Download Muscles of the Upper Limb

Muscles of the Upper Limb
In general a skeletal muscle is a muscle that is attached to a bone through a tendon. Skeletal
Muscles produce body motions; stabilize body positions, store and move substances within the
body and also produce body heat. Skeletal Muscle works primarily in a voluntary matter.
Muscles of the upper limb consist of muscles that attach to the shoulder girdle, including the
arm, forearm, wrist, hand, and fingers.
Muscles that act on the shoulder
The Pectoralis Major
The Deltoid forms the rounded contour of the shoulder, it originates from three separate set of
fibers: Anterior fibers arise from the anterior border and upper surface of the lateral clavicle,
Lateral fibers arise from the acromion of scapula, Posterior fibers arise from the spine of scapula.
The Deltoid muscle inserts on the Deltoid Tuberosity of the humerus. The Different fibers are
responsible separate actions: Anterior fibers flex and medially rotate arm at shoulder joint,
Lateral fibers abduct arm at shoulder joint, Posterior fibers extend and laterally rotate the arm at
the shoulder joint. The Deltoid Muscle is supplied by the axillary nerve.
The Subscapularis Muscle is a large triangular muscle that fills the subscapular fossa of the
scapula and forms part of the posterior wall of the axilla. The Subscapularis originates from the
subscapular fossa of the scapula, and inserts on the Lesser Tubercle of the Humerus. The
Subscapularis Muscle is responsible for medially rotating the arm at the shoulder joint. The
Subscapularis is supplied by the upper and lower subscapular nerve.
The Supraspinatus Muscle is a rounded muscle named for its location. It originates from the
supraspinous fossa of the scapula, and inserts on the Greater Tubercle of the humerus. The
Supraspinatus is responsible for assisting the deltoid muscle in abducting the arm at the shoulder
joint. The Supraspinatus is supplied by the subscapular nerve.
The Infraspinatus is a triangular muscle, also named for its location. It originates from the
infraspinous fossa of the scapula, and inserts on the Greater Tubercle of the humerus. The
Infraspinatus muscles are responsible for laterally rotating the arm at the shoulder joint. It is
supplied by the subscapular nerve.
The Teres Major is a thick flattened Muscle inferior to the teres minor. It originates from the
inferior angle of the scapula and inserts on the lesser tubercle of the Humerus. The Teres Major
extends the arm at the shoulder joint and assists in adduction and medial rotation of the arm at
the shoulder joint. It is supplied by the lower subscapular nerve.
The Teres Minor is a cylindrical, elongated muscle often inseparable from the Infraspinatus. It
originates from the Inferior lateral border of the scapula and inserts onto the greater tubercle of
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Humerus. It laterally rotates and extends the arm at the shoulder joint. The Teres Minor is
supplied by the axillary nerve.
Muscles of the Arm
The Coracobrachialis is an elongated narrow muscle of the arm. It originates from the coracoids
process of the scapula, and inserts on the middle of the medial surface of shaft of the humerus.
The Coracobrachialis flexes and adducts arm at the shoulder joint. It is supplied by the
Musculotaneous nerve.
The Biceps brachii is the large muscle on the anterior surface of the arm; it has two heads, a
long head and a short head. The Long head originates from the Supraglenoid Tubercle, and the
Short head Originates from the coracoid process of the scapula. Both the Long head and short
head of the Biceps Brachii insert on the radial Tuberosity of the humerus and Bicipital
aponeurosis. The Biceps Brachii flexes the forearm at the elbow joint. It is supplied by the
Musculotaneous nerve.
The Brachialis is deep to the Biceps Brachii; it is the most powerful flexor of the forearm at the
elbow joint. It originates from the distal, anterior surface of the humerus and inserts on to the
ulnar Tuberosity and coranoid process of the ulna. The Brachialis flexes the forearm at the
shoulder joint. It is supplied by the musculocutaneous and radial nerve.
