Download The upper limb

The upper limb
山东大学医学院 解剖教研室
李振华
The muscles of back
Superficial group
 Trapezius 斜方肌
 Latissimus dorsi 背阔肌
 Levator scapulae 肩胛提肌
 Rhomboideus菱形肌
Deep group
 Erector spinae 竖脊肌
 Splenius 夹肌
 Thoracolumbar fascia 胸腰
筋膜
The muscles of thorax
Extrinsic muscles
 Pectoralis major 胸大肌
 Pectoralis minor 胸小肌
 Serratus anterior 前锯肌
Intrinsic muscles
 Intercostales externi


肋间外肌
Intercostales interni
肋间内肌
Intercostales intimi
肋间最内肌
Major muscles of the trunk
Trapezius



Origin: superior nuchal line, external
occipital protuberance, ligamentum
nuchae and spinous processes of
seventh cervical and all thoracic
vertebrae
Insertion: lateral third of clavicle,
acromion, and spine of scapulartery
Acton: upper fibers elevate scapula,
lower fibers depress scapula; if
scapula is fixed, one side acting along,
draws head toward the same side,
and turn face to opposite side; both
sides together, draw head directly
backward
Latissimus dorsi
 Origin: spinous processes
of lower six thoracic and
all lumbar vertebrae,
median sacral crest, and
posterior part of iliac crest.
 Insertion: floor of
intertubercular groove of
humerus.
 Action: trunk fixed,
extends, adducts and
medially rotates arm ; arm
fixed, elevates trunk.
Erector spinae


Position: fills the
vertebral groove on
each side of the spine
Action: extends
vertebral column
(draw head backwar)
Pectoralis major
 Origin: medial half of
clavicle,sternum,1th-6th
costal cartilages.
 Insertion: crest of greater
tubercle of humerus.
 Action: flexes, adducts
and rotates arm medially;
arm fixed, elevates trunk;
elevates ribs 1-6,aidding
in forced inspiration.
The Muscles of Upper Limb
Muscles of shoulder
 Deltoid
 supraspinatus
 Infraspinatus
 Teres minor
 Teres major
 subscapularis
Muscles of arm
 Antererior group




Biceps brachii
肱二头肌
Coracobrachialis
喙肱肌
Brachialis
肱肌
Posterior group
– triceps brachii
肱三头肌
Muscles of forearm

Superficial layer



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
Brachioradialis 肱桡肌
Pronator teres 旋前圆肌
Flexor carpi radialis 桡侧腕屈肌
Palmaris longus 掌长肌
Flexor carpi ulnaris 尺侧腕屈肌

Third layer



Flexor digitorum
profundus 指深屈肌
Flexor pollicis longus 拇
长屈肌
Fourth layer－ pronator
quadratus 旋前方肌
Action: flex radiocarpal
joint and fingers,
pronate forearm

Second layer－
flexor digitorum
superficials 指浅屈肌
Posterior group (10)

Superficial layer (5)





Extensor carpi radialis
longus 桡侧腕长伸肌
Extensor carpi radialis
brevis 桡侧腕短伸肌
Extensor digitorum 指
伸肌
Extensor digiti minimi
小指伸肌
Extensor carpi ulnaris
尺侧腕屈肌
Deep layer (5)
 Supinator旋后肌
 Abductor pollicis longus




拇长展肌
Extensor pollicis brevis拇
短伸肌
Extensor pollicis longus
拇长伸肌
Extensor indicis
示
指伸肌
Action: extend
radiocapral joint and
fingers, and supinate
forearm
Muscles of hand
 Lateral group－thenar 鱼际 (4)


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

Abductor pollicis brevis拇短展肌
Flexor pollicis brevis 拇短屈肌
Opponens pollicis 拇对掌肌
Adductor pollicis 拇收肌
Action: flex, abduct, adduct
and oppose thumb
Medial group－hypothenar (3)


Abductor digiti minimi 小指展肌
Flexor digiti minimi brevis小指短屈
肌


Opponens digiti minimi小指对掌肌
Action: flex, abduct , and oppose
little finger
Intermedial group
 Lumbricales 蚓状肌(4)－
flex fingers at MP joints;
extend fingers at IP joints
 Palmar interossei 骨间掌
侧肌(3)－ adduct fingers
towards middle finger at
MP joints
 Dorsal interossei 骨间背侧
肌(3)－abduct fingers
away from middle finger at
MP joints
Major muscles of upper limb
Deltoid
 Origin: lateral third of
clavicle, acromion, and
spine of scapula
 Insertion: deltoid tuberosity
of humerus
 Action: abducts，flexes and
medically rotates, extends,
and laterally rotates arm
Teres major



