1

JOINTS OF THE UPPER LIMB

2

JOINTS OF UPPER LIMB

� Joints in pectoral girdle • Sternoclavicular joint (SC joint)• Acromioclavicular joint (AC joint)• Glenohumeral joint (shoulder joint)

� Elbow joint� Proximal radioulnar joint� Distal radioulnar joint� Joints of hand

3

Joints in the pectoral girdle

� Three joints in the pectoral girdle. They usually move simultaneously.• Sternoclavicular joint (SC joint)• Acromioclavicular joint (AC joint)• Glenohumeral joint (shoulder joint)

� Range of motion of the pectoral girdle is related to scapulothoracic and glenohumeral movements

� The important movement: scapular movement:� elevation and depression� protraction and retraction� and rotation of the scapular

4

Sternoclavicular (SC) joint

� Articulation: Sternal end of clavicle articulates with manubrium of the sternum and 1st costal cartilage. It is a saddle type of synovial joint, but functions a ball and socket joint.

� One articular disc divides the joint into two compartments and serves as shock absorber of forces

� Articular capsulesurrounds the SC joint, including epiphysis at the end of clavicle.

5

� Ligaments• Anterior SC ligaments reinforce the capsule anteriorly• Posterior SC ligaments reinforce the capsule posteriorly• Interclavicular ligament strengths the capsule superiorly• Costoclavicular ligament anchors the inferior surface of the

sternal end of the clavicle to the 1st rib and its costal cartilage

Sternoclavicular (SC) joint

6

Acromioclavicular (AC) joint� A plane type of synovial joint� Articulation: The acromial end of the clavicle articulates with the

acromion of the scapula. Joint surfaces are separated by an articular disc.

� The joint capsule is relative loose, but it is strengthened by ligaments and trapezius muscle fibers.

� Ligaments• AC ligament connects

the acromion to the clavicle, strengthens the AC joint superiorly

• Coracoacromial ligament connects coracoid process and the acromial process of scapula

Coracoacromial ligamentAcromioclavicular (AC) ligament

7

• Coracoclavicular ligament unites the coracoid process of the scapula to the clavicle. It consists of two ligaments:

– Conoid ligament connects the root of the coracoid process of scapula to the inferior surface of the clavicle

– Trapezoid ligament is the connection between the superior surface of the coracoid process and the trapezoid line of the clavicle

Acromioclavicular (AC) joint

Coracoclavicular ligament

8

Glenohumeral joint (shoulder joint)

� A ball-and-socket type of synovial joint, has wide range of movement, but is relatively unstable

� Articulation: The humeral head articulates with glenoid cavity of the scapula. Glenoid labrum is a ringlike fibrocartilaginous, it deepens the glenoid cavity of the scapula

Glenoid labrum

Anterolateral view of glenoid cavity

9

� Fibrous articular capsule is loose. Superiorly the fibrous layer of the joint capsule encloses the proximal attachment of the long head of biceps brachii to the supraglenoid tubercle of the scapula within the joint.

Glenohumeral joint (shoulder joint)

� Coracohumeral ligament strengthens the capsule superiorly

� Glenohumeral ligaments run from the glenoid labrum at the superior aspect of glenoid cavity of the scapula and blend distally with the fibrous capsule as it attaches to the anatomical neck of the humerus, strengthening the anterior aspect of the articular capsule

10

Glenohumeral joint (shoulder joint)

� Transverse humeral ligamentstrengths the capsule and bridges the gap between the two tubercles. It holds the synovial sheath and tendon of the biceps brachii in place during movements of the joint

� Coraco-acromial arch � is formed by inferior aspect of

acromion and coracoid processof the scapula with the coracoacrominal ligament.

• Its function is to prevent the humeral head superior displacement from the glenoidcavity

11

Movement and injury of glenohumeral joint

� Movements: Flexion and extension, abduction and adduction, rotation (medial and lateral), and circumduction

� Dislocation of the glenohumeral joint• Caused by direct or indirect injuries• Most dislocations of the humeral head occur in the downward

direction

12

Elbow joint

� A hinge type of synovial joint� Two articulation: humero-ulnar and

humero-radial articulations. Trochlea and capitulum of the humerus articulate with the trochlear notch of the ulna and the head of the radius respectively.

� Articular capsule is weak anreriorly and posteriorly but is strengthened on each side by collateral ligaments.

