Joints of the upper limb – Study these joints on the prosections
Acromioclavicular joint
1. Review the bones that are relevant to the acromioclavicular joint:
- Acromion
- Coracoid process of the scapula
- Lateral end of the clavicle
2. Identify the capsule of the acromioclavicular joint. The angle of the articulating surfaces of the
acromion and clavicle causes the acromion to move inferior to the distal end of the clavicle when the
acromion is forced medially.
3. Identify the coracoclavicular ligament, (Figure 98) which supports the acromioclavicular joint. It
consists of two parts:
- Conoid ligament – medial
- Trapezoid ligament – lateral
The coracoclavicular ligaments prevent the acromion from moving inferiorly relative to the clavicle,
thus strengthening the acromioclavicular joint.
Glenohumeral joint (shoulder joint)
It is a ball and socket synovial joint with a wide range of motion. The shoulder joint has a greater degree
of movement than any other joint in the body. This is due to the small area of contact between the head
of the humerus and the glenoid fossa of the scapula and the loose joint capsule. The stability of the
shoulder joint depends on the function of the muscles of the rotator cuff.
1. Review the bony features pertinent to the Glenohumeral joint:
- Glenoid fossa of the scapula
- Head of the humerus
- Anatomical neck of the humerus
- Greater tubercle of the humerus
- Lesser tubercle of the humerus
2. Identify the thin fibrous articular capsule of the glenohumeral joint (Figure 99)
3. The four rotator cuff muscles surround the shoulder joint and blend with the capsule. Identify the
rotator cuff muscles: (Figure 6.37, Figure 102)
- Subscapularis muscle attaches to the lesser tubercle of the humerus and medially rotates the
humerus
- Supraspinatus muscle attaches to the greater tubercle of the humerus and initiates
abduction of the arm. Its tendon of insertion may be difficult to see as it is hidden below the
coracoacromial ligament
- Infraspinatus muscle and teres minor muscle attach to the greater tubercle of the humerus
and laterally rotate the humerus
4. Identify the coracoacromial ligament. The coracoacromial ligament, the acromion and the coracoid
process prevent the superior displacement of the head of the humerus
5. On the prosection where the joint capsule has been opened, identify the following: (Figure 101, 102)
- Glenoid fossa and glenoid labrum
- Head of the humerus covered with articular cartilage
- Anatomical neck of the humerus
- Glenohumeral ligaments are thickenings of the fibrous capsule
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- Tendon of the long head of the biceps brachii muscle. It passes through the glenoid cavity
and is attached to the supraglenoid tubercle.
Elbow joint and proximal radioulnar joint
The elbow joint consists of two parts:
- A hinge joint between the trochlea of the humerus and the trochlear notch of the ulna
- A gliding joint between the capitulum of the humerus and the head of the radius
The proximal radioulnar joint is a pivot joint that occurs between the head of the radius and the radial
notch of the ulna
1. Review the bony features of the elbow region:
- Humerus – radial fossa, coronoid fossa, lateral and medial epicondyles of the humerus,
capitulum, trochlea
- Ulna – olecranon, coronoid process, radial notch
- Radius – head, neck and tuberosity of the radius
2. Identify the thick fibrous articular capsule of the elbow joint
3. Identify the ulnar collateral ligament (Figure 116). It extends from the medial epicondyle to the ulna
4. Identify the radial collateral ligament (Figure 116,117). It extends from the lateral epicondyle to the
side of the anular ligament.
5. Identify the anular ligament (Figure 117, 119). It is attached to both ends of the radial notch of the
ulna, encircles the head of the radius and prevents it from being dislocated downwards. The radius can
freely rotate in the anular ligament
6. On the prosection where the joint has been opened anteriorly (Figure 119) identify
- Radial fossa and coronoid fossa of the humerus
- Capitulum and trochlea of the humerus
- Coronoid process of the ulna
- Head of the radius
7. Pronate and supinate the forearm and notice that the head of the radius freely rotates in the anular
ligament (Note that on the prosection the supinator muscle is still present)
8. Identify the interosseous membrane between the radius and the ulna.
Wrist joint (radiocarpal joint) and distal radioulnar joint
The wrist joint (radiocarpal joint)is the articulation between the distal end of the radius and the proximal
carpal bones namely the scaphoid and lunate. The movements permitted at this joint are flexion,
extension, adduction and abduction. The scaphoid and lunate bones transmit forces from the hand to the
forearm and thus are most commonly fractured in a fall on the outstretched hand.
The distal radioulnar joint is a pivot joint between the head of the ulna and the ulnar notch on the radius.
1. Review the bony features of the wrist region:
- Articular surfaces of the distal end of the radius
- Articular surfaces of the head of the ulna
- Carpal bones – scaphoid and lunate
2. The wrist is reinforced by
- Radiocarpal ligaments
- Radial and ulnar collateral ligaments
3. On the prosection where the radiocarpal joint has been opened posteriorly, identify: (Figure 135, 136)
- Concave surface on the radius for the scaphoid bone
- Concave surface on the radius for the lunate bone
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- Convex articular surface of the scaphoid bone
- Convex articular surface of the lunate bone
- Articular disc of the distal radioulnar joint. The disc holds the distal ends of the radius and
ulna together and separates the cavity of the distal radioulnar joint from the radiocarpal (wrist)
joint.
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