The hand is a complex structure whose muscles allow for a wide range of movements. More than 30 individual muscles in the hand and forearm work together to achieve these varied movements. The muscles provide arm movement with unparalleled flexibility, extremely precise control, and the strength needed for a variety of activities.
Six flexor muscles are located on the anterior or palmar side of the forearm,
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• Abductor thumb
• Flexor digitorum brevis
• Adductor pollicis
• Interosseous muscle
• Abductor of the little finger
• Flexor digiti brevis

[Start at top] These are long, thin muscles that run through the wrist with the help of tendons.
Flexor carpi radialis and flexor carpi ulnaris, originate on humerus the upper part of the hand and end at the carpal and macula joints on the palmar side of the hand.
Working together, these muscles flex the hand at the wrist. The flexor carpi radialis also flexes the hand toward the thumb, while the flexor carpi ulnaris abducts the hand toward the little finger.
The remaining three flexor muscles are the finger flexors, which are located on the inside of the forearm from elbow joint to your fingertips.

The flexor tendons and median nerve pass through a bony canal in the wrist known as the carpal tunnel. Repetitive stress on the flexor tendons can cause them to become inflamed and affect the median nerve, resulting in pain, numbness and tingling known as carpal tunnel syndrome.

Extensors of the hand and fingers

Nine extensor muscles, found at the back of the forearm, extend the arm and fingers. They are antagonists to the muscles that flex the hands and fingers.
Several muscles in the forearm control the rotation of the radius around the elbow, rotating the wrist and arm.

The arm muscles can be broken down into three main areas: thenar(lateral or big side palms), hypothenar(medial or small side of the palm) and intermediate(middle arm) muscles.

Muscles thenar, which are located at the base of the thumb, provide flexibility to the hand and the ability to grasp and squeeze objects. One of these muscles abductor thumb, provides a sideways movement of the thumb against the other fingers, allowing you to pinch a small object between the thumb and index finger to lift it. Abductor thumb And adductor pollicis work as antagonists - bending and straightening the thumb.
The muscles that flex, extend and abduct the little finger form a small bulge on the inside palms. These muscles work together to provide a wide range of motion to the little finger.

Located in the middle of the palm between the metacarpal bones intermediate muscles together they move the metacarpal bones from the second to the fifth and the phalanges from the second to fifth fingers in different directions.
Four lumbrical muscles, which get their names from their worm-like shapes, help the flexors and extensors in extending the fingers at the interphalangeal joints. All these muscles provide a wide range of movements of the hands and fingers.

47. Age and gender characteristics of muscle development, the influence of work activity and physical education and sports on muscle development.

48. Formations of the auxiliary apparatus of muscles (fascia, fascial ligaments, fibrous and osteofibrous canals, synovial sheaths, mucous bursae, sesamoid bones, pulleys) and their functions.

49. Abdominal muscles: topography, origin, attachment and functions.

50. Muscles of inspiration. Muscles of exhalation.

52. Neck muscles: topography, origin, attachment and functions.

53. Muscles that flex the spine.

54. Muscles that extend the spine.

55. Muscles of the anterior surface of the forearm: origin, attachment and functions.

56. Muscles of the posterior surface of the forearm: origin, attachment and functions.

57. Muscles that produce forward and backward movements of the upper limb girdle.

58. Muscles that produce up and down movements of the upper limb girdle.

59. Muscles that flex and extend the shoulder.

60. Muscles that abduct and adduct the shoulder.

61. Muscles that supinate and pronate the shoulder.

62. Muscles that flex (main) and extend the forearm.

63. Muscles that supinate and pronate the forearm.

64. Muscles that flex and extend the hand and fingers.

65. Muscles that abduct and adduct the hand.

66. Thigh muscles: topography and functions.

67. Muscles that flex and extend the hip.

68. Muscles that abduct and adduct the thigh.

69. Muscles that supinate and pronate the thigh.

70. Muscles of the lower leg: topography and functions.

71. Muscles that flex and extend the lower leg.

72. Muscles that supinate and pronate the lower leg.

73. Muscles that flex and extend the foot.

74. Muscles that abduct and adduct the foot.

75. Muscles supinating and pronating the foot.

76. Muscles that hold the arches of the foot.

77. General center of gravity of the body: age, gender and individual characteristics of its location.

78. Types of balance: angle of stability, conditions for maintaining body balance.

79. Anatomical characteristics of anthropometric, quiet and tense body position.

80. Hanging on straight arms: anatomical characteristics, features of the external respiration mechanism.

81. General characteristics of walking.

82. Anatomical characteristics of 1, 2 and 3 phases of a double step.

83. Anatomical characteristics of the 4th, 5th and 6th phases of the double step.

84. Standing long jump: phases, muscle work.

85. Anatomical characteristics of a backflip.

65. Muscles that abduct and adduct the hand.

Retract the hand: flexor carpi radialis, extensor carpi radialis longus and brevis, abductor pollicis longus, extensor pollicis longus, extensor brevis thumb. In addition, the muscles running from the forearm to the index finger take a small part in abduction of the hand.