The Brachioradialis Originates from the lateral border of the distal end of the humerus, and
inserts onto the styloid process of the ulna. The Brachioradialis flexes the forearm at the elbow
joint. It is supplied by the radial nerve.
Muscles on the forearm
The Triceps brachii is the large muscle located on the posterior surface of the arm. It has three
heads, the long head, the lateral head and the medial head. The long head originates from the
infraglenoid tubercle, the lateral head originates from the lateral and posterior surface of the
humerus superior to the radial groove, the Medial head originates from the posterior surface of
the humerus inferior to the radial groove. All the heads inserts on the olecranon of the Ulna. The
Triceps Brachii extends the forearm at the elbow joint, and also extends the arm at the shoulder
joint. It is supplied by the radial nerve.
The Aconeus is a small muscle on the posterior aspect of the elbow joint. It originates from the
lateral epicondyle of the humerus, and inserts on the olecranon and superior portion of the shaft
of the ulna. The Aconeus extends the forearm at the elbow joint and is supplied by the radial
nerve.
The Pronator teres originates from the medial epicondyle of the humerus and coranoid process
of the ulna, and inserts onto the midlateral surface of the radius. The Pronator Teres pronates the
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forearm at the radioulnar joint, and flexes the forearm at the elbow joint. It is supplied the medial
Nerve.
The Pronator quadratus is a square shaped muscle on the distal forearm. It originates from the
distal portion of the shaft of the ulna and inserts onto the distal portion of the shaft of the radius.
The Pronator Quadratus pronates the forearm at the radioulnar joints. It is supplied by the median
Nerve.
The Supinator is a broad muscle, curved around the upper third of the radius. It originates from
the lateral epicondyle of the humerus, and near the radial notch of the ulna, it inserts onto the
lateral surface of the proximal one-third of the radius. The Supinator supinates the forearm at the
radioulnar joints. It is supplied by the deep radial nerve.
The Flexor carpi radialis originates on the medial epicondyle of the humerus, it inserts on the
second metacarpal, and the third metacarpal. The Flexor Carpi Radialis acts to flex and abduct
the hand. It is supplied by the Median nerve.
The Palmaris Longus is seen as a small tendon between the flexor carpi radialis and the flexor
carpi ulnaris. It originates from the Medial epicondyle of the humerus and inserts onto the upper
part of the flexor retinaculum, and the palmar aponeurosis. The Palmaris longus weakly flexes
the hand at the wrist joint. It is supplied by the Median nerve.
The Flexor Carpi Ulnaris originates from the Medial epicondyle of the humerus and the
superior posterior border of the ulna, it inserts onto the Pisiform, Hamate, and the base of the
fifth metacarpal. This muscle extends and adducts the hand at the wrist joint. It is supplied by the
deep radial nerve.
The Flexor digitorum superficialis is an extrinsic flexor muscle of the fingers at the proximal
interphalangeal joints. It originates from the Medial epicondyle of the humerus, the coranoid
process of the ulna, and a ridge along the lateral margin of the anterior surface of the radius. It
inserts onto the middle phalanx of each finger. The Flexor digitorum superficialis flexes the
middle phalanges of the fingers at the proximal interphalangeal joints, and it also flexes the
metacarpophalangeal joints and wrist joint. This muscle is supplied by the Median nerve.
The Flexor pollicis longus arises from the grooved anterior surface of the body of the radius and
the interosseous membrane. It inserts onto the base of the distal phalanx of the thumb. The
Flexor pollicis longus flexes the distal phalanx of the thumb at the interphalangeal joint. It is
supplied by the Median nerve.
The Flexor digitorum profundus originates from the upper 3/4 of anterior & medial surfaces of
ulna, and inserts onto the inserts onto the base of the distal phalanx of the thumb. The Flexor
digitorum profundus flexes the distal and middle phalanges of each finger at the interphalangeal
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joints, the proximal phalanx of each finger at the metocarpophalangeal joint, and the hand at the
wrist joint. It is supplied by the Median nerve. It is supplied by the Radial nerve.
