Anatomy of the joints of the upper limb

1. Shoulder joint, Sterno-clavicular
joint, Acromio-clavicular joint
Dr. Mohammed mahmoud Mosaed

2. Sternoclavicular Joint
• Articulation: between the sternal end of the clavicle, the manubrium sterni, and
the first costal cartilage .
• Type: Synovial double-plane joint
• Capsule: This surrounds the joint and is attached to the margins of the articular
surfaces. Synovial membrane: This lines the capsule and is attached to the margins
of the cartilage covering the articular surfaces
• Ligaments: The capsule is reinforced by the strong sternoclavicular ligaments
(anterior and posterior), interclavicular ligament
• Accessory ligament: The costoclavicular ligament is a strong ligament that runs
from the junction of the first rib with the first costal cartilage to the inferior surface
of the sternal end of the clavicle
• Articular disc: This flat fibrocartilaginous disc lies within the joint and divides the
joint's interior into two compartments. Its circumference is attached to the interior
of the capsule, but it is also strongly attached to the superior margin of the
articular surface of the clavicle above and to the first costal cartilage below.
• Nerve supply: The supraclavicular nerve and the nerve to the subclavius muscle
• Vascular supply by branches from the internal thoracic and suprascapular arteries.

4. Ligaments: The capsule is reinforced by the strong sternoclavicular ligaments (anterior
and posterior), interclavicular ligament
Accessory ligament: The costoclavicular ligament is a strong ligament that runs from
the junction of the first rib with the first costal cartilage to the inferior surface of the
sternal end of the clavicle

5. Sternoclavicular joint

6. Movements and relations
• Forward and backward movement of the
clavicle takes place in the medial
compartment. Elevation and depression of
the clavicle take place in the lateral
compartment.
• Muscles Producing Movement
• The forward movement of the clavicle is
produced by the serratus anterior muscle.
• The backward movement is produced by the
trapezius and rhomboid muscles.
• Elevation of the clavicle is produced by the
trapezius, sternocleidomastoid, levator
scapulae, and rhomboid muscles.
• Depression of the clavicle is produced by
the pectoralis minor and the subclavius
muscles

7. Acromioclavicular Joint
• Articulation: This occurs between the acromion of the scapula and the
lateral end of the clavicle .
• Type: Synovial plane joint
• Capsule: This surrounds the joint and is attached to the margins of the
articular surfaces
• Ligaments: Superior and inferior acromioclavicular ligaments reinforce
the capsule;
• Accessory ligament: The very strong coracoclavicular ligament extends
from the coracoid process to the undersurface of the clavicle. It has
trapezoid and conoid parts; It is largely responsible for suspending the
weight of the scapula and the upper limb from the clavicle.
• Articular disc from the capsule, a wedge-shaped fibrocartilaginous disc
projects into the joint cavity from above .
• Synovial membrane: This lines the capsule and is attached to the margins
of the cartilage covering the articular surfaces.
• Nerve supply: The suprascapular nerve
• Vascular supply from the suprascapular and thoracoacromial arteries

9. • Ligaments: Superior and inferior acromioclavicular ligaments reinforce
the capsule;
• Accessory ligament: The very strong coracoclavicular ligament extends
from the coracoid process to the undersurface of the clavicle. It has
trapezoid and conoid parts; It is largely responsible for suspending the
weight of the scapula and the upper limb from the clavicle.

10. Movements and relations
• A gliding movement takes place when the scapula
rotates or when the clavicle is elevated or
depressed.
• Important Relations
• Anteriorly: The deltoid muscle
• Posteriorly: The trapezius muscle
• Superiorly: The skin

11. Shoulder Joint
• Articulation: This occurs between the rounded
head of the humerus and the shallow, pear-shaped
glenoid cavity of the scapula.
• The articular surfaces are covered by hyaline
articular cartilage, and the glenoid cavity is
deepened by the presence of a fibrocartilaginous
rim called the glenoid labrum.
• Type: Synovial ball-and-socket joint

14. • Capsule: This surrounds the joint and is
attached medially to the margin of the
glenoid cavity outside the labrum;
laterally it is attached to the anatomic
neck of the humerus. The capsule is thin
and lax, allowing a wide range of
movement.
• It is strengthened by fibrous slips from
the tendons of the subscapularis,
supraspinatus, infraspinatus, and teres
minor muscles (the rotator cuff muscles).
• Synovial membrane: This lines the
capsule and is attached to the margins of
the cartilage covering the articular
surfaces . It forms a tubular sheath
around the tendon of the long head of
the biceps brachii. It extends through the
anterior wall of the capsule to form the
subscapularis bursa beneath the
subscapularis muscle.

15. Ligaments of shoulder joint
• Ligaments:
• The glenohumeral ligaments
are three weak bands of
fibrous tissue that strengthen
the front of the capsule.
• The transverse humeral
ligament strengthens the
capsule and bridges the gap
between the two tuberosities.
• The coracohumeral ligament
strengthens the capsule above
and stretches from the root of
the coracoid process to the
greater tuberosity of the
humerus .

16. • Accessory ligaments: The coracoacromial
ligament extends between the coracoid process
and the acromion. Its function is to protect the
superior aspect of the joint.

17. • Nerve supply: The axillary and suprascapular
nerves.

18. Movements of the shoulder joint
• The shoulder joint has a wide range of movement
• The following movements are possible:
• Flexion: by the anterior fibers of the deltoid, pectoralis major
(clavicular head), biceps, and coracobrachialis muscles.
• Extension: by the posterior fibers of the deltoid, latissimus dorsi, and
teres major muscles.
• Abduction: by supraspinatus to 18⁰ and deltoid to 90⁰
• Adduction: by the pectoralis major, latissimus dorsi, teres major, and
teres minor muscles.
• Lateral rotation: by the infraspinatus, the teres minor, and the
posterior fibers of the deltoid muscle.
• Medial rotation: by the subscapularis, the latissimus dorsi, the teres
major, and the anterior fibers of the deltoid muscle.
• Circumduction: This is a combination of the above movements

20. Important Relations
• Anteriorly: The subscapularis muscle and the axillary
vessels and brachial plexus.
• Posteriorly: The infraspinatus and teres minor
muscles.
• Superiorly: The supraspinatus muscle, subacromial
bursa, coracoacromial ligament, and deltoid muscle.
• Inferiorly: The long head of the triceps muscle, the
axillary nerve, and the posterior circumflex humeral
vessels.
• The tendon of the long head of the biceps muscle
passes through the joint and emerges beneath the
transverse ligament.

21. Stability of the Shoulder Joint
• The shallowness of the glenoid fossa of the scapula
and the lack of support provided by weak ligaments
make this joint an unstable structure.
• Its strength almost entirely depends on the tone of
the short muscles that bind the upper end of the
humerus to the scapula namely, the subscapularis in
front, the supraspinatus above, and the infraspinatus
and teres minor behind. The tendons of these
muscles are fused to the underlying capsule of the
shoulder joint. Together, these tendons form the
rotator cuff.
• The least supported part of the joint lies in the
inferior location, where it is unprotected by muscles.