Flexor carpi radialis starts from the medial epicondyle of the shoulder and the intermuscular septum, the muscle passes to the hand under the flexor retinaculum ligament and attaches to the base of the 2nd metacarpal bone. Being a multi-articular muscle, it is involved not only in the movements of the hand, but also in flexing the forearm at the elbow joint.

Extensor carpi radialis longus starts from the lateral edge of the humerus, the intermuscular septum and the lateral epicondyle, passes under the extensor retinaculum ligament and the extensor pollicis longus tendon and is attached to the base of the 2nd metacarpal bone. Due to the fact that the resultant of this muscle passes very close to the transverse axis of the elbow joint, its participation in flexion of the forearm is not significant. Being a strong extensor of the hand, it also produces some abduction during isolated contraction.

Extensor carpi radialis brevis starts from the lateral epicondyle of the humerus, the fascia of the forearm and attaches to the base of the 3rd metacarpal bone. Being an extensor of the hand, the muscle also abducts it.

Abductor pollicis longus muscle, starts from the dorsum of the radius and ulna and the interosseous membrane and attaches to the base of the 1st metacarpal bone. This muscle abducts the thumb if it is not fixed by antagonist muscles. If it is fixed, she retracts the hand. When the thumb is abducted to failure, further muscle work is also manifested in the abduction of the hand.

Extensor pollicis longus starts from back surface elbow and radius, interosseous membrane of the forearm and is attached to the distal phalanx of the thumb. The tendon of this muscle passes under the extensor retinaculum ligament in a separate channel, crossing the tendons of the extensor carpi radialis. By extending the distal phalanx, the muscle simultaneously pulls the thumb back somewhat. If it is fixed, then the muscle is involved in abduction of the entire hand.

Extensor pollicis brevis starts from the posterior surface of the ulna and radius, attaches to the proximal phalanx of the thumb, which it extends, simultaneously abducting the entire finger. If the finger is fixed, then the muscle is involved in abduction of the entire hand.

Lead the brush: flexor carpi ulnaris, extensor carpi ulnaris.

Flexor carpi ulnaris starts from the medial epicondyle of the humerus, from the ulna and the fascia of the forearm. The distal end reaches the pisiform bone, to which it is attached. From the pisiform bone to the hamate and to the 5th metacarpal bones there are ligaments that are a continuation of the traction of this muscle.

Extensor carpi ulnaris originates from the lateral epicondyle of the humerus, collateral radial ligament and fascia of the forearm. Descending onto the hand, the muscle runs between the head and the styloid process of the ulna and attaches to the base of the 5th metacarpal bone. Being an extensor of the hand, the extensor carpi ulnaris also adducts it.

The muscles of the hand are located mainly on the palmar surface of the hand and are divided into lateral group(muscles of the thumb), medial group (muscles of the little finger) and middle group. On the dorsum of the hand are the dorsal (back) interosseous muscles.

Lateral group

The short muscle that abducts the thumb (m. abductor pollicis brevis) (Fig. 120, 121) abducts the thumb, slightly opposing it, and takes part in flexion of the proximal phalanx. It is located directly under the skin on the lateral side of the eminence of the thumb. It begins on the scaphoid bone and ligament of the palmar surface of the wrist, and is attached to the lateral surface of the base of the proximal phalanx of the thumb.

