Medial bundle, fasciculus medialis , is formed by the anterior branches of the eighth cervical and first thoracic nerves (CVIII - ThI).
It gives off the lateral pectoral nerve, medial pectoral nerve, ulnar nerve, medial cutaneous nerve of the shoulder, medial cutaneous nerve of the forearm, medial root of the median nerve.
1. Lateral thoracic nerve, n. pectoralis lateralis(CV - CVIII, ThI), departs from the upper trunk or slightly lower - from the lateral bundle of the plexus and, heading downwards, passes in front of the axillary artery, gives branches to the deep part of the pectoralis major muscle, often sending a connecting branch to the nerve innervating the pectoralis minor muscle .
2.Medial pectoral nerve, n. pectoralis medialis(CV - CVIII), departs from the lower trunk or below - from the medial bundle of the plexus and, following downwards, passes between the axillary artery and vein, giving the final branches to the pectoralis major and minor muscles.
3. Ulnar nerve, n. ulnaris(Cvii - СVIII), located initially medial from the axillary and the beginning of the brachial arteries; at the level of the middle third of the shoulder it departs from the brachial artery to the medial periphery of the shoulder towards the medial intermuscular septum of the shoulder, often running in its thickness, and in the lower half of the shoulder it lies behind it.
Here the ulnar nerve, accompanied by the superior ulnar collateral artery, follows, located on the medial head of the triceps brachii muscle, down into the groove between the medial epicondyle of the humerus and the olecranon process, where it lies directly on the bone in the groove of the ulnar nerve and is covered only by fascia and skin. In this area, the nerve gives off a thin articular branch to the capsule of the elbow joint.
Coming out of this gap, the trunk of the ulnar nerve passes between the heads of the flexor carpi ulnaris muscle and lies on the anterior surface of the forearm between the flexor digitorum profundus and the flexor carpi ulnaris muscle, medially to the ulnar arteries and veins. In the lower part of the forearm, the flexor carpi ulnaris tendon covers it along with the vessels.
The ulnar nerve does not give off branches in the shoulder. In the area of the forearm there is a connecting branch between it and the median nerve.
At the border of the middle and lower thirds of the forearm, sometimes above or below, the trunk of the ulnar nerve divides into its terminal branches: the thinner dorsal branch of the ulnar nerve and the thicker palmar branch of the ulnar nerve.
Branches of the ulnar nerve:
1) muscle branches, rr. musculares, to the muscles: flexor carpi ulnaris and ulnar part of the deep flexor digitorum (to the ring finger and little finger); in the thickness of the muscle, the branches of the ulnar nerve connect with the branch of the median nerve, which innervates the rest of the muscle;
2) dorsal branch of the ulnar nerve, r. dorsalis n. ulnaris, passes between the ulna bone, closer to its head, and the tendon of the flexor carpi ulnaris, follows to the dorsum of the hand, where, perforating the fascia, it breaks up into branches to the skin of the ulnar side of the dorsum of the hand and the back of the fingers, giving off the dorsal digital nerves:
a) dorsal digital nerves, nn. The digitales dorsales, five in number, innervate the skin of the dorsal surface of the little finger, ring finger and ulnar side of the middle finger. On the little finger, the nerves reach the base of the nail, and on the ring and middle fingers they extend only within the skin of the proximal phalanx;
b) connecting branches (non-permanent) with the superficial branch of the radial nerve and with the branches of the medial, dorsal and lateral cutaneous nerves of the forearm;
c) palmar branch of the ulnar nerve, r. palmaris n. ulnaris, follows along with the ulnar artery and is a continuation of the main trunk of the ulnar nerve. In the distal forearm, a small palmar cutaneous branch arises from it, sometimes in the form of two thin nerves.
It sends a branch to the ulnar artery and, piercing the fascia of the forearm, between the flexor carpi ulnaris and the superficial flexor digitorum, goes to the skin of the ulnar edge of the wrist joint, to the skin of the eminence of the little finger and to the skin of the little finger. Between this branch and the medial cutaneous nerve of the forearm there is a connecting branch.
From the superficial branch, r. superficialis, depart:
a) common palmar digital nerve, n. digitalis palmaris communis, lies under the palmar aponeurosis along the fourth interosseous space. Here it divides into the palmar digital nerves, nn. digitales palmares proprii, which includes two branches: the own palmar digital nerve of the little finger (innervates the skin of the radial side of the little finger) and the own palmar digital nerve of the ring finger (innervates the skin of the ulnar surface of the ring finger and the skin of the dorsal surface of the middle and distal phalanges of the same finger);
b) cutaneous branches pierce the thickness of the palmaris brevis muscle and innervate the skin of the area of the eminence of the little finger;
c) connecting branch with the third common palmar digital nerve from the median nerve;
d) own palmar digital nerve, n. digitalis palmaris proprius, located at the ulnar edge of the palmar aponeurosis along the muscles of the eminence of the little finger, passes to the palmar surface of the little finger, innervating the skin of its ulnar edge;
The areas of distribution of the cutaneous nerves of the belt and the free part of the upper limb, right (semi-schematic).
e) muscular branch - one or more thin nerves to the palmaris brevis muscle (sometimes to other muscles of the eminence of the little finger).
The terminal branches of the cutaneous nerves of the fingers end in lamellar bodies, corpuscula lamellosa, - encapsulated receptors.
