Canine Hindlimb Anatomy

Introduction[edit | edit source]

The hindlimb skeleton of the canine includes the pelvic girdle, consisting of the fused ilium, ischium, and pubis, and the bones of the hindlimb. The bones of the hindlimb are the femur, patella, fabellae (sesamoid bones), tibia, fibula, tarsus and meta-tarsus and the digital bones. The size of hindlimb bones varies due to the significant variation in size for breeds of dogs.[1]

The canine pelvic limb

Osteology of Pelvic Limb[edit | edit source]

Dogs have small, tight feet, walking on their toes; their rear legs are fairly rigid and muscular. The pelvic limb bears 40-45% of the dog's weight and provides the majority of the propulsion for locomotion.

Dog anatomy lateral skeleton

The basics of the bones are:

  1. The femur: part of the dog’s leg situated above the knee on the hind leg
  2. The stifle or knee: the joint that sits on the front of the hind leg in line with the abdomen
  3. Tibia and fibula: the part of the hind leg beneath the knee to the hock
  4. The hock: strangely shaped joint that makes a sharp angle at the back of the dog’s leg (corresponds to the human’s ankle)
  5. Tarsals and metatarsals: equivalent to human bones in feet – excluding toes[2]


Watch this 3 minute video on the canine pelvic limb bones.

[3]

Os coxae (Pelvis Bone)[edit | edit source]

Bones canine pelvis and femur
  • Os coxae, composed of the fused ilium, ischium, and pubis and acetabulum
  • Canine pelvis, positioned between the dorsal and transverse planes (though it is closer to the dorsal plane) and it is relatively small and narrow
  • Wide canine ischiatic or ischial tuberosities project caudally to form a broad ischiatic table.
  • The canine pelvis shape from a ventral view resembles a rectangle[1]
  • The symphysis pelvis is relatively long and has two portions, the symphysis ischii and symphysis pubis[1]
  • Tuber coxae and tuber sacrale are both palpable[4]
  • Tuber ischii is positioned underneath the hamstrings

Femur[edit | edit source]

Bones of the canine tibia, fibula and talus

Heaviest and largest canine bone[1]

  • Has a relatively thick and short femoral neck and a short and wide shaft with a narrow isthmus in the middle
  • Greater trochanter is lateral to the head of the humerus[3]
  • Lesser trochanter is distal to head of humerus[3]
  • Trochanteric fossa: Caudal depression  between  the  trochanters[3]
  • Third trochanter: Lateral aspect distal to greater trochanter[3]
  • Extensor fossa: depression on lateral condyle (distal) for insertion of the long digital extensor[3]
  • Femoral trochlea: Groove on distal femur for articulating with patella that is bound by two ridges of which the medial is thicker[3]

Patella[edit | edit source]

The canine patella, or kneecap, is the largest sesamoid bone in the body[1]

  • It is an ossification in the quadriceps femoris muscle[1]
  • The patella alters the pull, increases the moment arm, protects the quadriceps tendon, and provides a greater contact surface for the tendon on the trochlea of the femur than would exist without the patella. The canine patellar articular surface is mildly convex[1]

Fabellae[edit | edit source]

Two small sesamoid bones that are embedded in the heads of the gastrocnemius muscle[1]

  1. The sesamoid in the lateral head is the largest of the two. It is palpable, and articulates with the lateral femoral condyle
  2. The sesamoid in the medial head is smaller and may not have a distinct facet on the medial femoral condyle.

Tibia[edit | edit source]

Major bone in the crus (the crus is the part of the leg between the stifle (knee) and the tarsus (ankle), including the soft tissue structures[4])[1]

  • Proximal tibia is wider than the distal cylindrical tibia
  • Medial and lateral tibial condyles, an intercondylar eminence, and a tibial tuberosity are all positioned on the proximal tibia
  • Large tibial tuberosity  -  patellar ligament
  • Tibial plateau slopes distally from cranial to caudal. The extensor groove, on the cranial tibia and lateral to the tibial tuberosity, provides a pathway for the long digital extensor muscle. There is a popliteal notch on the caudal tibia in the midline, where the popliteal vessels course
  • Tibia articulates with the fibula proximally, along the interosseous crest, and distally
  • The tibial cochlea articulates with the trochlea of the talus to form the talocrural joint
  • Cochlea = two grooves separated by a ridge[4]

Fibula[edit | edit source]

Is a long, slender bone that articulates with the tibia and also serves as a site for muscle attachment[1]

  • Does not bear much weight[4]
  • A distinctive groove exists in the lateral malleolus, the sulcus malleolaris lateralis, through which the tendons of the lateral digital extensor and peroneus brevis muscles pass[1]

Tarsals and metatarsals[edit | edit source]

Dogs and cats have 7 tarsal bones[4]