	Rice. 120. Muscles of the hand (palm surface): 1 - pronator quadratus; 2 - flexor pollicis longus: a) abdomen, b) tendon; 3 - muscle opposing the thumb; 4 - flexor retinaculum; 5 - flexor pollicis brevis; 6 - short muscle, abductor pollicis; 7 - muscle adducting the little finger; 8 - palmar interosseous muscles; 9 - adductor pollicis muscle: a) oblique head, b) transverse head; 10 - lumbrical muscle; 11 - dorsal interosseous muscle; 12 - superficial digital flexor tendon; 13 - sheath of the tendons of the fingers; 14 - tendon of the deep flexor digitorum
	Rice. 121. Muscles of the hand (palm surface): 1 - pronator quadratus; 2 - tendon of the brachioradialis muscle; 3 - tendon flexor ulnaris brushes; 4 - tendon flexor radialis brushes; 5 - muscle opposing the thumb to the hand; 6 - flexor pollicis brevis; 7 - palmar interosseous muscles; 8 - short muscle, abductor pollicis; 9 - dorsal interosseous muscles
	Rice. 122. Muscles of the hand (dorsal surface): 2 - extensor of the little finger; 3 - extensor carpi ulnaris tendon; 4 - extensor finger; 5 - extensor carpi radialis longus tendon; 7 - tendon of the long extensor pollicis; 8 - extensor tendon of the little finger; 9 - muscle that abducts the little finger; 10 - extensor tendon; 11 - extensor tendon of the index finger; 12 - dorsal interosseous muscles; 13 - flexor pollicis longus tendon
	Rice. 123. Muscles of the hand (dorsal surface): 1 - short extensor pollicis; 2 - abductor pollicis longus muscle; 3 - extensor carpi ulnaris; 4 - extensor carpi radialis longus tendon; 5 - finger extensor tendons; 6 - tendon of the short extensor carpi radialis; 7 - extensor tendon of the little finger; 8 - tendon of the extensor pollicis longus; 9 - extensor tendon of the index finger; 10 - dorsal interosseous muscles; 11 - muscle that abducts the little finger; 12 - adductor pollicis muscle; 13 - extensor tendon of the little finger; 14 - tendon of the abductor pollicis longus muscle; 15 - finger extensor tendons; 16 - lumbrical muscles

The short flexor pollicis brevis (m. flexor pollicis brevis) (Fig. 120, 121) flexes the proximal phalanx of the thumb. This muscle is also located just under the skin and has two heads. The starting point of the superficial head is on the ligamentous apparatus of the palmar surface of the wrist, and the deep head is on the trapezius bone and the radiate ligament of the wrist. Both heads are attached to the sesamoid bones of the metacarpophalangeal joint of the thumb.

The muscle opposing the thumb to the hand (m. opponens pollicis) (Fig. 120, 121) opposes the thumb to the little finger. Located under short muscle, abductor thumb, and is a thin triangular plate. The muscle starts from the ligamentous apparatus of the palmar surface of the wrist and the tubercle of the costoptrapezius, and is attached to the lateral edge of the first metacarpal bone.

The muscle that adducts the thumb (m. adductor pollicis) (Fig. 120, 123) adducts the thumb and takes part in the flexion of its proximal phalanx. It lies the deepest of all the muscles of the eminence of the thumb and has two heads. The starting point of the transverse head (caput transversum) is located on the palmar surface of the IV metacarpal bone, the oblique head (caput obliquum) is on the capitate bone and the radiate ligament of the wrist. The attachment point for both heads is located at the base of the proximal phalanx of the thumb and the medial sesamoid bone of the metacarpophalangeal joint.

Medial group

Short palmaris muscle(m. palmaris brevis) stretches the palmar aponeurosis, forming folds and dimples on the skin in the area of ​​the eminence of the little finger. This muscle, which is a thin plate with parallel fibers, is one of the few cutaneous muscles available in humans. It has a point of origin on the inner edge of the palmar aponeurosis and the ligamentous apparatus of the wrist. The place of its attachment is located directly in the skin of the medial edge of the hand at the eminence of the little finger.

The muscle that abducts the little finger (m. abductor digiti minimi) (Fig. 122, 123) abducts the little finger and takes part in the flexion of its proximal phalanx. It is located under the skin and is partially covered by the palmaris brevis muscle. The muscle originates from the pisiform bone of the wrist and attaches to the ulnar edge of the base of the proximal phalanx of the little finger.

The short flexor of the little finger (m. flexor digiri minimi) bends the proximal phalanx of the little finger and takes part in its adduction. It is a small, flattened muscle covered by skin and partly by the palmaris brevis muscle. Its point of origin is located on the hamate and ligaments of the wrist, and its attachment point is on the palmar surface of the base of the proximal phalanx of the little finger.

The muscle adducting the little finger (m. opponens digiti minimi) (Fig. 120) opposes the little finger to the thumb. The outer edge of the muscle is covered by the short flexor of the little finger. It begins on the hamate and ligamentous apparatus of the wrist, and is attached to the ulnar edge of the fifth metacarpal bone.