13

� Radial collateral ligament extends from the lateral epicondyle of the humerus to the head of radius. It encircles and holds the head of the radius in the radial notch of the ulna

� Ulnar collateral ligament extends from the medial epicondyle of the humerus to the coronoid process and olecranon of the ulna. It consists of three bands:• The anterior cordlike band• The posterior fanlike band• Oblique band

Ligaments of elbow joint

Elbow joint

14

� Movements of the elbow joint• Flexion and extension

� Carrying angle: ~170° between the long axes of the ulna and humerus

Elbow joint

15

Proximal radioulnar Joint

� A pivot type of synovial joint. The head of radius articulates with radial notch of the ulna

� Fibrous capsule encloses the joint and is continuous with that of the elbow joint

� Anular ligament attaches to the ulna anterior and posterior to its radial notch, surrounding the articulating bony surfaces

� Movement: Pronation and supination

16

Distal radioulnar joint

� A pivot type of synovial joint. The head of ulna articulates with ulnar notch of the radius.

� A fibrocartilaginous articular disc (“triangular ligament”) binds the ends of the ulna and radius together and is main uniting structure of the joint

� Anterior and posterior ligaments strengthen the fibrous capsule of the joint

� Movement:Pronationand supination

17

� Interosseous membrane is a sheet of fibrous tissue. It joints the radius and ulna in a fibrous joint (syndesmosis)

� Proximal radioulnar joint

� Distal radioulnar joint

Connections between ulna and radius

Medial view of ulna and radius

18

Joints of Hand: Wrist Joint (Radiocarpal joint)

� A condyloid type of synovial joint

� Articulation:The distal end of radius and the articular disc of the distal radioulnar joint articulate with proximal row of carpal bones (except for the pisiform)

� Anterior (palmar radiocarpal) ligaments and posterior (dorsal radiocarpal) ligament strengthen fibrous capsule. They make hand to follow the radius during supination of the forearm

Ligaments of the wrist joint

19

� Ulnar collateral ligament connects the ulnar styloid process to triquetrum and enhances medial side of the joint

� Radial collateral ligament connects radial styloid process to scaphoid and enhances lateral side of the joint

� Movements• Flexion and extension• Abduction (radial deviation) and

adduction (ulnar deviation)• Circumduction

Joints of Hand: Wrist Joint (Radiocarpal joint)

Coronal section of the right wrist and hand

radius

ulna

Radial collateral ligamentUlnar collateral

ligament

Wrist joint

Articular disc

20

Joints of Hand: Intercarpal Joints

� Include• Joints between the carpal bones

of the proximal row• Joints between the carpal bones

of the distal row• The midcarpal joint between the

proximal and distal rows of carpal bones

• Pisotriquetral joint � They are plane synovial joints� Carpal bones united by anterior,

posterior, and interosseous ligaments

Coronal section of right wrist and hand

21

Joints of Hand: Carpometacarpal (CMC) & Intermetacarpal (IM) Joints

� CMC joints are the plane type of synovial joint. The CMC joint of the thumb is a saddle joint

� Metacarpals articulate with each other at their bases to form IM joints, the CMC joint of the thumb is between the trapezium and the base of the 1st metacarpal

� Articular capsule surrounds joints � Bones united by anterior, posterior, and

interosseous ligaments� Movement:

� CMC joint of the thumb: flexion-extension, abduction-adduction, and circumduction

� No movement at CMC joints of the 2nd and 3rd digits� 4th finger is slightly mobile� 5th finger, extremely mobile

22

Joints of Hand: Metacarpophalangeal (MCP) & Interphalangeal (IP) joints

� MCP joints are the condyloid type of synovial joint. The heads of the metacarpals articulate with the bases of the proximal phalanges

� IP joints are the hinge type of synovial joint. The heads of the phalanges articulate with the bases of more distally located phalanges

� Fibrous capsule encloses each joint� Strong palmar ligaments, collateral

ligaments, and transverse metacarpal ligaments strengthen the joints

� Movements• 2nd- 5th MP joints: flexion-extension,

abduction-adduction, and circumduction• 1st MP joint: flexion-extension• IP joints: Flexion- extension

Transverse metacarpal ligaments

23

Reading materials

� Moore, Agur, & Dalley (4th ed.)p. 475-490

� Moore, Agur, & Dalley (5th ed.)p.465-484

24

Study Questions

1. Name the joints in upper limb and find their locations and articulations in the skeleton.

2. Name the ligaments that enhance the stability of AC joint, SC joint, shoulder joint, elbow joint and joints of hand.

3. Pronate your hand and then supinate it. What articulations have moved?

4. Is elbow joint uniaxial or biaxial?5. Describe the movements of the CMC joints, IM joints,

Metacarpophalangeal and Interphalangeal joints6. What is pectoral girdle?