Origin: dorsal surface
of inferior angle of
scapula
Insertion: crest of
lesser tubercle of
humerus
Action: medially
rotates and adducts
arm
Biceps brachii
 Origin: long head,
supraglenoid tubercle; short
head, coracoid process
 Insertion: radical tuberosity
 Action: supinator of forearm,
flexor of elbow joint, weak
flexor of should joint
Pronator teres
 Origin: medical epicondyle of
humerus and deep fascia of
forearm
 Insertion: middle of lateral
surface of radius
 Action: pronation of forearm
and flexion of elbow
Triceps brachii



Origin: long head,
infraglenoid tubercle; lateral
head, above groove for
radical n., medical head,
below groove for radical n.
Insertion: olecranon of ulna
Action: extends elbow joint),
long head can extend and
adduct shoulder joint
Supinator



Origin: lateral epicondyle
of humerus and upper
part of lateral border of
ulna
Insertion: upper third of
anterior surface of radius
Action: supination of
forearm
Arteries of upper limb
Axillary artery



Continuation of subclavian artery at
lateral border of first rib
Becomes brachial artery at lower
border of teres major
Divided into three parts by overlying
pectoralis minor



First portion, above muscle－gives rise
to thoracoacromial a. 胸肩峰动脉
Second portion, behind muscle－gives
rise to lateral thoracic a. 胸外侧动脉
Third portion, below muscle－gives
rise to subscapular a. 肩胛下动脉,
anterior and posterior humeral
circumflex a. 旋肱前、后动脉; the
former then divides into throcodorsal
a. 胸背动脉 and circumflex scapular a.
旋肩胛动脉
Brachial artery
 Continuation of axillary
artery
 Divides into radial and
ulnar arteries at level of
neck of radius
 Branches



Deep brachial a. 肱深动脉
－accompanies with
radial nerve
Superior ulnar collaeral a.
尺侧上副动脉－
accompanies with ulnar
nerve
Inferior ulnar collateral a.
尺侧下副动脉
Radial artery and branches
 Radial recurrent a. 桡侧返动脉
 Superfical palmar branch 掌浅支
 Principal artery of thumb 拇主要动脉
Ulnar artery and branches
 Ulnar recurrent a. 尺侧返动脉
 Common interosseous artery
骨间总动脉
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

Anterior interossous a. 骨间前动脉
Posterior interosseous a. 骨间后动脉
Deep palmar branch
掌深支
Superficial palmar arch 掌
浅弓
 Formed by ulnar artery
and superficial palmar
branch of radial artery
 Curve of arch lies across
the palm, level with the
distal border of fully
extended thumb
 Gives rise to three
common palmar digital
arteries each then divides
into two proper palmar
digital arteries
Deep palmar arch 掌深弓
 Formed by radial artery
and deep palmar branch
of ulnar artery
 Curve of arch lies across
upper part of palmar at
level with proximal border
of extended thumb
 Gives rise to three palmar
metacarpal arteries
Veins of the upper limb
Deep veins: accompany the
arteries of the same region and
bear similar names
Superficial veins
 Cephalic vein 头静脉


Arises from the lateral side of
the dorsal venous rete of hand
Ascends on radial side of the
forearm to the elbow and then
in the lateral side of biceps
brachii furrow, continues up the
arm in the deltopectoral groove
and then to the infraclavicular
fossa, where it pierces
clavipectoral fascia to drain into
axillary vein

Basilic vein 贵要静脉



Arises from the medial side
of the dorsal venous rete of
hand
Ascends on the ulnar side of
forearm to the elbow and
then in the medial bicepital
brachii furrow to middle of
the arm where it pierces the
deep fascia and joins the
brachial vein or axillary vein
Median cubital vein 肘正中静
脉
links cephalic vein and basilic
vein in the cubital fossa. It is
a frequent site for
venipuncture to remove a
sample of blood or add fluid
to the blood
The lymphatic drainage of upper limb
Lymphatic vessels
 Superficial－follow the
superficial veins, drain into
supratrochlear and axillary
lymph nodes
 Deep－accompany main
vessels, end in axillary lymph
nodes
lymph nodes
 Cubital lymph node: lies above
medial epicondyle of humerus
 Axillary lymph node－arranged
in five groups
Axillary lymph nodes腋淋巴结




