MSS01 Upper Limb Bones And Joints Flashcards
Upper limb regions
- Shoulder
- Arm (Brachium)
- Forearm (Antebrachium)
- Hand (Manus)
—> wrist
—> palm
—> digits (thumb/pollex, index, middle, ring, small/digitus minimus)
Upper limb bones
- Clavicle
- Scapula
—> clavicle + scapula = Pectoral girdle - Humerus
- Ulna
- Radius
- Bones of hands
Clavicle
- S-shaped bone
- **- Acromial end
- **- Sternal end
- superior surface
- inferior surface
Scapula
Anterior:
**- Coracoid process (project anteriorly)
**- Glenoid fossa: shoulder joint socket (join humerus)
—> supraglenoid tubercle (muscle attachment)
—> infraglenoid tubercle (muscle attachment)
- Scapular notch (foramen for supraclavicular nerve)
- Subscapular fossa
Posterior:
- **- Spine
- **- Acromion (join clavicle)
- Superior angle
- Inferior angle
- Supraspinous fossa (SA for muscle attachment)
- Infraspinous fossa (SA for muscle attachment)
Humerus
Anterior:
- Head (Proximal)
- Anatomical neck
- Greater / Lesser tubercle
* **4. Intertubercular (bicipital) groove (attach long bicep tendon) - Surgical neck
* **6. Deltoid tuberosity - Lateral / Medial supracondylar ridge
* **8. Radial fossa
* **9. Coronoid fossa
* **10. Lateral / Medial epicondyle (ulnar nerve)
* **11. Capitulum (anterior) (connect head of Radius)
Posterior:
- **1. Radial groove / Spiral groove (for radial nerve)
- **2. Ulnar groove (for ulnar nerve)
- **3. Olecranon fossa
- **4. Trochlea (滑輪, posterior) (connect trochlear notch on Ulna)
Capitulum + Trochlea = 同一組野
Radius
Anterior:
1. Head (proximal)
2. Neck
**3. Radial / Bicipital tuberosity (proximal)
**4. Interosseous membrane
—> transmit force between radius and ulnar
***5. Styloid process (distal)
Posterior:
6. Dorsal tubercle
Ulna
- slightly longer than radius
- **1. Olecranon (扣住humerus epicondyle)
- **2. Trochlear notch (扳手: 扣住trochlea)
3. Coronoid process
4. Radial notch
5. Ulnar tuberosity
6. Head (distal) - **7. Styloid process
Bones of the hand
1. Carpals (wrist) —> Scaphoid —> Lunate —> Triquetral —> Pisiform (on top of triquetral) —> Trapezium —> Trapezoid —> Capitate (頭狀骨) —> Hamate (有個勾) 2. Metacarpals (palm) 3. Phalanges (fingers, long bones) (4. Sesamoid bones)
Most of joints in our limbs are synovial joints
- Joint cavity containing synovial fluid (secreted by synovial membrane)
- Articular cartilage (hyaline cartilage)
- Synovial membrane (入面)
- Fibrous capsule (出面)
- Bursa (lubricate muscle lying above it —> cushion between bones and tendons / muscles around a joint)
Range of motion and stability of synovial joints depend on
- Shape of articular surfaces
- Ligaments
- Muscle tone (a low level of contractile activity in relaxed muscles which does not produce active movements)
Sternoclavicular joint
Synovial double-planed joint
Medial end of clavicle articulates with "socket" formed by manubrium and 1st costal cartilage —> ball and socket joint —> Clavicle movement: 1. Up/down 2. Forward/backward 3. Rotation
- Costoclavicular ligament
—> between clavicle and 1st costal cartilage - Articular disc (fibrocartilage)
—> divides joint cavity into 2 compartments
Clavicle and scapula move as a unit, movements at this joint are produced by muscles that act on either bone
Acromioclavicular joint
Synovial plane joint
- Acromioclavicular ligament
—> Acromion + Clavicle - Coracoclavicular ligament
—> Coracoid process + Clavicle
—> ***hold clavicle and scapula together so move together as a unit - Articular disc (fibrocartilage)
Shoulder joint
Synovial ball-and-socket joint
Humeral head insert into shallow glenoid fossa (deepened by fibrocartilage **glenoid labrum)
—> mobile but unstable
—> loose-fitting
—> stability by **Rotator cuff
—> weak inferiorly: full abduction —> dislocation —> ***Axillary nerve injury
Movement:
- Extension / Flexion
- Abduction / Adduction
- Lateral / Medial rotation
- Circumduction
Abduction up to 90o (locked by greater tubercle coming into contact with upper margin of glenoid)
—> 150o involves lateral rotation of scapula (inferior angle向外擰)
—> 180o involves movement of the spinal column
Subacromial bursa lies above the shoulder joint
—> **Subacromial bursitis
—> **”Painful arc syndrome”
Elbow joint
Synovial hinge joint
- Trochlea (humerus) + Trochlear notch (ulna)
—> Humeroulnar joint
additional articulation:
2. Capitulum (humerus) + Disc-like head (radius)
—> Humeroradial joint
Synovial cavity is continuous with that of Proximal radioulnar joint
Capsule is thickened on either side to form collateral ligaments:
- Radial collateral ligament (of elbow joint): contain Annular ligament —> not attached to the radius: allows independent rotation of the radius
- Ulnar collateral ligament (of elbow joint)
Long axis of arm and forearm: forms a carrying angle of 10o-20o
—> more pronounced in women
—> disappears when extended arm is pronated
Radioulnar joint
- Proximal radioulnar joint
- Synovial pivot joint
- Radial head + Radial notch (ulna) + **Annular ligament
- Annular ligament **not attached to radius (on ulna) (箍住radius) —> not attached to the radius: allows independent rotation of the radius
- ***“Pulled-elbow”: radial head slips out of annular ligament - Distal radioulnar joint
- Synovial pivot joint
- Ulnar head + Ulnar notch (radius)
- Triangular articular disc
