Joints Flashcards
The Hip Joint
Classification;
It is a synovial ball and socket joint.
It has 3 axes and 3 degrees of freedom and therefore permits a wide range of locomotor activities.
Articular Surfaces
The hip joint is the articulation between the head of the femur and the acetabulum of the innominate bone.
The Acetabulum
Is a hemispherical hollow on the outer surface of the innominate bone.
The articular surface of the acetabulum forms an incomplete ring (the lunate surface) broadest at its upper part where the pressure of the body weight falls.
It is covered with articular cartilage which is thickest where the lunate surface is broadest.
The depth of the acetabulum is increased by a fibrocartilaginous rim, the acetabular labrum.
The Head of the Femur
Forms 2/3rds of a sphere.
The head is completely covered with articular (hyaline) cartilage, except over the fovea capitis.
The Joint (Fibrous) Capsule - is a strong and dense sleeve. It is attached: to the margin of the acetabulum. It is thicker anteriorly and superiorly. It surrounds the neck of the femur, along the whole length of the intertrochanteric line and to a line on the under surface of the neck beside the lesser trochanter.
Movements: flexion, extension, med rotation, lat rotation, abduction and adduction
The Knee Joint
Classification:
The Knee Joint is a synovial bicondylar hinge joint between the condyles of the femur and condyles of the tibia, and the patella, anteriorly.
Articular Surfaces
Femur – the 2 condyles rest on the femur, united by the patellar surface. The condyles form 2 prominences, convex in both planes.
Tibia – these are the cartilage covered surfaces on the superior surface of each tibial condyle. The medial articular surface is oval and slightly concave. The lateral articular surface is smaller, rounded and concave transversely but concavo-convex from front to back.
Patella – this surface is oval and can be divided be a vertical ridge into a larger lateral and a smaller medial area.
Joint Capsule
There is no complete capsule present but it is a thick ligamentous sheath composed of muscle tendons and their expansions. It is convenient to think of it as a cylindrical sleeve passing between tibia and femur, deficient anteriorly where the patella fits.
Movements: flexion and extension
The Ankle (talocural) Joint
Classification:
It is a synovial hinge joint between the distal ends of the tibia and fibula (mortise) and the body of the talus (tenon).
Articular Surfaces
Tibia – the distal end of the tibia provides a continuous articular surface which receives the trochlear surface and medial edge of the body of the talus.
The trochlear surface is concave anteroposteriorly and slightly convex transversely with a blunt sagittal ridge (medially).
Fibula – the medial surface of the lateral malleolus of the fibula forms the lateral surface of the mortise of the joint. The articular surface is triangular.
Talus – the body of the talus forms the whole of the distal surface of the ankle joint, articulating superiorly and medially with the tibia and laterally with the fibula.
The cartilage covered trochlear surface is convex anteroposteriorly with a central longitudinal groove bound by medial and lateral lips. The surface is slightly concave transversely. The comma shaped medial surface articulates
with the lateral surface of the medial malleolus. The lateral surface articulates with medial surface of the lateral malleolus.
Joint Capsule
This completely surrounds the joint, attaching above to the articular margins of the tibia and fibula, and below to the articular margins of the talus, except anteriorly where it attaches to the neck of the talus. The Synovial Membrane lines the joint capsule.
Movements: Dorsiflexion, Plantaflexion, inversion and eversion
The Glenohumeral Joint
Classification: A synovial, ball and socket joint. An articulation between the head of humerus (ball) and glenoid fossa (socket) of the scapula.
Articular Surfaces
Head of the Humerus (HOH) – forms 2/5th of a sphere and is covered in hyaline cartilage. It faces superiorly, medially and posteriorly.
Glenoid Fossa – is situated at the superolateral angle of the scapula. It is pear-shaped, concave both vertically and transverse. It faces laterally, anteriorly and slightly superiorly. The glenoid is expanded and deepened by a fibrocartilaginous collar (glenoid labrum)
Joint Capsule
This is a loose cylindrical sleeve between the two bones. It attaches to the scapula at the margins of the glenoid labrum, anteriorly and inferiorly, and to the labrum superiorly and posteriorly.
It attaches to the humerus to the anatomical neck, around the articular margins of the head, medial to the greater and lesser tubercles, except inferiorly where it joins the medial surface of the shaft about 1cm below the articular margin. The synovial membrane is loose inferiorly this accommodates for abduction of the arm.