－arranged in five groups
Lateral lymph nodes 外侧淋巴结－
lie around the distal end of axillary
vein , receiving drainage from the
arm, forearm, and hand
Pectoral lymph nodes 胸肌淋巴结
－lie along lateral thoracic vessels,
receive afferents from anterior
thoracic wall including central and
lateral portion of mamma
Subscapular lymph node 肩胛下淋
巴结－along subscapular vessels,
receive lymph from nape and
scapular region
Efferents above three groups pass to
central lymph node


Central lymph node中央淋巴
结－lie in fat of axillary fossa,
receive drainage from all the
above nodes, efferents pass
to apical lymph node
Apical lymph node 尖淋巴结



Lie in the apex of the axilla,
along the proximal end of
axillary vessels
Receive drainage chiefly
from central lymph node ,
upper portion of mamma
Efferents form subclavian
trunk, the right subclavian
trunk joints the right
lymphatic duct; left usually
drains directly into thoracic
duct
Brachial plexus 臂丛
Formation:


Five roots: formed by anterior
rami of C5-C8 and T1 spinal
nerves, roots C5～C7give rise to
long thoracic n.胸长神经
Three trunks





The upper trunk is formed by the
joining of root C4,C5,C6.
The middle trunk is the
continuation of root C7.
The lower trunk is formed by the
joining of root C8 and T1.
Six divisions: above clavicle,
trunks form anterior and
posterior divisions
Three cords: below clavicle,
divisions form three cords that
surround the second portion of
axillary a.
Position:
passes through the scalene fissure to
posterosuperior of subclavian artery, then
enters the axilla to form lateral, medial
and posterior cords
Main branches

Lateral cord
 Musculocutaneous n. 肌皮神经
 Lateral root to median n. 正中神经外侧
根

Medial cord
 Medial root to median n. 正中神经内侧根
 Ulnar n. 尺神经
 Medial brachial cutaneous n.臂内侧皮
神经

Medial antebrachial cutaneous n.
前臂内侧皮神经

Posterior cord



radial n. 桡神经
axillary n. 腋神经
thoracodorsal n. 胸背
神经

Musculocutaneous
肌皮神经
Distribution: Biceps
brachii, brachalis and
coracobrachialis ‘BBC
nerve’; skin on
anterior aspect of
forearm

Median 正中神经


Distribution: Flexor of
forearm except
brachioradialis, flexor
carpi ulnaris and ulnar
half of flexor digitorum
profundus, thenar except
adductor pollicis, first two
lumbricals; skin of thenar,
central part of palm,
palmar aspect of radial
three and one-half fingers,
including middle and
distal fingers on dorsum
Injury: Apehand 猿手
produces sign of benediction,
in which the index and
middle fingers cannot be
flexed and the thumb
cannot be opposed

Ulnar nerve

Distribution: Flexor
carpi ulnaris, ulnar half of
flexor digitorum
profundus, hypothenar
muscles, interossei, 3rd
and 4th lumbricals and
adductor pollicis; skin of
hypothenar, palmar
surface of ulnar one and
one-half fingers, ulnar
half of dorsum of hand,
posterior aspect of ulnar
two and one-half fingers

Injury: clawhand

Radial 桡神经


Distribution: Extensor
muscles of arm and
forearm, brachioradialis;
skin on back of arm,
forearm, and radial side
of dorsum of hand and
radial two and one-half
fingers
Injury: Wristdrop

Axillary 腋神经


Distribution: Deltoid
and teres minor
muscle; skin over
deltoid and upper
posterior aspect of arm
Injury: result in deltoid
andteres minor
paralysis (loss of
shoulser abdution and
weel external rotation)
with loss of sensation
over the deltoid
Regional anatomy of upper limb
山东大学医学院 解剖教研室
李振华
Parts and regions





Shoulder region－junction of arm
and trunk
Arm－between should and elbow
Elbow－bend of arm, joint
between arm and forearm
Forearm－between elbow and
hand
Hand
Surface anatomy





