The borders and layers of the upper limb`s regions
The upper limb is separated from the trunk by sulcus deltoideopectoralis anteriorly, posterior border of the deltoid posteriorly, and the line connecting the lower edges of the pectoralis major and latissimus dorsi inferiorly.
The upper limb can be divided into following regions:
Besides, there are the common regions for the upper limb and chest (infraclavicular region) and for the upper limb and back (scapular region).
Borders: superior – acromial end of the clavicle, acromion, outer third of the scapular spine; anterior and posterior borders correspond to the edges of the deltoid muscle.
Layers:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial layer of the deltoid fascia;
- deltoid muscle;
- deep layer of the deltoid fascia;
- the subdeltoid space;
- the proximal end of the humerus.
The subdeltoid space.
It is between the deep layer of the deltoid fascia and proximal end of the humerus. It contains the subdeltoid synovial bursa; the tendons of the suoraspinatis, infraspinatus and teres minor which are attached to the greater tubercle of the humerus; and the posterior circumflex humeral artery and vein and axillary nerve. The space is continuous with subtrapezoid space.
Borders: anterior — the border of the pectoralis major; posterior – the border of the latissimus dorsi; medial — the line connecting the lower edges of the pectoralis major and latissimus dorsi over the III rib; lateral — the line connecting the lower edges of the pectoralis major and latissimus dorsi over the inner edge of the upper arm.
Layers:
- skin;
- subcutaneous tissue;
- superficial fascia;
- axillary fascia;
- axillary space.
The axillary space.
Anterior wall: clavipectoral fascia covering the pectoralis minor;
Medial wall: thoracic layer of the pectoral fascia covering the serratus anterior;
Lateral wall: the brachial fascia covering the biceps brachii and coracobrachialis;
Posterior wall: subscapular fascia covering the subscapular muscle.
The axillary space contains the axillary artery with its branches; the axillary vein with its tributaries; the branches of the brachial plexus; and lymph nodes.
Borders: superior – the horizontal line passing through the acromioclavicular joint; inferior – the horizontal line passing through the inferior scapular angle; medial – medial border of the scapula; lateral – the vertical line passing through the lateral point of the acromion.
Layers:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial alyer of the proper facia of the back;
- trapezius and latissimus dorsi;
- supraspinous and infraspinous fasciae;
- supraspinatus, infraspinatus, teres minor;
- scapula;
- subscapular muscle.
The spaces:
Supraspinous space: is between the supraspinous fascia and supraspinous fossa of the scapula; contains the supraspinatus and supracsapular vessels and nerve.
Infraspinous space: is between the infraspinous fascia and infraspinous fossa of the scapula; contains the infraspinatus, teres minor, circumflex scapular vessels and branch of the transverse cervical artery with accompanying vein.
Antescapular space which is divided into anterior slit (between serratus anterior and intercostal muscles) and posterior slit (between subscapularis and serratus anterior).
Borders: superior – clavicle; medial – external edge of the sternum; inferior – horizontal line passing through the III intercostal space; lateral – anterior edge of the deltoid.
Layers:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial layer of the pectoral fascia;
- pectoralis major;
- superficial subpectoral space;
- deep layer of the pectoral fascia (its part within the clavipectoral triangle is called the clavipectoral fascia);
- pectoralis minor; deep subpectoral space;
- thoracic layer of the pectoral fascia;
- intercostal muscles and ribs.
Superficial subpectoral space: is between the fasciae covering pectoralis major and minor; it contains the thoracoacromial vessels and lateral and medial pectoral nerves.
Deep subpectoral space: is between the fasciae covering pectoralis minor and intercostal muscles.
The subpectoral spaces both connect to the axillary space.
The triangles: clavipectoral is between the clavicle and upper edge of the pectoralis minor; it contains the subclavian vessels and the proximal parts of the axillary vessels. Pectoral triangle corresponds to the pectoralis minor; subpectoral is between the lower edges of the pectoralis minor and major. All triangles contain the axillary artery and its branches, axillary vein and its tributaries, and the branches of the brachial plexus.
Borders: superior the line connecting the lower edges of the pectoralis major and latissimus dorsi over the inner edge of the upper arm; inferior – about 3 cm above the humeral epicondyles.
The anterior and posterior brachial regions are separated from each other by the lines passing alongside the biceps brachii.
Layers of anterior brachial region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial layer of the brachial fascia;
- coracobrachialis and biceps brachii;
- deep layer of the brachial fascia;
- brachialis
Layers of posterior brachial region:
- skin ;
- subcutaneous tissue ;
- superficial fascia ;
- brachial fascia;
- triceps brachii;
The brachial fascia forms medial and lateral intermuscular septa which are attached to the humerus and separate the anterior muscle compartment from the posterior one.
In the anterior brachial region in the medial bicipital sulcus between the superficial fascia and brachial fascia, the basilica vein and medial cutaneous brachial and anterbrachial nerves pass. In the same sulcus, the brachial artery, brachial veins and median nerve enveloped by the brachial fascia pass. In the lateral bicipital sulcus between the superficial fascia and brachial fascia, the cephalic vein passes.
