Elbow and Knee Joints Flashcards
Which kind of joint are elbow and knee joints ?
Hinge Joints
What are some characteristics of all hinge joints ?
- articular surfaces are reciprocally shaped
- strong collateral ligaments
- muscles are grouped at the sides of the joint where they do not interfere with movement
What are the 2 joints making up the elbow joint ?
Humero-radial and humero-ulnar joints
What movements does the proximal radio-ulnar joint allow for?
Supination and pronation
The knee joint allows for free movement in how many planes ?
One plane
Describe the main features of the elbow joint capsule.
- Single fibrous capsule for 3 joints
- lined by synovial membrane
- attaches to the articular margins
- strengthened by radial and ulnar collateral ligaments
What are the weak areas of the elbow joint capsule ?
Capsule is weaker anteriorly and posteriorly
Does the radial collateral ligament attach to the radius ?
No
What are ligaments surrounding the elbow joint ? What is the role of each ?
Anular ligament: holds the radial head in place, but allows its rotatory movement for supination and pronation
Interosseal membrane: holds the radius and ulna together and transmits forces from the radius to the ulna; muscle attachment
What is the possible result of an excessively forceful pull on the hand ?
Dislocation of the radial head from the anular ligament
Which joints are in use during pronation and supination ?
Proximal and distal radio-ulnar joints
Describe the main features of the knee joint capsule.
- fibrous
- lined by synovial membrane
- attaches to the articular margins
- has collateral ligaments supporting the sides of the joint
- has intra- articular ligaments and cartilages
- INCOMPLETE (Anteriorly, replaced by the quadriceps tendon (patellar ligament), the patella and fat pads on either side of patellar ligament)
What are the augmentations of the knee joint capsule ?
- ANTERIORLY, by the iliotibial tract and patellar retinacula from quadriceps
- POSTERIORLY, by the oblique popliteal ligament (expansion of the semimembranous) and the arcuate popliteal ligament
What bursaes communicate with the articular cavity of the knee joint ?
- Suprapatellar bursa
- popliteus bursa
- anserine bursa
- gastrocnemius bursa
What are the collateral ligaments of the knee joint ? What is their respective role ? Where do they extent from, and where do they extend to ? Are they fused to the joint capsule (if yes, anything else they are fused to ?) ?
Lateral (Fibular) ligament:
- prevents adduction of leg
- from Lateral femoral epicondyle to Head of fibula
- Not fused to joint capsule
Medial (Tibial) ligament:
- prevents abduction of leg
- from Medial femoral epicondyle to Tibial condyle
- fused to joint capsule and medial meniscus
Where is the tendon of popliteus found ?
Between the lateral fibular ligament and the knee capsule
Allocate each of the following characteristics to either medial, or lateral collateral ligament of the knee: broad, strong, flat
Medial collateral ligament: broad, flat
Lateral collateral ligament: strong
How many menisci are there around the knee joint ? What is their names ?
2
Medial meniscus and Lateral meniscus
Which connective tissue are menisci usually made of ?
Fibrocartillage
What are the functions of the medial and lateral menisci of the knee ?
- Increase the congruence of articular surfaces
- Dissipate the forces/stress on articular cartilage
- Absorb shock
- Decrease friction
- Participate in locking of knees
- Proprioception
Where, and how are the medial and lateral menisci of the knee connected ?
Anteriorly, by the transverse ligament of the knee
Where do the medial and lateral menisci of the knee move during flexion and extension of the knee?
They move antero-posteriorly
Describe the vascularity of the menisci of the knee.
Inner 2/3 is avascular, outer 1/3 partially vascular
Where are the horns of the menisci of the knee attached to ?
To the intercondylar region of the tibial plateau
What are surrounding structures attached to the medial and lateral menisci of the knee respectively ?
Medial meniscus: to the joint capsule AND to the medial collateral ligament
Lateral meniscus: to the joint capsule and to the tendon of the popliteus muscle but NOT to the lateral collateral ligament
Where does the Meniscofemoral ligaments extend from and to ?
From the posterior horn of lateral meniscus, to medial condyle of femur
What are the two cruciate ligaments of the knee called ?
Anterior and posterior cruciate ligaments
What are the functions of the anterior and posterior cruciate ligaments respectively ?
Anterior cruciate ligament:
- Prevents anterior movement of tibia and hyperextension
- Act as a pivot for rotatory movements between the bones
Posterior cruciate ligament:
- Prevents posterior movement of tibia (walking downhill)
- Act as a pivot for rotatory movements between the bones
True or false: Parts of the cruciate ligaments of the knee are taut in all positions of the joint.
True
What do the Q-angle and the Carrying angle refer to respectively ?
Q-angle: angle between the anatomical axis of the femur and that of the tibia
Carrying angle: angle between the long axes of arm and forearm.
Is the carrying angle more pronounced in males or females ? Why ?
More pronounced in the female to account for the wider pelvis
What is the carrying angle approximately equal to, in males, and in females ?