Deep branch, r. profundus, begins at the radial surface of the pisiform bone. This branch passes through the proximal portions of the muscles forming the eminence of the little finger, between the short flexor and abductor muscles of the little finger, and, piercing the muscle opposite the little finger, penetrates, accompanied by the deep branch of the ulnar artery, into the deep space of the palm between the tendons of the long flexors and the interosseous muscles. It runs slightly arched, almost along the deep palmar arterial arch towards the thumb.
The deep branch sends the following nerves:
a) connecting branches with the first common palmar digital nerve of the median nerve;
b) articular branches to the articular capsules and periosteum of the hand bones;
c) muscle branches, rr. musculares, which are directed to the muscles of the eminence of the thumb; elevations of the little finger (m. abductor digiti minimi, m. flexor digiti minimi brevis, m. opponens digiti minimi); middle muscle group of the hand (mm. lumbricales III, IV, mm. interossei palmares et dorsales);
d) the perforating branches penetrate through the interosseous spaces onto the dorsum of the hand, where they connect with the branches of the interosseous dorsal nerve of the forearm.
4.Medial cutaneous nerve of the shoulder, n. cutaneus brachii medialis(CVIII, ThI, sometimes ThII, ThIII), originates from the medial bundle of the brachial plexus and is located in the axillary cavity anterior to the subscapularis muscle and latissimus dorsi, first in front of the axillary artery, and then lies medial to it.
Here the nerve connects with the lateral cutaneous branch of the second thoracic nerve, sometimes the third thoracic nerve (ThIII), which are called the intercostobrachial nerves, nn. intercostobrachiales. Two, sometimes three small nerve trunks pierce the axillary and brachial fascia and branch in the skin of the axillary cavity, the anterior and posteromedial surfaces of the shoulder to the medial epicondyle of the humerus and olecranon.
5. Medial cutaneous nerve of the forearm, n. cutaneus antebrachii medialis(CVIII, ThI), lies in the axillary cavity together with the axillary artery, and in the shoulder area - with the brachial artery and median nerve. Having reached the middle of the shoulder, it passes through the fascia at the place where the medial saphenous vein of the upper limb penetrates through it, and, emerging into the subcutaneous layer (sometimes more proximally), it divides into the anterior branch and the ulnar branch:
1) anterior branch, r. anterior, is located in front of the aponeurosis of the biceps brachii muscle, on the radial side of the medial saphenous vein, then lies behind the intermediate vein of the elbow and branches in the skin of the ulnar half of the palmar surface of the forearm to the area of the wrist joint.
Along its course, the anterior branch connects with the branches of the lateral cutaneous nerve of the forearm (from the musculocutaneous nerve);
2) ulnar branch, r. ulnaris, is located on the ulnar side of the medial saphenous vein of the arm, descends along the ulnar edge of the forearm and, passing with its branches to its dorsal surface, reaches the area of the wrist joint.
Along its course, the ulnar branch connects with the branches of the posterior cutaneous nerve of the forearm (from the radial nerve) and with the branches of the dorsal branch of the ulnar nerve.
6. C radius nerve, n. medianus(CVI - ThI), is formed by the lateral root, extending from the lateral fascicle, and the medial root, extending from the medial fascicle. Both roots, connecting at an acute angle, form a loop, which is located on the anterior surface of the axillary artery.
Following further along one trunk, the median nerve is adjacent to the radial side of the brachial artery and, together with it, is located under the fascia of the shoulder in the medial groove of the shoulder. Having reached the middle of the shoulder, the nerve crosses the artery in front, is located on its ulnar side and gives off 2-3 branches to the capsule of the elbow joint.
Continuing its course, it, together with the brachial artery, passes in the ulnar fossa under the aponeurosis of the biceps brachii muscle on the forearm. Here the median nerve is accompanied at some distance by the ulnar artery, which is located behind the nerve.
Penetrating further between both heads of the pronator teres, the median nerve goes to the midline of the forearm, fits under the tendon of the superficial flexor of the fingers and, accompanied by the median artery, follows between the superficial and deep flexors of the fingers to the area of the wrist joint.
Between the tendons of the flexor carpi radialis and palmaris longus, the median nerve, together with the tendons of both digital flexors, passes under the flexor retinaculum in the carpal tunnel to the hand, where it divides into its terminal branches.
In the area of the hand under the palmar aponeurosis, the terminal branches of the median nerve are located between the superficial palmar arch of the ulnar artery and the tendons of the superficial flexor of the fingers, giving a number of articular branches to the capsules of the wrist joints and joints of the I-III (IV) fingers from the palmar surface.
Branches of the median nerve:
1) anterior interosseous nerve (forearm), n. interosseus (antebrachii) anterior, originates from the main trunk of the median nerve at the level of the pronator teres and, following distally, accompanied by the anterior interosseous artery, is located between the long flexor pollicis and the deep flexor digitorum, reaching the pronator quadratus.
It innervates the flexor pollicis longus, flexor digitorum profundus (radial portion to the index and middle fingers), and pronator quadratus;
2) connecting branches with the ulnar nerve, rr. communicantes cum nervo ulnari, in the thickness of the deep flexor digitorum.
In addition, a number of connecting branches are described:
a) in the area of the shoulder with the musculocutaneous nerve (sometimes 2-3), unstable, located in the upper third of the shoulder;
b) in the area of the hand with the superficial branch of the ulnar nerve and with the superficial branch of the radial nerve;
3) muscle branches, rr. musculares.
