The elbow complex serves the ______ by providing mobility for positioning the _____ in space

______ at the elbow complex enhances the hand’s mobility, working in conjunction with stability for skilled movements involving tool

Elbow joint includes

Humeroulnar and humeroradial joints classififed as a _______ joint that functions as a ________ joint

Proximal and distal ______ joints work together as one functional unit, producing forearm rotation

Humeroradial and humeroulnar joint degree of freedom

Elbow joint has ___ major ligaments and ___ associated muscles

Five associated muscles in elbow jts

Radioulnar joints have ___ ligaments and ___ associated muscles

Muscles associated with radioulnar jts

The elbow joints and distal radioulnar jt share a single joint capsule but form distinct articulations

Articulating surfaces of the humerus

Located on anterior aspect of distal humerus

Forming part of the humerulnar articulation

Hourglass shaped and angled medially, lying slightly anterior to the humeral shaft

Located on the anterior lateral surface of the distal humerus

Forms part of the humeroradial articulation

What separates the trochlea and capitulum

Located above the trochlea

Designed to receive the coronoid process of the ulna at the end of elbow flexion

Situated above the capitulum

Designed to receive the head of the radius in elbow flexion

Located on the posterior side of the distal humerus

Designed to receive the olecranon process of ulna at the end of the elbow extension

The articulating surface at the humeroulnar jt is the

A deep, semicircular, concave surface

The articulating surface at the humeroradial jt is the

Slightly cup-shaped concave surface known as the fovea

Slightly cup-shaped concave surface

Occurs as sliding motion of the ulnar trochlear ridge on the humeral trochlear groove

Shallow concave radial head sliding iver the convex capitulum

Joint surfaces are slightly incongruent

against valgus(outward) forces

Against varus(inward) forces

Primary fiber of MCL

Primary fiber of LCL

Fibers of LCL

MCL fibers

The humeroulnar, humeroradial and inferior radioulnar joints are enclosed in a single joint capsule

Attaches to the ulna along the coronoid process margin and blends with the annular ligament

Attaches above the coronoid and radial fossae of the humerus

Continuous with the collateral ligaments

Located between the capsule and synovial membrane near the olecranon, coronoid and radial fossa

Joint capsule of elbow is _____,______,_____ in the anterior and posterior regions

Capsule contains folds that expand to allow full elbow motion

Lines the coronoid, radial and olecranon fossae as well as the medial trochlear surface and the lower part of the annular ligament

Plays crucial role in valgus stability at the elbow, preventing the joint from moving too far inward

MCL: primary stabilizer against valgus stress, especially between 20 to 120 deg of flexion

MCL: Tightens in a reciprocal manner eith the elbow flexing and extending, and provides crucial restraint at various flexion angles

MCL: helps limit elbow extension but is less important for valgus stability

MCL: Ligament connects the medial humeral epicondyle to the coronoid process of the ulna, with a broad insertion that helps distribute stress

MCL: Injuries often occur during activities with repeated valgus stress, such as pitching in sports

Important for stabilizing against varus stress and longitudinal distraction

Crucial for maintaining the stability of the elbow joint during various movements

Major flexors of the elbow

Mobility

Origin far from jt

Insertion near the jt

Muscle fibers almost perpendicular to the bony lever where it is inserted

Moment arm is nice if fibers are almost perpendicular to the bone being pulled

Rotary effect

Stability

Origin near the jt

Insertion far from jt

Muscle fibers are parallel to the bony lever where it is inserted

When it contracts, it pulls the bony lever and results to compression or approximation

Compression/translatory effect

Shunt muscle of elbow flexors

Spurt muscle of elbow flexors

Affected by FA position

Unaffected by FA position

MMT of brachialis

MMT of brachioradialis

MMT of biceps brachii

Major extensors of elbow

Strongest head of triceps

Prone to active/passive insufficiency head of triceps

Which is active whether resisted/unresisted in the triceps head

Triceps brachii: FA position

Triceps: Shoulder position

Small muscle that assists in elbow extension and acts as a stabilizer during FA rotation (supination)

Everytime the biceps brachii contracts, this muscle simultaneously contracts

Provides elbow extension just to counteract the elbow flexion produced by the biceps brachii

Flexion and extension is cancelled out by this muscle leaving supination

Opposes unwanted action of the agonist

Forearm supination prime mover

Synergist of forearm supination

Unwanted action of biceps in forearm supination

Traditionally, the axis for elbow flexion and extension is considered a relatively fixed _______ line that passes through the center of _______ and ________ of the humerus, bisecting the humeral shaft

Purpose of knowing traditional axis of motion of elbow

When UE is in the anatomical position, the long axes of the humerus and FA form an acute angle medially at the elbow

The angulation of carrying angle is due to the medial aspect of the trochlea extending more proximally that the lateral aspect. This configuration shifts the medial ulna trochlear notch upward, resulting in a lateral deviation or valgus angulation of the ulna relative to humerus.

The carrying angle helps in tasks like carrying a bucket without it hitting the lower limb, as it allows the hand to be positioned above thee center of the mass of the weight

Carrying angle: no significant difference in carrying angle between males and females

Carrying angle: femlae children typically have a larger carrying angle compared to male children

Carrying angle is formed by

Lateral angulation at the elbow

Females have larger careying angle

Normal values for male carrying angle

Normal values for female carrying angle