10-15 degrees in males
>15 degrees in females
Where do flexors of the elbow and knee pass, relative to the elbow and knee joint respectively ?
Anterior to the elbow joint
Posterior to the knee koint
What are the flexors of the elbow ?
Main: Brachialis (and control the extension produced by gravity)
Also: Brachioradialis (when the forearm is midway between pronation and supination), Biceps brachii (esp. when supinated), Pronator teres and the wrist/digit flexors (Palmaris longus, flexor carpi radialis, flexor digitorum superficialis)
What is the major flexor origin ?
Medial epicondyle
What is another movement enabled by biceps brachii, besides flexion of the elbow ?
Supination
Name the origin and insertion of the main flexors of the elbow.
BRACHIALIS
Origin: Distal half of anterior surface of humerus
Insertion: Coronoid process and tuberosity of ulna
BICEPS BRACHII:
Origin: Short head: Coracoid process of scapula Long head: supraglenoid tubercle of scapula
Insertion: Tuberosity of radius and fascia of forearm via bicipital aponeurosis (lacertus fibrosus)
BRACHIORADIALIS:
Origin: Proximal part of lateral supraepicondylar ridge of humerus
Insertion: Distal end of the radius just proximal to the radial styloid process
PRONATOR TERES
How are the flexors of the elbow innervated ?
Supplied by the musculocutaneous nerve except Brachioradialis (radial nerve) and pronator teres
True or False: Brachioradialis is the only muscle supplied by the radial nerve that brings about flexion.
True
What are the extensors of the elbow ?
Main: Triceps Brachii (but gravity takes over most of the time)
Also: Anconeus, Superficial forearm extensors (Extensors carpi radialis longus and brevis, Extensor carpi ulnaris, Extensors digitorum and digiti minimi)
What is another function of the long head of the triceps (besides extension of the elbow) ?
Preventing dislocation of the abducted shoulder
What is the name of the indentation between lateral and medial heads of triceps ?
Radial (spiral) groove of humerus
Radial nerve and Profunda brachii artery
What is the origin and insertion of the extensors of the elbow ?
TRICEPS
Origin: Long head: infraglenoid tubercle of scapula Lateral head: posterior surface of humerus, superior and lateral to the radial groove Medial head: posterior surface of humerus, medial and inferior to the radial groove
Insertion: Olecranon
ANCONEUS
Origin: Lateral epicondyle of humerus
Insertion: Lateral surface of olecranon and superior part of posterior surface of ulna
How are extensors of the elbow innervated ?
Supplied by the radial nerve (including the superficial forearm extensors)
Which structures keep the radius in place ?
Anular ligament, the interosseous membrane and the inferior radio-ulnar joint
What are the pronators of the elbow ? Which one initiates pronation ?
Pronator Teres and Pronator Quadratus (initiates it)
What are the supinators of the elbow ?
Main: Biceps Brachii
Also: Supinator
What is the origin and insertion of the pronators of the elbow ?
PRONATOR TERES
-Origin:
Ulnar head- coronoid process of ulna
Humeral head- Medial epicondyle of humerus
-Insertion: Middle of convexity of lateral surface of radius
PRONATOR QUADRATUS
-Origin: Distal quarter of anterior surface of ulna
-Insertion: Distal quarter of anterior surface of radius
What is the origin and insertion of the supinators of the elbow ?
SUPINATOR:
- Origin: Lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa, crest of ulna
- Insertion: Lateral, posterior, and anterior surfaces of proximal third of radius
BICEPS BRACHII:
Origin: Short head: Coracoid process of scapula Long head: supraglenoid tubercle of scapula
Insertion: Tuberosity of radius and fascia of forearm via bicipital aponeurosis (lacertus fibrosus)
How are the pronators of the elbow innervated ?
Median Nerve
How are the supinators of the elbow innervated ?
Supinator muscle is supplied by radial nerve
Biceps brachii is innervated by musculocutaneous nerve
What is the most powerful supinator when the elbow is flexed ?
Biceps Brachii
Which structure passes through supinator muscle ?
Deep branch of the radial nerve
List the structures present in the antecubital fossa, lateral to medial.
- biceps brachii tendon
- brachial artery and vein
- median nerve
- superficial veins (median cubital vein)
What are the main movements at the knee ?
Flexion and Extension
What other movements may take place at the knee when the knee is in a semiflexed position and the foot is off the ground ?
Medial and lateral rotation of the tibia with respect to the femur
True or false: Long muscles acting across two joints (e.g. the hamstrings, rectus femoris) can only work efficiently across one joint at a time.
True
What are the flexors of the knee ?
Biceps femoris Semitendinosus Semimembranosus Gastrocnemius Gracilis Sartorius Plantaris
What is the origin and insertion of the flexors of the knee ?
