Human Anatomy upper limb

1. Shoulder Region
Dr. Lijalem Kassa (RN,BSc, MD)

2. Shoulder
• Shoulder is the region of upper limb attachment
to the trunk and neck.
• The bone framework of the shoulder consists of:
– pectoral girdle—clavicle and scapula
– proximal end of the humerus.

3. Shoulder
• Trapezius and deltoid muscles
– Together form the smooth muscular contour over
the lateral part of the shoulder.
– They connect scapula and clavicle to the trunk and
to the arm, respectively.

4. Bones
Clavicle
• the only bony attachment between trunk and
upper limb.
• It is palpable along its entire length
• has a gentle S-shaped contour, with forward-
facing:
– medial convex part
– Lateral concave part

6. • It has two ends:
– acromial end:
• Flat
• has a facet for articulation with acromion of scapula.
– sternal end
• robust and somewhat quadrangular in shape
• has a facet for articulation with manubrium and first
costal cartilage.

7. • inferior surface of the lateral third of clavicle possesses:
– conoid tubercle—a distinct tuberosity consisting of a
tubercle
– trapezoid line—lateral roughening for attachment
coracoclavicular ligament.
• The superior surface is smoother than the inferior
surface.

8. Scapula
• a large, flat triangular bone with:
– three angles (lateral, superior, and inferior)
– three borders (superior, lateral, and medial)
– two surfaces (costal and posterior)
– three processes (acromion, spine, and coracoid
process)

10. • Glenoid cavity:
– a shallow, somewhat comma-shaped cavity
– It is on the lateral angle of the scapula
– articulates with the head of the humerus to form
the glenohumeral joint

11. • Infraglenoid tubercle:
– A large triangular-shaped roughening inferior to
the glenoid cavity
– It is the site of attachment for the long head of the
triceps brachii muscle.

12. • Supraglenoid tubercle:
– is located superior to the glenoid cavity
– site of attachment for the long head of biceps brachii
• Spine subdivides posterior surface into:
– supraspinous fossa
– infraspinous fossa

13. • The acromion
– Is an anterolateral projection of the spine
– Arches over the glenohumeral joint
– Articulates with the clavicle.

14. • Spinoglenoid notch/greater scapular notch:
– region between the lateral angle of the scapula and the
attachment of the spine
• costal surface
– is characterized by a shallow concave subscapular fossa
over much of its extent
– provide for muscle attachment with its margin
– It move freely over the underlying thoracic wall together
with its related muscle (subscapularis)

15. • Coracoid process
– a hook-like structure on the superior border
– is positioned directly inferior to the lateral part of the
clavicle
– projects anterolaterally
• suprascapular notch—lies immediately medial to
the root of the coracoid process.

16. Proximal Humerus
• It consists of head, anatomical neck, greater and lesser
tubercles, surgical neck, and superior half of shaft of
humerus.
• The head:
– is half-spherical in shape
– projects medially and somewhat superiorly
– articulate with the much smaller glenoid cavity of the
scapula.

18. • Anatomical neck:
– is a narrow constriction immediately distal to the
head.
– It lies between:
• head and greater and lesser tubercles laterally
• head and shaft medially

19. • Greater and lesser tubercles
– serve as attachment sites for the four rotator cuff muscles
• Greater tubercle:
– is lateral in position.
– marked by three large smooth facets:
• superior facet
• middle facet
• inferior facet

20. • Lesser tubercle:
– anterior in position
– Site for attachment of the subscapularis muscle
• Intertubercular sulcus (bicipital groove)
– separates the lesser and greater tubercles
– Has lateral and medial lips and floor

21. • Deltoid tuberosity:
– a large V-shaped tuberosity on the lateral surface
of the humerus
– It continuous with lateral lip of the intertubercular
sulcus
– Site for deltoid muscle insertion

22. • Surgical neck
– It is oriented in the horizontal plane between head,
anatomical neck, and tubercles proximally and shaft,
distally.
– Common site of fracture of humerus due to its weakness
– Axillary nerve and the posterior circumflex humeral artery,
passes immediately posterior to it.
• They can be damaged by fractures in this region

23. Joints
• Joints in shoulder complex are sternoclavicular,
acromioclavicular and glenohumeral joints.
• sternoclavicular and acromioclavicular joints:
– link the two bones of the pectoral girdle to each other
and to trunk.
– combined movements on them enable scapula to be
positioned over a wide range on the thoracic wall
• substantially increasing 'reach' by the upper limb.

24. • Sternoclavicular joint
– Occurs between clavicle and manubrium together
with first costal cartilage
– It is synovial and saddle-shaped.
– allows movement of the clavicle, in the
anteroposterior and vertical planes, and some
rotation also occurs.

26. • Acromioclavicular joint
– synovial joint
– between a facet on the acromion and a facet on
the acromial end of the clavicle
– allows movement in anteroposterior and vertical
planes together with some axial rotation

28. • The acromioclavicular joint
• is reinforced by:
– acromioclavicular ligament
– Coracoclavicular ligament
• It is not directly related to the joint
• it spans the distance between coracoid process and
inferior surface of the acromial end of the clavicle

29. • Coracoclavicular ligament
– it comprises an anterior trapezoid ligament and a
posterior conoid ligament
– Important ligament because it:
• Provides much of the weight bearing support for the
upper limb on the clavicle
• maintains the position of the clavicle on the acromion

30. • Glenohumeral joint
– a synovial ball and socket articulation
– It is between the head of the humerus and the
glenoid cavity of the scapula
– It is multiaxial with a wide range of movements
provided at the cost of skeletal stability.

32. • Articular surfaces:
– are large spherical head of the humerus and the
small glenoid cavity of the scapula
– Each of the surfaces is covered by hyaline cartilage

33. • The synovial membrane
– loose inferiorly—enables accommodation of abduction of arm.
– protrudes through apertures in fibrous membrane—form bursae
– folds around the tendon of the long head of the biceps brachii
muscle
– extends along the tendon as it passes into the intertubercular
sulcus.
• All these synovial structures reduce friction between the tendons
and adjacent joint capsule and bone.