In the region of the shoulder, the median nerve gives off no branches (except for the indicated connecting branch with the musculocutaneous nerve). In the forearm, muscle branches arise from the main trunk of the median nerve at the level of the medial epicondyle of the humerus and go to the pronator teres, flexor carpi radialis, palmaris longus and flexor digitorum superficialis;
4) palmar branch of the median nerve, r. palmaris n. mediani, - a thin branch (sometimes two), departs from the main trunk of the median nerve in the region of the lower third of the forearm between the tendons of the flexor carpi radialis and the long palmaris muscle, pierces the fascia of the forearm and branches in the skin of the palmar surface of the wrist joint, thumb and palm;
5) common palmar digital nerves I, II, III, nn. digit ales palmares communes I, II, III, are formed by branching the main trunk of the median nerve. They arise at the level of the distal edge of the flexor retinaculum, are located under the palmar aponeurosis and the superficial palmar arch in the first, second and third interosseous spaces, sending thin cutaneous branches penetrating through the palmar aponeurosis into the skin of the palm in the area of its middle sections.
Muscle branches arise from each common palmar digital nerve and innervate the following muscles of the palm region:
a) first common palmar digital nerve - m. abductor pollicis brevis, m. flexor pollicis brevis (caput superficiale), m. opponens pollicis, m. lumbricalis I;
6) second common palmar digital nerve - m. lumbricalis II;
c) third common palmar digital nerve - m. lumbricalis III (not constant).
Then the common palmar digital nerves give off the proper palmar digital nerves, nn. digitales palmares proprii, which innervate the skin of the radial and ulnar edges of the palmar surface of the thumb, index, middle fingers and the skin of the radial edge of the same surface of the ring finger. The first common palmar digital nerve sends 3 nerves: two to the thumb and one to the index finger, the second sends two to the index and middle fingers, and the third sends two to the middle and ring fingers.
The proper palmar digital nerves of the thumb innervate the skin of the radial and ulnar edges of the palmar surface of the thumb and send connecting branches to the superficial branch of the radial nerve.
The intrinsic digital nerves that innervate the skin of the index, middle and ring fingers send branches to the skin of the dorsal surface of the middle and distal phalanges of the same fingers.
Brachial plexus(plexus brachialis) formed by the anterior branches of the 4 lower cervical spinal nerves and the anterior branch of the 1st thoracic spinal nerve. In the plexus in relation to the clavicle, two parts are distinguished: supraclavicular (pars supraclaviculars) and subclavian (pars infraclavicularis). The first is located within the lateral triangle of the neck, the second - in the axillary cavity.
From supraclavicular part plexuses begin with short branches (Fig. 254).
Subclavian part plexus is represented by three bundles: lateral (fasc. lateralis), rear (fasc. posterior) and medial (fasc. medialis). The long nerves of the upper limb originate from the subclavian part of the plexus. The musculocutaneous nerve and the lateral root of the median nerve begin from the lateral fascicle; from the medial - the medial root of the median nerve, the ulnar and medial cutaneous nerves of the shoulder and forearm; from the posterior - the radial and axillary nerves.
Short branches:
1. Dorsal nerve of the scapula(n. dorsalis scapulae) Innervates the levator scapulae muscle, rhomboid major and rhomboid minor.
2. Long thoracic nerve(n. thoracicus longus) innervates the serratus anterior muscle.
3. Subclavian nerve(n. subclavius) innervates the muscle of the same name.
4. Suprascapular nerve(n. suprascapularis) innervates the supraspinatus and infraspinatus muscles, the capsule of the shoulder joint.
Rice. 254. Brachial plexus:
1 - anterior branches of the spinal nerves from C 5 to Th 1; 2 - medial plexus bundle; 3 - rear beam; 4 - lateral bundle; 5 - ulnar nerve; 6 - median nerve; 7 - radial nerve; 8 - axillary nerve; 9 - musculocutaneous nerve; 10 - 1st rib
5. Subscapular nerve(n. subscapularis) innervates the subscapularis, teres major and vastus dorsi muscles.
6. Thoracic nerves- medial And lateral(nn. pectorales medialis et lateralis)- innervate the pectoralis major and minor muscles.
7. Axillary nerve(n. axillaris) innervates the deltoid muscle, teres minor muscle, capsule of the shoulder joint and the skin of the outer surface of the shoulder.
Long branches (Fig. 255, 256):
1. Musculocutaneous nerve(n. musculocutaneus) innervates the anterior muscle group of the shoulder. The continuation of this nerve is called lateral cutaneous nerve of the forearm(n. cutaneus antebrachii lateralis). It innervates the skin of the anterolateral surface of the forearm.
2. Median nerve(n. medianus) there are no branches on the shoulder. In the forearm, the nerve gives off branches to the anterior group of muscles, with the exception of the flexor carpi ulnaris and the medial half of the flexor digitorum profundus, which are innervated by the ulnar nerve. In the hand, the median nerve is divided into 3 common palmar digital nerve(nn. digitales palmares communes), which in turn are divided into the palmar digital nerves (nn. digitales palmares proprii), going to the skin of I, II, III and the outer surface of the IV fingers.
From the first common digital nerve, muscle branches arise to the muscles of the eminence of the thumb, with the exception of the adductor pollicis muscle and the deep head of the flexor pollicis brevis muscle. The branches of this nerve also go to the I and II lumbrical muscles.
3. Ulnar nerve(n. ulnaris) there are no branches on the shoulder. On the forearm it gives branches to the elbow joint, flexor carpi ulnaris and part of the flexor digitorum profundus. Innervates the skin of the medial surface of the IV and V fingers, the muscles of the eminence of the little finger, the interosseous muscles, the III and IV lumbrical muscles, the adductor pollicis muscle and the deep head of the flexor pollicis brevis muscle.