Shoulder region: acromion, spine of scapula,
coracoid process, greater tubercle, anterior
and posterior axillary folds
Arm－medial and lateral biceps brachii
furrow, deltoid tuberosity
Elbow－medial and lateral epicondyles, head
of radius, olecranon, tendon of biceps brachii
Forearm－between elbow and hand
Hand－styloid process, dorsal tubercle
Anatomical snuff box
鼻烟壶


When the thumb is
abducted and extended, a
triangular hollow appears
between the tendon of the
extensor pollicis longs
medially and the tendons of
the extensor pollicis brevis
and abductor pollicis longus
laterally.
The floor of the snuff box is
the scaphoid and trapezium
bones and crossed by the
radial a..
Carring angle 提携角
1650～1700
Mamma 乳房
Position


Lie in superficial fascia
over the pectorals
major and pectoral
fascia
Extend from 3rd to 7th
ribs vertically, and from
parasternal line to
midaxillary line
transversally
Structures－contains skin,


mammary glands and
adipose tissue
Each brest has about 15～
20 lobes of mammary
gland
Each lobe radiates out
from the nipple and has a
lactiferous duct输乳管
which opens separately on
the summit of the nipple
and possesses a dilated
lactiferous sinuses输乳管
窦 just prior to its
termination

Suspensory ligaments of
breast乳房悬韧带
(cooper’s ligaments )－
strands of connective
tissue runs between
skin and deep fascia
and serve to support
the mammary glands
Axillary fossa 腋窝

The axillary fossa is a
pyramid-shaped space
through which major
neurovascular structures
pass between the thorax
and upper extremity
Boundaries


The apex is a triangular
space limited by the
first rib, the scapula,
and the middle third of
clavicle.
The base－skin and
fascia of the axillary
fossa

The anterior wall


Pectoralis major, pectoralis minor and subclavius muscles
Clavipectoral fascia 锁胸筋膜


The deep faxcia which extends between subclavius, coracoid
process and pectoralis minor muscles
The structures pass through the clavipectoral faxcia



Cephalic v.
Thoracoacromial a.
Lateral pectoral n.

The posterior wall－teres major,
latissimus dorsi, subscapularis and
scapula
Trilateral and quadrilateral foramina 三
边孔和四边孔

Between the subscapularis and teres
major, there is a long triangular space
whose lateral side is surgical neck of
humerus. The long head of triceps
brachii subdivides this space into a
medial trilateral foramen and a lateral
quadrilateral foramen.

The posterior humeral circumflex a.
and axillary n. pass through the
quadrilateral foramen.

The circumflex scapular a. passes
through the triangular space to reach
the dorsum of the scapula.

The broad medial wall－serratus anterior，intercostal

muscles and upper four ribs
The narrow lateral wall－coracobrachialis, biceps brachii
and intertubercular groove
Contents
Brachial plexus, axillary a. and principal branches, axillary v.
and tributaries, axillary lymph nodes and loose connective
tissue
Brachial plexus 臂丛
Formation:


Five roots: formed by anterior rami of C5C8 and T1 spinal nerves, roots C5～
C7give rise to long thoracic n.胸长神经
Three trunks





The upper trunk is formed by the joining of
root C4,C5,C6.
The middle trunk is the continuation of root
C7.
The lower trunk is formed by the joining of
root C8 and T1.
Six divisions: above clavicle, trunks form
anterior and posterior divisions
Three cords: below clavicle, divisions form
three cords that surround the second
portion of axillary a.
Position:
passes through the scalene fissure to
posterosuperior of subclavian artery, then
enters the axilla to form lateral, medial and
posterior cords
Main branches

Lateral cord



Musculocutaneous n. 肌皮神经
Lateral root to median n. 正中神经外侧根
Medial cord




Medial root to median n. 正中神经内侧根
Ulnar n. 尺神经
Medial brachial cutaneous n.臂内侧皮神经
Medial antebrachial cutaneous n.
前臂内侧皮神经

Posterior cord



radial n. 桡神经
axillary n. 腋神经
thoracodorsal n. 胸背神经

Axillary sheath 腋鞘
－extension of deep
cervical fascia of the
neck, forming a tubular
sheath that surrounds
axillary a. and v., and
brachial plexus
Axillary artery
Continuation of subclavian artery at
lateral border of first rib
Becomes brachial artery at lower
border of teres major
Divided into three parts by overlying
pectoralis minor






First portion, above muscle－gives rise
to thoracoacromial a. 胸肩峰动脉
Second portion, behind muscle－gives
rise to lateral thoracic a. 胸外侧动脉
Third portion, below muscle－gives rise
to subscapular a. 肩胛下动脉, anterior
and posterior humeral circumflex a. 旋
肱前、后动脉; the former then divides into
throcodorsal a.胸背动脉 and circumflex
scapular a. 旋肩胛动脉
Axillary lymph node－arranged in five groups

Lateral lymph nodes－lie around the distal end
of axillary artery vein , receive afferent vessels
from upper limb.

