Anatomy II: Locomotor Apparatus - Muscles of the Hindlimb

Learning Objectives

  • Understanding Key Terminology

    • Locomotor apparatus, muscular system, myology.

    • Differences between muscle types:

    • Smooth muscle

    • Cardiac muscle

    • Skeletal muscle

    • Important anatomical structures:

    • Tendon

    • Bursa (bursae)

    • Tendinous sheath (synovial vagina)

    • Tendinous recess

    • Fascia (fasciae)

    • Aponeurosis (aponeuroses)

    • Retinaculum (retinacula)

Muscles of the Hindlimb

Origin, Insertion, Action, and Innervation

Muscles Acting on the Hip

  • Gluteal Group

    • Superficial gluteal

    • Middle gluteal

    • Deep gluteal

    • Tensor fascia lata

  • Medial Group

    • Gracilis

    • Pectineus

    • Adductor

    • External obturator

    • Sartorius

  • Caudal Group (Hamstrings)

    • Biceps femoris

    • Semitendinosus

    • Semimembranosus

Muscles Acting on the Stifle

  • Cranial Group (ExtENSOR of the Stifle)

    • Quadriceps femoris

  • Caudal Group (FLEXOR of the Stifle)

    • Popliteus

Muscles Acting on the Tarsus and Toes

  • Cranio-lateral Face of the Leg (FLEXORS of the Hock)

    • Cranial tibialis

    • Peroneus tertius

    • Peroneus longus

  • FLEXORS of the Hock and EXTENSORS of the Toes

    • Long digital extensor

    • Lateral digital extensor

    • Medial digital extensor

  • Caudal Face of the Leg (EXTENSORS of the Tarsus)

    • Gastrocnemius

  • EXTENSORS of the Tarsus and FLEXORS of the Toes

    • Deep digital flexor

    • Superficial digital flexor

Functional Anatomy of the Horse

Suspensory Apparatus

  • Components:

    • Suspensory ligament (third interosseus muscle)

    • Distal sesamoido-phalangeal ligaments

    • Proximal sesamoid bones

    • Palmar sesamoid ligament (intersesamoid ligament)

  • Function: Supports the fetlock joint and prevents hyperextension.

Reciprocal Apparatus

  • Components:

    • Peroneus tertius

    • Calcaneum tendon

  • Function: Allows simultaneous movements of the stifle joint and tarsal joint through two tendinous cords.

Stay Apparatus

  • Components:

    • Lacertus fibrosus

    • Suspensory apparatus

    • Reciprocal apparatus

  • Function: Keeps the horse standing without muscular effort, prevents excessive flexion or hyperextension in multiple joints.

Hindlimb Myology

Joint Flexion Angles

  • Understanding joint operations is essential before studying associated muscles in the hindlimb.

Anatomical Structures of the Hindlimb

  • Include diagrams and images from Collin's modified work for better visualization.

Additional Insights

Horse Digit Anatomy

  • Key aspects to remember: Anatomy compared to building kit:

    • Individual bones (osteology)

    • Articulated bones (arthrology)

    • Surrounding structures (myology, neuroanatomy, vascular anatomy).

References

  1. R. Barone, Anatomie compare des animaux domestiques, Ed Vigot, 1989.

  2. B. Collin, Anatomie du cheval, myologie, Ed Derouaux-ordina, 1989.

  3. B. Collin, Anatomie du chien, myologie, Ed Derouaux-ordina, 2002.

  4. A. Hennau, Notes d'anatomie compare bovine, mouton et chevre, Ed liege universite, 1999.

  5. A. Gabriel et al., Notes d'anatomie comparee du porc, du chat du lapin et des oiseaux, Ed liege universite, 2005.

  6. C. Pasquini et al., Anatomy of domestic animals, muscles, Ed SUDZ, 2007.

  7. K.M. Dyce et al., Textbook of veterinary anatomy, Ed Saunders Elsevier, 2010.

  8. E. König and H.G. Liebich, Veterinary anatomy of domestic mammals, Schattauteur, 2004.