4. Medial cutaneous nerve of the shoulder(n. cutaneus brachii medialis) innervates the skin of the medial surface of the shoulder.
5. Medial cutaneous nerve of the forearm(n. cutaneus antebrahii medialis) innervates the skin of the medial surface of the forearm.
6. Radial nerve(n. radialis) innervates the posterior muscle groups of the shoulder and forearm, the skin of the posterior and inferolateral surface of the shoulder, the skin of the posterior surface of the forearm, the skin of the dorsal surface of the I, II and the outer side of the III fingers (Fig. 257).
Rice. 255. Long branches of the brachial plexus, view from the anteromedial side. The pectoralis major and minor muscles are cut and removed:
1 - lateral bundle; 2 - rear beam; 3 - medial bundle; 4 - axillary artery; 5 - subscapular nerve; 6 - subscapularis muscle; 7 - subscapular artery; 8 - artery circumflexing the scapula; 9 - thoracodorsal nerve; 10 - thoracodorsal artery;
1 - latissimus dorsi muscle; 12 - medial cutaneous nerve of the shoulder; 13 - radial nerve; 14 - deep artery of the shoulder; 15 - triceps brachii muscle; 16 - ulnar nerve; 17 - medial cutaneous nerve of the forearm; 18 - medial epicondyle; 19 - lateral cutaneous nerve of the forearm; 20 - biceps brachii; 21 - superior ulnar collateral; 22 - median nerve; 23 - brachial artery; 24 - coracobrachialis muscle; 25 - pectoralis major muscle; 26 - axillary nerve; 27 - musculocutaneous nerve; 28 - deltoid muscle; 29 - pectoralis minor muscle; 30 - deltoid branch (from the thoracoacromial artery); 31 - thoracoacromial artery
Rice. 256. Nerves of the hand. Palm side, front view:
1 - ulnar nerve; 2 - tendon retinaculum; 3 - muscle that abducts the little finger; 4 - muscle that flexes the little finger; 5 - common palmar digital nerves (from the ulnar nerve); 6 - muscle opposing the little finger; 7 - tendons of the muscles - long flexor fingers; 8 - own palmar digital nerves (from the ulnar nerve); 9 - own palmar digital nerves (from the median nerve); 10 - muscle that adducts the thumb (transverse head);
11 - common palmar digital nerves (from the median nerve); 12 - short muscle that flexes the thumb; 13 - short muscle, abductor pollicis; 14 - median nerve (palmar branch)
Rice. 257. Nerves of the upper limb (photo from the specimen):
a - shoulder girdle: 1 - lateral bundle of the brachial plexus; 2 - posterior bundle of the plexus; 3 - medial bundle; 4 - pectoralis minor muscle (cut); 5 - musculocutaneous nerve; 6 - axillary nerve; 7, 9 - branches of the brachial plexus, forming the median nerve (10); 8 - radial nerve; 11 - medial cutaneous nerve of the shoulder; 12 - ulnar nerve; 13 - medial cutaneous nerve of the forearm; 14 - biceps brachii; 15 - deltoid muscle
Rice. 257. Continuation:
b - shoulder: 1, 3 - branches of the medial cutaneous nerve of the forearm; 2 - medial saphenous vein of the arm; 4 - ulnar nerve; 5 - median nerve; 6 - biceps brachii; 7 - lateral saphenous vein of the arm; 8 - lateral cutaneous nerve of the forearm
Rice. 257. Continuation:
c - hands (palmar surface): 1 - median nerve, splitting into common palmar digital nerves; 2 - superficial palmar arterial arch; 3 - branch of the ulnar nerve to the muscles of the hand; 4 - ulnar artery and nerve
DORSALA NERVE(nervus dorsalis scapulae) is a short branch of the supraclavicular part of the brachial plexus. It arises from the anterior branch of the spinal nerve (C 5), pierces the middle scalene muscle and innervates the rhomboid major and minor muscles and the levator scapulae muscle.
SUPRASCULAR NERVE(nervus suprascapularis) - originates from the superior trunk, passes through the notch of the scapula and innervates the supraspinatus and infraspinatus muscles.
LATERAL THORACIC NERVE(nervus pectoralis lateralis) - a short branch of the brachial plexus, innervates the pectoralis major and minor muscles.
MEDIAL THORACIC NERVE(nervus pectoralis medialis) - departs from the medial bundle, innervates the pectoralis major and minor muscles.
LONG THORACIC NERVE(nervus thoracicus longus) - a short branch of the brachial plexus, passes through the middle scalene muscle and innervates the serratus anterior muscle.
SUBScapular NERVE(nervus subscapularis) - a short branch of the brachial plexus, innervates the subscapularis and teres major muscles.
SUBCLAVAYAN NERVE ( nervus subclavius ) - a short branch of the brachial plexus innervates the muscle of the same name.
Thoracospinal Nerve(nervus thoracodorsalis) - a short branch of the brachial plexus, runs along the lateral edge of the scapula and innervates the latissimus dorsi muscle.
AXILLARY NERVE(nervus axillaris ) - a short branch of the brachial plexus, arises from the posterior secondary trunk, passes through the quadrilateral foramen and innervates the teres minor and deltoid muscles.
MUSCULOCUTANEOUS NERVE ( nervus musculocutaneus) is a long branch of the brachial plexus. It departs from the lateral bundle, pierces the coracobrachialis muscle and then lies between the brachialis and biceps muscles, innervates them and continues into the lateral cutaneous nerve of the forearm.