Pectoral lymph nodes－lie along lateral thoracic
vessels, receive afferents from anterior thoracic
wall including central and lateral portion of
mamma

Subscapular lymph node－along subscapular
vessels, receive lymph from nape and scapular
region

Efferents above three groups pass to central
lymph node

Central lymph node－lie in fat of axillary fossa,
receive lymph from all the above nodes, efferents
pass to apical lymph node

Apical lymph node－lie in the apex of the axilla,
along the proximal end of axillary vessels,
receive afferents chiefly from central lymph node ,
upper portion of mamma; efferents form
subclavian trunk, the right subclavian trunk joints
the right lymphatic duct; left usually drains
directly into thoracic duct
Cubiral fossa 肘窝
Boundaries




Base－line drawn through
epicondyles of humerus
Apex－brachioradialis
laterally and pronator teres
medially
Roof－skin, superficial
faxcia, deep faxcia and
aponeurosis of biceps
Floor－brachialis, supinator
and capsule of elbow joint
Contents－from lateral to
medial
 Biceps brachii tendon
 Brachial a.－divides into
radial and ulnar a.,usually
at apex of fossa
 Median n.
Lateral to the biceps brachii
tendon－radial n. and
lateral antebrachial
cutaneous n.
Carpal tunnel 腕管
Flexor retinaculum
 Thickening of deep fascia in
the hand
 Attached laterally to
scaphoid and trapeziun and
medially to pisiform and
hamate
 Form an osseofibrous
tunnel (carpal tunnel) with
carpal groove－transmits
median n., flexor digitorum
supericialis, flexor digitorum
profundus, and flexor
pollicus longus from
forearm into hand
Teninous sheath of flexor pollicis longus
Common flexor
sheath
Skin incisions
Superficial fascia
Cephalic v.
Lateral cutaneous branch
Anterior cutaneous branch
Clavipectoral fascia
锁胸筋膜


The deep faxcia which
extends between
subclavius, coracoid
process and
pectoralis minor
muscles
The structures pass
through the
clavipectoral faxcia



Cephalic v.
Thoracoacromial a.
Lateral pectoral n.
Axillary a.
Thoracoacromial a.
Lateral pectoral n.
Musculocutaneous n.
Medial antebrachial cutaneous n.
Median n.
Ulnar n.
Medial brachial cutaneous n.
Intercostobrachial n.
Thoracodorsal n. & a.
Long thoracic n. & lateral thoracic a.
Posterior humeral circumflex a.
& axillary n.
Circumflex scapular a.
Radial n.
Musculocutaneous n.
Median n.
Medial brachial
cutaneous n.
Deep brachial a.
Ulnar n.
Superior ulnar coleteral a.
Medial antebrachial
cutaneous n.
Musculocutaneous n.
Median n.
Axillary a.
Medial antebrachial
cutaneous n.
Medial brachial cutaneous n.
Brachial a.
Deep brachial a.
Superior ulnar coleteral a.
& Ulnar n.
Inferior ulnar coleteral a.
Lateral anterachial cutaneous n.
& cephelic v.
Medial interracial cutaneous n.
& basiic v.
Median cubital v.
Ulnar n.
Brachial a.
Radial a.
Radial recurrent a.
Radial n.
Median n.
Ulnar a.
Ulnar recurrent a.
Ulnar n.
Muscolocutaneous n.
Brachial a.
Radial n.
Radial recurrent a.
Radial a.
Ulnar recurrent a.
Common interosseous a.
Median n.
Ulnar a., v. & n.
Palmar aponeurosis
Superficial palmar a.
Ulnar a.
recurrent n.
Posterior region of upper limb
山东大学医学院 解剖教研室
李振华
Skin incisions
Cutaneous n. and
superificial v.
Trapezium
Levator scapular
Deltoid
Rhomboideus
Triangle of ausculation
Latissimus dorsi
Thoracolumbar fascia
Suprascapular n.& a.
Supraspinatus
Teres minor
Infraspinatus
Axillary n.
Posterio humeral
circumflex a.
Deep brachial a.
Teres major
Radial n.
Radial n.
Deep
brachial a.
Posterior interosseousa.
Posterior interosseous n.
Hand
山东大学医学院 解剖教研室
李振华
Palm of hand 手掌
Flexor retinaculum 屈肌支持带
 Thickening of deep fascia in the
hand
 Attached laterally to scaphoid and
trapeziun and medially to pisiform
and hamate
Carpal tunnel 腕管


