Elbow & Forearm Flashcards
What joints make up the elbow?
Humeroulnar Joint and Humeroradial Joint
What type of joint is the Humeroulnar Joint?
Uniaxial, Hinge Joint
Which joint is motion actually occuring in the elbow?
Humeroulnar Joint
Which joint is for stability at the elbow?
Humeroradial Joint
What is the end feel on full extension of the Humeroulnar Joint?
Bony/Hard, because of olecranon process of ulna that moves into the olecranon fossa of the humerus, limiting further motion
What articulates at the Humeroradial Joint?
The capitulum articulates with the head of the humerus
What is the end feel on full flexion of the humeroradial joint?
Soft/Springy, because biceps & brachialis meet forearm and limits further motion
What type of joint is the Radioulnar Joint?
Uniaxial or Pivot Joint
Proximal Radioulnar Joint is located where?
At the proximal end, the head of the radius pivots within the radial notch of the ulna
Distal Radioulnar Joint is located where?
At the distal end; the distal end of the radius rotates around the distal end of the ulna
Radioulnar Joint allows only what motion?
Supination or Pronation
What plane and axis pronation/supination occuring?
Transverse plane/ Vertical Axis
Which bone is stationary during pronation/supination?
Ulna; the radius moves around the ulna which is locked in place by its bony shape at the proximal end
A muscle must attach where, to be able to pronate or supinate the forearm?
Radius
What is the plane and axis for flexion/extension of the elbow?
Sagittal Plane/ Anterior Posterior Axis
What is the ROM for full flexion?
5-0-145*
What is valgus?
Elbows bending outward
What plane and axis is valgus?
Frontal Plane/ Medial Lateral Axis
What is the function for normal cubital valgus?
to keep a carrying object away from the body, i.e. carrying a spider, carrying the trash
What is the normal carrying angle for women?
10-15
What is the normal carrying angle for men?
5*
What is varus?
elbows bent inward, deviated toward the midline
Arthrokinematics for the Humeroulnar Joint
In the open chain elbow flexion, the concave trochlear notch of the proximal ulna slides and rolls anteriorly on the convex trochlea of the humerus
(Posteriorly for elbow extension)
Arthrokinematics for the Humeroradial Joint during flexion
concave radial head rolls and slides anteriorly on convex capitulum of humerus
Arthrokinematics for the Humeroradial Joint during pronation/supination
the radius spins about its own axis
Is the radial head convex or concave?
Both
Arthrokinematics for Proximal Radioulnar Joint
Convex radial head spins within concave radial notch of the ulna and the annular ligament
Arthrokinematics for Prox. Radioulnar Joint during pronation/supination
The radius spins about its own axis in place, in the direction of the moving thumb.
Clockwise-Left hand pronation
Counterclockwise-Right hand pronation
Arthrokinematics for Distal Radioulnar Joint
During S/P, the distal radioulnar joint rolls and slides in the same direction across the stationary ulna
Bony Landmarks of the Scapula and their muscle attachments
Coracoid Process- short head of biceps
Supraglenoid Tubercle- long head of biceps
Infraglenoid Tubercle- long head of triceps
Bony Landmarks of the Humerus and their muscle attachments
Trochlea- articulates with ulna
Coronoid fossa-receives coronoid process of ulna during F/E
Medial Epicondyle-Pronator Teres
Lateral Epicondyle-Anconeus & Supinator
Medial Supracondylar Ridge-anterior lip for brachialis & pronator teres, posterior lip for medial head of triceps
Lateral Supracondylar Ridge- brachioradialus
Coronoid Process
Brachialis
Radial Notch
Head of Radius
Radial Head
?
Bicipetal (Radial) Tuberosity
Biceps Brachii
Elbow Joint Supporting Structures
Joint Capsule
Medial (Ulnar) Collateral Ligament
Lateral (Radial) Collateral Ligament
Superficial Olecranon Bursa
What type of joint is the elbow?
Synovial
Which portion of the joint capsule limits elbow extension?
Anterior portion; during ext anterior is tight while posterior has “slack”
Which portion of the joint capsule limits elbow flexion?
Posterior portion
What does the joint capsule protect during elbow extension?
It protects elbow against medial (valgus) and lateral (varus) directed forces
What does the Medial (Ulnar) Collateral Ligament do?
Provides medial stability and contributes to weight bearing stability
Protects elbow against medial (valgus) directed forces
What ligament is subjected to stress during throwing activites?
Medial Collateral Ligament (Ulnar Collateral Ligament)
What does the Lateral (Radial) Collateral Ligament do?
Provides lateral stability and contributes to weight bearing stability
Protects against lateral (varus) directed forces
What ligament is subjected to stress during activities such as backhand in tennis?
Lateral (Radial) Ligament
Superficial Olecranon Bursa
Superficial location makes it susceptible to injury and inflammation, it is a shock absorber, you cannot palpate it unless its inflammed
Forearm Supporting Structures
Annular Ligament
Interosseus Membrane
Articular Disk
Distal Radioulnar Joint Capsule
Annular Ligament
Holds head of radius against ulna
B/c of constant contact b/w R & U it helps create the pivot (spin) action of this joint ((CW or CCW))
Interosseus Membrane
Transmits forces proximally through forearms
Provides stability b/w radius & ulna prox and distally
Becomes taut during pronation
Provides more surface area for attachment of forearm and wrist muscles
Articular Disk
Improves articulation of distal radioulnar joint
Improves radiocarpal articulation
Distal Radioulnar Joint Capsule
Provides stability to the distal radioulnar joint
Reinforced by palmar & dorsal capsular ligaments
Brachialis
Strong elbow flexor w/ palm down
Gets supinator out of way
Lies deep to the biceps brachii
No attachment on radius, no role in S/P
Biceps Brachii
has 2 heads that attach to scapula-allows muscles to assist in shoulder flexion
Forearm supination “corkscrew”
Muscle activity increases when elbow flexion is combined w/ shoulder flexion
Synergistic force couple w/ brachialis
Brachioradialis
Lateral side of Radius
2 attachments: Humerus, Radius
Elbow Flexion: most effective when elbow is in neutral
Triceps Brachii
Elbow Extension
Assist shoulder extension bc it crosses GH joint
Anconeus
Keeps annular ligament from being pinched in olecranon fossa during elbow extension
Assists in stabilizing the elbow in medial-lateral directions
Small MA, low torque producing potential
Not a prime mover in any joint action, assists in elbow ext
Pronator Teres
Forearm pronator
Elbow Flexion
Works in synergy w/ pronator quadratus
Crosses elbow anteriorly
Pronator Quadratus
Forearm pronator
Works in synergy w/ pronator teres
Stablizes distal radioulnar joint
Supinator
Supination
Works in syngergistic force couple w/ biceps brachii
Wraps around elbow joint laterally from posterior surface to anterior surface
Nerve Innervation of Brachialis & Biceps Brachii
Musculocutaneous Nerve
Nerve Innervation of Brachioradialis, Triceps Brachii & Supinator
Radial Nerve
Nerve Innervation of Pronator Teres & Pronator Quadratus
Median Nerve
