; To drain into the centre group and partly into the inferior deep lateral cervical lymph nodes directly.

(2) The pectoral lymph nodes (anterior group) 4 ~ 5 in number; To lie along lower border of the pectoral minor in the relation to the lateral thoracic vessels; To receive the lymph from the skin and muscles of the anterior and lateral walls of the body above the level of the umbilicus and central and lateral parts of the mammary gland; To drain into the central an apical lymph nodes.

(3) The subscapular lymph nodes (posterior group)

6 ~ 7 in number; To lie along the lower margin of the posterior wall of the axlla and the subscapular vessels; To receive the lymph from the skin and muscles of the lower part of the back of the neck and dorsal aspect of the trunk as low as the iliac crest; To drain into the central group.

(4) The central lymph nodes (central group)

3 ~ 4 in number; To embed in the fat of the axilla; To receive the afferent from all the preceding lymph nodes; To drain into the apical lymph nodes

(5) The apical lymph nodes (apical group)

6 ~ 12 in number; To situate partly posterior to the upper portion of the pectoralis minor and partly under the clavipectoral fascia which is along first part of the axillary vein; To receive the lymph from the upper part of the mammary gland and the efferents of all the other axillary lymph nodes; The afferents of these nodes unite to form the subclavian trunk.

. The humeromuscular tunnel

It is formed by three heads of triceps brachii and the sulcus for radial nerve of humerus. It extends downwards from the medial to the lateral side of the back of middle part of the humerus; It transmits the radial nerve and the deep

brachial vessels.

Ⅳ. The cubital fossa It is a triangular depression at the bend of the elbow. The doundaries---- laterally--- the brachioradialis; Medially---the pronator teres; Speriorly--- the base An imaginary line between the two humeral epicondyles. The contents---- from the lateral to medial sides radial n. , lateral antebrachial cutaneous n. , tendon of biceps brachii, terminal part of brachial a. and vein, median n. few deep cubital lymph nodes

which lie at the bifurcation of the artery.