Topography of the axillary, subclavian, deltoid and scapular topographic-anatomical regions.
INTRODUCTION
Traditionally, a difficult academic discipline in a medical school is topographic anatomy and operative surgery. Studying a subject involves a large amount of information to be absorbed.
One of the most difficult sections of topographic anatomy for students remains the topography of the limbs. For better assimilation of the material, it is necessary to introduce new teaching aids into the educational process.
The purpose of this manual is to help students master the program material on the topography of the limbs.
The objectives of practical study are primarily to provide a layer-by-layer description of the areas. Regions in topographic anatomy are parts of the human body that are separated from adjacent areas by conventional or natural boundaries and have a structure that is different from other adjacent areas.
The most important point in the topography of the limbs is the position of the neurovascular bundles. Their topography is determined by their relationship to the muscles, intermuscular spaces and fascia that form the vascular sheaths. N.I. Pirogov formulated the laws of the construction of vascular sheaths, which contribute to the spontaneous stopping of bleeding when the vessels are damaged and are ways of spreading purulent leaks.
The first law is that all vascular sheaths are formed by the fascia of the muscles located near the vessels.
The second law indicates the shape of the vascular sheaths, which is defined as prismatic.
The third law concerns the relationship of the vascular sheaths to the deep tissues, the apex of which is directly or indirectly connected to the nearby bone or joint capsule.
Further development of the teachings of N.I. Pirogov’s idea of the relationship between vessels and fascia was his position on the case structure of the fascial-muscular system of the limbs. Each section of the limb is a collection of fascial bags, or sheaths, located in a certain order around one or two bones.
CHAPTER 1
TOPOGRAPHIC ANATOMY OF THE SHOULDER GIRLD, SHOULDER, ELBAR AND FOREARM
Topography of the axillary, subclavian, deltoid and scapular topographic-anatomical regions.
· Axillary region (regio axillaris)
.
Borders:
front
– skin fold over the outer, free edge of the pectoralis major muscle;
back
– the lower edge of the latissimus dorsi and teres major muscles;
internal line
(conditional), connecting the edges of the indicated muscles on the chest;
external line
, connecting the same muscles on the inner surface of the shoulder.
Layer structure
With the limb abducted, the area has the appearance of a fossa (fossa axillaris), which, when the skin, fascia, fiber, vessels and nerves are removed, turns into a cavity (cavum, s. spatium axillare). The skin is covered with hair and contains many apocrine and sebaceous glands. The superficial fascia is almost not expressed. The fascia proper is denser at the edges of the armpit and thinner in the center. Walls of the axillary cavity: anterior mm. pectoralis major et minor, posterior mm. subscapularis, latissimus dorsi u teres major; internal - lateral part of the chest (up to the IV rib inclusive), covered with m. serratus anterior; outer - the medial surface of the humerus with m covering it. coracobrachialis and short head m. biceps.
In the posterior wall of the armpit, two openings are formed between the muscles, through which vessels and nerves pass from the axillary region to the deltoid and scapula.
Four way hole
limited from above – m. subscapularis and m. teres minor, below – m. teres major, medially – long head m. triceps, laterally – by the surgical neck of the humerus. n pass through it. axillaris u vasa circumflexa humeri posteriora.
Three way hole
limited from above – mm. subscapularis and teres minor; below – m. teres major, laterally – with the long head m. triceps. The circumflex scapula artery (a. circumflexa scapulae) passes through it to the posterior surface of the scapula.
The neurovascular bundle of the axillary region is located at the inner edge of m. coracobrachialis and short head m. biceps. V. axillaris
lies medial and superficial to the artery and surrounding nerves.
A.axillaris
begins at the lower edge of the 1st rib and passes into the brachial artery at the lower edge of m. latissimus dorsi. The relative position of the elements of the neurovascular bundle varies depending on the level.
First department
(clavipectoral triangle)
Trigonum clavipectorale limited above
clavicle and m.
subclavius, below
– the upper edge of the pectoralis minor muscle;
the base of the triangle is
the lateral edge of the sternum.
V.axillaris is located below and medially, the plexus brachialis bundles are located above and laterally, a. axillaris lies between the vein and the plexus bundles. The subclavian (apical) lymph nodes are adjacent to the axillary vein in front and from the inside. In the first section, the axillary artery gives off: a. thoracica suprema
, branches in the area of the upper two intercostal spaces,
a.
thoracoacromialis , the branches of which supply blood to the deltoid muscle, shoulder joint and both pectoral muscles.
Second department
(thoracic triangle)
Trigonum pectorale corresponds to the projection of the pectoralis minor muscle.
Behind the artery is the posterior bundle of the brachial plexus; Laterally - the lateral bundle that separates the artery from the axillary vein. In the second section, a. departs from the axillary artery . thoracica lateralis
, walking accompanied by n. thoracicus longus.
Third department
(inframammary triangle)
Trigonum subpectorale is limited at the top
the lower edge of the pectoralis minor muscle,
below
- the free edge of the pectoralis major muscle,
the base
- the edge of the deltoid muscle.
The axillary artery in this triangle is surrounded on all sides by nerves. The nerves of the upper limb arise from the three bundles of the brachial plexus. From the outer bundle n. musculocutaneus
and lateral
root n.
medianus , from the internal – medial
root n.
medianus, nn. ulnaris, cutaneus antebrachii medialis and cutaneus brachii medialis , from the rear –
nn.
axillaris u radialis (the largest nerve of the brachial plexus). The median nerve or its roots adjoins the brachial artery in front; behind the artery are the radial and axillary nerves. Lateral to the artery are the musculocutaneous nerve, medial to the ulnar nerve, internal cutaneous nerve of the forearm, internal cutaneous nerve of the shoulder and axillary vein. As a rule, the vein is wide, it covers a group of nerves lying medial from the artery, and reaches the artery.