34. • Joint stability is provided by:
– rotator cuff muscles
– long head of the biceps brachii muscle
– related bony processes
– extracapsular ligaments

35. • Rotator cuff muscles
– Inludes:
• Supraspinatus
• Infraspinatus
• teres minor
• subscapularis muscles

37. • Rotator cuff muscles
– stabilizes and holds the joint without compromising
arm's flexibility and range of motion.
– Their tendons form a musculotendinous collar that
surrounds posterior, superior, and anterior aspects of
the joint

38. • Tendon of the long head of biceps brachii:
– passes superiorly through the joint
– restricts upward movement of the humeral head on
the glenoid cavity.
• skeletal arch formed superiorly by the coracoid
process and acromion and the coraco-acromial
ligament also stabilizes the joint

39. • Vascular supply
– anterior circumflex humeral artery
– posterior circumflex humeral artery
– suprascapular artery
• Innervated by:
– Suprascapular nerve
– Axillary nerve
– lateral pectoral nerve

40. Muscles
• The two most superficial muscles of the shoulder are
the trapezius and deltoid muscles
• Together, they provide the characteristic contour of
the shoulder:

42. • Deep to trapezius scapula is attached to
vertebral column by three muscles:
– Levator scapulae
– Rhomboid minor
– Rhomboid major

43. • Trapezius
– Origin: Superior nuchal line up to spinous process of
TXII
– Insertion: spine of the scapula, acromion, and lateral
one-third of clavicle
– Nn: Motor spinal part of accessory nerve (CN XI).

44. • Trapezius
– Action:
• Powerful elevator of the scapula
• abduction of humerus above horizontal
• middle fibers retract scapula
• lower fibers depress scapula

45. • Deltoid
– Origin: spine of the scapula, acromion and lateral
one-third of clavicle
– Insertion: Deltoid tuberosity
– Nn: Axillary nerve

46. • Deltoid
– Action:
• Major abductor of arm (abducts arm beyond initial 15°
done by supraspinatus)
• clavicular fibers assist in flexing the arm
• posterior fibers assist in extending the arm

47. • Levator scapulae
– Origin: Transverse processes of CI to CIV vertebrae
– Insertion: medial border of scapula
– Nn:
• Branches directly from anterior rami of C3 and C4 spinal
nerves
• dorsal scapular nerve
– Action: Elevates the scapula

48. • Rhomboid minor
– Origin: Spinous processes of CVII and TI vertebrae
– Insertion: root of the spine of the scapula
– Nn: Dorsal scapular nerve
– Action: Elevates and retracts the scapula

49. • Rhomboid major
– Origin: Spinous processes of TII-TV vertebrae
– Insertion: medial border of scapula
– Nn: Dorsal scapular nerve
– Action: Elevates and retracts the scapula

50. POSTERIOR SCAPULAR REGION
Muscles
• Supraspinatus
– Origin: supra-spinous fossa of the scapula
– Insertion: superior facet of the greater tubercle of
the humerus
– Nn: Suprascapular nerve
– Function:
• Rotator cuff muscle
• initiation of abduction of arm up to 15°

52. • Infraspinatus
– Origin: infra-spinous fossa of the scapula
– Insertion: Middle facet of the greater tubercle of
the humerus
– Nn: Suprascapular nerve
– Function:
• Rotator cuff muscle
• lateral rotation of arm at the glenohumeral joint

53. • Teres minor
– Origin: posterior surface of the scapula
– Insertion: Inferior facet of the greater tubercle of
the humerus
– Nn: Axillary nerve
– Action:
• Rotator cuff muscle
• lateral rotation of arm at the glenohumeral joint

54. • Teres major
– Origin: inferior angle of the scapula
– Insertion: Medial lip of the intertubercular sulcus
– Nn: Inferior subscapular nerve
– Action: Medial rotation and extension of the arm
at the glenohumeral joint

55. • Long head of triceps brachii
– Origin: Infraglenoid tubercle on scapula
– Insertion: olecranon process of ulna
– Nn: Radial nerve
– Action:
• Extension of the forearm at the elbow joint
• accessory adductor and extensor of the arm at the
glenohumeral joint

56. Gateways to the Posterior Scapular Region
• Suprascapular foramen
– is the route through which structures pass
between the base of the neck and the posterior
scapular region
– It is formed by:
• suprascapular notch of the scapula
• suprascapular ligament—converts the notch into a
foramen.

58. • Suprascapular foramen
– Contents:
• suprascapular nerve
• suprascapular artery and the suprascapular vein (above
the ligament)

59. • Quadrangular space
– Provides communication between axilla and
posterior scapular region
– boundaries are formed by:
• teres minor, superiorly
• surgical neck of the humerus, laterally

60. • Quadrangular space
– Boundaries:
• teres major, inferiorly
• long head of triceps brachii, medially
– Contents:
• axillary nerve
• posterior circumflex humeral artery and vein

61. • Triangular space
– Communicates axilla with posterior scapular
region
– Boundaries:
• long head of triceps brachii, laterally
• teres major, inferiorly
• teres minor, superiorly
– Content: circumflex scapular artery and vein

62. • Triangular interval
–Boundaries:
• long head of triceps brachii, medially
• shaft of the humerus, laterally
• teres major, inferiorly

63. • Triangular interval
– serves as a passageway between:
• anterior and posterior compartments of the arm
• posterior compartment of the arm and the axilla
– Contents:
• radial nerve
• profunda brachii artery and vein

64. Nerves
• Suprascapular nerve
– originates in the base of the neck from the superior
trunk of the brachial plexus.
– Through suprascapular foramen it reaches the
posterior scapular region
– lies in the plane between bone and muscle in
posterior scapular region

65. • Suprascapular nerve
– Enters the infraspinous fossa through the
spinoglenoid notch
– innervates
• supraspinatus muscle
• infraspinatus muscle.
– It has no cutaneous branches

66. • Axillary nerve
– originates from the posterior cord of the brachial
plexus.
– Through the quadrangular space it enters the
posterior scapular region
– it is directly related to the posterior surface of the
surgical neck of the humerus.

67. • Axillary nerve
–Innervates:
• deltoid and teres minor muscles.
• Its branch, superior lateral cutaneous nerve of
the arm—skin over the inferior part of the
deltoid muscle

68. Arteries and veins
• Arteries
– Three major arteries are found in this region:
• Suprascapular artery
• posterior circumflex humeral artery
• circumflex scapular artery
– These arteries contribute to the anastomosis
around the scapula

70. • Suprascapular artery
– originates as a branch of thyrocervical trunk/
directly from 3rd part of the subclavian artery.
– enters the posterior scapular region superior to
the suprascapular foramen

71. • Posterior circumflex humeral artery
– originates from the third part of the axillary artery in
the axilla
– enter the posterior scapular region through the
quadrangular space
– supplies the related muscles and the glenohumeral
joint.

