How’s plexus brachialis formed by?
ventral/anterior branches of:
Where does plexus brachialis locate in ?
The spatium interscalenum between m. scalenus anterior et medialis (costa prima). It takes place behind and above a. subclavia.
How is plexus brachialis divided?
Has 3 large truncus:
- Truncus superior formed by ventral branches of C5 and C6 spinal nerves. n. suprascapularis and n. subclavius
–> all truncus join and form fasciculus posterior (fibers from C5 – T1) = Divisiones posteriores
–> Divisiones anteriores of truncus superior et medius join and form fasciculus lateralis (fibers C5 – C7)
–> Division anterior of truncus inferior form fasciculus medialis (fibers C8 – T1)
> > These 3 fasciculi enter apertura superior cavi axillaris (bordered by: clavicula, margo superior scapulae,
costa prima).
Topographically plexus brachialis is divided into pars supraclavicularis et pars infraclaviuclaris.
Pars supraclavicularis plexus brachialis
Placed in trigonum colli laterale (bordered by: m. sternocleidomastioideus, m.trapezius, clavicula) and it can be palpate in fossa supraclavicularis major.
7 brances arise from pars supraclavicularis.
Pars infraclavicularis plexus brachialis
Placed into the axilla. Formed by 3 fasciculus that surrounds a. axillaris:
Innervate:
m. coracobrachialis (N. musculocutaneus)
m. biceps brachii (N. musculocutaneus)
m. brachialis (N. musculocutaneus)
m. triceps brachii (N. radialis rami musculares)
m. anconeus (N. radialis rami musculares)
the skin on the posterior region of brachii (N. radialis–> n. cutaneous brachia posterior)
the skin to thenar/ art.cubiti (N. cutaneous antebrachii lateralis, r. superficialis n. radialis, r. dorsalis n. ulnaris, n. cutaneous antebrachii medialis)
art. cubiti (rr. articulares n. ulnaris & medianus)
1st and 2nd mm. lumbricales (nn. digitales
palmares communes rr. musculares from n. medianus)
m. abductor pollicis brevis (nn. digitales
palmares communes rr. musculares from n. medianus)
m. opponens pollicis (nn. digitales
palmares communes rr. musculares from n. medianus)
m. flexor pollicis brevis (caput
superficiale) (nn. digitales
palmares communes rr. musculares from n. medianus)
m. pronator teres (N. medianus gives off rr. musculares)
m. palmaris longus (N. medianus gives off rr. musculares)
m. flexor digitorum superficialis (N. medianus gives off rr. musculares)
m. flexor digitorum profundus (radial side, N. interosseus antebrachii anterior from n. medianus)
m. pronator quadratus (N. interosseus antebrachii anterior from n. medianus)
the skin on the medial surface of antebrachii (N. cutaneous antebrachii medialis)
the skin on the medial surface of brachium (N. cutaneus brachii medialis)
mm. interossei palmares et dorsales (ramus profundus n. ulnaris)
III and IV mm. lumbricales (ramus profundus n. ulnaris)
M. adductor pollicis (ramus profundus n. ulnaris)
m. flexor pollicis brevis (ramus profundus n. ulnaris)
m. flexor carpi ulnaris (rr. musculares n. ulnaris)
m. flexor digitorum profundus (pars ulnaris, rr. musculares n. ulnaris)
antebrachii lateral, posterior 1st and 2nd layer muscles (ramus profundus n. radialis )
skin of the posterior surface of antebrachii (n. cutaneous antebrachii posterior n. radialis)
M. deltoideus
M. teres minor
Art. humeri (N. axillaris together with n. suprascapularis/subscapulares sensory)
the skin of the upper arm at the lateral region (n. cutaneous brachii lateralis n. axillaris)
Arteriae membri superioris
a. subclavia
- Arises at the left side from arcus aortae and at the right side from truncus brachiocephalicus
- Continues as a. axillaris behind clavicula
- Extends to cavitas axillaris and becomes a. brachialis
- At fossa cubiti a. brachialis divides into the terminal branches: a. radialis and a. ulnaris
- On the palmar side of the wrist the terminal branches of a. radialis and a. ulnaris from arcus palmaris superficialis et profundus
- These palmar arches supply the hand and the fingers with oxygenated blood
Supply:
m. supraspinatus (a. suprascapularis)
m. infraspinatus (a. suprascapularis branch from a.subclavia)
the upper portion of m. trapezius (r. superficialis a. transversa colli)
mm. superficialis pars posterior colli (r. superficialis a. transversa colli)
mm. rhomboidei (r. profundus or a. dorsalis scapulae from a. transversa colli)
mm. superficialis dorsi (r. profundus or a. dorsalis scapulae from a. transversa colli)
m. subclavius (r. clavicularis of a.thoracoacromialis)
rete acromiale (r. acromialis of a.thoracoacromialis)
m. deltoideus (r. deltoideus of a.thoracoacromialis, a. circumflexa humeri posterior)
m. pectoralis major et minor (rr. pectorals of a.thoracoacromialis)
m. serratus anterior (a. thoracica lateralis, a. thoracodorsalis)
m. pectoralis major et minor (a. thoracica lateralis)
–> skin above them (a. thoracica lateralis)
glandula mammaria (rr. mammarii lateralis of a.thoracica lateralis)
m. subscapularis (a. thoracodorsalis)
m. latissimus dorsi (a. thoracodorsalis)
art. humeri (a. circumflexa humeri posterior)
mm. anterior brachii superficialis (rr. musculares a. brachialis)
mm. posterior brachii (rr. musculares a. profunda brachii from a. brachialis)
mm. antebrachii anterior et lateralis (rr. musculares of a. radials both and of a. ulnaris anterior
mm. profundi antebrachii anterior (rr. musculares a. interossea anterior of ulnaris)
mm. digiti minimi and overlying skin (r. palmaris profundus a. ulnaris)
Lymph vessels of the upper extremity
Lymp vessels of the upper extremity are arranged in 2 networks: deep and superficial.