In the third section, the axillary artery produces:
1) a. subscapularis
– the most powerful branch of the axillary artery;
2) a.circumflexa humeri anterior
;
3) a.circumflexa humeri posterior
, which goes to the foramen quadrilaterum along with the axillary nerve.
A. subscapularis, accompanied by veins of the same name, runs along the outer edge of the subscapularis muscle and splits into terminal branches ( a. thoracodorsalis
u
a.
circumflexa scapulae ), with a.
circumflexa scapulae passes through the foramen trilaterum. The musculocutaneous nerve pierces the coracobrachialis muscle and passes into the anterior region of the shoulder. Along the anterior surface of the subscapularis muscle passes the subscapularis nerve ( n. subscapularis
) to the subscapularis and teres major muscles, and the dorsal thoracic nerve (
n. thoracodorsalis
) to the latissimus dorsi muscle, both nerves usually arise from part of the brachial plexus.
Axillary artery (a.axillaris), vein (v.axillaris) and brachial plexus bundles
are projected on the border between the anterior and middle third of the width of the axillary fossa or, according to N.I. Pirogov, the projection of these formations corresponds to the anterior edge of hair growth.
· Lymph nodes of the axillary region:
There are five interconnected groups:
1. Thoracic nodes (nodi lymphatici axillares pectorales) – they receive lymph from the anterior-lateral surface of the chest, abdomen (above the navel) and mammary gland;
2. Lateral group (nodi lymphatici axillares laterales) – from the muscles, bones and joints of the upper limb and mammary gland;
3. Posterior group - subscapular lymph nodes (nodi lymphatici axillares subscapulares), receive lymph from the skin and muscles of the upper back and shoulder joint;
4. Central nodes (nodi lymphatici axillares centrales) lie in the center of the fat accumulation of the armpit. In the central nodes, the superficial lymphatic vessels of the upper limb, chest, back and part of the vessels of the mammary gland end;
5. Apical (nodi lymphatici axillares apicales) - all efferent vessels from all groups of nodes in the axillary region merge into them. These nodes are associated with the nodes of the mammary gland, pleura, cervical and supraclavicular lymph nodes.
· Subclavian region (regio infraclavicularis)
.
Corresponds to the clavipectoral triangle trigonum clavipectorale.
Borders:
top –
clavicle and m. subclavius;
lower
– a horizontal line passing through the third rib in men and the upper edge of the mammary gland in women or the upper edge of the pectoralis minor muscle;
from the inside
– lateral edge of the sternum;
outside
– anterior edge of the deltoid muscle.
Layer structure
The skin is thin, mobile, innervated by the supraclavicular nerve from the cervical plexus. The subcutaneous tissue is well developed, the superficial fascia, attached to the collarbone, forms the suspensory ligament of the mammary gland. The proper fascia (fascia pectoralis) covers m. with a thin plate. pectoralis major, spurs of the fascia divide the muscle into three parts: clavicular, pectoral and abdominal.
Deeper than the pectoralis major muscle there is a cellular space, the superficial subpectoral space, and behind this space there is a deep fascia of the region - the coracoclavicular-costal (f. clavipectoralis).
Neurovascular bundle of the subclavian region:
Behind the pectoralis major muscle between v. axillaris and the brachial plexus bundle is located a. axillaris. Within trigonum clavipectorale a. axillaris branches in the area of the upper two intercostal spaces into a. thoracica suprema
, and
a.
thoracoacromialis , the branches of which supply blood to the deltoid muscle (
r. deltoideus
), shoulder joint (
r. acromialis
) and both pectoral muscles (
rr. pectorales
).
Projection of the neurovascular bundle: in the middle of the clavicle.
· Deltoid region (regio deltoidea)
.
The area corresponds to the location of the deltoid muscle and shoulder joint.
Borders:
top
– line of muscle attachment to the outer third of the clavicle, acromion and outer third of the scapular spine;
lower
– conditional line connecting the lower edges of m. pectoralis major and m. latissimus dorsi;
front
and
posterior
correspond to the edges of the deltoid muscle.
Layer-by-layer topography
The skin is thick and inactive. Subcutaneous fatty tissue is better developed above the acromial portion of the muscle and has a cellular structure; it may contain an acromial subcutaneous bursa, which is well expressed in people who carry heavy weights on the shoulder. The superficial fascia is fixed to the acromion and fused in this place with its own fascia. The proper fascia of the deltoid region forms a sheath for the deltoid muscle, and numerous processes go from the fascia to the muscle, penetrating into the depths between its bundles. The muscle gives the area a rounded shape and covers the outside of the shoulder joint. Deeper than the deltoid muscle, between it and the humerus, there is a cellular subdeltoid space (spatium subdeltoideum), in which, in addition to fiber, there are tendons of the muscles attached to the proximal end of the humerus, synovial bursae, vessels and nerves. The blood supply to the area is due to the a.circumflexa humeri anterior and a.circumflexa humeri posterior, innervation is mainly due to the n.axillaris
Neurovascular bundle region:
Axillary nerve (n. axillaris - from segments C7-C5)
, containing motor fibers for the deltoid muscle, passes into the subdeltoid space from the axillary region, is directed accompanied by
a.
et v. circumflexa humeri posterior , bending around the surgical neck of the humerus from back to front.N.
axillaris gives branches to the shoulder joint and skin. In addition to the posterior circumflex artery of the humerus, a similar anterior branch of the axillary artery passes into the subdeltoid space - a.
circumflexa humeri anterior .