72. • Circumflex scapular artery
– It is a branch of the subscapular artery that
– enters the posterior scapular region through the
triangular space

73. • Veins
– generally follow the arteries
– And connect with vessels in the neck, back, arm,
and axilla.

74. Pectoral Region
• It is external to the anterior thoracic wall
• and anchors the upper limb to the trunk.
• It consists of:
– a superficial compartment containing skin, superficial
fascia, and breasts; and
– a deep compartment containing muscles and
associated structures

76. Muscles of the pectoral region
• Pectoralis major
– Origin: Medial half of clavicle, sternum, first seven costal
cartilages, aponeurosis of external oblique
– Insertion: lateral lip of intertubercular groove
– nn: Medial and lateral pectoral nerves
– Action: Adduction, medial rotation, and flexion of the
humerus at the shoulder joint

77. • Pectoralis minor
– Origin: 3rd-5th ribs and related intercostal spaces
– Insertion: Coracoid process of scapula
– Nn: Medial pectoral nerves
– Action:
• Depresses tip of shoulder
• protracts scapula

78. • Subclavius
– Origin: Rib I
– Insertion: middle third of clavicle
– Nn: Nerve to sub-clavius
– Action: Pulls clavicle medially to stabilize
sternoclavicular joint

79. Arm
79

80. Arm
• It is the region of the upper limb between the
shoulder and the elbow
• Divided into two compartments by medial and
lateral intermuscular septa:
– Anterior compartment
– Posterior compartment
80

81. Bones
Humerus
• In cross-section, the shaft is triangular with:
– anterior, lateral, and medial borders
– anterolateral, anteromedial, and posterior
surfaces
81

83. Bones
Humerus
• Radial groove
– On the posterior surface and adjacent part of the
anterolateral surface
– passes diagonally down the bone
– radial nerve and the profunda brachii artery lie in
this groove.
83

84. Bones
Humerus
• Lateral and medial supraepicondylar ridges
– Expanded distal part of the humerus
84

85. Bones
Humerus
• The condyle
– Capitulum
• articulates with the radius
• Lateral in position
– Trochlea
• articulates with the ulna of the forearm
• lies medial to the capitulum.
85

86. 86

87. Bones
Humerus
• Two epicondyles
– medial epicondyle
• a large bony protuberance
• is the major palpable landmark
• projects medially from the distal end of the humerus.
– lateral epicondyle is
• It is lateral to the capitulum
87

88. Bones
Humerus
• Radial fossa
– occurs immediately superior to the capitulum
– on the anterior surface of the humerus
• Coronoid fossa
– superior to the trochlea.
– adjacent to the radial fossa
88

89. Bones
Humerus
• Olecranon fossa
– occurs immediately superior to the trochlea
– on the posterior surface of the humerus
89

90. Proximal end of the radius
• Consists of
– a head
– a neck
– radial tuberosity
90

91. Proximal End of Ulna
• much larger than the proximal end of the radius
• consists of:
– Olecranon process
– coronoid process
– trochlear notch
– radial notch
– tuberosity of ulna
91

92. 92

93. Muscles
Anterior Compartment
• Coracobrachialis
– Origin: coracoid process
– Insertion: mid-shaft of humerus
– Innervation: Musculocutaneous nerve
– Action: Flexes the arm at the gleno-humeral joint
93

94. Muscles
Anterior Compartment
• Biceps brachii
– Origin:
• Long head-supraglenoid
• short head-coracoid process
– Insertion: Radial tuberosity
– Innervation: Musculocutaneous nerve
94

95. 95

96. Muscles
Anterior Compartment
• Biceps brachii
– Action:
• Powerful flexor of the forearm at the elbow joint
• supinator of the forearm
• accessory flexor of the arm at the glenohumeral
joint
96

97. Muscles
Anterior Compartment
• Brachialis
– Origin: Anterior aspect of humerus
– Insertion: Tuberosity of the ulna
97

98. Muscles
Anterior Compartment
• Brachialis
– Innervation:
• Musculocutaneous nerve
• small contribution by the radial nerve
– Action: Powerful flexor of the forearm at the
elbow joint
98

99. Muscle
Posterior Compartment
• Triceps brachii
– Origin:
• Long head-infraglenoid tubercle
• lateral and medial heads-posterior suface of humerus
– Insertion: Olecranon
99

100. 100

101. Muscle
Posterior Compartment
• Triceps brachii
– Innervation: Radial nerve
– Function:
• Extension of the forearm at the elbow joint.
• Long head can also extend and adduct the arm at the
shoulder joint
101

102. 102

103. Arteries
Brachial Artery
• It is the major artery of the arm
• found in the anterior compartment
• Begins as a continuation of the axillary artery at
the lower border of the teres major muscle
• terminates just distal to the elbow joint by
dividing into the radial and ulnar arteries.
103

104. 104

105. Arteries
Brachial Artery
• In the proximal arm, the brachial artery lies on
the medial side.
• In the distal arm, it moves laterally
• And assume a position midway between the
lateral epicondyle and the medial epicondyle
• The brachial artery is palpable along its length.
105

106. Arteries
Brachial Artery
• Branches in the arm include:
– to adjacent muscles
– two ulnar collateral vessels
– profunda brachii artery
– nutrient arteries to the humerus
106

107. Arteries
Brachial Artery
• Profunda brachii artery
– the largest branch of the brachial artery
– passes into and supplies the posterior
compartment of the arm
– With the radial nerve they pass through the
triangular interval
– They then pass along the radial
107

108. Veins
• Brachial veins
– Paired and they pass along the medial and lateral
sides of the brachial artery
– receive tributaries that accompany branches of
the artery
– join the basilic, or axillary, vein.
108

109. 109

110. Veins
• Basilic vein
– passes vertically in the distal half of the arm
– penetrates deep fascia to assume a position
medial to the brachial artery,
– then becomes the axillary vein at the lower border
of the teres major muscle.
110

