Lecture 3 -- Structures and functions of Distal Hindlimb

What are the components of the stifle joint?

Femur + tibia + Patella

What bone is this? Describe the bony structure of this bone.

What structures make up the femora-tibial components of the stifle joint?

Femoral condyles, Tibial condyles
Intercondylar fossa of femur, Intercondylar eminence of tibia (Non-articular)

What is the function of the non-articular component of stifle joint

Allow ligament attachment

What are the C-shaped cartilage in stifle joint?

Meniscus

What are the functions of meniscus?

1. Stabilise joint

2. Cushioning

3. Proprioception (Contain nerve ending → Painful if damaged)

To which part of the tibia does the meniscus attach?

Tibial condyles

List out all three meniscal ligaments.

1. Menisco-tibial ligament
   → Hold meniscus - intercondylar eminence of tibia

2. Transverse ligament

   → Hold between the cranial aspects of menisci

3. Menisco-femoral ligaments

   → Hold lateral meniscus to intercondylar fossa of femur

Apart from meniscal ligaments, what other ligaments support the stifle joint?

1. Collateral ligaments (Medial and Lateral)

   → Medial epicondyle femur - tibia

   → Lateral epicondyle femur - fibula + tibia

2. Cranial cruciate ligaments

   → Divide into craniomedial + caudolateral band

   Medial femoral condyle + Lateral femoral condyle - Intercondylar eminence of tibia

3. Caudal cruciate ligaments

   → intercondylar fossa of femur - Intercondylar eminence of tibia

What is the function of the Cruciate ligaments?

1. Maintain femur on menisci

2. Resist rotation

What happens if cranial cruciate rupture?

1. Joint instability

2. Positive cranial draw sign → Excessive forward (cranial) movement of tibia relative to femur

Which cruciate ligament is most prone to damage?

Cranial cruciate ligament

Because cranial cruciate ligaments is shorter than caudal cruciate ligaments

Which muscle does the patellar ligament allow to exert force?

Patellar ligament allows the insertion of quadriceps (& sartorius) on tibial tuberosity

Where is the patella held? How does the patella move within the stifle joint?

Patella is held in trochlear groove → No lateral movement is allowed

When patella pulled proximally → Extension;
When patella pulled distally → Flexion

What supports the patella and holds it in place within the trochlear groove?

1. Medial and lateral trochlear ridges

2. Lateral & medial femoro-patellar ligaments (Orange)

3. Fascia / retinaculum (Light yellow) → Joint capsule reinforcement within the retinaculum

What are the 3 Synovial joint compartments in the stifle joint?

• Femoro-patellar

• Medial femoro-tibial

• Lateral femoro-tibia

What structures make up the femoro-patellar components of the stifle joint?

• Medial and lateral trochlear ridges

• Medial and lateral femoro-patella ligament

• Retinaculum

What are the special features of a cat’s stifle joint in radiography?

1. Pointed patella compared to dog

2. Medial labella often not mineralised (Still present! Just cannot be seen in X ray)

3. Lateral fabella + politeal sesamoid is visible

Name the stifle extensors

Sartorius (2 heads), Quadriceps muscle

How many head does sartorius have? What are the origin and insertion points of the sartorius? Which nerves innervate sartorius muscle?

2 heads

• Cranial part
  O: Crest of ilium
  I: Femur

• Caudal part
  O: Ventral iliac spine of ilium
  I: Tibial tuberosity (Join the patellar ligament together with rectus femoris)

Nerve: Femoral nerve

How many head does quadriceps have? What are the origin and insertion points of all heads of quadriceps? Which nerves innervate quadriceps?

Quadriceps has four heads:

Innervated by femoral nerve

1. Rectus femoris

   • O: Ventral ilium

   • I: Tibial tuberosity via patellar ligament

2. Vastus lateralis

   • O: Lateral Femur

   • I: Tibial tuberosity via patellar ligament

3. Vastus medialis

   • O: Medial Femur

   • I: Tibial tuberosity via patellar ligament

4. Vastus intermedius

   • O: Cranial femur

   • I: Tibial tuberosity via patellar ligament

What are the stifle flexors muscles?

Biceps femoris, Semitendinosus, Semimembranosus, Gastrocnemius

Where are the stifle flexors located in relation to the stifle joint?

Caudal to stifle joint

What are the origin and insertion points of Gastrocnemius? Which nerves innervate Gastrocnemius?

O: Caudal aspect of femur

I: Calcaneus via the common calcanean tendon

N: Tibial nerve (Branch of sciatic nerve)

How many rows are the tarsal bones arranged in, and how are they distributed?

3 rows

Proximal row:

• Talus + Calcaneus

Middle row:

• Central + IV

Distal row:

• I, II, III and IV

Which tarsal bone is the largest?

Calcaneus

Name the key structure of tarsus

Tuber calcanei = Calcanea tuberosity

What are the function of sustentaculum tali of calcaneus?

Projects medially → Allow the passage of DDFT

What is the centre of ossification of tarsus?

Other than calcaneus (2 centre of ossification), other tarsal bone have one centre of ossification

List out all the tarsus joint

1. Tarso-crural joint = Tarso-tarsal joint

2. Proximal inter-tarsal joint

3. Distal inter-tarsal joint

4. Tarso-metatarsal joint

Which tarsal joint has the most movement?

Tarso-crural joint

What is the Proximal intertarsal joint?

Talus & calcaneus – Central & IV

What is special about the trochlea of the talus bone?

Trochlea of talus bone is not vertical = Not straight → When there is flexion, the joint and the hindlimb automatically move laterally instead of in a straight line → Avoid overreaching or hitting the forelimb especially when they are doing long strides e.g. running

What supports the tarsus joint?

1. Collateral ligaments

   • Calcaneus - metatarsal bone

2. Plantar ligament

3. Fibrocartilagenous of joint capsule

4. Retinaculum (On top of the plantar ligament and fibrocartilagenous)

   1. On top of the palmar ligament and fibrocartilagenous

What types of collateral ligaments are there in the tarsus joint?

• Long collateral ligaments (medial and lateral):

  • Medial: from the tibia to the 2nd metatarsal

  • Lateral: from the fibula to the 5th metatarsal

• Short (intertarsal) collateral ligaments:

  • Between adjacent tarsal (bridge) bones