  • Tarsus, or hock, consists of the talus, calcaneus, a central tarsal bone, and tarsal bones I to IV[1]
  • Talus articulates with the distal tibia and has prominent ridges. At the talocrural joint, two convex ridges of the trochlea of the talus articulate with two reciprocal concave grooves of the cochlea of the tibia[1]
  • Orientation of the grooves and ridges deviates laterally approximately 25 degrees from the sagittal plane. This deviation allows the hindpaws to pass lateral to the forepaws when dogs gallop[1]
  • The calcaneus is large and serves as the insertion of the common calcaneal tendon[1]
  • The central tarsal bone lies between the talus and the numbered tarsal bones I to III[1]
  • Tarsal IV is large and articulates with the calcaneus and metatarsal bones, spanning this entire region[1]
  • The hindpaw has five metatarsal bones[1]
  • Reduced first MT and digit (dew claw) often absent[4]

Joints of the pelvic limb[edit | edit source]

1. Sacro-iliac joint[edit | edit source]

Type:[4]Synchondrosis ( synovial joint) - sacropelvic surface of ilium; Joint capsule present

ROM:[4] Minimal as this joint is designed for stability; Accessory movements = rotation

Supporting structures:[4]Dorsal and ventral sacroiliac ligaments; Sacrotuberous

2. Hip[edit | edit source]

Type:[4] Ball and socket; Femoral head and acetabulum of the ilium, ischium and pubis; A band of fibrocartilage on the rim of the acetabulum deepens acetabulium

Supporting structures of canine pelvic limb.jpeg

ROM:[4] Flexion and extension; Minimal adduction and abduction

Supporting structures:[4] Acetabular lip (fibrocartilage) continues as transverse ligament; Ligament of the femoral head; Synovial structures and tendon sheaths: Large joint capsul, Internal obturator

3. Stifle (Knee joint)[edit | edit source]

Complex joint, combines sliding, gliding and rotation as the joint flexes and extends. This hind joint in dogs is often the largest synovial joint in the body. The stifle joint joins three bones, the femur, patella and tibia[2].

Type:[4] Hinge joint with  two cartilages/menisci; Femur and tibia - femorotibial (condylar); Femur and patella – femoropatellar (gliding joint)

ROM:[4] Flexion and extension; At the end of flexion, there is internal rotation; At the end of extension, there is external rotation

Joints of canine pelvic limb .jpeg

Supporting structures:[4]

  • Patellar ligament (patella is a sesamoid within the quadriceps  tendon)  
  • Medial collateral ligament (fused with joint capsule and medial meniscus)
  • Lateral collateral ligament (separated from lateral meniscus by popliteus tendon)
  • Cranial cruciate ligament: Caudolateral femur to cranial tibial. Prevents anterior translation of the tibial relative to the femur
  • Caudal cruciate ligament: Craniomedial femur to caudal tibia. Prevents caudal translation of the tibial relative to the femur
  • Lateral meniscus has an extra ligament, called the meniscofemoral ligament
    1. Connects the caudal lateral meniscus to the femur
    2. Femoropatellar ligaments – lateral and medial
    3. Extend from epicondyles to patella

4. Hock (tarsal)[edit | edit source]

Supporting structures of canine hock

Connects the paw (talus and calcaneus bones) to the shin bones (tibia and fibula). Held together by a collection of ligaments, located primarily on the inner and outer sides of the joint

Type:[4] Tarsocrural joint (TCJ) - has the greatest movement; Proximal and distal intertarsal joint; Tarsometatarsal joint; Intertarsal

ROM[4]: TCJ - Flexion and extension and lateral and rotatory accessory movement; Others - small amount or translatory and rotatory ROM

Ligaments of the tarsal joint[4]:

  • Medial and lateral collateral (both have long and short parts)
  • Intertarsal ligaments
  • Proximal extensor retinaculum
  • Transverse ligament on distal tibia
  • Holds down tendons of long digital extensor and cranial tibial
  • Distal extensor retinaculum
  • Holds down tendon of long digital extensor
  • Long plantar ligament - connects calcaneus to metatarsus
  • Flexor retinaculum - thickening of deep fascia over plantar aspect of tarsus
  • Form the tarsal canal with the tarsal bones containing:
    • Tendon and sheath of deep digital flexor
    • Plantar branch of saphenous artery and vein
    • Medial and lateral plantar nerves

Muscles of the Hind Limb[edit | edit source]

[5]

Muscles of the Hip[edit | edit source]

[4]
Muscle Origin Insertion Action Nerve Supply
Pectineus Pubis Femur Adducts the limb and flexes the hip Obturator
Iliopsoas

Iliacus

Psoas


Ventral surface of lumbar vertebrae

Ventral surface of the wing of Ilium

Lesser of trochanter of femur Flexes hip and externally rotates the thigh Ventral branches of lumbar spinal nerves
Gracilis Pubis symphysis Medial tibia Adducts limb Obturator
Adductors Pubic surface limb symphysis Adducts limb Obturator
Internal Obturator Pelvic floor Trochanteric fossa of the femur Lateral rotation of the femur Ischiatic nerve
Gemelli Ischium Trochanteric fossa of the femur Lateral rotation of the femur Ischiatic nerve
External Obturator Ventral surface of pubis ischium Trochanteric fossa of the femur Adducts thigh Ischiatic
Quadratus femoris Ischium Caudal surface of the femur Extends hip and adducts thigh Obturator
Deep Gluteal Body of ischium On or near greater trochanter Extension and abduction Gluteal
Muscle of canine hip.jpeg