111. Veins
• Cephalic vein
– passes superiorly on the anterolateral aspect of
the arm
– Then through the anterior wall of the axilla to
reach the axillary vein.
111

112. Nerves
• Musculocutaneous nerve
– enters the arm by passing through the
coracobrachialis muscle
– continues as the lateral cutaneous nerve of
forearm.
112

113. 113

114. Nerves
• Musculocutaneous nerve
– It provides:
• motor innervation to all muscles in the anterior
compartment of the arm
• sensory innervation to skin on the lateral surface of the
forearm
114

115. Nerves
• Median nerve
– It is related to the brachial artery throughout its course:
– in proximal regions, it is immediately lateral to the brachial
artery
– In distal regions, it crosses to the medial side of the
brachial artery and lies anterior to the elbow joint.
– has no branches to the arm
115

116. Nerves
• Ulnar nerve
– enters the arm with the median nerve and axillary artery
– It passes through proximal regions medial to the axillary
artery.
– It passes posterior to the medial epicondyle
– and then into the anterior compartment of the forearm.
– It has no major branches in the arm.
116

117. Nerves
• Radial nerve
– originates from the posterior cord of the brachial
plexus
– it lies posterior to the brachial artery.
– Accompanied by the profunda brachii artery,
– enters the posterior compartment of the arm by
passing through the triangular interval.
117

118. 118

119. Nerves
Radial nerve
• In the arm, the radial nerve has muscular and cutaneous
branches
• Muscular branches include those to:
– triceps brachii
– Brachioradialis
– extensor carpi radialis longus
– lateral part of the brachialis
119

120. Nerves
Radial nerve
• Branch to the medial head of the triceps brachii
arises in the axilla
• Cutaneous branches that originate in the
posterior compartment of the arm are:
– inferior lateral cutaneous nerve of arm
– posterior cutaneous nerve of forearm
120

121. Elbow Joint
• Involves three separate articulations:
– between trochlear notch of the ulna and the trochlea
– between head of the radius and the capitulum
– between head of the radius and the radial notch of
the ulna
• proximal radio-ulnar joint
121

122. 122

123. Elbow Joint
• It is hinge type joint allowing felxion and
extention of forearm
• But, it also pronates and supinates forearm at
superior radio-ulnar joint
123

124. Elbow Joint
• Vascular supply
– through an anastomotic network of vessels
derived from branches of:
• Brachial
• profunda brachii
• Radial
• ulnar
124

125. Elbow Joint
• Innervation is predominantly by radial and
musculocutaneous nerves
125

126. Cubital Fossa
• is an important area of transition between the
arm and the forearm.
• is a triangular depression formed between
two forearm muscles:
– brachioradialis
– pronator teres
126

127. Cubital Fossa
• base is an imaginary horizontal line between the two
epicondyles.
• floor of is formed mainly by the brachialis muscle.
127

128. 128

129. Cubital Fossa
• contents from lateral to medial are:
– tendon of the biceps brachii muscle;
– brachial artery;
– median nerve
129

130. 130

131. Forearm
131

132. Forearm
• part of the upper limb that extends between the
elbow joint and the wrist joint.
• most structures pass between the arm and
forearm through/in relation to cubital fossa
except ulnar nerve
• structures pass between the forearm and the
hand through, or anterior to, the carpal tunnel
132

133. • The bony framework consists of radius and the ulna
• The radius
– lateral in position
– small proximally and large distally
• The ulna
– medial in the forearm
– large proximally and small distally.
133

134. • Superior and inferior radio-ulnar joints
– allow the distal end of the radius to swing over the
adjacent end of the ulna
• resulting in pronation and supination of the hand.
134

135. • Forearm is divided into anterior and posterior
compartments, separated by:
– a lateral intermuscular septum
• passes from the anterior border of the radius to deep fascia
surrounding the limb,
– an interosseous membrane
• links adjacent borders of the radius and ulna
– deep fascia along the posterior border of the ulna.
135

136. • Muscles in the anterior compartment:
– flex the wrist and digits
– pronate the hand.
• Muscles in the posterior compartment
– extend the wrist and digits
– supinate the hand.
136

137. Bones
• The shaft of the radius
– narrow proximally, where it is continuous with the
radial tuberosity and neck
– much broader distally
– triangular in cross-section, with:
• three borders (anterior, posterior, and interosseous);
• three surfaces (anterior, posterior, and lateral).
137

138. 138

139. • Styloid process
– diamond shaped distal end of the lateral surface
of the radius
139

140. • The shaft of the ulna
– broad superiorly and narrow distally to form a
small distal head
– triangular in cross-section and has:
• three borders (anterior, posterior, and interosseous);
• three surfaces (anterior, posterior, and medial).
140

141. 141

142. • The distal end of the ulna
– characterized by a rounded head and the ulnar
styloid process
142

143. Joints
• Distal radio-ulnar joint
– occurs between head of the ulna and the ulnar
notch on the end of the radius
– It is synovial joint
– Allows the distal end of the radius to move
anteromedially—pronation of the hand
143

144. Muscles
Anterior Compartment
• Are in three layers:
– Superficial layer
– Intermediate layer
– Deep layer
144

145. Muscles
Anterior Compartment
• Supeficial layer includes:
flexor carpi ulnaris
palmaris longus
flexor carpi radialis
pronator teres
145

146. Muscles
Anterior Compartment
• Intermediate layer include:
– Flexor digitorum superficialis
• Deep layer:
– flexor digitorum profundus
– flexor pollicis longus
– pronator quadratus
146

147. Muscles
Anterior Compartment
• All of them are innervated by the median
nerve, except:
– flexor carpi ulnaris
– medial half of flexor digitorum profundus
• They are innervated by the ulnar nerve.
147

148. • Superficial layer
– All four muscles have a common origin from the
medial epicondyle of the humerus
– Except pronator teres, all of them extend distally
into the hand
148

149. 149

150. Intermediate layer
• Flexor digitorum superficialis
– has two heads:
• humero-ulnar head
– medial epicondyle of the humerus
– coronoid process of the ulna
– radial head
• anterior oblique line of the radius.
150

151. 151

152. Intermediate layer
• Flexor digitorum superficialis
– median nerve and ulnar artery pass deep to it
between the two heads.
152