LATERAL CUTANEOUS NERVE OF THE FOREARM(nervus cutaneus antebrachii lateralis) - the terminal branch of the musculocutaneous nerve, innervates the skin of the lateral side of the forearm.
MEDIAL CUTANEOUS NERVE OF THE SHOULDER(nervus cutaneus brachii medialis) - originates from the medial bundle, innervates the skin of the medial side of the shoulder.
MEDIAL CUTANEOUS NERVE OF THE FOREARM(nervus cutaneus antebrachii medialis) - originates from the medial bundle, lies next to the medial vein of the arm and innervates the skin of the medial side of the forearm.
MEDIA NERVE ( nervus medianus) - is formed by the fusion of two roots from the medial and lateral bundles of the brachial plexus. On the shoulder it lies in the medial groove, passes through the cubital fossa and between the heads of the pronator and on the forearm it lies between the superficial and deep flexor fingers, and in the lower third of the forearm - in the median groove. It does not produce branches on the shoulder; it produces muscular and palmar branches on the forearm.
ANTERIOR INTEROSSEAL NERVE OF THE FOREARM(nervus interosseus antebrachii anterior) - departs from the median nerve at the level of the elbow joint and descends along the interosseous membrane of the forearm. Innervates the radiocarpal and intermetacarpal joints, the flexor pollicis longus, the pronator quadratus and the radial part of the deep flexor digitorum.
MUSCULAR BRANCHES OF THE MEDIA NERVE(rami musculares nervi mediani) - innervate the pronator teres, flexor carpi radialis, palmaris longus, superficial flexor digitorum.
PALMAR BRANCH OF THE MEDIA NERVE(ramus palmaris nervi mediani) - originates in the lower third of the forearm and innervates the muscles of the palm: I and II lumbricals, abductor pollicis brevis, superficial head of the flexor pollicis brevis, opponens muscle and gives cutaneous branches.
nervi digitales palmares communes) - three in number pass along the 1-3 intermetacarpal spaces and innervate the corresponding part of the skin of the palm.
nervi digitales palmares proprii) - the terminal branches of the common palmar digital nerves, innervate the skin of the palmar surface of I, II, III and the radial part of the IV fingers.
ULNA NERVE(nervus ulnaris) - a long branch of the brachial plexus, extending from the medial bundle. On the shoulder it passes in the medial groove, then from behind it goes around the medial epicondyle of the humerus and on the forearm it passes between the heads of the flexor carpi radialis. It does not produce branches on the shoulder; it gives off muscular branches to the forearm and in its lower third is divided into dorsal and palmar branches.
MUSCULAR BRANCHES OF THE ULNA NERVE ( rami musculares nervi ulnaris) - innervate the flexor carpi ulnaris and the ulnar part of the deep flexor digitorum.
DORSAL BRANCH OF THE ULNA NERVE ( ramus dorsalis nervi ulnaris) - innervates the ulnar part of the skin of the back of the palm and gives rise to the dorsal digital nerves.
DORSAL DIGITAL NERVES(nervi digitales dorsales) - the terminal branches of the dorsal branch of the ulnar nerve, innervate the skin of the dorsal surface of the V, IV and ulnar half of the III fingers.
PALMAR BRANCH OF THE ULNA NERVE(ramus palmaris nervi ulnaris) - divided into superficial and deep branches. Innervates the ulnar part of the skin of the palm.
SUPERFICIAL BRANCH(ramus superficialis) - divided into common palmar digital nerves and a muscular branch to the palmaris brevis muscle.
COMMON PALMAR DIGITAL NERVES ( nervi digitales palmares communes) - usually one branch passing between the fourth and fifth metacarpal bones.
PROPER PALMAR DIGITAL NERVES ( nervi digitales palmares proprii) - innervate the skin of the palmar surface of the little finger and the ulnar side of the fourth finger.
DEEP BRANCH(ramus profundus) - goes around the hamate and innervates the hypothenar muscles, palmar and dorsal interosseous muscles, 3 and 4 lumbrical muscles, the abductor pollicis muscle and the deep head of the flexor pollicis brevis muscle.
RADIAL NERVE(nervus radialis) - departs from the posterior bundle of the brachial plexus, passes through the canal of the radial nerve on the shoulder, lies between the brachial and brachioradialis muscles and at the level of the elbow joint is divided into deep and superficial branches.
POSTERIOR CUTANEOUS NERVE OF THE SHOULDER ( nervus cutaneus brachii posterior) - innervates the skin of the posterior surface of the shoulder.
POSTERIOR CUTANEOUS NERVE OF THE FOREARM ( nervus cutaneus antebrachii posterior) - innervates the skin of the posterior surface of the forearm.
MUSCULAR BRANCHES OF THE RADIAL NERVE ( rami musculares nervi radialis) - innervate the muscles of the posterior group of the shoulder: triceps, ulnaris, as well as the brachioradialis muscle and the long extensor carpi radialis.
DEEP BRANCH OF THE RADIAL NERVE(ramus profundus nervi radialis) - pierces the supinator and innervates the entire posterior group of muscles of the forearm (with the exception of the long extensor carpi radialis).
POSTERIOR INTEROSSEAL NERVE OF THE FOREARM(nervus interosseus antebrachii posterior) – the terminal branch of the deep branch of the radial nerve.
