Veterinary Dog Anatomy

Note: All the notes provided us from gcvs 

recomended book Guide To The Dissection Of Dog By Howard E. Evans, PhD 

Lecture no 6

BONES OF THE PELVIC LIMB(continued)

Veterinary Anatomy  GCVS 1st semester

Femur

The femur or thigh bone, is the

largest bone in the body. The flexor angle of the hip

is about 110 degrees. The flexor angle at the stifle is

from 130 to 135 degrees.

The femur is a typical long bone with a cylin-drical body and two expanded extremities. The

proximal extremity presents on its medial side a

smooth, nearly hemispherical head,most of which

is articular except for a small shallow fossa begin-ning near the middle of the head and usually ex-tending to its caudomedial margin. This fossa is

the fovea capitis femoris,to which the ligament

of the head of the femur attaches. The head is at-tached to the medial part of the proximal extrem-ity by the neckof the femur. The neck is distinct

but short and provides attachment for the joint

capsule. The greater trochanter,the largest emi-nence of the proximal extremity, is located directly

lateral to the head. To it attach the middle glu-teal and deep gluteal. The trochanteric fossais a

deep cavity medial to the greater trochanter. The

gemelli and the external and internal obturators

insert in this fossa. The lesser trochanter,a pyra-midal projection at the proximal end of the medial

side of the body of the femur, serves for the in-sertion of the iliopsoas. A ridge of bone extends

from the summit of the greater trochanter to the

lesser trochanter. This, the intertrochanteric crest,

represents the caudolateral boundary of the tro-chanteric fossa. The quadratus femoris inserts on

the crest at the level of the lesser trochanter. The

third trochanteris poorly developed. It appears at

the base of the greater trochanter as a small, rough

area on which the superficial gluteal inserts. The

third and lesser trochanters are located in about

the same transverse plane. The vastus parts of the

quadriceps femoris attach to the smooth proximal

cranial part of the femur. The bodyof the femur is slightly convex crani-ally. Viewed cranially, the body presents a smooth,

rounded surface. The caudal surface is rough and

is limited by medialand lateral lips.The lips,

closest together in the middle of the body, diverge

as they approach each extremity. The proximal

part of the medial lip ends in the lesser trochanter,

the distal part at the medial supracondylar tuber-osity. The proximal part of the lateral lip ends in

the third trochanter, the distal part at the lateral

supracondylar tuberosity. The adductor inserts on

most of the caudal rough surface, whereas a ten-don extends from the pectineus to the distal part

of the medial lip, where the semimembranosus

also attaches.

The distal extremity of the femur presents sev-eral articular surfaces. The trochlea,with ridges,

is the smooth groove on the craniodistal part of

the bone for articulation with the patella.The

medial trochlear ridge is usually thicker than the

lateral. The patella is a sesamoid in the tendon

of insertion of the large quadriceps femoris that

extends the stifle. It aids in the protection of the

tendon and the joint, but its chief purpose is re-direction of the tendon of insertion of the quad-riceps. The trochlea of the femur is continuous

with the condyles, which articulate, both directly

and through fibrocartilaginous menisci, with the

tibia. The medial and lateral condylesare sepa-rated from each other by the intercondylar fossa,

a deep, wide space. The two condyles are similar

in shape and surface area. Each is convex trans-versely and longitudinally. At the depth of the

intercondylar fossa the cruciate ligaments attach.

On the caudodorsal aspect of each femoral con-dyle is a facet on which a sesamoid bone (fabella) rests. The medial and lateral fabellae are in the

tendons of origin of the medial and lateral heads

of the gastrocnemius muscle. Proximal to these

sesamoid facets are the medial andlateral supra-condylar tuberositiesfrom which the gastrocne-mii arise. The superficial digital flexor also arises

from the lateral tuberosity. The popliteal surface

is a large, flat, triangular area on the caudal sur-face of the distal extremity proximal to the con-dyles and intercondylar fossa. The medial and

lateral epicondylesare rough areas on each side,

proximal to the condyles. They serve for the at-tachment of the collateral ligaments of the stifle.

The lateral epicondyle also gives rise to the pop-liteus. The small extensor fossais located on the

lateral epicondyle at the junction of the lateral

condyle and the lateral lip of the trochlea; from

it arises the long digital extensor. The semimem-branosus is inserted just proximal to the medial

epicondyle.

Posted in: 1st semester