153. Deep layer
• Flexor digitorum profundus
– Origin; anterior and medial sides of the ulna
– It gives rise to four tendons, which insert into the
four medial fingers.
– Innervation;
• lateral half—anterior interosseous
• the medial half—ulnar nerve
153

154. 154

155. Deep layer
• Flexor digitorum profundus
– It flexes the metacarpophalangeal and
interphalangeal joints of medial four digits and
wrist joint
155

156. Deep layer
• Flexor pollicis longus
– origin; anterior surface of radius
– Insertion; Palmar surface of base of distal phalanx of
thumb
– Innervation; Median nerve (anterior interosseous nerve)
– Action; flexes interphalangeal joint of the thumb; can also
flex metacarpo-phalangeal joint of the thumb
156

157. Deep layer
• Pronator quadratus
– Origin; Linear ridge on distal anterior surface of ulna
– Insertion; Distal anterior surface of radius
– Innervation; Median nerve (anterior interosseous
nerve)
– Action; Pronation
157

158. Arteries
• The largest arteries in the forearm are in the
anterior compartment
• pass distally to supply the hand, and give rise
to vessels that supply the posterior
compartment
158

159. 159

160. • Brachial artery
– enters the forearm by passing through the cubital
fossa.
– At the apex of the cubital fossa, it divides into its
two major branches
• radial artery
• ulnar artery
160

161. • Radial artery
– Originates from the brachial artery at the neck of
the radius
– Passes along the lateral aspect of the forearm
– It is just deep to the brachioradialis muscle in the
proximal half of the forearm
161

162. Radial artery
• Related to the superficial branch of the radial
nerve in the middle third of the forearm
– medial to the tendon of the brachioradialis muscle
162

163. Radial artery
• In the distal forearm, it lies:
– immediately lateral to the large tendon of the
flexor carpi radialis muscle
• It can be located using the flexor carpi radialis muscle
as a landmark.
163

164. • Radial artery
– leaves the forearm, passes around the lateral side
of the wrist
– penetrates the dorsolateral aspect of the hand
between the bases of metacarpals I and II
164

165. • Branches of the radial artery originating in the
forearm include:
– a radial recurrent artery
– a small palmar carpal branch
– superficial palmar branch
165

166. • Superficial palmar branch of radial artery
– somewhat larger branch
– enters the hand by passing through, the thenar
muscles at the base of the thumb
– anastomoses with the superficial palmar arch
formed by the ulnar artery.
166

167. Ulnar artery
• It is larger than the radial artery
• passes down the medial side of the forearm
• leaves the cubital fossa by passing deep to
pronator teres muscle
• then passes in the fascial plane between flexor
carpi ulnaris and flexor digitorum profundus
muscles.
167

168. Ulnar artery
• In the distal forearm
– Remains tucked under the anterolateral lip of the
flexor carpi ulnaris tendon—not easily palpable.
– the ulnar nerve is immediately medial to it .
168

169. • Ulnar artery
– Enters the hand by passing lateral to the pisiform
bone and superficial to the flexor retinaculum
– It is often the major blood supply to the medial
three and one-half digits.
169

170. • Branches of the ulnar artery that arise in the
forearm include:
– ulnar recurrent artery
– common interosseous artery
– dorsal carpal branch
– palmar carpal branch
170

171. • Branches of the ulnar artery
– Ulnar recurrent artery
• It has anterior and posterior branches
• contribute to an anastomotic network around the
elbow joint
– common interosseous artery
• It divides into anterior and posterior interosseous
arteries
171

172. • Posterior interosseous artery
– passes dorsally over the proximal margin of the
interosseous membrane into the posterior
compartment
172

173. • Anterior interosseous artery
– passes distally along the anterior aspect of the
interosseous membrane
– supplies muscles of the deep compartment of the forearm
and the radius and ulna.
– It terminates by joining the posterior interosseous artery.
173

174. Veins
• Deep veins
– generally accompany the arteries
– ultimately drain into brachial veins
174

175. Nerves
• Nerves in this compartment are:
– median
– ulnar nerves
– superficial branch of the radial nerve
175

176. 176

177. Median nerve
• It innervates all muscles in this compartment
except:
– flexor carpi ulnaris
– medial part of the flexor digitorum profundus
177

178. Median nerve
• It leaves the cubital fossa by passing between:
– the two heads of the pronator teres muscle
– humero-ulnar and radial heads of the flexor
digitorum superficialis muscle
178

179. Median nerve
• It continues a straight linear course distally down deep
surface of the flexor digitorum superficialis muscle.
• Just proximal to the wrist:
– it moves around the lateral side of flexor digitorum
superficialis
– and becomes more superficial in position
– lying between the tendons of the palmaris longus and flexor
carpi radialis muscles.
179

180. Median nerve
• It enters the palm of the hand by passing
through the carpal tunnel
180

181. Branches of median nerve:
• Anterior interosseous nerve
– The largest branch of the in the forearm
– It innervates the muscles in the deep layer
• flexor pollicis longus
• lateral half of flexor digitorum profundus
• pronator quadratus
181

182. Branches of median nerve:
• Anterior interosseous nerve
– terminates as articular branches to joints of the
distal forearm and wrist.
– passes distally with the anterior interosseous
artery
182

183. Branches of median nerve:
• A small palmar branch
– originates immediately proximal to the flexor
retinaculum
– innervates the skin over the base and central palm.
– it passes into the hand superficial to the flexor
retinaculum of the wrist.
183

184. Ulnar nerve
• Enters the this compartment by passing posterior to
medial epicondyle
• In the forearm, it innervates only:
– flexor carpi ulnaris muscle
– medial part of the flexor digitorum profundus muscle
• passes down in the plane between flexor carpi ulnaris
and flexor digitorum profundus
• Then it lies under the lateral lip of the flexor carpi
ulnaris tendon
184

185. • The ulnar artery is lateral to it in the distal
two-thirds of the forearm
• Both the ulnar artery and nerve enter the
hand by passing:
– superficial to the flexor retinaculum immediately
lateral to the pisiform bone
185

186. • In the forearm the ulnar nerve gives rise to:
– 2 muscular branches
– two small cutaneous branches
• palmar branch
– originates in the middle of the forearm
– supply skin on the medial side of the palm
186

187. In the forearm the ulnar nerve gives rise to:
• larger dorsal branch
– originates in the distal forearm
– passes posteriorly deep to the tendon of the flexor
carpi ulnaris
– innervates skin on
• dorsal side of the back of the hand
• posterior surfaces of the medial one and one-half digits.
187