Supeficial lymph vessels collect the lymph from the skin and subcutaneous tissue. There are 3 groups of
superficial lymp vessels: lateral, medial and anterior. Lymph vessels are divided into 2 groups according to their location and lymph flow direction:
1- Lateral superficial lymph vessels collect the lymph from lateral side of the wrist (1-3 fingers) and
drain it to axillary lymph nodes.
2- Medial superficial lymph vessels collect the lymph from medial side of the wrist (4-5 fingers),
medial side of antebrachii and drain it to the cubital lymph nodes
3- Anterior superficial lymph vessels collect the lymph from the wrist, ventral side of antebrachii and
drain it to the cubital lymph nodes
The deep lymph vessels accompany the deep blood vessels. They collect the lymph from the muscles, tendons,
joints and bones and drain it to the deep lymph nodes.
The lymph nodes of the upper extremity
The lymph nodes of the upper extremity are divided into 2 groups: superficial and deep lymph nodes.
The superficial lymph nodes:
- Nodi lymphoidei supratrochleares
o Placed in fossa cubiti above epicondylus medialis humeri
o Number are from 1 to 2
o Afferent lymph vessels collect the lymph from wrist and medial side of antebrachii
o Efferent lymph vessels accompany v. basilica and deep blood vessels
- Nodi lymphoideideltopectorales
o Number are from 1 to 2
o Lie in sulcus deltoideopectoralis near v. cephalica near clavicula
o Afferent lymph vessels collect lymph from lateral side of antebrachii
The deep lymph nodes:
- Nodi lymphoidei antebrachii
o Lie in upper third of antebrachii along a. ulnaris
- Nodi lymohoidei cubitales profundi
o Placed in fossa cubiti near blood vessels
- Nodi lymphoidei brachiales
o Situated in the middle part of upper arm along a. brachialis
Nodi lymphoidei axillares
high in number (30-45).
v. mediana antebrachii
o Ascendes in the middle of the anterior aspect of the antebrachii between v. basilica and v.
cephalica
o In fossa cubiti it flows into v. mediana cubiti
o Sometimes it divides into 2 veins, which join v. cephaliva or v. basilica
v. basilica
o Begins from rete venosum dorsale manus at the ulnar side
o At first passes on the dorsal side of the antebrachii
o On the proximal third of the antebrachii it reaches the anterior side of antebrachii
o In the region of upper arm it lodges in sulcus bicipitalis medialis
o In the middle region it passes together with n. cutaneous antebrachii medialis through fascia
brachii and flows to v. brachialis
v. cephalica
o Formed on the radial side of rete venosum dorsale manus
o Reachs art. radiocarpalis
o Continues to the anterior side of antebrachii and passes along the radial border till fossa cubiti
o Forms a slanting anasthomose v. mediana cubiti
o Joins to vv. brachiales
o Flows into v. basilica
o In the region of upper arm lodges into sulcus bicipitalis lateralis
o Continues along sulcus deltoideopectoralis
o Reches trigonum clavicopectorale, where it penetrates fascia clavicopectoralis
o Flows into v. axillaris
o In the region of antebrachii it receives unconstant v. cephalica accessoria
o The latter arises from rete venosum dorsale manus
o Form the dorsal side of antebrachii
o Flows into v. cephalica distally from art. cubiti
vv. superficiales s. vv. subcutaneae
Form rete venosum dorsale manus on the dorsal surface of the wrist, the latter being formed by networks of
vv. digitales dorsaes and the vein continuations of vv. metacarpales dorsales.
v. cephalica
v. basilica
v. mediana antebrachii
N. musculocutaneous
(C5 – C7)
Passes sidelong, penetrates m.coracobrachialis. Passes between m. biceps brachii and m. brachialis.