SUPERFICIAL BRANCH OF THE RADIAL NERVE(ramus superficialis nervi radialis) - on the forearm it passes along with the radial artery, in the distal part of the forearm it goes to the back of the hand and breaks up into the dorsal digital nerves.
DORSAL DIGITAL NERVES(nervi digitales dorsales) - innervates the skin of the back of the first two and a half fingers and the corresponding area of the skin of the back of the hand.
THORACIC NERVES(nervi thoracici) - twelve pairs of spinal nerves exiting through the intervertebral foramina of the thoracic vertebrae.
INTERCOSTAL NERVES(nervi intercostales) - anterior branches of the thoracic nerves. In the middle of the intercostal space, the lateral cutaneous branch (thoracic/abdominal) departs from the intercostal nerve. The lateral branches of the mammary gland arise from the fourth to sixth intercostal nerves. The intercostal nerves end in the anterior cutaneous branch, which is divided into medial and lateral branches.
INTERCOSTOBRACHIAL NERVES(nervi intercostobrachiales) - originate from the first to third intercostal nerves and innervate the skin of the posteromedial part of the upper third of the shoulder.
SUBCHOSTAL NERVE ( nervus subcostalis) is the anterior branch of the twelfth thoracic nerve, passing below the last rib.
LUMBAR PLEXUS(plexus lumbalis) - part of the lumbosacral plexus, formed by the anterior branches of the I-III lumbar nerves and partially the XII thoracic and IV lumbar nerves. Innervates the skin and muscles of the anterior and lateral abdominal area, the anterior and lateral surfaces of the thigh, the skin of the medial surface of the knee joint, lower leg and medial edge of the foot.
BRANCHES OF THE SUPRACLAVICAL PART OF THE BRACHIAL PLEXUS; AREAS OF INNERVATION. The brachial plexus, plexus brachialis, is formed by the anterior branches of the four lower cervical, part of the anterior branch of the IV cervical and I thoracic spinal nerves. In the interstitial space, the anterior branches form three trunks: the upper trunk, truncus superior, the middle trunk, truncus medius, and the lower trunk, truncus inferior. These trunks emerge from the interscalene space into the greater supraclavicular fossa and stand out here, together with the branches extending from them, as the supraclavicular part, pars supraclavicularis, of the brachial plexus.
The branches extending from the brachial plexus are divided into short and long. Short branches arise mainly from the trunks of the supraclavicular part of the plexus and innervate the bones and soft tissues of the shoulder girdle. 1. Dorsal nerve of the scapula, n. dorsdlis scapulae, starts from the anterior branch of the V cervical nerve, lies on the anterior surface of the levator scapulae muscle. Then between this muscle and the posterior scalene muscle, the dorsal scapular nerve travels backward along with the descending branch of the transverse cervical artery and branches into the levator scapulae and rhomboid muscles. 2. Long thoracic nerve, n. thordcicus longus, originates from the anterior branches of the V and VI cervical nerves, descends down behind the brachial plexus, lies on the lateral surface of the serratus anterior muscle between the lateral thoracic artery in front and the thoracodorsal artery behind, innervates the serratus anterior muscle. 3. Subclavian nerve, n. subcldvius, is directed by the shortest route to the subclavian muscle in front of the subclavian artery. 4. Suprascapular nerve, n. suprascapuldris, extends laterally and backwards. Together with the suprascapular artery, it passes through the notch of the scapula under its superior transverse ligament into the supraspinous fossa, and then under the acromion into the infraspinatus fossa. Innervates the supra- and infraspinatus muscles, the capsule of the shoulder joint. 5. Subscapular nerve, n. subscapuldris runs along the anterior surface of the subscapularis muscle, innervates this and the teres major muscles. 6. Thoracospinal nerve, n. thoracodorsails, along the lateral edge of the scapula descends to the latissimus dorsi muscle, which it innervates. 7. Lateral and medial thoracic nerves, pp. pectordles lateralis et medidlls, start from the lateral and medial fascicles of the brachial plexus, go forward, pierce the clavipectoral fascia and end in the major (medial nerve) and minor (lateral nerve) pectoral muscles, 8. Axillary nerve, n. axilldris, starts from the posterior bundle of the brachial plexus. Along the anterior surface of the subscapularis muscle it goes down and laterally, then turns back and, together with the posterior circumflex humeral artery, passes through the quadrilateral foramen. After wrapping around the surgical neck of the humerus from behind, the nerve lies under the deltoid muscle. The axillary nerve innervates the deltoid and teres minor muscles and the capsule of the shoulder joint. The terminal branch of the axillary nerve, the superior lateral cutaneous nerve of the shoulder, cutaneus brdchii lateralis superior, goes around the posterior edge of the deltoid muscle and innervates the skin covering the posterior surface of this muscle and the skin of the upper part of the posterolateral region of the shoulder. BRANCHES OF THE SUBCLAVICAL PART OF THE BRACHIAL PLEXUS; AREAS OF INNERVATION. The long branches of the brachial plexus arise from the lateral, medial and posterior bundles of the infraclavicular part of the brachial plexus. The lateral pectoral and musculocutaneous nerves, as well as the lateral root of the median nerve, originate from the lateral fascicle. The medial thoracic nerve, medial, cutaneous nerves of the shoulder and forearm, the ulnar nerve and the medial root of the median nerve begin from the medial fascicle. The axillary and radial nerves arise from the posterior bundle. 1. The musculocutaneous nerve, n. musculocutaneus, begins in the axillary fossa behind the pectoralis minor muscle. The nerve is directed laterally and downward, piercing the brachiocracoid muscle. Having passed through the belly of this muscle in an oblique direction, the musculocutaneous nerve is then located between the posterior surface of the biceps brachii muscle and the anterior surface of the brachialis muscle and exits into the lateral ulnar groove. Having supplied these three muscles with muscle branches, rr. musculares, as well as the capsule of the elbow joint, the musculocutaneous nerve in the lower part of the shoulder pierces the fascia and descends to the forearm as the lateral cutaneous nerve of the forearm, n. cutaneus antebrachii lateralls. The terminal branches of this nerve are distributed in the skin of the anterolateral surface of the forearm up to the eminence of the thumb. 2. The median nerve, n. medianus, does not give branches on the shoulder. On the forearm it innervates with its muscle branches, rr. musculares, a number of muscles: pronator teres and quadratus, flexor digitorum superficialis, flexor pollicis longus, palmaris longus, flexor carpi radialis, flexor digitorum profundus, i.e. all the muscles of the anterior surface of the forearm, except the flexor carpi ulnaris and the medial part of the deep flexor fingers. The largest branch is the anterior interosseous nerve, the interosseus anterior nerve innervates the deep muscles of the anterior surface of the forearm and gives off a branch to the anterior part of the wrist joint. The terminal branches of the median nerve are the three common palmar digital nerves, pp. digitales palmares communes.