188. Radial Nerve
• bifurcates into deep and superficial branches in
the lateral border of the cubital fossa
• The deep branch
– predominantly motor
– passes between the two heads of the supinator
muscle to access muscles in the posterior
compartment of the forearm.
188

189. • The superficial branch
– Sensory
– It passes down the anterolateral aspect of the forearm
deep to the brachioradialis muscle
– Accompanies radial artery.
– continues into the hand where it innervates skin on the
dorsolateral surface.
•
189

190. Posterior Compartment
Muscles
• occur in two layers: superficial and deep layers.
• They are associated with:
– movement of the wrist joint
– extension of the fingers and thumb
– supination.
• All of them are innervated by the radial nerve.
190

191. Muscles of Posterior Compartment
Superficial layer
• The seven muscles:
– Brachioradialis
– extensor carpi radialis longus
– extensor carpi radialis brevis
– extensor digitorum
– extensor digiti minimi
– extensor carpi ulnaris
– anconeus
191

192. 192

193. Muscles of Posterior Compartment
Superficial layer
• All have a common origin from epicondyle of
the humerus
• Except for the brachioradialis and anconeus
all of them extend as tendons into the hand.
193

194. Muscles of Posterior Compartment
Deep layer
• Consists of five muscles:
– Supinator
– abductor pollicis longus
– extensor pollicis brevis
– extensor pollicis longus
– extensor indicis
194

195. 195

196. Muscles of Posterior Compartment
Deep layer
• Except for the supinator muscle, all these muscles
– originate from the posterior surfaces of the radius, ulna,
and interosseous membrane
– pass into the thumb and fingers
• All of them are innervated by the posterior
interosseous nerve
– the continuation of the deep branch of the radial nerve.
196

197. Muscles of Posterior Compartment
Deep layer
• abductor pollicis longus, extensor pollicis
brevis and extensor pollicis longus
– emerge from between the extensor digitorum and
the extensor carpi radialis brevis tendons—out
cropping muscles.
197

198. Posterior Compartment
Arteries
• Blood supply occurs predominantly through:
– Radial artery
– posterior interosseous artery
– anterior interosseous artery
198

199. Posterior Compartment
Arteries
Posterior interosseous artery
• Originates from the common interosseous—branch
of the ulnar artery
• passes dorsally over the proximal margin of
interosseous membrane and into the posterior
compartment of the forearm.
199

200. Posterior Compartment
Arteries
Posterior interosseous artery
• It contributes a branch, the recurrent interosseous artery
• then passes between the supinator and abductor pollicis
longus muscles
• It receives the the anterior interosseous artery,
• Terminates by joining the dorsal carpal arch of the wrist.
200

201. Posterior Compartment
Arteries
Anterior interosseous artery
• a branch of the common interosseous branch
of the ulnar artery
• It is situated in the anterior compartment of
the forearm on the interosseous membrane.
201

202. Posterior Compartment
Arteries
Radial artery
• has muscular branches, to the extensor
muscles on the radial side of the forearm.
202

203. Posterior Compartment
Veins
Deep veins
• generally accompany the arteries.
• They ultimately drain into brachial veins
203

204. Posterior Compartment
Nerves
Radial nerve
• The nerve of the posterior compartment of
the forearm
• Most of the muscles are innervated by the
deep branch
204

205. 205

206. Posterior Compartment
Nerves
Radial nerve
• In the cubital fossa, radial nerve innervates:
– brachioradialis
– extensor carpi radialis longus
206

207. Nerves of Posterior Compartment
Radial nerve
Deep branch of radial nerve:
• originates from the radial nerve in the lateral wall of the
cubital fossa deep to the brachioradialis muscle
• It innervates the extensor carpi radialis brevis and
supinator muscle
• And becomes the posterior interosseous nerve after
emerging from between the two heads of the supinator
muscle
207

208. Nerves of Posterior Compartment
Radial nerve
The posterior interosseous nerve :
• Supplies the remaining muscles in the
posterior compartment
• terminates as articular branches
208

209. 209

210. The Hand

211. Hand
• It is the region of the upper limb distal to the
wrist joint.
• It is subdivided into three parts:
– Wrist
– Metacarpus
– digits

212. • The five digits consist of the laterally positioned thumb and,
medial to the thumb, the four fingers-the index, middle,
ring, and little fingers.
• In the normal resting position, the fingers form a flexed
arcade, with the little finger flexed most and the index
finger flexed least.
• In the anatomical position, the fingers are extended.

213. • The hand has an anterior surface (palm) and a dorsal surface
(dorsum of hand).
• Abduction and adduction of the fingers are defined with
respect to the long axis of the middle finger
• In the anatomical position, the long axis of the thumb is
rotated 90° to the rest of the digits
• Many of the features of the upper limb are designed to
facilitate positioning the hand in space.

214. Bones
• There are three groups of bones in the hand:
– eight carpal bones
– five metacarpals (I to V)
– Phalanges—thumb has only two, the rest of the
digits have three

216. • Carpal bones and metacarpals of II to V:
– tend to function as a unit
– form much of the bony framework of the palm.
• Metacarpal bone of the thumb:
– functions independently
– has increased flexibility at the carpometacarpal joint
to provide opposition of the thumb

217. • Carpal bones
– Bones of the wrist
– are arranged in two rows, a proximal and a distal
row, each consisting of four bones

218. • Proximal row :
– From lateral to medial it consists of:
• scaphoid
• lunate
• triquetrum
• pisiform

219. • Pisiform is a sesamoid bone in the tendon of
flexor carpi ulnaris
• The scaphoid has a prominent tubercle on its
lateral palmar surface that is directed
anteriorly.

220. • Distal row
–From lateral to medial it consists of:
• trapezium bone
• trapezoid
• Capitate
• Hamate

221. • Distal row
– Trapezium has a tubercle on its palmar surface
– Capitate is the largest of the carpal bones
– Hamate has a prominent hook (hook of hamate)
on its palmar surface

222. • Articular surfaces
– All of them articulate with each other
– Carpal bones in the distal row articulate with
metacarpals of the digits.
– With the exception of the metacarpal of the thumb,
all movements of the metacarpal bones on the carpal
bones are limited.
– proximal surfaces of the scaphoid and lunate
articulate with the radius to form the wrist joint.