Axillary nerve ( n. axillaris
) and the posterior circumflex artery of the humerus (
a. circumflexa humeri posterior
) are projected at the intersection of a vertical line drawn from the posterior angle of the acromion with the posterior edge of the deltoid muscle.
· Scapular region
Includes the soft tissues lying on the back of the scapula.
Borders:
top
– line connecting the acromion with the spinous process C VII;
lower
– a horizontal line drawn through the angle of the blade;
medial
– inner edge of the shoulder blade;
lateral
– a vertical line running from the base of the acromion down.
Layer-by-layer topography
The skin is thick with limited mobility. Subcutaneous fatty tissue is penetrated by numerous fibrous strands. The superficial fascia is dense, fixed by fibrous cords to the skin and its own fascia. The proper fascia is thin and underdeveloped. Below it are located m. trapezius u m. latissimus dorsi, constituting the superficial muscle layer of the region.
The scapular spine divides the region into two fossae: supraspinatus and infraspinatus. The superficial muscles do not cover the entire scapula; the outer part of the infraspinatus fossa remains free of them.
Under the trapezius muscle and the latissimus dorsi muscle there are dense aponeurotic sheets of the sub- and supraspinatus fascia, which, together with the posterior surface of the scapula, form bone-fibrous beds filled with deep layer muscles and a small amount of fiber. In the supraspinous bed there is m. supraspinatus, in the infraspinatus – m. infraspinatus. M begins from the outer edge of the scapula. teres minor, and from its lower corner – m. teres major.
Neurovascular bundles of the scapular region:
In the scapular region there are two neurovascular bundles:
First
consists of
a.v.
suprascapularis (branch of the thyrocervical trunk from the subclavian artery) and
n.
suprascapularis (from the brachial plexus), innervating the supraspinatus and infraspinatus muscles. The vessels and nerve pass through the scapular notch into the supraspinatus fossa, are located first under the supraspinatus muscle, and then, going around the free edge of the scapular spine, penetrate into the infraspinatus bed. Here the suprascapular artery forms numerous anastomoses with the branches of the circumflex scapular artery (from the subscapular artery).
Second
the neurovascular bundle consists of
the descending branch of the transverse artery of the neck (ramus descendens a. transversae colli)
(from the subclavian artery),
the veins of the same name
and
the dorsal nerve of the scapula (n. dorsalis scapulae)
(from the brachial plexus), which run along the internal, vertebral, edge of the shoulder blade. The artery takes part in the formation of the scapular arterial circle, located directly on the bone in the infraspinatus fossa. The anastomoses of these arteries form the “scapular arterial circle” and play an important role in the development of collateral circulation during ligation of the axillary artery.
Anatomy of the shoulder joint
Joint arthroscopy > Shoulder joint > Anatomy of the shoulder joint
shoulder joint consists of the glenoid cavity of the scapula, as well as the head of the humerus. These articular surfaces are covered with hyaline cartilage, and the sizes of the surfaces do not correspond to each other. The area of the head is more than three times the total area of the scapula cavity. It is important to know that the congruence of the articular surfaces becomes greater due to the presence of the articular lip located along the edge of the joint cavity.
The articular capsule is fixed on the scapula along the very edge of the articular cartilage of the joint cavity, as well as along the outer edge of the articular labrum; the articular capsule is attached to the humerus along the anatomical neck. The joint capsule is spacious, weakly stretched. In the lower section, this capsule is thin, and throughout the rest of its length it is reinforced by the muscle tendons woven into it (infraspinatus, supraspinatus, subscapularis, teres minor).
During movements in the shoulder joint, the listed muscles pull back the joint capsule, preventing it from being pinched in the space between the articular surfaces of the bones.
The joint capsule on the humerus spans as a bridge over the intertubercular groove. Here is the tendon of the long head of the biceps brachii muscle, which originates from the supraglenoid tubercle, as well as the edge of the articular labrum, passing through the cavity of the shoulder joint and lying in the intertubercular groove. Located in the cavity of the shoulder joint, the tendon of the biceps brachii muscle is covered with a synovial membrane that accompanies it in the area of the intertubercular groove, located 2-5 centimeters below the level of the anatomical neck, then wraps up and, moving along the tendon, passes into the synovial membrane of the joint capsule.
On the inner surface of the joint capsule there are three glenohumeral ligaments . These ligaments are attached to the anatomical neck of the humerus on one side and to the articular lip of the scapula on the other. The superior and middle ligaments are separated by the openings of the bursa, which is located in the area under the subscapularis muscle. Ligaments help strengthen the anterior surface of the shoulder joint capsule.
The shoulder joint also has a powerful coracobrachial ligament. It looks like a compaction of the fibrous layer of the articular capsule, located from the outer edge of the coracoid process towards the greater tubercle of the humerus.
It is important to note that the coracoacromial ligament , located above the shoulder joint, forms the arch of the shoulder together with the acromion, as well as the coracoid process of the scapula. The shoulder arch allows you to protect the shoulder joint from above, and also inhibit shoulder abduction together with the tension of the joint capsule. In addition, it inhibits raising the arm forward or to the side at a level above the shoulder. Further upward movement of the hand is performed by moving the shoulder blade along with it.
The shoulder joint is triaxial; its shape is classified as a ball-and-socket joint. Due to the fact that this joint is the most mobile joint in the human body, the hand is characterized by significant freedom of movement.