Movements: flexion, extension, med rotation, lat rotation, abduction, adduction
The Elbow Joint
Classification: A synovial, hinge joint.
Articulation between the trochlea surface and capitulum of the humerus and trochlear notch of the ulna and head of the radius.
Articular Surfaces
Trochlea Surface of the Humerus – This is pulley-shaped and is divided by a groove, which runs obliquely distal and laterally and therefore accounts for the carrying angle at the elbow joint. It presents a concave surface in the frontal plane and a convex surface in the sagittal plane. It forms almost a complete circle, the surface of which is covered in cartilage. The groove of the trochlea is limited medially by a sharp, prominent ridge and laterally by a lower and blunt ridge. Immediately above the trochlea, anteriorly, is the concave coronoid fossa, which receives the coronoid process of the ulnar during flexion.
Capitulum – This is a hemisphere on the anterior and inferior aspects of the humerus. The medial border is truncated forming the capitulotrochlear groove. Above the capitulum anteriorly is the radial notch, which receives the rim of the head of the radius during flexion.
Trochlear Notch of the Ulna – The proximal, deep, trochlear notch of the ulna articulates with the trochlear surface of the humerus. It has a rounded, curved longitudinal ridge extending from the tip of the olecranon process superiorly to the tip of the coronoid process inferiorly.
Head of the Radius – The superior surface of the head of the radius is concave for articulation with the capitulum. The cartilage of this surface is continuous with that around the sides of the head.
Joint Capsule
A fibrous capsule completely encloses the elbow joint, including the superior radioulnar joint.
Anteriorly, the capsule arises from the medial epicondyle away from the articular surface of the trochlea. It arches upwards and laterally attaching to the margins of the coronoid and radial fossae, and to the articular margin of the capitulum as it reaches the lateral epicondyle.
Posteriorly, the capsule follows the lateral margins of the capitulum and arches upwards around the olecranon fossa, returning to the medial epicondyle.
Distally, the capsule attaches to the margins of the trochlear notch around the olecranon and coronoid processes. It attaches to the annular ligament of the radius and blends with the medial and lateral collateral ligaments of the joint.
Movements: Flexion and extension
The Superior-radioulnar Joint
Classification:
A synovial, pivot joint. An articulation between the head of the radius rotating within the fibro-osseous ring formed by the radial notch of the ulna and the annular ligament.
Articular surfaces
Radial head - surrounded by hyaline cartilage
Radial notch - this forms 1/5th of the fibro-osseous ring
Annular Ligament – this forms the remaining 4/5ths of the articular surface, which encircles the head, and neck of the radius. The ligament is strong and is attached to the anterior and posterior margins of the radial notch of the ulna. The diameter between its lower borders is narrower than that above, so it cups in under the head of the radius and acts as a restraining ligament preventing downward displacement of the head through the ring.
Quadrate Ligament – this stretches from the lower border of the radial notch of the ulna to the adjacent medial surface of the neck of the radius. The fibres run in a criss-cross manner, so on movement, some fibres are always under tension.
Joint Capsule and Synovial membrane - it is continuous with the elbow joint and therefore shares the same joint capsule - this capsule does not attach to the radius and this would prevent joint movements
Movements: pronation and supination
The Inferior-radioulnar Joint
Classification:
A synovial, pivot joint. This articulation is between the head of the ulna and the ulnar notch on the lower end of the radius. The joint is closed inferiorly by an articular disc, which passes between the radius and the ulna.
Articular surfaces
Head of the Ulna – it is the slightly expanded lower end of the bone. The crescent- shaped articular surface on the lateral and anterior aspects is covered with hyaline cartilage and articulates with an intra-articular disc.
Ulnar Notch of the Radius – it is situated between the two edges of its interosseous border, faces medially and is covered by hyaline cartilage.
Articular Disc – is a triangular, fibrocartilaginous articular disc which unites the radius and the ulna. It is attached by its apex to the lateral side of the root of the ulna styloid process, and by its base to the sharp inferior edge of the ulnar notch.
The Interosseous Membrane – stretches between the interosseous borders of the radius and the ulna, passing obliquely downwards and medially from radius to ulna. As well as providing a firm connection between the radius and the ulna, the interosseous membrane separates and increases the area of attachment of the deep muscles of the forearm.