223. • Carpal arch
– The carpal bones form an arch in coronal plane whose
base is directed anteriorly.
– The lateral side of this base is formed by the tubercles
of the scaphoid and trapezium.
– The medial side is formed by the pisiform and the
hook of hamate.

224. • Metacarpals
– Numbered as I-V beginning from thumb to little fingers,
respectively
– consists of:
• a base
– All them articulate with the carpal bones and with each
other
• a shaft
• distally, a head
– All of them articulate with the proximal phalanges of
digits.

225. • Phalanges
– The phalanges are the bones of the digits
– the thumb has two-a proximal and a distal phalanx
– the rest of the digits have three-a proximal, a
middle, and a distal phalanx.

226. • Phalanges
– Each phalanx has
– a base
– a shaft
– distally, a head.
• The base of each proximal phalanx articulates
with the head of the related metacarpal bone.

227. Joints
Wrist joint
• It is a synovial joint
• It is between
• distal end of radius and articular disc overlying the
distal end of the ulna
– They form concave surface
• scaphoid, lunate, and triquetrum
– Together, their articular surfaces form an oval shape with a
convex contour

228. • allows movement around two axes; hand can be:
– Abducted and adducted at the wrist joint
– Flexed and extended at the wrist joint
• hand can be adducted to a greater degree than it
can be abducted—styloid process of radius
extends further distally than the ulnar

229. Carpal/ Intercarpal joints
• synovial joints
• Formed between the carpal bones
• movement is limited
• But, they contribute in abduction, adduction,
flexion, and, particularly, extension.

230. • Carpometacarpal joints
– between the metacarpals and the related distal
row of carpal bones

231. • Metacarpophalangeal joints
– joints between the distal heads of the metacarpals
and the proximal phalanges
– are condylar joints, which allow:
– Flexion, Extension
– Abduction, Adduction
– Circumduction, limited rotation

232. • Interphalangeal
– Between adjacent phalanges
– hinge joints that allow mainly flexion and
extension.

233. Carpal tunnel
• It is formed by:
–Sides and roof—carpal arch
–flexor retinaculum—anterior wall
• attaches to medial and lateral walls of base of
the carpal arch

234. Carpal tunnel
• Contents
– Tendons of flexor digitorum profundus a nd
superficalis, flexor pollicis longus
– Median nerve

236. • Palmar aponeurosis
– is a triangular-shaped condensation of deep fascia
that covers the palm
– It is anchored to the skin in distal regions
– The apex of the triangle is continuous with the
palmaris longus tendon

237. Anatomical snuffbox
• A triangular depression formed on the posterolateral side
of the wrist by:
– lateral border—tendons of abductor pollicis longus and extensor
pollicis brevis
– medial border—tendon of extensor pollicis longus
– Floor—scaphoid and trapezium
• Contents:
– Superficial radial nerve
– Radial artery

239. Intrinsic muscles of the hand
• Palmaris brevis
– Origin: Palmar aponeurosis and flexor retinaculum
– Insertion: skin on medial margin of the hand
– nn: Superficial branch of the ulnar nerve
– Action: Improves grip

240. Intrinsic muscles of the hand
• Dorsal interossei (four muscles)
– Origin: Adjacent sides of metacarpals
– Insertion: Extensor hood
– Nn: Deep branch of ulnar nerve
– Action: Abduction digits at metacarpophalangeal
joints

242. Intrinsic muscles of the hand
• Palmar interossei (four
muscles)
– Origin: Sides of metacarpals
– Insertion: Extensor hoods
– Nn: Deep branch of ulnar nerve
– Action: Adduction of digits at
the metacarpophalangeal joints

243. Intrinsic muscles of the hand
• Adductor pollicis
– Origin:
• Transverse head- metacarpal III
• oblique head-capitate and bases of metacarpals II and
III
– Insertion: extensor hood
– Nn: Deep branch of ulnar nerve
– Action: Adducts thumb

245. Intrinsic muscles of the hand
• Lumbricals (four muscles)
– Origin: Tendons of flexor digitorum profundus
– Insertion: Extensor hoods
– Nn:
• Medial two by the deep branch of the ulnar nerve
• lateral two by digital branches of the median nerve
– Action: Flex metacarpophalangeal joints while
extending interphalangeal joints

247. Thenar muscles
• Opponens pollicis
– Origin: Tubercle of trapezium
– Insertion: metacarpal I
– Nn: Recurrent branch of median nerve
– Action: Medially rotates thumb

249. Thenar muscles
• Abductor pollicis brevis
– Origin: Tubercles of scaphoid and trapezium
– Insertion: extensor hood of thumb
– Nn: Recurrent branch of median nerve
– Action: Abducts thumb at metacarpophalangeal
joint

250. Thenar muscles
• Flexor pollicis brevis
– Origin: Tubercle of the trapezium
– Insertion: Proximal phalanx of the thumb
– Nn: Recurrent branch of median nerve
– Action: Flexes thumb at metacarpophalangeal
joint

251. Hypothenar muscles
• Opponens digiti minimi
– Origin: Hook of hamate
– Insertion:Medial aspect of metacarpal V
– Nn: Deep branch of ulnar nerve
– Action: Laterally rotates metacarpal V

252. Hypothenar muscles
• Abductor digiti minimi
– Origin: Pisiform
– Insertion: Proximal phalanx of little finger
– Nn: Deep branch of ulnar nerve
– Action: Abducts little finger at
metacarpophalangeal joint

253. Hypothenar muscles
• Flexor digiti minimi brevis
– Origin: Hook of the hamate
– Insertion: Proximal phalanx of little finge
– Nn: Deep branch of ulnar nerve
– Action: Flexes little finger at metacarpophalangeal
joint

254. Arteries and veins
• Blood supply to the hand is by the radial and
ulnar arteries
• They form two interconnected vascular arches
(superficial and deep) in the palm
• Vessels to the digits, muscles, and joints originate
from the two arches and the parent arteries:

255. Arteries
• Radial artery contributes substantially to
supply the thumb and the lateral side of the
index finger
• remaining digits and the medial side of the
index finger are supplied mainly by the ulnar
artery.