3. The ulnar nerve does not give branches on the shoulder. On the forearm, the ulnar nerve innervates the flexor carpi ulnaris and the medial part of the flexor digitorum profundus, giving them muscle branches, rr. musculdres, as well as the elbow joint. The dorsal branch of the ulnar nerve goes to the back of the forearm between the flexor carpi ulnaris and the ulna.
4. The medial cutaneous nerve of the shoulder, n. cutaneus brachii medidlis, starts from the medial bundle of the brachial plexus and accompanies the brachial artery. Two or three branches pierce the axillary fascia and the fascia of the shoulder and innervate the skin of the medial surface of the shoulder.
5. The medial cutaneous nerve of the forearm, n. cutaneus antebrachii medidlis, emerges from the axillary fossa, adjacent to the brachial artery. Innervates the skin of the anteromedial surface of the forearm. 6. Radial nerve, n. radialis starts from the posterior bundle of the brachial plexus at the level of the lower edge of the pectoralis minor muscle between the axillary artery and the subscapularis muscle. Together with the deep brachial artery, the radial nerve passes through the so-called brachiomuscular canal, bends around the humerus and leaves the canal in the lower third of the shoulder on its lateral side. Next, the nerve pierces the lateral intermuscular septum of the shoulder and goes down between the brachialis muscle and the beginning of the brachioradialis muscle. At the level of the elbow joint, the radial nerve is divided into superficial and deep branches. r. profundus. The superficial branch, r.superficiales, innervates the palmar digital nerves of the median nerve.
In the shoulder, the radial nerve innervates the muscles of the posterior group of the shoulder (triceps brachii and olecranon muscles) and the shoulder bursa.
In the brachial muscular canal, the posterior cutaneous nerve of the forearm, cutaneus antebrachii posterior, departs from the radial nerve and innervates the skin of the posterior surface of the lower shoulder and the skin of the posterior surface of the forearm.
Dorsal nerve of the scapula - n. dorsalis scapulae (C5) descends along the medial edge of the scapula along with the ramus descendens art. transversae coli. Provides innervation m. rhomboideus and m. levator scapulae.
Suprascapular nerve
Suprascapular nerve - n. suprascapularis (from C5 and C6) on the neck is part of the neurovascular bundle a.vv. etn. suprascapularis. The bun crosses the neck in an oblique direction, from front to back and reaches the incisura scapulae. Here the artery and veins pass into the fossa supraspinata through the notch, and the nerve passes over the ligament covering it. This nerve innervates m. supraspinatus, m. infraspinatus and the capsule of the shoulder joint.
Long thoracic nerve
Long thoracic nerve - n. thoracicus longus (from C5-C7) - the nerve passes from the neck to the subarchial fossa, then to the limb and immediately lies along the lateral edge of the chest wall, along the anterior edge of m. serratus anterior superior and gives it innervation. Usually in the upper part of the anterior chest wall next to it there is a. thoracica lateralis.
Subscapular nerve
Subscapular nerve - n. subscapularis (C5-C8) runs along the lateral and lower edge of the scapula and gives off branches to m. subscapularis, m. teres major and m. latissimus dorsi.
Axillary nerve
Axillary nerve - n. axillaris (C5-C6) is the largest nerve of all the short branches of the supraclavicular part of the brachial plexus. The axillary nerve goes to the foramen quadrilaterum and enters the posterior surface of the humerus in the area of its surgical neck. It gives branches to the shoulder joint, to the muscles m. deltoideus and m. teres minor. In addition, in the region of the posterior edge of the deltoid muscle, the axillary nerve gives off the cutaneous branch n. cutaneus brachii lateralis superior to the skin of the deltoid region and posterolateral region of the shoulder.
Moving from the neck to the upper limb, the brachial plexus enters the axillary cavity, its first floor, corresponding to the trigonum claviopectoralis. It enters here in the form of three bundles, covered with a single fascial capsule. In the second floor of the axilla, corresponding to the trigonum pectoralis, the bundles are separated from each other, and here the fasciculus lateralis et medialis, as well as the fasciculus posterior, can be distinguished. When moving to the third floor of the axillary cavity - trigonum subpectoralis - the bundles are divided into separate nerves, which are long branches of the brachial plexus, with the exception of n. axillaris.