Movements
Rotation of the distal end of the radius around the head of the ulnar – during pronation and supination.
The Radiocarpal (wrist) Joint
Classification:
A synovial, ellipsoid joint. It is formed between the distal surfaces of the radius and articular disc, and the scaphoid, lunate and triquetral of the proximal row of the carpal bones.
Articular Surfaces
The distal surface of the Radius and the Articular Disc form a concave ellipsoid surface.
The scaphoid, Lunate and Triquetral form a convex articular surface.
Joint Capsule
This completely encloses the joint by attaching distally to the anterior and posterior edges of the radius and ulna. Laterally and medially it attaches to the radial and ulnar styloid processes, respectively. It attaches distally to the anterior and posterior margins of the articular surfaces of the carpal bones and blends with the collateral ligaments.
Movements: flexion, extension, radial deviation and ulnar deviation
Facet Joints
Classification: plane, synovial joints.
Articular surfaces: The shape and orientation of the joint surfaces vary in the 3 regions.
In the Cervical Spine the articular surfaces are flat and oval and lie in an oblique plane. The superior facets face upwards, backwards and slightly medially. The inferior facets face downwards, forwards and slightly laterally. All movements are possible.
In the Thoracic spine the articular surfaces on the superior processes project almost vertically. The superior processes face mainly backwards, but slightly upwards and laterally.
The inferior processes face forwards and slightly downwards and medially. Lateral flexion and rotation are possible.
In the Lumbar spine the articular surfaces project upwards and downwards.
The superior surfaces are concave and face medially and backwards.
The inferior processes are directed forwards and laterally. Flexion and extension are possible
Joint capsule and synovial membrane – Each joint is surrounded by a thin fibrous capsule attached to the margins of the articular surfaces. Synovial membrane lines the capsule.
The Atlanto-occipital Joint
Classification:
A synovial, ellipsoid joint. It is an articulation between the occipital condyle and the facet on the lateral mass of the atlas.
Articular Surfaces:
Articular facets on the Atlas, Articular surfaces of the Occipital Condyles
Joint Capsule and Synovial Membrane
Each of the joints is enclosed by a loose fibrous capsule lined by synovial membrane. This attaches to the margins of the articular surface
Movements - flexion and extension
The Lateral Atlanto-axial Joint
Classifications: Synovial, plane joints. An articulation between the superior articular processes on the axis and those on the inferior lateral masses of the atlas.
Articular Surfaces :
Superior articular processes of the Axis
Inferior facets of the lateral mass of the Atlas
Joint Capsule and Synovial Membrane
Each of the joints is enclosed by a loose fibrous capsule lined by synovial membrane. This attaches to the margins of the articular surface
Ligaments
Accessory Atlantoaxial Ligament – passes downwards and medially from the back of the lateral mass of the atlas to the back of the body of the axis.
Movements: rotation
The Medial Atlanto-axial Joint
Classification:
Synovial, pivot joint: An articulation between the dens of the axis and the ring formed by the anterior arch and the transverse ligament of the atlas.
Articular Surfaces:
Anterior facet on the dens of the Axis
Facet on the posterior surface of the anterior arch of the Atlas
Transverse Ligament of the Atlas
Joint Capsule and Synovial Membrane
Each of the median joints is enclosed by a thin fibrous capsule lined by synovial membrane.
Movements: rotation
The Costochondral Joint
Classification:
It is a primary cartilaginous joint. An articulation between the anterior roughened end of the rib and the lateral end of the rib cartilage.
Movement:
Slight bending of the cartilage at the junction of the rib. The cartilage may show some twisting movement at the sternum.
The Manubriosternal Joint
Classification:
It is a secondary cartilaginous joint. An articulation between the inferior surface of the manubrium and the upper body of the surface of the sternum. The bone ends are covered with hyaline cartilage, between which is a fibrocartilaginous disc.
Ligaments
Longitudinal fibrous bands strengthen the joint anteriorly and posteriorly. It is also strengthened by the sternocostal radiate ligaments.
The Xiphisternal Joint
Classification:
It is a secondary cartilaginous joint. The xiphoid process is an irregular shaped piece of cartilage joined to the body of the sternum.
