BONES & JOINTS OF THE UPPER LIMB
. UPPER LIMB:ability to place thehandin the proper position in spaceby movements at the scapulothoracic, glenohumeral, elbow, radio-ulnar, and wrist joints LOWER LIMB: support, stability, and locomotion
Pectoral girdle& bones of the free part of the upper limb superior appendicular skeleton Pelvicgirdle & bones of the free part of the lower limb inferior appendicular skeleton The clavicles and scapulae of the pectoral girdle are supported, stabilized, and moved by axio-appendicular muscles that attach to the relatively fixed ribs, sternum, and vertebrae of the axial skeleton.
CLAVICLE- LITTLE KEY • only bony attachment between trunk & upper limb • palpable along its entire length • has a gentle S-shaped contour • forward-facing convex part medial • forward-facing concave part lateral
Although designated as a long bone, the clavicle has no medullary (marrow) cavity. It consists of spongy (trabecular) bone with a shell of compact bone. (Click on thekey in thepreviousslideandreadthefirstsentence)
Functions of the clavicle •Serves as a moveable, rigid support from which the scapula and free limb are suspended, keeping them away from the trunk so that the limb has maximum freedom of motion. The support formed by the clavicle is movable and allows the scapula to move on the thoracic wall at the “scapulothoracic joint,” increasing the range of motion of the limb. Fixing the point of the support in position, especially after its elevation, enables elevation of the ribs for deep inspiration. •Forms one of the bony boundaries of the cervico-axillary canal (passageway between the neck and the arm), affording protection to the neurovascular bundle supplying the upper limb. •Transmits shocks (traumatic impacts) from the upper limb to the axial skeleton.
scapula • posterolateralaspect of the thorax, on the2nd-7th ribs • three angles (lateral, superior, and inferior) • three borders (superior, lateral, and medial) • two surfaces (costal and posterior) • three processes (acromion, spine, and coracoid process)
HUMERUS- ARM BONE • largest bone in the upper limb • articulates with the scapula at the glenohumeral joint • articulateswiththe radius and ulna at the elbow joint • In cross-section, the shaft of the humerus is somewhat triangular with: • anterior, lateral, and medial borders • anterolateral, anteromedial, and posterior surfaces
Fossae • Coronoid fossa • adjacent to the radial fossa superior to the trochlea. • receives the coronoid process of the ulna during full flexion of the elbow. • Olecranon fossa • largest fossa • immediately superior to trochlea on the posterior surface of the distal end of humerus • accommodates the olecranon of the ulna during full extension of the elbow. • Radial fossa • a shallow fossa • immediately superior to the capitulum on the anterior surface of the humerus • accommodates the edge of the head of the radius when the forearm is fully flexed.
The two forearm bones serve together to form the second unit of an articulated mobile strut (the first unit being the humerus), with a mobile base formed by the shoulder, that positions the hand. However, because this unit is formed by two parallel bones, one of which (the radius) can pivot about the other (the ulna), supination and pronation are possible. This makes it possible to rotate the hand when the elbow is flexed.
LateraltoMedial Proximal-Distal S L T P T T C H
Carpal arch The carpal bones do not lie in a flat plane; rather, they form an arch, whose base is directed anteriorly. Lateralside of this base is formed by tubercles of the scaphoid and trapezium. Medialside is formed by the pisiform and the hook of hamate.
JOINT TYPE MOVEMENT SternoclavicularSaddle,fxn: ball-and-socketRaising (60°) & rotating the clavicle Anterior and posterior movements of the clavicle AcromioclavicularPlaneAnteroposteriorand vertical planes together with some axial rotation ShoulderBallandsocketCircumduction ElbowHingeFlexion and extension Prox. radioulnarPivot Pronation & supination • DistalradioulnarPivot Pronation & supination
JOINT TYPE MOVEMENT • WristCondyloid (ellipsoid) type Circumduction IntercarpalPlane Gliding Flexion & extension of the hand Abduction & adduction of the hand CarpometacarpalPlaneCircumduction, someaxialrotation,Thumb- SaddleOpposition [thumb] IntermetacarpalPlane MetacarpophalangealCondyloidFlexion-extension-abduction-adduction InterphalangealHingeFlexion-extension
LIGAMENTS Anterior and posterior sternoclavicular ligaments Costoclavicular ligament Interclavicular ligament Acromioclavicularligament Coracoclavicular ligament-conoid ligament & trapezoid ligament Glenohumeral ligaments Coracohumeral ligament Transverse humeral ligament Coracoacromial ligament Medial (ulnar) and lateral (radial) collateral ligaments Annular ligament Anterior and posterior ligaments of thedistalradio-ulnarjoint Dorsal and palmar radiocarpal ligaments Ulnar collateral ligament Radial collateral ligament Anterior, posterior, and interosseousligaments Palmar and dorsal carpometacarpal and palmar and dorsal intermetacarpal ligaments Interosseus metacarpal ligaments Superficial and deep transverse metacarpal ligaments Medial and lateral collateral ligaments Palmar ligaments Sternoclavicularjoint Acromioclavicularjoint • Shoulderjoint Elbowjoint Wristjoint Intercarpaljoints Carpometacarpal & Intermetacarpaljoints Metacarpophalangeal & interphalangealjoints
SOME FUNCTIONAL ANATOMY OF THE LIGAMENTS Anterior & posterior sternoclavicular ligaments reinforce the joint capsule anteriorly & posteriorly. Interclavicularligament strengthens the capsule superiorly. Costoclavicularligament limits elevation of the pectoral girdle. Sternoclavicularjoint Acromioclavicularligament strengthensthe acromioclavicular joint superiorly. However, the integrity of the joint is maintained by extrinsic ligaments, distant from the joint itself. Acromioclaviularjoint coracoclavicular ligament Glenohumeralligamentsstrengthen the anterior aspect of the joint capsule. Coracohumeralligamentstrengthensthecapsulesuperiorly. Transverse humeral ligamentholds the synovial sheath and tendon of the biceps brachii in place during movements of the glenohumeraljoint. Shoulderjoint
SOME FUNCTIONAL ANATOMY OF THE LIGAMENTS Lateralcollateral ligamentcomplex doesn't contribute as much to elbow stability as does the medial collateral ligament complex. Elbowjoint Anular ligament of the radius, which encircles and holds the head of the radius in the radial notch of the ulna. permits pronation and supination of the forearm. Proximalradio-ulnarjoint Palmarradiocarpal ligaments strong and directed so that the hand follows the radius during supination of the forearm. Dorsalradiocarpal ligaments take the same direction so that the hand follows the radius during pronation of the forearm. The joint capsule is also strengthened medially by the ulnar collateral ligament. T The joint capsule is also strengthened laterally by the radial collateral ligament. S Wristjoint