Lateral bundle - gives one leg to form n. medianus, as well as n. musculocutaneus.
The second leg n emerges from the medial bundle. medianus, n. ulnaris, n. cutaneus brachii and antebrachii medialis.
Posterior bundle - gives n. radialis and n. axillaris (Fig. 8).
Median nerve
Median nerve - n. medianus (C5 - C8+ Th1) is formed by the fusion of two legs (one from the medial bundle, the second from the lateral). The nerve lies in front of a. axillaris, then lies in the sulcus bicipitalis medialis, where it passes next to a. brachialis. In the upper third of the groove it lies lateral to the artery, in the middle third in front of a. brachialis and in the lower third medially from it (Fig. 9). The nerve does not give branches on the shoulder. In the cubital fossa, the nerve passes medially from the artery under m. pronator teres, and then lies between the superficial and deep flexor digitorum in the midline in the sulcus medianus and exits onto the palm under the retinaculum flexorum, where it can be mistaken for a tendon. On the forearm, the nerve gives branches to all muscles of the forearm, except m. flexor carpi ulnaris. In addition, n. medianus in the upper third of the forearm gives off to n. interosseus anterior, which lies on the interosseous membrane along with a. et vv. interossea anterior and innervates m. flexor digitorum profundus, m. flexor policis longus and m. pronator quadratus, as well as the wrist joint (Fig. 10).
Through the canalis carpalis, the nerve penetrates the palm and gives off a superficial cutaneous branch, which innervates a small area of thenar skin and palm. On the palm n. medianus innervates the skin of 3.5 fingers, starting with the thumb and ending with the medial surface of the ring finger, as well as the thenar muscles, except m. adductor policis longus and the deep head of the t. flexor policis brevis, as well as the first and second lumbrical muscles (Fig. 11).
Musculocutaneous nerve
Musculocutaneous nerve - n. musculocutaneus (C5-C7). In the upper part of the shoulder, the nerve pierces m. coracobrachialis and innervates m. coracobrachialis, t. biceps brachii and t. brachialis. On the shoulder, the nerve lies laterally between m. biceps and m. brachialis, and then, passing to the ulnar fossa, becomes the cutaneous nerve - n. cutaneus antebrachii lateralis, which innervates the skin of the radial side of the forearm and the skin of the thenar on the back side (Fig. 8).
Ulnar nerve
Ulnar nerve - n. ulnaris (C7-C8, YOU). It passes along the medial surface of the shoulder and, at the border of the middle and lower third of the shoulder, pierces the medial intermuscular septum along with a. et v. collateralis ulnaris superior (Fig. 9), enters the posterior bed of the shoulder, goes down, bending around the medial epicondyle of the shoulder and lies in the sulcus cubitalis posterior (Fig. 12). Here it is covered only by skin, subcutaneous fatty tissue and its own fascia. On the forearm, the nerve passes into the sulcus ulnaris and lies as part of the neurovascular bundle a., vv., n. ulnaris (Fig. 10).
The first branches of n. ulnaris appear on the forearm - this is rami articulares to the elbow joint. Next come the branches to m. flexor carpi ulnaris and the adjacent part of m. flexor digitorum profundus.
At the level of the wrist joint, branches extend to the hypothenar skin. Here the nerve gives off cutaneous branches to the back of the hand, where it innervates the skin of the V, VI and ulnar half of the third finger r. dorsalis n. ulnaris (Fig. 10).
Another branch of ramus palmaris n. ulnaris at the level of the pisiform bone is divided into superficial and deep branches. The superficial branch gives off a branch to m. palmaris brevis, to the skin of the ulnar side of the palm and nn. digitales palmares proprii to both sides of the little finger and the ulnar side of the fourth finger.
Deep branch n. ulnaris passes into the subtendinous space of the hand, accompanying the deep palmar arterial arch. There it gives branches to all the muscles of the little finger (hypothenar), all the interosseous muscles m.m. interossei, the third and fourth worm-shaped muscles (m.m. lumbricales), as well as m. adductor policis, etc. flexor policis brevis (deep head). In addition, the final part of the deep branch n. ulnaris is an anastomosis with n. medianus (Fig. 11).
Radial nerve
Radial nerve - n. radialis (C5-C8, Th1). The nerve leaves the posterior bundle in the armpit area and passes behind a. axillaris and in the upper part of the shoulder area lies between the muscles, enters the canalis nervi radialis, accompanied by a. profunda brachii (Fig. 12), bends around the humerus in a spiral direction from the inside to the outside, pierces the lateral intermuscular septum from back to front and exits in the ulnar fossa between m. brachioradialis and m. brachialis (Fig. 10).
On the shoulder the nerve gives off: Material from the site
- Muscular branches for m. triceps brachii and m. anconeus. From branch r. anconeus gives off a small branch to the lateral epicondyle of the humerus and the capsule of the elbow joint.
- Posterior and lateral, inferior cutaneous branches of the shoulder, n.n. cutan ei brachii posterior et lateralis inferior - for the skin of the posterior and lower part of the lateral surface of the shoulder.
- Posterior cutaneous nerve of the forearm n. cutaneus anterbrachii posterior - lateral posterior terminal nerve of the forearm. Inners the skin of the posterior surface of the forearm.
- Muscular branches to m. brachioradialis and m. extensor carpi radialis longus.
In the area of the ulnar fossa in the sulcus cubitalis lateralis anterior, the radial nerve is divided into superficial and deep branches.