256. Nerves
• It is supplied by ulnar, median, and radial nerves
• All three nerves contribute to cutaneous innervation.
• ulnar nerve innervates all intrinsic muscles of the hand
except the three thenar muscles and the two lateral
lumbricals, which are innervated by the median nerve.
• radial nerve only innervates skin on the dorsolateral side
of the hand.

257. Ulnar nerve
• enters the hand lateral to the pisiform and
dorsomedially to the ulnar artery
• Immediately distal to the pisiform, it divides
into:
– a deep branch—mainly motor
– a superficial branch—mainly sensory

258. Ulnar nerve
• The deep branch supplies
– hypothenar muscles
– Interossei
– adductor pollicis
– two medial lumbricals

259. Guyon's canal
• a fibro-osseous tunnel between the hook of the
hamate and the flexor tendons
• deep branch of the ulnar nerve passes through it
• small outpouchings of synovial membrane (ganglia)
from the joints of the carpus may compress the nerve
– producing sensory and motor symptoms.

260. Ulnar nerve
superficial branch of the ulnar nerve
• innervates
– palmaris brevis muscle
– skin on the palmar surface of the little finger and
the medial half of the ring finger

261. Median nerve
• It innervates
– skin on the thumb, index and middle fingers, and lateral
side of the ring finger
– Thenar muscles
• nervous system, using touch, gathers information
about the environment from thumb and index finger

262. Median nerve
• It enters the hand by passing through the
carpal tunnel
• And divides into a recurrent branch and
palmar digital branches

263. Superficial branch of the radial nerve
• The only part of the radial nerve that enters the hand
• It enters the hand by passing over the anatomical
snuffbox
• It innervates skin over:
– dorsolateral aspect of the palm
– dorsal aspects of lateral three and one-half digits distally to
terminal interphalangeal joints.

264. Cutaneous innervation of the hand

265. Cutaneous innervation of the hand

266. Classification of Joints

267. Classification of Joints
• There are three classes of joints based on the
manner or type of material by which bones
are united.
– Synovial joints
– fibrous joints
– cartilaginous joints

268. Synovial Joints
• The articulating bones are united by a joint (articular)
capsule
• articular capsule is composed of an outer fibrous
layer lined by a serous synovial membrane.
• The joint cavity of a synovial joint is a potential space
that contains lubricating synovial fluid
– secreted by the synovial membrane

269. Synovial Joints
• articular cartilage covers the articulating surfaces of
the bones
• And all other internal surfaces are covered by
synovial membrane.
• periosteum investing the participating bones
external to the joint blends with the fibrous layer of
the joint capsule.

270. Fibrous Joints
• The articulating bones of fibrous joints are united by
fibrous tissue.
• The amount of movement occurring depends on the
length of the fibers uniting the articulating bones.
• The sutures of the cranium are examples of fibrous
joints
– These bones are close together, either interlocking along a
wavy line or overlapping.

271. Fibrous Joints
• A syndesmosis type of fibrous joint unites the
bones with a sheet of fibrous tissue, either a
ligament or a fibrous membrane.
• Consequently, this type of joint is partially
movable.

272. Fibrous Joints
• Examples of syndesmosis:
– interosseous membrane that joins the radius and
ulna
– A dentoalveolar syndesmosis (gomphosis)—
articulation between the root of the tooth and
the alveolar process of the jaw.

273. Cartilaginous Joints
• The articulating structures of cartilaginous joints
are united by hyaline cartilage or fibrocartilage.
• Primary cartilaginous joints/synchondroses:
– bones are united by hyaline cartilage, which permits
slight bending during early life.
– are usually temporary unions, such as the bony
epiphysis and the shaft are joined by an epiphysial
plate.

274. • Secondary cartilaginous joints/symphyses
– are strong, slightly movable joints united by
fibrocartilage.
– E.g. fibrocartilaginous intervertebral discs
between the vertebrae
• provide strength, shock absorption and considerable
flexibility to the vertebral column

275. Synovial Joints
• the most common type of joint
• provide free movement between the bones
• they are joints of locomotion, typical of nearly all limb
joints.
• usually reinforced by accessory ligaments that are
either:
– separate (extrinsic)
– a thickening of a portion of the joint capsule (intrinsic).

276. Synovial Joints
• Some synovial joints have a fibrocartilaginous
articular disc or meniscus

277. Synovial Joints
Types
• There are six major types depending on the shape of the
articulating surfaces and/or the type of movement they
permit:
• Plane joints:
– permit gliding or sliding movements in the plane of the articular
surfaces.
– The surfaces of the bones are flat or almost flat,
– movement is limited by their tight joint capsules.
– An example is the acromioclavicular joint

278. Synovial Joints
Types
• Hinge joints
– permit flexion and extension only, movements that occur
in one plane (sagittal) around a single axis that runs
transversely—uniaxial joints.
– The joint capsule is thin and lax anteriorly and posteriorly
where movement occurs
– bones are joined by strong, laterally placed collateral
ligaments.
– elbow joint is a hinge joint.

279. Synovial Joints
Types
• Saddle joints
– permit abduction and adduction as well as flexion and
extension, movements occurring around two axes at
right angles to each other—biaxial joints that allow
movement in two planes, sagittal and frontal.
– The performance of these movements in a circular
sequence (circumduction) is also possible.

280. Synovial Joints
Types
• Saddle joints
– The articular surfaces are shaped like a saddle
(i.e., they are reciprocally concave and convex).
– The carpometacarpal joint at the base of the 1st
digit (thumb) is a saddle joint.

281. Synovial Joints
Types
• Condyloid joints
– permit flexion and extension as well as abduction and
adduction—biaxial.
– However, movement in one plane (sagittal) is usually
greater (freer) than in the other.
– Circumduction, more restricted than that of saddle
joints
– The metacarpophalangeal joints are condyloid joints.

282. Synovial Joints
Types
• Ball and socket joints
– allow movement in multiple axes and planes—
multi-axial joints:
• flexion and extension
• abduction and adduction
• medial and lateral rotation
• Circumduction.

283. Synovial Joints
Types
• Ball and socket joints
– the spheroidal surface of one bone moves within
the socket of another.
– The hip joint is a ball and socket joint

284. Synovial Joints
Types
• Pivot joints
– permit rotation around a central axis—uniaxial
– a rounded process of bone rotates within a sleeve
or ring.
– The median atlantoaxial joint is a pivot joint