Anatomy of the hand
The hand includes the distal part of the limb, which is located to the periphery of the line connecting the styloid processes of the radial and ulnar bones of the forearm. The proximal part of the hand is the wrist area (regiocarpi), distal are the metacarpus and fingers (digiti). The hand is distinguished between the palm (palma manus) and the back (dorsum manus).
Wrist area (regio carpi). Boundaries. The wrist is limited proximally by a line located 1 cm above the styloid processes of the radius and ulna, distally by a line drawn parallel to the first under the pisiform bone. There are anterior (palm) and posterior (dorsal) regions of the wrist.
Front area. Layers. The skin is thin, mobile, and forms three transverse folds. The upper one is located at the level of the head of the ulna, the middle one corresponds to the extreme points of the line of the radiocarpal joint, the lower one runs along the line of the midcarpal joint. The sources of v. are located in the subcutaneous tissue. cephalica and v. basilica, the terminal branches of n. cutaneus antebrachii medialis and n. cutaneus antebrachii late-ralis, as well as the palmar branches of n. media-nus and n. ulnaris.
The fascia proper, thickening, forms the flexor retinaculum (retinaculum flexorum). It, in the form of a bridge, spans over the bones of the wrist, covered with deep ligaments. As a result, the carpal canal (canalis carpi) appears, in which the tendons of the superficial and deep flexor fingers and the median nerve pass. The eight flexor tendons are located in the synovial sac, which projects 2 cm proximal to the retinaculum flexorum. In turn, canalis carpi, bifurcating towards the radius and ulna bones, forms two canals - canalis carpi radialis and canalis carpi ulnaris. The m. tendon is located in the radial canal of the wrist. flexorcarpi radialis, surrounded by a synovial sheath. The latter is located 1-2 cm proximal to the flexor retinaculum. In the ulnar canal of the wrist, which is a continuation of the ulnar groove of the forearm, vasa ulnaria and n. ulnaris are located at the pisiform bone. The nerve lies medial to the artery.
Posterior area. Layers. The skin is thicker than in the anterior area of the wrist and is mobile. The sources of v. are located in the subcutaneous tissue. cephalica and v. basilica, as well as Mr. superficialis n. radialis, r. dor-salis n. ulnaris, terminal branches of n. cutaneus antebrachii posterior. The fascia proper, thickening, forms the extensor retinaculum (retinaculum extensorum).
The septa extending from the extensor retinaculum at the dorsum of the wrist form six canals containing the extensor tendons, surrounded by synovial sheaths. In the first channel (counting from the outside) there are tendons m. abductorpollicis longus, etc. extensor pollicis bre-vis, in the second - tendons in. extensor carpi radialis longus and m. extensor carpi radialis brevis, in the third - tendon m. extensor pollicis longus, in the fourth - tendons of m. extensor digitorum and m. extensor indicis, in the fifth - tendon m. extensor digiti minimi, in the sixth - tendon m. extensor carpi ulnaris. In the fourth canal, together with the extensor tendons of the fingers, the posterior interosseous nerve of the forearm passes, located deeper than the tendons.
The radial artery, passing to the back of the hand through the anatomical “snuffbox”, is located under the tendons of m. abductor pollicis longus, etc. extensor pollicis brevis and, penetrating the first interosseous space, goes further to the palm. From the radial artery in the anatomical “snuffbox” the dorsal carpal branch (r. carpalis dorsalis) departs, which takes part in the formation of the dorsal arterial network of the wrist (rete carpi dorsale).
Rice. Arteries of the palmar surface of the hand.
The bone base of the wrist is made up of 8 short bones, which are arranged in two rows. The proximal (first) row of the wrist is formed, starting from the thumb, by four bones: scaphoid (os scaphoideum), lunate (os lunatum), triquetrum (os trique-trum) and pisiform (os pisiforme). The distal (second) row also consists of four bones: trapezium (os trapezium, s. os multangulum), trapezoid (os trapezoideum), capitate (os capitatum) and hamate (os hama-tum).
Rice. Deep palmar arch.
The wrist joint (articulatio radiocarpea) has the shape of a block. The glenoid cavity is formed by the carpal articular surface (facies articularis carpalis) and discus triangularis, the articular head is formed by the proximal surface of the bones of the first row of the wrist - scaphoid, lunate, triquetrum, which are interconnected by intercarpal ligaments - lig. intercarpea. The capsule of the wrist joint is strengthened from the sides by the radial (lig. collaterale carpi radiale), running from the styloid process of the radius to the scaphoid, the ulnar (lig. collaterale carpi ulnare), running from the styloid process of the ulna to the triquetral and pisiform bones, and the collateral ligaments of the wrist. In addition, on the palmar side the joint is strengthened by the palmar radiocarpeum ligament (lig. radiocarpeum palma), with the dorsal radiocarpeum ligament (lig. radiocarpeum dorsale), running from the radius to the bones of the first row of the wrist (scaphoid, lunate, triquetrum ).
Between the first and second rows of carpal bones (except for the pisiform bone) is the midcarpal joint (articulatio mediocarpea), which has its own articular capsule. It is strengthened by short ligaments that run transversely from one bone to another. On the dorsal surface of the joint there are dorsal intercarpal ligaments (ligg. intercarpea dorsalia), on the palmar - palmar intercarpal (ligg. intercarpea palmaria) and radiate (lig. carpi radiatum) carpal ligaments. The latter goes in bundles from the capitate bone to the neighboring bones.
