CHAPTER 6. PELVIC LIMB
Like the forelimb, the pelvic limb is divided into regions with each region supported by bones
of the appendicular skeleton.
A.
B.
C.
D.
Hip - bones of the pelvic girdle
Thigh - femur, patella
Leg (crus) - tibia, fibula
Hindfoot (pes) - tarsal bones, metatarsal bones, bones of the digits
The bones of the pelvis consists of the sacrum, the first caudal vertebrae and the ossa
coxarum (pelvic girdle). The ossa coxarum is composed of two hip bones (os coxae). The two os
coxae are fused midventrally at the pelvic symphysis. Each os coxae is formed by the fusion of four
bones, three of which are important clinically. They are the ilium, ischium and pubis. Refer to your
text and study the individual bones. Fusion of these bones occurs at about 3-6 months of age.
This should be kept in mind when radiographs are taken of puppies. The small acetabular bone is
not readily identifiable. On a skeleton and on radiographs, identify the sacroiliac joint. This
combined synovial and cartilagenous joint attaches the hind limb to the vertebral column.
The pelvic cavity is important clinically. Note its position and angle with the ground. The angle
changes with different breeds of dogs. The size of the canal is of importance in parturition. If the
puppy is too big or the canal too small, dystocia will result.
The os coxae is an example of a flat bone. The ilium has a wide cranial wing. On the dorsal
surface of the wing, locate the cranial and caudal dorsal iliac spines. These spines together with
the area between them is called the tuber sacrale. The ventral surface of the wing has similar
spines. These two small eminences together with the area between them, form the tuber coxae
(hook bone of cattle). Identify the iliac crest which is the ridge between the tubers.
Figure 6-1. Left-Dorsal view of ossa coxarum. Right-Lateral view of right ox coxae. (Photos by Paul Rumph)
Notice the large acetabulum which articulates with the femur. Identify the lunate surface and
acetabular fossa. One of the features of hip dysplasia is an abnormally shallow acetabulum.
Between the acetabulum and the tuber sacrale is the curved greater ischiatic notch. Directly
above the acetabulum notice the ischiatic spine. It is located at the junction of ilium and ischium.
Directly caudal to the ischiatic spine is the lesser ischiatic notch. Caudal to this notch is the
"knob-like" ischiatic tuberosity (also called the tuber ischiadicum, tuber ischii, or the pin bone in
cattle). In the dog, the ischiatic tuberosity extends medially to the ischiatic arch which is the
caudally positioned, crescent shaped, concave, depression between the right and left ischiatic
tuberosities. In the floor of the pelvic canal notice the large obturator foramen. Locate the
iliopubic eminence (sometimes called the iliopectineal eminence).
On radiographs identify the portions of the ox coxae mentioned above. On a live animal
palpate the wing of the ilium, tuber coxae, and the ischiatic tuberosity.
The femur is the long bone of the thigh. Proximally, it articulates with the acetabulum to form
the hip joint. Distally the femur articulates with: the tibia forming the femorotibial joint; and with
the patella forming the femoropatellar joint. These distal articulations are collectively called the
stifle joint.
Figure 6-2. Cranial view of right femur. (Photos by Paul Rumph)
The head of the femur articulates with the acetabulum. The head is supported by a slender
neck. The large eminence directly lateral to the head is the greater trochanter. Between the
greater trochanter and the head, and on the caudal portion of the proximal surface is the
trochanteric fossa. Ventromedial to this fossa lies the lesser trochanter. Evidence of a small third
trochanter can be seen distal to the greater trochanter.
The distal end of the femur has several articular surfaces. The trochlea is the pully-like
depression for articulation with the patella. The patella is actually a sesamoid bone in the tendon
of the quadriceps femoris muscle. The knob-like medial and lateral condyles are for articulation
with the tibia. If the groove of the trochlea is too shallow, lateral patellar luxation may result.