Borders: superior – about 3 cm above the humeral epicondyles; inferior — about 3 cm below the humeral epicondyles.
Layers of anterior cubital region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- brachial and anterbrachial fasciae;
- biceps brachii;
- brachialis, pronator teres and brachiradialis.
Under the superficial fascia, superficial lymph nodes are placed and the superficial veins and nerves pass: cephalic and basilic veins, intermedial cubital vein, lateral and medial cutaneous anterbrachial nerves.
Under the brachial and anterbrachial fasciae between the muscles, the following vessels and nerves pass: brachial artery, radial and ulnar arteries and accompanying veins, and also median and radial nerves.
Layers of posterior cubital region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- brachial and anterbrachial fasciae;
- tricpes, anconeus and posterior antebrachial muscles.
Borders: superior — about 3 cm below the humeral epicondyles; inferior – 1 cm above the styloid processes.
The antebrachial region is divided into anterior and posterior by the lines connecting the humeral epicondyles with the styloid processes.
Layers of anterior antebrachial region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- anterbrachial fascia;
- the anterior antebrachial muscles: first layer: brachioradialis, pronator teres, flexor carpi radialis, flexor carpi ulnaris; the second layer: flexor digitorum superficialis; the third layer: flexor pollicis longus and flexor digitorum profundus;
- Parona-Pirogov`s space (between the flexor digitorum profundus on one side and pronator quadratus with interosseous membrane on the other side)
- the fourth layer: pronator quadratus.
- ulna, radius and interosseous membrane.
Under the superficial fascia, the superficial veins and nerves pass: cephalic and basilic veins, lateral and medial cutaneous anterbrachial nerves.
Under the brachial and anterbrachial fasciae between the muscles, the following vessels and nerves pass: radial and ulnar arteries and accompanying veins, and also median and ulnar nerves and superficial branch of the radial nerve.
Layers of posterior antebrachial region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- anterbrachial fascia;
- the posterior antebrachial muscles: first layer: extensor carpi radialis longus and brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris; the second layer: supinator, abductor pollicis longus, extensor pollicis longus and brevis, extensor indicis.
- ulna, radius and interosseous membrane.
Under the superficial fascia, the superficial veins pass (the tributaries of the cephalic and basilic veins).
Between the muscles of the first and second layers there is a space connecting with the Parona-Pirogov`s space through the openings in the interosseous membrane and containing the deep branch of the radial nerve and posterior interosseous vessels.
Borders: superior -1 cm above the styloid processes; inferior – the line passing through the distal transverse skin fold of the carpus.
The carpal region is divided into anterior and posterior by the continuations of the lines connecting the humeral epicondyles with the styloid processes.
Layers of anterior carpal region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- anterbrachial fascia which thickens here to form the flexor retinaculum;
- radial carpal canal; carpal tunnel; ulnar carpal canal;
- carpal bones.
Under the superficial fascia, the superficial veins and nerves pass: cephalic and basilic veins, lateral cutaneous anterbrachial nerve and palmar branch of the median nerve.
The content of the carpal canals: see the table «Topography of limbs».
Layers of posterior carpal region:
- skin;
- subcutaneous tissue;
- superficial fascia;
- anterbrachial fascia which thickens here to form the extensor retinaculum;
- six extensor osseo-fibrous canals;
- carpal bones.
The content of the extensor osseo-fibrous canals:
- abductor pollicis longus and extensor pollicis brevis.
- extensor carpi radialis brevis and extensor carpi radialis longus.
- extensor pollicis longus.
- extensor digitoni and extensor indicis.
- extensor digiti minimi.
- extensor carpi ulnaris.
Under the superficial fascia, the superficial veins and nerves pass: tributaries of the cephalic and basilic veins, superficial branch of the radial nerve, dorsal branch of the ulnar nerve.
Borders: proximal – the line passing through the distal transverse skin fold of the carpus; distal – the palmodigital fold
Layers of palmar region of the hand:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial layer of the palmar fascia which thickens in the middle of the palm to form the palmar aponeurosis;
In the middle of the palm:
- lumbricals and tendons of the flexor digitorum superficialis and profundus
- deep layer of the palmar fascia;
- palmar interossei muscles;
- dorsal interossei muscles
In the lateral region:
- thenar muscles and tendon of the flexor pollicis longus
In the lateral region:
- hypothenar muscles
Under the palmar aponeurosis there is a superficial palamar arterial arch and the branches of the median and ulnar nerves; under the deep layer of the palmar fascia there is a deep palmar arterial arch.
The superficial layer of the palmar fascia gives the intermuscular septa into the depth of the palm. These septa separate three spaces in the palm: thenar space (between the superficial layer of the palmar fascia and the I metacarpal bone), hypothenar space (between the superficial layer of the palmar fascia and the V metacarpal bone) and midpalmar space (between the palmar aponeurosis and the deep layer of the palmar fascia).
Layers of dorsal region of the hand:
- skin;
- subcutaneous tissue;
- superficial fascia;
- superficial layer of the dorsal fascia;
- tendons of the extensor muscles;
- deep layer of the dorsal fascia;
- dorsal interossei muscles
If you found an error, highlight it and press Shift + Enter or click here to inform us.