The third joint is located between the bones of the second row of the wrist and the bases of the metacarpal bones - carpometacarpal joints (articulationes carpo-metacarpeae). These joints are flat, strengthened by the dorsal and palmar carpometacarpal ligaments (lig. carpometa-carpea dorsalia et palmaria) (Fig.).
Rice. Muscles of the hand, palmar surface.
The carpometacarpal joint of the thumb (articulatio carpometacarpea pollicis) is completely separate from the other carpometacarpal joints. This is a typical saddle joint with great mobility. It allows flexion, extension, opposition (oppositio), as well as circular movement (circumductio).
The blood supply to the wrist joint is carried out by the articular network (rete articulare). Participate in the formation of this networka. radialis, a. ulnaris, aa. interossea anterior et posterior. Venous outflow - into the veins of the same name.
Innervation - from n. ulnaris, n. radialis et n. medianus.
Palm (palma manus). Boundaries. At the top, i.e. proximally, the border of the palm is a transverse line, conventionally drawn under the pisiform bone; below is the palmar-digital fold. Upon examination, two elevations are clearly identified; one is formed by the muscles of the thumb (the-nar), the other by the muscles of the fifth finger (hypothenar). Between these elevations there is a depression.
Layers. The skin is smooth, dense, inactive, as it is connected to the palmar aponeurosis located underneath it by bundles of fibrous fibers. It has no hair and is full of sweat glands. Subcutaneous tissue is inactive. In addition to small blood and lymphatic vessels, it contains branches of the median and ulnar nerves, which also innervate the skin of the palm. The branches of the common palmar digital nerves (digitales palmares communes) are also located here.
The palmar aponeurosis (aponeurosis palmaris) is a triangular tendon plate, which is a continuation of the tendon of the palmaris longus (m. palmaris longus) onto the palm. In the middle part of the palm it is relatively thick and strong, and on the sides it is less developed and represents fascial sheets for the palmar muscular elevations. In the distal direction, the aponeurosis is divided into several (4-5) bundles going to the skin of the fingers. In the form of processes, it is directed to the sheaths of the digital tendons, and in the form of fascial sheets - to the interosseous muscles. In the palm of the palm, from this aponeurosis, with septa extending deep to the III and V bones of the metacarpus, three fascial beds are formed: two lateral for the muscles of the thumb and fifth fingers, the third in the middle, in which the flexor tendons of the fingers are located. The eminence of the thumb includes four muscles: the short muscle that abducts the thumb (m. abductor pollicis brevis), laterally the muscle that opposes the thumb (m. opponens pollicis), and the medial short flexor pollicis (m. flexorpollicis brevis) ). Between the two heads of the flexor pollicis brevis is the flexor pollicis longus tendon. Even more medial is the muscle that adducts the thumb (m. adductor pollicis).
The eminence of the small finger (little finger) also includes four muscles: the short palmar muscle (m. palmaris brevis), the abductor of the little finger (m. abductor digiti minimi), the short flexor of the little finger (m. flexor digiti minimibrevis), etc. opponens digiti minimi is a muscle that opposes the little finger.
In the tissue under the palmar aponeurosis between it and the deeper tendon of the superficial flexor of the fingers (m. flexordigitorum superficialis) there is a superficial arterial palmar arch - arcus palmarissuperficialis (Fig. 207). It is formed mainly by the ulnar artery and the superficial palmar branch of the radial artery (ramus palmaris superficialis a. radialis).
Three, sometimes four, common palmar digital arteries (aa. digitales palmares communes) depart from the superficial palmar arch, which at the level of approximately the metacarpophalangeal joints are divided into their own palmar digital arteries (aa. digitales palmares propriae), vascularizing adjacent sides of the fingers, except first. Below the superficial palmar arch are branches of the median and ulnar nerves, which give rise to the common palmar digital nerves, which divide into the proper digital nerves. The median nerve, as a rule, sends sensory nerves to the I, II and III fingers and the radial side of the IV finger, the ulnar nerve - to the ulnar surface of the IV finger and the V finger.
The deep palmar arterial arch is located under the flexor tendons. It is separated from them by fiber and deep palmar fascia and is located on the interosseous muscles. This arch is mainly formed by the terminal section of the radial artery, connecting with the deep branch of the ulnar artery (ramus palmaris profundus arteriae ulnaris) (Fig. 208). Typically, four palmar metacarpal arteries (aa. metacarpeepalmares) depart from this arterial arch, connecting with the dorsal arteries of the same name and, at the level of the metacarpophalangeal joints, flowing into the common palmar digital arteries. Deep; The palmar arch is located proximal to the superficial arch.
In the depths of the palm there are three interfascial cellular spaces: the outer, or the-nar space, the inner, or hypo-thenar space, and the middle - palmar space. The outer cellular space is located between the synovial sheath of the flexor pollicis longus tendon and the third metacarpal bone (os metacarpale tertium) and is separated from the middle cellular space by a fascial septum running deep from the palmar aponeurosis to the third metacarpal bone. The middle cellular space is also delimited from the inner space by a fascial septum running from the palmar aponeurosis to the fifth metacarpal bone. This space consists of superficial and deep sections. The superficial section is located between the palmar aponeurosis and the finger flexor tendons, the deep section is located between these tendons and the deep palmar fascia.