Muscles of the Hip and Stifle 1[edit | edit source]

[4]
Muscle Origin Insertion Action Nerve Supply
Superficial gluteal Dorsal to hip joint Third trochanter Abducts hip Gluteal
Tensore fascia lata Tuber coxae Lateral femoral fascia Hip flexion and stifle extension via

tension on the lateral femoral fascia

Gluteal
Biceps femoris Ischiatic tuberosity Tibial tuberosity, tibial crest, medial tuberosity of the tuber calcanei via the calcaneal tendon[6] Extends and abducts hip Gluteal
Semitendinosus Ischiatic tuberosity Tibia and calcaneal tuberosity Extend hip, flex stifle, extend tarsus Ischiatic
Semimembranosus Ischiatic tuberosity Femur and tibia Extends hip, flexes or extends stifle Ischiatic
M f canine hip.jpeg
M of canine hip and stifle.jpeg


Muscles of the Hip and Stifle 2[edit | edit source]

[4]
Muscles Origin Insertion Action Nerve supply
Middle gluteal Wing of ilium Greater trochanter Extension and abduction Gluteal
Rectus femoris Ilium (cranioventral iliac spine) Patella and patellar tuberosity Flexes the hip and extends the stifle Femoral
Vastus lateralis Proximal femur Patella and patellar tuberosity Extends the stifle Femoral
Vastus medialis Proximal femur Patella and patellar tuberosity Extends the stifle Femoral
Vastus intermedius Proximal femur Patella and patellar tuberosity Extends the stifle Femoral

Muscles of the Stifle, Hock and Pes[edit | edit source]

[4]
Muscles Origin Insertion Action Nerve Supply
Gastrocnemius Distocaudal surface of the femur Calcaneal tuberosity Extends tarsus and flexes stifle Tibial
Long digital extensors Extensor fossa of femur Extensor processes of distal phalanges Flexes hip and extends stifle Peroneal
Soleus Head of fibula Tendon and lateral head of gastrocnemius Extends tarsus Tibial
Lateral digital extensor Fibula Lateral aspect of digit Extend digit and flexes tarsus Peroneal
Deep digital flexor Tibia and fibula Distal phalanges Extends tarsus and flexes digit Tibial
Superficial digital flexor Caudal distal femur, deep to gastrocnemius Calcaneal tuberosity and middle phalanx Flexes stifle, extends tarsus and flexes digit Tibial
Muscles of canine stiffle, hock, pes.jpeg

Nerves of the Pelvic Limb[edit | edit source]

Femoral nerve (L4, L5 sometimes L3, L6)[edit | edit source]

  • Muscle innervation - stifle extensors (quadriceps), iliopsoas[4]
  • Cutaneous innervation - medial aspect of limb

Obturator nerve (L5, L6)[edit | edit source]

  • Muscle innervation - adductors - obturator, gracilis[4]
  • Cutaneous innervation - nil

Gluteal nerve (L6, L7, S1)[edit | edit source]

  •  Muscle innervation - gluteals, TFL, biceps femoris, semitendinosus[4]
  • Cutaneous innervation - nil

Sciatic nerve (L6, L7, S1, S2)[edit | edit source]

  • Muscle innervation - biceps femoris, semitendinosus, semimembranosus[4]
  • Cutaneous innervation - see tibial and fibula branches

Tibial nerve (S1, S2)[edit | edit source]

  • Muscle innervation - extensors of hock, flexors of digits[4]
  • Cutaneous innervation - caudal aspects of the limb below stifle

Fibular nerve[edit | edit source]

  • Muscle innervation - flexors of the hock, extensors of the digits[4]
  • Cutaneous innervation - cranial and lateral aspects of limb

References[edit | edit source]

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 Canine Anatomy.Basic Science of Veterinary Rehabilitation. Cheryl Riegger-Krugh, Darryl L. Millis, and Joseph P. Weigel
  2. 2.0 2.1 Mobility Health Dog anatomy Available:https://mobility-health.com/pages/dog-anatomy#:~:text=The%20stifle%20or%20knee%20is,corresponds%20to%20a%20human%27s%20ankle) (accessed 14.10.2022)
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Pinoy Vet AnatomistSkeletal System (Part 5)- Bones of the pelvic limb. Available from https://www.youtube.com/watch?v=IWSzVpTTYpQ on 5/5/21
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26 4.27 Van Der Walt, A. Managing Disorders of the Canine Hind Limb. Plus Course, 2021.
  5. Veterinary Anatomy. Muscles of the Hip Joint - Rump Muscles in the Dog. Available from https://www.youtube.com/watch?v=7l_ur3AFxsk (last accessed 4/1/2021]
  6. Vet-Anatomy. Biceps muscle of thigh [Biceps femoris muscle] - Musculus biceps femoris. Available from: Ahttps://www.imaios.com/en/vet-Anatomy/Vet-Anatomical-Part/Biceps-muscle-of-thigh-Biceps-femoris-muscle (last accessed 30/5/2021).