Middle group

Vermiform muscles (mm. lumbricales) (Fig. 120, 123) bend the proximal phalanges of the II–V fingers and straighten their middle and distal phalanges. There are four muscles in total, all of them have a spindle-shaped shape and are directed to the II–IV fingers. All four muscles begin from the radial edge of the corresponding tendon of the deep flexor digitorum, and are attached to the dorsal surface of the base of the proximal phalanges of the II–IV fingers.

The palmar interosseous muscles (mm. interossei palmares) (Fig. 120, 121) flex the proximal phalanges, extend the middle and distal phalanges of the little finger, index and ring fingers, simultaneously bringing them to the middle finger.

They are located in the interosseous spaces between the II–V metacarpal bones and represent three muscle bundles. The first interosseous muscle is located on the radial half of the palm, its origin point is the medial side of the II metacarpal bone, the second and third interosseous muscles are located on the ulnar half of the palm, their origin point is the lateral side of the IV and V metacarpal bones. The place of muscle attachment is the base of the proximal phalanges of the II–V fingers and the articular capsules of the metacarpophalangeal joints of the same fingers.

Dorsal interosseous muscles (mm. interossei dorsales) (Fig. 120, 121, 122, 123) flex the proximal phalanges, extend the distal and middle phalanges, and also abduct the little finger, index and ring fingers from the middle finger. They are the muscles of the dorsum of the hand. This group consists of four fusiform bipennate muscles, which are located in the interosseous spaces of the dorsum of the hand. Each muscle has two heads, which begin from the lateral surfaces of two adjacent metacarpal bones facing each other. The place of their attachment is the base of the proximal phalanges of the II–IV fingers. The first and second muscles are attached to the radial edge of the index and middle fingers, and the third and fourth are attached to the ulnar edge of the middle and ring fingers.

The muscles of the hand, according to their position, are divided into two groups: the muscles of the palmar and the muscles of the dorsal surfaces. Moreover, among the muscles of the palmar surface there are distinguished - the thenar region, the muscles of the eminence of the little finger - the hypothenar region and the muscles of the middle group.

Muscles of the eminence of the thumb

1. Abductor pollicis brevis muscle, m. abductor pollicis brevis.
2. Flexor pollicis brevis, m. flexor pollicis brevis.
3. The muscle opposing the thumb to the hand, m. opponens pollicis.
4. Muscle adductor pollicis, m. adductor pollicis.

Muscles of the eminence of the little finger

1. Palmaris brevis muscle, m.palmaris brevis.
2. Abductor digiti minimi muscle, m. abductor digiti minimi.
3. Flexor digitorum brevis, m. flexor digiti minimi brevis.
4. Muscle opposite the little finger, m. opponens digiti minimi.

Middle group muscles

1. Vermiform muscles, mm. lumbricales.
2. Palmar interosseous muscles, mm. interossei palmares.

Muscles of the palmar surface

Muscles of the eminence of the thumb

1. Abductor pollicis brevis muscle, m. abductor pollicis brevis, lies on the lateral side of the eminence of the thumb, directly under the skin. Originates from the tendon of m. abductor pollicis longus, fascia antebrachii, from tuberositas ossis scaphoidei and retinaculum flexorum, is attached to the lateral surface of the base of the proximal phalanx of the thumb. Its tendon usually contains the sesamoid bone. Action: abducts the thumb, slightly opposing it, and takes part in flexion of the proximal phalanx. Innervation: n. medianus (C6-C7). Blood supply: n. palmaris superficialis a. radialis.
2. The short flexor pollicis brevis, m.flexor pollicis brevis, lies medially from the previous muscle and also directly under the skin. It starts from the retinaculum flexorum, from the ossa multangulum, trapezoideum, capitatum and the base of the first metacarpal bone. Directing distally, the muscle bundles are also attached radially: superficial (caput superficiale) - to the external sesamoid bone, and deep (caput profundum) - to both sesamoid bones of the metacarpophalangeal joint of the thumb. Action: flexes the proximal phalanx of the thumb. Innervation: superficial bundles - n. medianus (C6-C7), deep - n. ulnaris (C8 - Th1). Blood supply: r. palmaris superficialis a. radialis, arcus palmaris profundus.
3. The muscle opposing the thumb to the hand, m. opponens pollicis, has the shape of a thin triangular plate and lies under m. abductor pollicis brevis. The muscle starts from the tuberositas ossis multanguli and retinaculum flexorum, and is attached along the outer edge of the first metacarpal bone. Action: opposes the thumb to the little finger. Innervation: n. medianus (C6-C7). Blood supply: r. palmaris superficialis a. radialis, arcus palmaris profundus.
4. Muscle adductor pollicis, m. adductor pollicis, the deepest of the muscles of the eminence of the thumb. It originates in two heads, the muscle bundles of which are directed at an angle to one another: a) oblique head, caput obliquum, from lig. carpi radiatum, os capitatum and the palmar surface of the II and III metacarpal bones; b) transverse head, caput transversum. from the palmar surface of the metacarpal bone and the heads of the II and III metacarpal bones. Converging at an angle, the muscle bundles are attached to the base of the proximal phalanx of the thumb, the ulnar sesamoid bone and the capsule of the metacarpophalangeal joint. Action: adducts the thumb and takes part in the flexion of its proximal phalanx. Innervation: n. ulnaris (C,). Blood supply: arcus palmares superficialis et profundus.