In the superficial part of the middle cellular space there is the superficial palmar arterial arch and branches of the median and ulnar nerves. The upper (proximal) part of the deep section of the middle cellular space of the palm communicates through the carpal tunnel with the Pirogov cellular space located on the forearm. The lower (distal) part of this section along the lumbrical muscles communicates with the fiber on the back of the III, IV and V fingers. The internal cellular space, or hypothenar space, is limited anteriorly and medially by its own fascia, attached to the fifth metacarpal bone, and laterally by the septumintermusculare mediate. The hypothenar bed contains the muscles of the fifth finger (little finger).
Rear of the hand (dorsum manus). Layers. The skin is thin and mobile. Subcutaneous tissue is loose, stretchable, facilitating the accumulation of fluid during edema. In the subcutaneous tissue there are veins that form the retevenosum dorsale manus, which are the sources for v. cephalica from the radial side and v. basilica with ulna. There are also numerous branches of the radial (approximately on the radial half of the dorsum of the hand) and ulnar (on the ulnar half of the dorsum of the hand) nerves (rr. superficia-les n. radialis and rr. dorsales n. ulnaris) (Fig. 209). Each of them innervates the skin of two and a half fingers. Usually five branches belong to one and five to another nerve. In addition, in the subcutaneous tissue between the branches of both nerves there are numerous connections - zones where the innervation of one nerve overlaps with the branches of the other. These are zones of mixed skin innervation, located mainly in the areas of the II, III and IV fingers.
Consequently, the skin of these fingers can be innervated by branches of both the radial and ulnar nerves. The skin of the dorsum of the distal phalanges of the 1st, 2nd and 3rd fingers is innervated by the median nerve. In addition, the skin of the dorsal surface of the distal phalanx of the first finger can additionally be innervated by the terminal lateral branches of the musculocutaneous nerve.
The proper fascia of the dorsum of the hand is a continuation of the fascia of the forearm. It is well defined, thickened in the area of the radiocarpal joint and is called the extensor retinaculum (reti-naculum extensorum). Under this fascia there is a cellular space at the back of the hand, in which the tendons of the extensor muscles of the hand and fingers are located. These tendons, continuing from the forearm to the back of the hand, emerge from under the retinaculum extensorum. From it deep into the bones of the wrist there are septa that form osteo-fibrous receptacles for these tendons, inside of which there are synovial sheaths of the extensor tendons. The sheaths extend to the periphery to the back of the hand, generally reaching the middle of the metacarpal bones.
In the same area at the radial edge between the tendons of m. abductor pollicis longus, etc. extensor pollicis brevis, on the one hand, and m. extensor pollicis longus, on the other hand, there is a triangular depression. It is called the anatomical “snuffbox”, over which v passes in the subcutaneous tissue. cephalica, and in depth - the radial artery. The latter comes here from the sulcus radialis of the anterior (palmar) region of the forearm, located under the tendon of m. abductor pollicis longus, etc. extensor pollicis brevis.
The pulse of the radial artery in the anatomical “snuffbox” is usually clearly palpable; the artery crosses its bottom in an oblique direction, penetrates the first interosseous space and then goes to the palm, where it forms a deep palmar arterial arch. The next layer (in depth) is the deep fascia of the dorsum of the metacarpus, covering the dorsal interosseous muscles - mm. interossei dorsales.
Finger areas (regiones digititi). The bony basis of the fingers are the phalanges. The thumb (I) finger has two phalanges - proximal and distal (nail), the remaining fingers - three phalanges each: proximal, middle and distal. The proximal phalanges of the fingers are connected to the heads of the corresponding metacarpal bones, and therefore the articulating surfaces have depressions and protrusions. The shape of the connection between the main phalanx of the thumb and the first metacarpal bone is block-shaped and in the presence of relatively powerful and tense lateral ligaments in this joint, only flexion and extension are possible. Consequently, lateral movements, as well as others, are absent in this joint.
At the same time, fairly free movements occur in the carpometacarpal joint of the thumb, which is saddle-shaped; along with flexion, abduction and adduction (i.e., movements along the sagittal axis). In addition, peripheral circular movements are also possible in it, i.e. rotation of the first metacarpal bone and the thumb attached to its head. As for the other four metacarpophalangeal joints, their capsule is weakly stretched, and although it is strengthened on the sides by strong ligaments, they are also slightly stretched. Below, the joints have powerful accessory palmar ligaments. In this regard, the following movements are possible in the metacarpophalangeal joints: flexion and extension, abduction and adduction, circular movements of the fingers. The interphalangeal joints of all five fingers are almost identical in structure, namely: the distal end of one phalanx has a block-like shape and a small groove in the middle, the proximal end of the other phalanx has a comb corresponding to the groove. In these joints, due to this shape and tense lateral ligaments, only flexion and extension are normally possible: other movements are excluded.
Palmar region (regio digitalis palmaris). Layers. The skin of this area is distinguished by its own characteristics: instead of four rows of epithelial cells of the stratum corneum, as is observed in other areas, there are several dozen such rows. This is of great practical importance in the regeneration of this layer, for example, after its death due to injury or other pathological processes in this area of the fingers.
On the skin of the distal phalanges of the fingers, ridges are clearly visible, forming certain patterns. The branch of dermatoglyphics that studies finger patterns is often called fingerprinting. The variability of finger patterns is so great (especially in small details called minutiae) that they are almost never repeated between different individuals. Due to this, fingerprinting is widely used in forensic science. Skin ridges increase friction when in contact with surrounding objects, reducing slipping. In addition, the skin in the scallop area is richer in sensitive nerve endings and therefore serves as a tactile, tactile organ.