BICEPS FEMORIS
Long Head-
Origin: Ischial tuberosity
Insertion: Lateral side of the head of the fibula
Short Head-
Origin: linea aspera and lateral supracondylar line of femur
Insertion: lateral side of the head of the fibula
SEMITENDINOUS
Origin: ischial tuberosity
Insertion: medial surface of tibia
SEMIMEMBRANEOUS
Origin: ischial tuberosity
Insertion: medial tibial condyle
GASTROCNEMIUS
Origin:
Lateral head- lateral aspect of lateral condyle of femur
Medial head- popliteal surface of femur, superior to medial condyle
Insertion: Posterior surface of calcaneus via calcaneal tendon
GRACILIS and SARTORIUS
Origin: pelvis
Insertion: upper, medial tibia
PLANTARIS
Origin: Inferior end of lateral supracondylar line of femur and oblique popliteal ligament
Insertion: Posterior surface of calcaneus via calcaneal tendon
What is the main movement enabled my gastrocnemius, besides knee flexion ? How come it also flexes the knee ?
Plantar flexor of the ankle
Because it is attached to the femur (its origin)
What are the hamstring muscles ?
Semimembranous, semitendinous, biceps femoris
What movements do the hamstring muscles allow for ?
Flexion of the knee
Extension of hip
Which type of flexion exactly does the GASTROCNEMIUS muscle function in ?
When the foot is fixed and the person kneels down
What muscles is the Pes Anserinus muscle group made of ?
Semiteninosus, Gracilis, Sartorius
What is the function of Pes Anserinus as a muscle group ?
Adds significant dynamic stability to the medial
side of the knee
Where do the muscles of Pes Anserinus attach, relative to the medial-lateral axis of rotation of the knee ?
Posterior to it
What is the structure that Gluteus Maximus and Tensor Fasciae Latae insert into ?
The iliotibaial tract
What movements of the knee do the gluteus maximus and tensor fasciae latae facilitate ?
They support the knee in extension, until the hamstrings flex the knee
May also augment flexion
What are the extensors of the knee ?
Main: Quadriceps femoris
Also: Gluteus Maximus, Tensor Fascia Latae
What is the origin and insertion of the extensors of the knee ?
QUADRICEPS FEMORIS
Origin:
Rectus femoris- Anterior inferior iliac spine and ilium superior to acetabulum
Vastus lateralis- Greater trochanter and lateral lip of linea aspera
Vastus medialis- Intertrochanteric line and medial lip of linea aspera
Vastus intermedius- Anterior and lateral surfaces of shaft of femur
Insertion:
Base of patella
Tibial tuberosity via patellar ligament Patella and tibia via Medial and lateral
patellar retinacula
GLUTEUS MAXIMUS
Origin: via iliotibial tract
Insertion: via iliotibial tract
TENSOR FASCIA LATAE
Origin: via iliotibial tract
Insertion: via iliotibial tract
How is quadriceps femoris innervated ?
Supplied by femoral nerve
What does the femur do in the final stage of extension ?
Rotates medially to “screw” the knee into its stable, “close-packed” position
What are the roles of the lateral facets of the patella ?
- articulates with prominent lateral femoral condyle
- prevent dislocation during knee extension
- increase the insertion angle of quadriceps tendon
What are the anatomical features of a locked knee ?
- tightened ligaments
- flat surface of the femoral condyles are in contact with the tibia plateaus so joint surfaces become larger
- amount of muscle work needed to maintain the standing position is reduced
- vastus medialis locks the knee, aided by Gluteus maximus, tensor fascia latae
During flexion of the knee, what position must popliteus be in ?
Laterally rotated
What is the origin and insertion of the popliteus muscle ?
Origin: Posterior surface of tibia, superior to soleal line
Insertion: Lateral surface of lateral condyle of femur and lateral meniscus
What movements does popliteus participate in ?
Lateral rotation of the femur
Un-locking of the knee
Where is the Popliteal Fossa found ? What is its shape ?
Behind the knee joint
Diamond shape
What is the Popliteal Fossa bounded by ?
Biceps femoris, semimembranosus and tendon of semitendinosus and Lateral and medial heads of the gastrocnemius
Finish the sentence: The adductor canal opens to the popliteal fossa through ?
Adductor hiatus
What does the popliteal fossa contain ?
- Popliteal artery and vein, with their branches and tributaries (artery slightly medial to Vein)
- Tibial nerve
- Common fibular nerve
- Posterior cutaneous nerve of the thigh
- Terminal part of small saphenous vein
- Lymph nodes
- Fat
Which structure is at risk in knee dislocation and supracondylar fracture of the femur ?
Popliteal artery
How is the biceps reflex elicited ?
By tapping the biceps tendon in the antecubital fossa
How is the knee reflex elicited ?
By tapping the patellar ligament
Which nerve does the biceps reflex test ? Which spinal segments ?
Musculocutaneous nerve
C5 and C6
Which nerve does the knee reflex test ?
Which spinal segments ?
Femoral nerve
L3 and L4
What are the different levels of a reflex ?
- Absent
- Trace (Diminished)
- Normal
- Brisk
- Hyperactive
- Clonus
