Hindlimb - Anatomy & Physiology

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Common structures of the Proximal Hindlimb and Pelvis

Ilium

• The ilium makes up the craniodorsal part of the hip bone.
• It extends in a cranio-dorsal direction from the hip joint to the articulation with sacrum.
• It is made from a cranial wing and a caudal body.

Ilial Wing

• The margin of the wing is known as the iliac crest. Along the crest are two very important anatomical landmarks:
  • Tuber Coxae or Coxal Tuberosity forms the palpable point of the hip.
  • Sacral Tuber is the thickened mediodorsal angle of the ilial wing.
• The lateral surface of the wing provides a point of attachment for the gluteal muscles.
• The medial surface has two distinct parts:
  • The lateroventral part provides the point of insertion for many pelvic muscles.
  • The mediodorsal part articulate with the sacrum forming the sacroiliac joint
• The caudodorsal border of the wing is very concave and along its surface exists the greater sciatic notch. This is where the sciatic nerve runs over the ilium.

Ilial Body

• The only anatomical feature of note is the psoas tubercle on the ventral border. This provides attachment for the psoas muscle.

Ossification of the Ilium

Ischium

The Ischium can be divided into three main sections:

• The body
  • Is part of the acetabulum
  • The dorsal border is continuous with that of the ilium forming the ischiatic spine; this tapers towards the lesser sciatic notch.
• The caudal plate
  • Extends cranially into the symphysial and acetabular branches, which form the caudal borders of the obturator foramen.
  • The caudal section is thickened forming the ischial tuberosity. This is a visible landmark in most animals.
  • The medial caudal borders meet in a concave fashion forming a broad and deep notch called the ischial arch.
• The medial branch
  • This forms the caudal section of the pelvic symphysis

Ossification of the Ischium

Pubis

• The pubis is a L shaped bone that makes up one of the three bones of the pelvis.
• It consists of three parts:
  • Body
  • Transerse acetabular branch - the cranial edge of which is the pectin of pubis and forms the iliopubic emminence, to which some of the abdominal muscles attach.
  • Sagittal symphysial branch
• The two pubis fuse at the cranial section of the pubic symphysis. Lying of the ventral surface of the symphysis is the ventral pubic tubercle.
• The pubis form more than half the obturator foramen. This is an opening in the pelvic floor that allows the obturator nerve to pass through it; the foramen is closed by musculature and soft tissue.

Ossification of the Pubis

Femur

The femur is the strongest of the long bones and provides the origin and attachment for many muscles and tendons. This means that it is charcacteristically modelled for each species. Despite this it can be divided into three basic parts: The Femoral Head

• The head is offset from the main shaft of the femur, points in a medial direction and articulates with the acetabulum.
• It has a hemispherical articular surface with an associated notch, fovea capitis, which provides attachment for the intracasular ligament.
• Lateral to the head is the greater trochanter. This process provides attachment to the gluteal muscles.
• The trochantic fossa seperates the greater trochanter and the neck of the femur. It provides a site of insertion for the deep hip muscles.
• The lesser trochanter is a smaller process on the medial side that provides a site of attachment for the iliopsoas.

Femoral Shaft

• The caudal surface is roughened proximally and is framed by the medial and lateral lips
• These lips extend distally end enclose the popliteal surface. They also provide attachment for the adductor muscles.

Distal Extremity

• This consists of the medial and lateral condyles caudally and a trochlea cranially.
• The condyles articulate with the tibia and menisci to form the femorotibial joint.
• The intercondylar fossa lies between the condyles and is seperated from the polpiteal surface by the intercondylar line.
• Both condyles are roughened on their abaxial surfaces providing attachment for the collateral ligaments of the stifle joint.
• The extensor fossa is one of a pair of depressions on the lateral condyle. It is the more cranial of the two and forms an attachment point for the long digital extensor and third perineal muscle. The caudal depression givens origin to the popliteal.
• On the caudal aspect of each condyle are facets for the articulation with the fabellae. These are sesamoid bones that are embedded in the tendinous insertion of the gastrocneumius.
• The trochlea is made up of two ridges and a groove that articulate with the patella to form the femeropatellar joint.

Ossification Centers of the Femur

Joints of the Proximal Hindlimb

• Sacroiliac Joint
• Coxafemoral/Hip Joint

Common Structures of the Distal Hindlimb

• Tibia
• Fibula
• Tarsal bones
• Metatarsals

Joints of the Distal Hindlimb

• Stifle Joint
• Patella
• Tarsal Joint/Hock

Muscles of the Hindlimb

• Girdle Musculature
• Rump Muscles
• Muscles of the Stifle

Vasculature of the Hindlimb

• Arteries of the Hindlimb
• Veins of the Hindlimb
• Lymphatics of the Hindlimb

Species Specifics

• Canine Hindlimb
• Equine Hindlimb
• Bovine Hindlimb