The Extensor carpi radialis longus is one of the five main muscles that control movements at
the wrist. It originates from the lateral supercondylar ridge of the humerus and inserts onto the
second metacarpal. The Extensor carpi radialis longus extends and abducts the hand at the wrist
joint. It is supplied by the radial nerve.
The Extensor carpi radialis brevis originates from the lateral epicondyle of the humerus and
inserts onto the third metacarpal. This muscle and extends and abducts the hand at the wrist joint.
The flexor carpi radialis brevis is supplied by the radial nerve.
The Extensor digitorum is a muscle of the posterior forearm present in humans and other
animals. It extends the medial four digits of the hand. It originates from the lateral epicondyle of
the humerus and inserts onto the distal and middle phalanges of each finger. The Extensor
digitorum extends the distal and middle phalanges of each finger at the interphalangeal joints,
proximal phalanx of finger at the metocarpophalangeal joint.
The Extensor Digiti Minimi originates from the lateral epicondyle of the humerus and inserts
onto the tendon of the extensor digitorum on the phalanx. The Extensor digiti minimi extends the
proximal phalanx of little finger at the metocarpophalangeal joint and the hand at the wrist joint.
It is supplied by the deep radial nerve.
The Extensor carpi ulnaris originates from the lateral epicondyle of the humerus and posterior
border of the ulna, it inserts onto the fifth metacarpal. The Extensor carpi ulnaris extends and
adducts the hand at the wrist joint. It is supplied by the deep radial nerve.
The Abductor pollicis longus originates from the posterior surface of the middle of the radius
and, ulna , and the interosseous membrane, it inserts onto the first metacarpal. The Abductor
pollicis abducts the thumb at the carpometacarpal joint, thereby moving the thumb anteriorly.
The Extensor pollicis brevis originates from the dorsal surface of the body of the radius below
that muscle, and from the interosseous membrane and inserts onto the base of the first phalanx
of the thumb. The Extensor pollicis brevis extends the proximal phalanx of the thumb. It is
supplied by the Radial nerve.
The Extensor pollicis longus originates from the lateral part of the middle third of the posterior
surface of the body of the ulna below the origin of the Abductor pollicis longus, and from the
interosseous membrane. It inserts onto the base of the distal phalanx of the thumb. The Extensor
pollicis longus Extensor pollicis longus extends the terminal phalanx of the thumb; in
combination with the Extensor pollicis brevis, it helps to extend and abduct the wrist. It is
supplied by the deep radial nerve.
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The Extensor indicis originates from the posterior surface of the body of the ulna and inserts
onto the tendon of the extensor digitorum of the index finger. This muscles The Extensor indicis
extends the index finger, and by its continued action assists in extending the wrist. It is supplied
by the deep radial nerve.
Muscles of the hand
The muscles of the hand are divided into three groups: Thenar (lateral aspect of the palm),
Hypothenar(medial aspect of the palm),Intermediate(midpalmar).
THENAR:
The Abductor pollicis brevis is a flat, thin muscle located just under the skin. It originates from the
flexor retinaculum of the hand, the tubercle of the scaphoid bone, and the tubercle of the trapezium and
inserts onto the lateral side of the proximal thumb. The Abductor pollicis brevis abducts the thumb at the
carpometacarpal joint; it is supplied by the Medan nerve.
The Opponens pollicis is a small, triangular muscle in the hand, which functions to oppose the
thumb. It is one of the three Thenar muscles, lying deep to the abductor pollicis brevis and lateral
to the flexor pollicis brevis. It originates from the flexor retinaculum of the hand and the tubercle
of the trapezium and is inserted on the lateral side of the first metacarpal. The Opponens pollicis
flexes the thumb's metacarpal at the first carpometacarpal joint, which aids in opposition of the
thumb. It is supplied by the Median nerve.
The Flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar
muscles. It originates from the Flexor retinaculum, trapezium, and trapezoid and inserts onto the
lateral side of the proximal phalanx of the thumb. The Flexor pollicis brevis flexes the thumb at
the first metacarpophalangeal joint It is supplied by the Median and ulnar nerves.
The Adductor pollicis is a muscle in the hand that functions to adduct the thumb. It has two
heads: oblique and transverse. The oblique head originates from several slips from the capitate
bone, the bases of the second and third metacarpals, the intercarpal ligaments, and the sheath of
the tendon of the flexor carpi radialis, the Transverse head originates from the lower two-thirds
of the palmar surface of the third metacarpal bone. Both heads have the same insertion onto the
medial part of the base of the proximal phalanx of the thumb. The adductor pollicis adducts the
thumb at the carpometacarpal joint. It is supplied by the ulnar nerve.
HYPOTHENAR (medial aspect of the palm):
The Abductor digiti minimi muscle originates from the Pisiform and the tendon of the flexor
carpi ulnaris, and inserts onto the medial side of the proximal phalanx of the little finger. This
muscle abducts and flexes the little finger at the metacarpophalangeal joint. It is supplied by the
ulnar nerve.
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The Flexor digiti minimi brevis muscle originates from the hamate bone, and the palmar
surface of the flexor retinaculum of the hand, and is inserted onto the ulnar side of the base of the
first phalanx of the little finger. The flexor digiti minimi flexes the little finger. It is supplied by
the ulnar nerve.
The Opponens digiti minimi muscle originates from the flexor retinaculum and the hamate
bone and inserts onto the medial side of the fifth metacarpal. This muscle draws the 5th
metacarpal anteriorly and rotates it, bringing little finger into opposition with thumb. It is
supplied by the ulnar nerve.
INTERMEDIATE (midpalmar):
The lumbrical muscles are intrinsic muscles in the fingers that allow flexion at
the metacarpophalangeal joints, while maintaining extension at the interphalangeal joints. There
are four of these small, worm-like muscles on each hand. These muscles are unusual in that they
do not attach to bone. Instead they attach proximally to the tendons of flexor digitorum
profundus. This muscle originates from the lateral sides of the tendon and flexor digitorum
profundus of each finger and inserts onto the lateral sides of the tendon of the extensor digitorum
on the proximal phalanges of each finger. It is supplied by the Median and ulnar nerve.
The Palmar interossei are small muscles in the hand that lie on the anterior aspect of
the metacarpals. They are smaller than the dorsal interossei of the hand, which lie between the
metacarpals. There are three palmar interossei muscles they all originate from the sides of the
shafts of the metacarpals of all digits(except the middle one) and insert onto the sides of the
bases of the proximal phalanges of all digits (except the middle one). The palmar interosseous
muscles adduct the fingers towards the middle finger. It is supplied by the ulnar nerve.
The Dorsal interossei are muscles that occupy the space between the metacarpals. It originates
from the adjacent sides of the metacarpals and inserts on to the proximal phalanx of each finger.
The dorsal interossei abducts fingers 2-4 at the metacarpophalangeal joints; flexes fingers 2-4 at
the metacarpophalangeal joints; and extend each finger at the interphalangeal joints. It is
supplied by the ulnar nerve.
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Muscles of the Upper Limb
Works Cited
Gerard J.Tortora, M. T. (2009). Principles of Human Anatomy. Danvers, MA: John Wiley & Sons, Inc.
Musculoskeletal Radiology. (2007). Retrieved November 7, 2009, from Department of radiology,
University of washington: http://www.rad.washington.edu/academics/academic-sections/msk
Wikipedia. (2001, January 10). Retrieved November 6, 2009, from Wikipedia: the free encyclopedia:
http://en.wikipedia.org/wiki/Category:Muscles_of_the_upper_limb
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