Subcutaneous tissue contains a relatively large amount of adipose tissue. It is located between fibrous bridges running in a vertical direction from the papillary layer of skin to the periosteum of the phalanges and to the fibrous sheaths of the flexor tendons. This explains the mechanism of deep spread of purulent processes in the palmar area of the fingers.
The arteries of the fingers are located in the subcutaneous tissue and are located on the lateral surfaces. Since each finger has four arteries, they are located on these surfaces so that two of them lie closer to the palmar, and the other two to the back of the fingers, but, as a rule, from the sides. The most developed are those digital arteries that are located closer to the palmar area of the fingers and originate from the superficial palmar arterial arch. They reach the distal phalanges and enter them, forming here relatively small anastomotic arches. From them arise branches that form vascular networks in the soft tissues of the fingers, feeding the tissues of the palmar and dorsal areas of the distal phalanges of the fingers. The dorsal digital arteries, as a rule, do not reach the distal phalanges: their function is taken over by branches of the palmar digital arteries. The veins in the fingers are not satellites of the arteries, as in other areas of the limbs. From the palmar areas of the fingers they move to the back and here they continue their path further.
The innervation of the fingers is carried out by four digital nerves, located similarly to the arteries, but somewhat inward from them and from the fibrous tendon sheaths. On the palmar surface of the fingers, innervation is carried out by the branches of the median and ulnar nerves, on the dorsal surface - by the radial and ulnar nerves. Mixed cutaneous innervation is observed here. The dorsal digital nerves extend only to the middle phalanges, and then both areas of the fingers are innervated by the palmar digital nerves. On the palmar surface of the phalanges in the form of semi-cylinders there are fibrous canals (vagg. fibrosae digitorum manus), lined with parietal leaves of the synovial sheaths, which serve as receptacles for the tendons of the superficial and deep flexor fingers. On the sides they are tightly fused with the periosteum of the phalanges and hold the tendons in them in place during the movement of the fingers. Fibrous canals extend from the heads of the metacarpal bones to the distal phalanges; in some places they are so compacted that they take the form of annular, cruciate or other ligaments.
The fibrous-synovial sheaths contain the flexor tendons of the fingers. Each tendon of the superficial digital flexor is divided at its peripheral end into two legs, which are attached to the middle phalanx. Between the legs there is a relatively wide gap through which the deep digital flexor tendon passes, attaching to the distal phalanges. The synovial sheaths contain two tendons of the palmar area of the fingers - superficial and deep. In this case, on the II, III and IV fingers, the proximal border of the sheaths is at the level of the heads of the metacarpal bones, and the peripheral border is at the level of the bases of the distal phalanges. On the 1st and 5th fingers of the upper limb, the topographic relationships of the synovial sheaths and tendons are different. The flexor tendons of these two fingers are covered with synovial sheaths not only at the level of the fingers, but also on the palm and wrist 2-4 cm above the retinaculum flexorum.
At the level of the palm, both synovial sheaths are significantly dilated and appear as bursae or sacs. One of these bags, located at the fifth finger, ulnar edge of the palm and wrist, surrounds the tendons of both flexors - deep and superficial. This ulnar synovial sac, as a rule, does not have communications with the synovial sheaths of the palmar surface of other fingers. Another synovial sac, located at the first finger, radial edge of the palm and wrist, surrounds the tendon of the flexor pollicis longus. Both synovial sacs, as a rule, do not communicate with each other (except for rare exceptions), as well as with the sheaths of the flexor tendons of the II, III and IV fingers. These topographical features explain the spread of inflammatory processes along both synovial sacs proximally to the forearm and, in particular, to its cellular space.
The synovial membrane, which forms the tendon sheath, consists of two layers - the parietal (peritendinium), lining the walls of the fibrous canals, and the visceral (epithendinium), lining the tendon itself. At the point where the parietal leaf transitions into the visceral layer, a tendon mesentery (mesotendinium) is formed, through which fiber with vessels and nerves penetrate to the tendon. On the fingers of the hand there are significant areas of tendon, where the mesotendinium is very narrow and has the appearance of ligaments (vincula tendinum).
Dorsal region (regio digitalis dorsa-lis). Layers. The skin is much thinner than in the palmar area, covered with sparse, short hair, mainly on the proximal phalanges, where it is most mobile and has sebaceous glands. The subcutaneous fascia is loose, extensible, and contains a small layer of fat. The vessels and nerves of the region pass here, namely: two dorsal digital arteries (aa. digitales dorsales), extending from each a. interosseador-salis and reaching the middle phalanx along the edges of the fingers. Veins, as a rule, are not located parallel to the arterial trunks, but form plexuses. The nerve trunks are located almost parallel to the arteries and often on their inner side. In this case, as a rule, five trunks arise from the dorsal digital nerves of the radial nerve, five others - from the same branches of the ulnar nerve and innervate two and a half fingers, respectively. These nerves mainly reach only the middle phalanx of the fingers. The dorsal areas of the distal phalanges of these fingers receive innervation from the palmar nerves (with the exception of the little finger).
In the dorsum of the fingers, the extensor tendons form tendon stretches on each finger - digital aponeuroses. They are divided into three legs, with the middle leg attached to the base of the middle phalanx, and the lateral ones going to the periphery and attached to the base of the distal phalanx.
Operative surgery and topographic anatomy: lecture notes for universities
LECTURE 11. TOPOGRAPHIC ANATOMY OF THE HAND AREA
1. Boundaries.
The hand is delimited from the forearm by a line drawn 2 cm above the styloid process of the radius.