Muscles of the eminence of the little finger

1. The short palmaris muscle, m. palmaris brevis, is a thin plate with parallel muscle bundles. The muscle originates from the inner edge of the palmar aponeurosis and retinaculum flexorum and is woven into the skin of the eminence of the little finger. Action: stretches the palmar aponeurosis, forming a series of folds on the skin of the eminence of the little finger. Innervation: n. ulnaris [(C7), C8, Th1. Blood supply: a. ulnaris.
2. Abductor digiti minimi muscle, m. abductor digiti minimi, occupies the most medial position of all the muscles of this group, located directly under the skin and partially under the m. palmaris brevis. The muscle originates from the os pisiforme, tendon m. flexor carpi ulnaris and retinaculum flexorum, attaching to the ulnar edge of the base of the proximal phalanx of the little finger. Action: abducts the little finger and takes part in flexing its proximal phalanx. Innervation: n. ulnaris [(C7), C8 Th1. Blood supply: g. palmaris profundus a. ulnaris.
3. Flexor digitorum brevis, m. flexor digiti minimi brevis, has the appearance of a small flattened muscle lying lateral to the previous one and covered from above by m. palmaris brevis and skin. It originates from the hamulus ossis hamati, retinaculum flexorum and, moving distally, attaches to the palmar surface of the base of the proximal phalanx of the little finger. Action: bends the proximal phalanx of the little finger and takes part in its adduction. Innervation: n. ulnaris (C7-C8). Blood supply: g. palmaris profundus a. ulnaris.
4. Muscle opposite the little finger, m. opponens digiti minimi, lies inward from the previous one and is somewhat covered by it along the outer edge. The muscle originates from the hamulus ossis hamati and retinaculum flexorum and is attached to the ulnar edge of the fifth metacarpal bone. Action: Opposes the little finger to the thumb. Innervation: n. ulnaris (C7-C8). Blood supply: g. palmaris profundus a. ulnaris.

Middle group

1. Vermiform muscles, mm. lumbricales, numbering four, look like small fusiform muscles. Each of them starts from the radial edge of the corresponding tendon m. flexor digitorum profundus and is attached to the dorsal surface of the base of the proximal phalanges from the index finger to the little finger. Here they are woven into the dorsal aponeurosis of the index, middle, ring and little fingers from the radial edge. Action: bend the proximal phalanges of four fingers and straighten the middle and distal phalanges of the same fingers. Innervation: first and second - n. medianus, third and fourth - n. ulnaris (C8 Th1).Blood supply: arcus palmaris superficialis.
2. Palmar interosseous muscles, mm. interossei palmares, are three spindle-shaped muscle bundles located in the interosseous spaces between the metacarpal bones. The first interosseous muscle lies on the radial half of the palm and, starting on the ulnar side of the second metacarpal bone, is attached to the ulnar side of the metacarpophalangeal joint of the index finger and is woven into its dorsal aponeurosis. The second and third interosseous muscles are located on the ulnar half of the palm and, starting on the radial side of the IV and V metacarpal bones, are attached to the radial side of the bags of the metacarpophalangeal joints of the ring finger and little finger. Action: bend the proximal phalanges and straighten the middle and distal phalanges of the index and ring fingers and little finger, bringing these fingers to the middle finger. Innervation: n. ulnaris (C8 Th1). Blood supply: arcus palmaris profundus.

Dorsal muscles