It has two surfaces; coastal/anterior which is concave in shape and the posterior surface which is convex in nature.
Introduction to upper limb
INTRODUCTION TO UPPER
• The upper limb is associated with the lateral
aspect of the lower portion of the neck.
• It is suspended from the trunk by muscles and
a small skeletal articulation between the
clavicle and the sternum-the sternoclavicular
• Based on the position of its major joints and
component bones, the upper limb is divided
into shoulder, arm, forearm, and hand.
• The shoulder is the area of upper limb
attachment to the trunk .
• The arm is the part of the upper limb
between the shoulder and the elbow
• The forearm is between the elbow joint
and the wrist joint;
• While the hand is distal to the wrist joint.
• The axilla, cubital fossa, and carpal
tunnel are significant areas of transition
between the different parts of the limb.
• Important structures pass through, or are
related to, each of these areas.
Regional anatomy of the upper limb
• The shoulder is the region of upper limb
attachment to the trunk and neck.
• The bone framework of the shoulder consists
the clavicle and scapula, which form the
pectoral girdle (shoulder girdle); and
the proximal end of the humerus.
• The superficial muscles of the shoulder consist
of the trapezius and deltoid muscles, which
together form the smooth muscular contour
over the lateral part of the shoulder.
• These muscles connect the scapula and
clavicle to the trunk and to the arm,
Bones of the shoulder girdle
• The clavicle is the only bony attachment
between the trunk and the upper limb.
• It is palpable along its entire length and has a
gentle elongated S-shaped contour.
• Its sternal (medial) end is enlarged and
triangular where it articulates with the
manubrium of the sternum to form the
sternoclavicular (SC) joint.
• Its acromial (lateral) end is flat where it
articulates with the acromion to form the
acromioclavicular (AC) joint.
• The medial two-thirds of the body (shaft) of
the clavicle are convex anteriorly, whereas the
lateral third is flattened and concave
• These curvatures increases the resilience of
the clavicle and give it the appearance of an
elongated capital "S."
• Although designated as a long bone, the
clavicle has no medullary (marrow) cavity.
• It consists of spongy (cancellous) bone with a
shell of compact bone.
• The clavicle has 2 surfaces; a smooth superior
surface lying just deep to the skin and the
• The inferior surface of the clavicle is rough
because strong ligaments bind it to the 1st rib
near its sternal end and suspend the scapula
from its acromial end.
• The conoid tubercle, near the acromial end of the
clavicle, gives attachment to the conoid ligament- the
medial part of the coracoclavicular ligament.
• The subclavian groove in the medial third of the
clavicle is the site of attachment of the subclavius
• More medially is the impression for the costoclavicular
ligament, which binds the 1st rib to the clavicle.
• Near the acromial end of the clavicle is the trapezoid
line, to which the trapezoid ligament attaches; it is the
lateral part of the coracoclavicular ligament.
Variations of the Clavicle;
• The clavicle varies in shape more than most
other long bones.
• It is thicker and more curved in manual
workers, and the sites of muscular
attachments are more marked.
• The right clavicle is thicker and stronger than
the left and is usually shorter.
Fracture of the Clavicle;
• The clavicle is commonly fractured, often by
an indirect force resulting from violent
impacts to the outstretched hand during a fall
transmitted through the bones of the
hand, forearm and arm to the shoulder- or by
falls directly onto the shoulder itself.
• The weakest part of the clavicle is the junction
of its middle and lateral thirds which makes
this point more susceptible to fracture
Ossification of the Clavicle;
• The clavicle is the first long bone to begin to
develop, during the 5th and 6th embryonic
weeks in condensed mescnchyme.
• It completely ossifies by 25th to 31st years of
life making it the last of the epiphyses of long
bones to fuse.
• The scapula or shoulder blade is a triangular flat
bone that lies at the posteriolateral aspect of the
thorax where it covers from the 2nd-7th ribs.
• It comprises of:
three angles (lateral, superior, and inferior);
three borders (superior, lateral, and medial);
two surfaces (costal/anterior and posterior); and
three processes (acromion, spine, and coracoid
Spine of scapula
• The convex posterior surface is evenly divided
into two by the spine of the scapula into a
smaller supraspinous fossa and a much larger
• These three fossae gives attachments to some
fleshy muscles of the upper limb.
• A thick projecting ridge of bone called the
spine of the scapula continues laterally as the
flat expanded acromion which articulates with
acromial end of the clavicle forming the
• Superiorlaterally, the scapula forms the
shallow glenoid cavity which articulates
with the head of the humerus to form the
• Projecting anterolaterally to this cavity is
a structure that resembles a bending
finger pointing to the shoulder.
• This structure is called coracoid process.
Spine of scapula
Angles and borders of scapulae
• The scapula has three borders namely median,
lateral and superior.
• Also has three angles namely; superior, lateral
and inferior angles.
• In its anatomical position the thin median
border of the scapula runs parallel to and
approximately 5cm lateral to the spinous
process of the thoracic vertebrae.
• Hence, the median border is usually referred
to as the VERTEBRAE BORDER.
• From the inferior angle. The lateral
border runs superiolaterally towards the
apex of the axilla, hence sometimes
called the AXILLA BORDER.