Areas of the hand - wrist, metacarpus, fingers. It is divided by the radial and ulnar edges into palmar and dorsal regions. External landmarks
are the styloid processes of the ulna and radius, skin folds of the wrist, grooves and folds of the palm, palmar-digital and interdigital folds, heads of metacarpal bones and phalanges of the fingers.
2. Palmar area
.
At the level of the styloid processes, three transverse skin folds are visible. Proximally at the ulnar edge of the palm is the pisiform bone. Lateral to it is the neurovascular bundle. The middle wrist fold serves as the projection line of the wrist joint. Between the two elevations formed by the muscles of the 1st and 5th fingers there is a triangular palmar cavity,
with its apex facing proximally.
It corresponds to the location of the palmar aponeurosis. The proximal third of the longitudinal skin fold separating the thenar from the palmar aponeurosis is the Canavela exclusion zone
; the motor branch of the muscles of the median nerve of the first finger passes here.
Opposite the interdigital folds are three elevations - pads. They correspond to the commissural
openings of the palmar aponeurosis.
The synovial sheaths of the tendons of the II–IV fingers are projected into the grooves between the pads. The transverse folds of the palmar surface of the fingers correspond to the ligaments that strengthen the fibrous canals of the flexor tendons. The skin
is thick and inactive.
In the subcutaneous layer, at the base of the hypothenar, there are transverse bundles of the palmaris brevis muscle. At the lateral edge of the wrist there is r. palmaris superficialis a. radialis. The fascia
is a thickening of the distal fascia of the forearm.
Near the pisiform bone, the fascia forms a canal through which the neurovascular bundle passes. The flexor tendon retinaculum is a ligament consisting of transverse fibers thrown in the form of a bridge over the bony edges of the palmar surface of the wrist. The ligament is stretched between the scaphoid and trapezoid bones on one side, and the pisiform and hamate bones on the other. At this point, the carpal tunnel is formed,
through which the flexor tendons and median nerve pass. The anterior wall of the canal is the superficial layer of the ligament, the back wall is the carpal bones and the deep layer of the ligament. The proper fascia of the palm is expressed differently. The muscles of the eminences of the first and fifth fingers are covered with a thin plate, and on the palmar cavity it is represented by the palmar aponeurosis.
The longitudinal fibers of the aponeurosis are combined into 4 bundles, heading to the bases of the II and V fingers. The spaces between the longitudinal and transverse bundles of the aponeurosis are called commissural openings
.
From the longitudinal bundles of the aponeurosis to the deep transverse metacarpal ligaments, proximally under the aponeurosis, there are vertical tendon septa that form fibrous
intermetacarpal canals, where the lumbrical muscles are located.
There are two fascial intermuscular septa: lateral and medial.
Lateral - goes vertically deep, then horizontally forms a fold in the form of a fold, and attaches to the V metacarpal bone.
Medial
- attaches to the V metacarpal bone.
Fascial beds -
lateral, median and medial.
Lateral
, in front - proper fascia;
behind - deep fascia and first metacarpal bone; medially - lateral intermuscular septum; laterally - due to the attachment of its own fascia to the first metacarpal bone. It contains the muscles of the first finger - m. abductor pollicis brevis, m.flexor pollicis longus, m.flexor pollicis brevis, m. opponens pollicis, m. adductor pollicis .
Medial , in front and medially - the proper fascia, attached to the fifth metacarpal bone, behind - by the fifth metacarpal bone, laterally - by the medial intermuscular septum.
It contains the muscles of the fifth finger: m. abductor digiti minimi, m. opponens digiti minimi, m.flexor digiti minimi brevis. Median
: in front - palmar aponeurosis, behind - deep fascia, laterally and medially - intermuscular septa of the same name. It contains flexor tendons, dividing it into two slits: subgaleal and subtendinous, in which the superficial and deep arterial arches are located. The flexor tendons of the II–V fingers are located in the common synovial sheath from the Pirogov space to the middle of the metacarpal bones. The tendon of the fifth finger further lies in a separate synovial sheath and ends at the base of the distal phalanx.
3. Area of the back of the hand
: In the area of the wrist, at the radial edge of the hand, when the first finger is abducted, a fossa is visible - an
anatomical snuffbox
.
The radial artery and scaphoid bone are projected into it. At the apex of the styloid process of the ulna, a branch of the ulnar nerve is projected, innervating the skin of the 5th, 4th and ulnar side of the 3rd finger. At the apex of the styloid process of the radius, branches of the radial nerve are projected, innervating the I, II and radial side of the III finger. The projection of the wrist joint
follows an arc, the apex of which is 1 cm above the line connecting the apices of the styloid processes.
The projection of the gaps of the interphalangeal joints is determined in the position of full flexion of the fingers by 2–3 mm. below the convexities of the heads of the phalanges. The joint space of the metacarpophalangeal joints corresponds to a line located at 8–10 mm. below the heads of the metacarpal bones. The skin is thin and mobile. The subcutaneous tissue is loose, containing superficial vessels and nerves. The fascia at the level of the wrist joint is thickened and forms the extensor retinaculum
.
Under it there are 6 osteofibrous canals
.
The canals contain the extensor tendons of the hand and fingers. In the area of the metacarpus, between the proper and deep fascia, there is a subgaleal space
, where the extensor tendons of the fingers are located.
On the back of the fingers, the extensor tendon
consists of three parts, the middle one is attached to the base of the middle phalanx, and the two lateral ones are attached to the base of the distal phalanx. Above the proximal phalanx there is an aponeurotic stretch, into the edges of which the tendons of the lumbrical and interosseous muscles are woven. The interphalangeal joints are strengthened by lateral ligaments.