Part 4

• Biceps femoris


  Largest muscle of the thigh
• Biceps femoris


  • Origin: The sacrotuberous ligament and the ischiatic tuberosity
  • Insertion: by means of the fascia lata and crural fascia to the patella, patellar ligament and cranial border of the tibia; by means of the crural fascia to the subcutaneous part of the tibial body; the tuber calcanei
  • Action: To extend the hip, stifle and hock. The caudal part of the muscle flexes the stufle
  • Innervation: Sciatic nerve

  
• Semitendinosus


  • Origin: The ischiatic tuberosity
  • Insertion: The medial surface of the body of the tibia and the tuber calcanei by means of the crural fascia. Near its insertion, it lies on the medial head of the gastrocnemius and is covered by the gracilis muscle
  • Action: To extend the hip, flex the stifle and extend the hock
  • Innervation: Sciatic nerve

  
• Semimembranosus


  • Origin: The ischiatic tuberosity
  • Insertion: The medial lip of the caudal rough surface of the femur and the proximal end of the tibia
  • Action: To extend the hip. The part that attaches to the tibia flexes or extends the stifle, depending upon the position of the limb
  • Innervation: Sciatic nerve

  
• Sartorius


  • Origin: Cranial part – the crest of the ilium and the thoracolumbar fascia, Caudal part – the cranial ventral iliac spine and the adjacent ventral border of the ilium
  • Insertion: Cranial part – the patella, in common with the restuc femoris of the quadriceps, Caudal part – the cranial border of the tibia, in common with the gracilis
  • Action: to flex the hip. The cranial part extends the stifle; the caudal part flexes the stifle
  • Innervation: femoral nerve

  
• Gracilis


  • Origin: The pelvic symphysis by means of the symphysial tendon
  • Insertion: The cranial border of the tibia and with the semitendinosus, the tuber calcanei
  • Action: To adduct the limb, flex the stifle and extend the hip and hock
  • Innervation: Obturator nerve
• Pectineus


  • Origin: The cranial pubic ligament and the iliopubic eminence
  • Insertion: The distal end of the medial lip of the caudal rough face of the femur
  • Action: to adduct the limb
  • Innervation: Obturator nerve

  
• Adductor


  • Origin: The entire pelvic symphysis by means of the symphysial tendon, the adjacent part of the ischiatric arch and ventral surface of the pubis and ischium
  • Insertion: The entire lateral lip of the caudal rough face of the femur
  • Action: To adduct the limb and extend the hip
  • Innervation: Obturator nerve
• Tensor fasciae latae


  • Origin: The tuber coxae and adjacent part of the ilium; the aponeurosis of the middle gluteal muscle
  • Insertion: The lateral femoral fascia
  • Action: To tense the lateral femoral fascia, flex the hip and extend the stifle
  • Innervation: Cranial gluteal nerve

  
• Superficial gluteal


  • Origin: The lateral border of the sacrum and the first caudal vertebra, partly means of the sacrotuberous ligament; the cranial dorsal iliac spine by means of the deep gluteal fascia
  • Insertion: The third trochanter
  • Action: To extend the hip and abduct the limb
  • Innervation: Caudal gluteal nerve
• Middle gluteal


  • Origin: The crest and gluteal surface of the ilium
  • Insertion: The greater trochanter
  • Action: To extend and abduct the hip and to rotate the pelvic limb medially
  • Innervation: Cranial gluteal nerve
• Deep gluteal


  • Origin: The body of the ilium; the ischiatic spine
  • Insertion: The cranial aspect of the greater trochanter
  • Action: To extend and abduct the hip, and to rotate the pelvic medially
  • Innervation: Cranial gluteal nerve

  
• Internal obturator


  • Origin: The symphysis pelcvis and the dorsal surface of the ischium and pubis
  • Insertion: The trochanteric fossa of the femur
  • Action: To rotate the pelvic limb laterally at the hip
  • Innervation: Sciatic nerve
• Gemelli


  • Origin: The lateral surface of the ischium, caudal to the acetabulum and ventral to the lesser ischiatic notch
  • Insertion: The trochanteric fossa
  • Action: To rotate the pelvic limb laterally at the hip
  • Innervation: Sciatic nerve
• Quadratus femoris


  • Origin: The ventral surface of the pubis and ischium
  • Insertion: The trochanteric fossa
  • Action: To rotate the pelvic limb laterally
  • Innervation: Obturator nerve

  
• External Obturator


  • Origin: The ventral surface of the pubis and ischium
  • Insertion: The trochanteric fossa
  • Action: To rotate the pelvic limb laterally
  • Innervation: Obturator nerve
• Quadriceps femoris


  • Origin: Rectus femoris – ilium; vasti muscles – proximal femur
  • Insertion: tibial tuberosity
  • Action: To extend the stifle and flex the hip (rectus)
  • Innervation: Femoral nerve

  
• Iliopsoas


  • Origin: Psoas major – lumbar vertebrae; iliacus – cranioventral ilium
  • Insertion: lesser trochanter
  • Action: to flex the hip (major flexor of the hip)
  • Innervation: ventral branches of lumbar nerves, and femoral nerve
• Cranial tibial


  • Origin: The extensor groove and the adjacent articular margin of the tibia; the lateral edge of the cranial tibial border
  • Insertion: The plantar surface of the base of the metatarsals I and II
  • Action: To flex the tarsocrural joint and to rotate the paw laterally so that the plantarsurface faces medially
  • Innervation: Fibular nerve

  
• Long digital extensor


  • Origin: The extensor fossa of the femur
  • Insertion: The extensor processes of the distal phalanges of digits II, III, IV and V
  • Action: To extend the digits and flex the tarsus
  • Innervation: Peroneal nerve
• Peroneus longus/Fibularis longus


  • Origin: The lateral condyle of the tibia, proximal end of the fibula and the lateral epicondyle of the femur by means of the lateral collateral ligament of the stifle
  • Insertion: The 4th tarsal bone; the plantar aspect of the proximal ends of metatarsals
  • Action: To flex the tarsus and rotate the paw medially so that the plantar surface faces laterally
  • Innervation: Peroneal nerve

  
• Gastrocnemius


  • Origin: The medial and lateral supracondylar tuberosities of the femur
  • Insertion: The tuber calcanei
  • Action: To extend the tarsus and flex the stifle
  • Innervation: tibial nerve

  
• Superficial digital flexor


  • Origin: The lateral supracondylar tuberosity of the femur
  • Insertion: The tuber calcanei and the bases of the middle phalanges of digits II, III, IV, and V
  • Action: To flex the first two digital joints of the four principal digits; fles the stifle, extend the tarsus
  • Innervation: Tibial nerve
• Deep digital flexor (lateral and medial)

  • Origin: The proximal two-thirds of the tibia, the proximal half of the fibula and the adjacent interosseous membrane
  • Insertion: The plantar surface of the base of each of the distal phalanges
  • Action: To flex the digits and extend the tarsus
  • Innervation: Tibial nerve
• Popliteus


  • Origin: The lateral condyle of the femur
  • Insertion: The proximal third of the caudal surface of the tibia
  • Action: To flex and stifle and rotate the leg medially
  • Innervation: Tibial nerve