> Nerve is placed into sulcus bicipitalis lateralis
> runs laterally from distal tendon of m. biceps brachii above
epicondylus lateralis
> penetrates fascia brachii
> passes downwards to the anterior antebrachii region as n.cutaneous antebrachii lateralis.
> N. musculocutaneus gives off rr. musculares (= plur. =“rami”, sing.
= “ramus”, muscular branches), supply:
o m. coracobrachialis
o m. biceps brachii
o m. brachialis
> N. cutaneous antebrachii lateralis innervate the skin on the lateral region of forearm till thenar and art. cubiti
> Skin branches can join
o r. superficialis n. radialis
o r. dorsalis n. ulnaris
o n. cutaneous antebrachii medialis
N. medianus
A mixed nerve and it is formed by joining of radix lateralis C6
– C7 and radix medialis C8 – T1.
> Nerve is placed in axilla in front of a. axillaris
> Passes together with vasa brachialia along sulcus bicipitalis medialis
> In fossa cubiti n. medianus is below aponeurosis of m. biceps brachii, where it penetrates m. pronator teres
> Lodges between m. flexor digitorum superficialis et profundus and reaches sulcus medianus antebrachii
> Enters through canalis carpi and divides into nn. digitales palmares communes
N. medianus branches
1st nn. digitales palmares communes gives of 3 nn. digitales palmares proprii
2nd nn. digitales palmares communes divides into 2 nn. digitales palmares proprii
3rd nn. digitales palmares communes divides into 2 nn. digitales palmares proprii
> > nn. digitales palmares proprii wing from palmar side of the fingers to dorsal side
supply the skin on the:
o palmar side of pollicis, index finger and middle finger
o radial side of ring finger
o dorsal surface of phalangis distalis et media (for these fingers)
a. radialis branches
1) a. recurrens radialis
- Arises at fossa cubiti laterally from a. radialis
- Runs along sulcus cubitalis anterior lateralis
- Forms anastomosis with a. collateralis radialis from a. profunda bachii
> Both take part in the formation of rete articulare cubiti
2) rr. musculares
Supply mm. antebrachii anterior et lateralis
3) r. palmaris superficialis
Arises from a. radialis at the level of processus styloideus radii
On the palmar side of the wrist it gives blood supply to thenar muscles group and the skin over them
- Makes anastomosis with with terminal branch of a. ulnaris
x Form arcus palmari superficialis
4) r. carpalis palmaris
- Arises from a. radialis at the lower part of antebrachii
- Forms anastomosus with r. carpalis palmaris from a. ulnaris
- Branches from rete carpi palmare
5) r. carpalis dorsalis
- Arise from a. radialis at the dorsal side of the wrist in the “snuff box”
- Gives off 3 branches aa. digitales dorsales
x Supply the dorsal side of index finger from radial side and the pollicis
6) a. metacarpals dorsalis prima
- arises from a.radialis at the dorsal side of the wrist in the snuff box
- gives off 3 branches: aa. digitalis dorsal that supply the dorsal side of the index finger from radial side and the thumb
7) a. princeps pollicis
- Arise from a. radialis at the palmar side of the wrist
- Gives off 3 branches aa. digitales palmares
x Supply the palmar side of the thumb
and the radial side of the index finger
Anastomosis
Spatium interscalenum
m. scalenus anterior
m. scalenus medius
costa prima
behind it arteria subclavia –> a. transversa colli
nerves of plexus brachialis
Fasciculus posterior
n. radialis / axillaris
nn. subscapularis and n. thoracodorsalis
N. radialis (also branches)
In cavitas axillaris behind a. axillaris
> In brachial region it passes in Canalis humeromuscularis s. canalis n. radialis
retinaculum musculorum extensorum
6 canals, 9 muscles
sulcus deltoipectoralis
b. m. deltoideus / m. pectoralis major
Nodi lymphoideideltopectorales lie there near v. cephalica near clavicula
trigonum clavipectorale
clavicula, m. pectoralis minor, sternum
2) a. thoracoacromialis
- Short trunk that wings around upper border of m. pectoralis minor medially
- Penetrates fascia clavicopectoralis
Divides into 4 branches:
x r. acromialis, from rete acromiale
x r. clavicularis, supplies m. subclavius
x r. deltoideus, passes to m. deltoideus
x rr. pectorals, run to m. pectoralis major et minor and supply them