• The lateral border terminates in the
truncated lateral angle of the scapula,
where the thick glenoid cavity is located.
• The broad process adjacent to the cavity is the
head of the glenoid cavity while the
constricted part between the head and the
body is the NECK.
• The superior border is marked by the
suprascapular notch near the junction of the
medial 2/3rd and the lateral 1/3rd.
• It is the thinnest and shortest of the three
• The glenoid cavity is a shallow concave, oval
fossa of approximately 4cm long and 2-3cm
wide; for the reception of the head of the
• the cavity faces anterolateraly and slightly
• Fracture of the scapula;
• In most cases the scapulae are well protected
by muscles and its associated thoracic wall,
therefore, most fractures of the scapulae
involves the protruding subcutaneous
• The humerus (arm bone), the largest bone in
the upper limb, articulates with the scapula at
the scapulohumeral (shoulder) joint and the
radius and ulna at the elbow joint.
• Is composed of two extremities; proximal and
• The proximal end of the humerus consists of
the head, the anatomical neck, the greater
and lesser tubercles, the surgical neck, and
the superior half of the shaft of humerus.
• The head is half-spherical in shape and
projects medially and somewhat superiorly to
articulate with the much smaller glenoid
cavity of the scapula.
• The anatomical neck is very short and is
formed by a narrow constriction immediately
distal to the head.
• It lies between the head and the greater and
lesser tubercles laterally, and between the
head and the shaft more medially.
Greater and lesser tubercles;
• The greater and lesser tubercles are
prominent landmarks on the proximal
end of the humerus and serve as
attachment sites for the four rotator cuff
muscles of the glenohumeral joint.
• The greater tubercle is lateral in position.
• Its superior surface and posterior surface are
marked by three large smooth facets for
muscle tendon attachment:
the superior facet is for attachment of the
the middle facet is for attachment of
the inferior facet is for attachment of teres
• The lesser tubercle is anterior in position and
its surface is marked by a large smooth
impression for attachment of the
• A deep intertubercular sulcus (bicipital
groove) separates the lesser and greater
tubercles and continues inferiorly onto the
proximal shaft of the humerus .
• The tendon of the long head of the biceps
brachii passes through this sulcus.
• Roughenings on the lateral and medial lips and on
the floor of the intertubercular sulcus mark sites
for the attachment of the pectoralis major, teres
major, and latissimus dorsi muscles, respectively.
• The lateral lip of the intertubercular sulcus is
continuous inferiorly with a large V-shaped
deltoid tuberosity on the lateral surface of the
humerus midway along its length, which is where
the deltoid muscle inserts onto the humerus.
• In approximately the same position, but on
the medial surface of the bone, there is a thin
vertical roughening for attachment of the
• One of the most important features of the proximal end of
the humerus is the surgical neck.
• This region is oriented in the horizontal plane between the
expanded proximal part of the humerus (head, anatomical
neck, and tubercles) and the narrower shaft.
• The axillary nerve and the posterior circumflex humeral
artery, which pass into the deltoid region from the axilla, do
so immediately posterior to the surgical neck.
• Because the surgical neck is weaker than more proximal
regions of the bone, it is one of the sites where the humerus
commonly fractures. The associated nerve (axillary) and
artery (posterior circumflex humeral) can be damaged by
fractures in this region.
Shaft and distal end of the humerus
• The body/shaft of the humerus has two
• the deltoid tuberosity, laterally, for
attachment of the deltoid muscle, and the
oblique radial groove, posteriorly, in which the
radial nerve and deep artery of the arm
(Profunda brachii) lie as they pass between
the medial and the long and then the lateral
heads of the triceps brachii muscle.
• Distally, the bone becomes flattened, and
these borders expand as the lateral
supraepicondylar ridge (lateral supracondylar
ridge) and the medial supraepicondylar ridge
(medial supracondylar ridge).
• The lateral supraepicondylar ridge is more
pronounced than the medial and is roughened
for the attachment of muscles found in the
posterior compartment of the forearm.
• The two articular parts of the condyle, the
capitulum and the trochlea, articulate with the
two bones of the forearm.
• The capitulum articulates with the radius of the
• The trochlea articulates with the ulna of the
• It is pulley shaped and lies medial to the
The two epicondyles
• The medial epicondyle, a large bony protuberance, is the
major palpable landmark on the medial side of the elbow,
and projects medially from the distal end of the humerus.
• On its surface, it bears a large oval impression for the
attachment of muscles in the anterior compartment of the
• The ulnar nerve passes from the arm into the forearm
around the posterior surface of the medial epicondyle and
can be palpated against the bone in this location.
• The lateral epicondyle is much less pronounced than the
• It is lateral to the capitulum and has a large irregular
impression for the attachment of muscles in the posterior
compartment of the forearm.
• The three fossae
• Three fossae occur superior to the trochlea and
capitulum on the distal end of the humerus.
• The radial fossa is the least distinct of the fossae and
occurs immediately superior to the capitulum on the
anterior surface of the humerus.
• The coronoid fossa is adjacent to the radial fossa and is
superior to the trochlea.
• The largest of the fossae, the olecranon fossa, occurs
immediately superior to the trochlea on the posterior
surface of the distal end of the humerus.
• These three fossae accommodate projections from the
bones in the forearm during movements of the elbow