Formed by flexor retinaculum and
carpal groove
Transmits



Median n.
Flexor digitorum superficialis and
flexor digitorum profundus enclosed
by common flexor sheath
Flexor pollicus longus enclosed by
tendinous sheath of flexor pollicus
longus
Tendinous sheath of flexor pollicis longus
Common flexor
sheath
Deep palmar fascia
掌部深筋膜
Superficial layer
 Thenar fascia 鱼际筋膜
 Hypothenar fascia 小鱼际筋膜
 Palmar aponeurosis 掌腱膜
thick triangular membrane
Deep layer－palmar
interosseous fascia
骨间掌侧筋膜
Osseofascial compartments of palm
手掌骨筋膜鞘



Lateral compartment 外侧鞘
Medial compartment 内侧鞘
Intermediate compartment 中间鞘
Medial intermuscular septum
Laeral intermuscular septum
Palmar aponeurosis
Hypothenar fascia
Thenar fascia
Adductor pollicis
Palmar interosseous fascia
Intermediate compartment 中间鞘


Formed by palmar aponeurosis, Laeral and medial
intermuscular septum, palmar interosseous fascia
Contents: superficial palmar arch, a., v.,n., tendons of flexor
digitorum superficialis and profundus, lumbricales, common
flexor sheath
Fascia spaces 筋膜间隙


Thenar space 鱼际间隙
Midpalmar space掌中间隙
Midplmar septum
掌中隔
Thenar space
Midpalmar space
Dorsum of hand 手背
Extensor retinaculum



伸肌支持带
Thickening of deep faxcia of
forearm a wrist
Attached laterally to radius and
medially to styloid process of
ulna and triquetrum
Forms six fibrous compartments
for extensor tendons passing
from forearm into hand:






① tendons of abductor pollicis longus and extensor
pollicis brevis and their synovial sheaths;
② tendons of extensor carpi radialis longus and brevis
and their synovial sheaths;
③ tendon of pollicis longus and its synovial sheath;
④ tendons of extensor digitorum, extensor indicis and
their synovial sheaths;
⑤ tendon of extensor digiti minimi and its synovial
sheaths;
⑥ tendon of extensor carpi ulnaris and its synovial
sheaths
Fascia of the dorsal
hand


The superficial fascia
Deep fascia－the dorsal
fascia of hand


Superficial layer (dorsal
aponeurosis) 手背腱膜
Deep layer (dorsal
interosseous fascia)
骨间背侧筋膜
Two spaces


The dorsal subcutaneous space 手背皮下间隙
The dorsal subaponeurotic space 手背腱膜下间隙
Superficial fascia
Dorsal aponeurosis
Dorsal interosseous fascia
Dorsal subaponeurotic
space
Dorsal subcutaneous space
Nerves of hand


Median n.－thenar except adductor pollicis, first two lumbricals;
skin of thenar, central part of palm, palmar aspect of radial three
and one-half fingers, including middle and distal fingers on
dorsum
Ulnar n.－hypothenar muscles, interossei, 3rd and 4th lumbricals
and adductor pollicis; skin of hypothenar, palmar surface of ulnar
one and one-half fingers

Radial n.－skin of radial side of dorsum of hand and
radial two and one-half fingers
Fingers 手指

Pulp space 指髓间隙
On the palmar side of the tips of the
fingers and thumb. They contain fatty
tissue that is divided into numerous
compartments by fibrous septa that pass
between the distal phalanx and the skin.
The pulp space is limited proximally by the
firm adherence of skin and the distal
flexion crease to the underlying tissue; this
prevents pulp infection from spreading
proximally along the finger.

vessels :
有2条指掌侧固有动脉和2条指背动脉，分别走行于手指的两侧。

Nerves：
神经与同名动脉伴行。