This is most common in miniature and toy breeds. Medial luxation in toy breeds usually involves
other malformations of the femur and stifle joint. Between the condyles is the intercondylar
fossa. At the cranial edge of the lateral condyle is a tiny depression, the extensor fossa. The rough
lateral sides of the condyles are called the medial and lateral epicondyles, respectively.
Identify the portions of the femur mentioned above. Identify these structures on the
radiograph. On a live dog, palpate the greater trochanter, medial and lateral epicondyles and the
patella. Move the hip joint cranially and caudally as well as medially and laterally. Study the femur
with care, as fractures of this bone are common.
The tibia is the large long bone of the crus. It articulates with the tarsal bones distally at the
talocrural (tibiotarsal) joint. The complex of joints between the several small bones of the tarsus is
commonly called the hock joint or tarsal joints.
Figure 6-3. Cranial view of right tibia and fibula. (Photo by Paul Rumph)
The proximal end of the tibia flares out and has two wide articular surfaces, the medial and
lateral condyles. They are separated by the intercondylar eminence. The condyles have both
articular and nonarticular parts. On the caudal surface of the proximal end is a well defined
popliteal notch between the condyles. Directly opposite the popliteal notch on the cranial surface
of the tibia, is a distinct cranial border (the so-called tibial crest). At the proximal end of this
border is the pointed tibial tuberosity. On the lateral side of the tibial tuberosity is the well
defined depression termed the extensor groove.
The distal end of the bone features the complicated articular surface having two depressions
called the cochlea where the tibia articulates with the talus. The medial projecting part of this
distal extremity is the medial malleolus.
The long, thin fibula has enlarged proximal and distal extremities where they articulate with
the tibia. Note the head proximally and the lateral malleolus distally.
Locate these parts on radiographs.
The patella is one of the four sesamoid bones of the stifle. Locate the others (called fabellae)
on a radiograph.
The pes (hindfoot) consists of several subdivisions:
The tarsus is the region between the metatarsal bones and the true leg. It is supported by 7
short bones. The bones are arranged in three irregular rows. The proximal row has two bones, the
talus and the calcaneus. On the calcaneus, note the elongated tuber calcanei and the medially
projecting sustentaculum tali.
Figure 6-4. Left= Dorsal view of right tarsus. Right=plantar view of right tarsus.T=talus, Ca= calcaneus, Ce= central tarsal, distal
row are numbered, m2-m5 =metatarsals, tt= trochlea of talus, mm=medial malleolus, lm= lateral malleolus, tc=tuber calcaneus,
st=sustentaculum tali
Identify the above parts of the talus and calcaneus. Study also the middle and distal row of
tarsal bones. You are only expected to identify these bones by name on the radiographs or on an
articulated skeleton (specifically the central tarsal and tarsals I - IV).
The metatarsal bones resemble the metacarpal bones. They are numbered I - V from medial
to lateral. As in the forelimb, the phalanges are the major bones of the digits. However, the first
digit is frequently absent. When present, it is usually a vestigial structure composed only of a distal
phalanx. It may however, be a fully developed digit.
Approximate age at which selected hind limb ossification centers
of the dog fuse to the main portion of the bone.
Bone
Physis Location
Approximate
Closure Time
Os Coxae
Unity of 4 bones
Pelvic symphysis
Tuber ischii
Crest of ilium
3-6 months
5-6 years
11 months
1-2 1/2 years
Femur
Greater trochanter
Head
Lesser trochanter
Distal epiphysis
10 months
10 months
10 months
10 months
Tibia
Tibial tuberosity unites with condyles
Proximal physis
Distal physis
9 months
11 months
9 months
Fibula
Proximal physis
Distal physis
10 months
10 months
Calcaneus
Tuber calcanei
6 months
Metatarsal
II - V
7 months
Epiphyseal plates or physes visible between centers of ossification in the pelvic limb of dogs less
than 12 months of age.
Dissection of Pelvic Limb
REMOVE THE SKIN FROM THE LIMB AS FAR DISTALLY AS THE MIDDLE OF THE CRUS. CLEAN
THE LOOSE SUPERFICIAL FASCIA FROM THE RIGHT CAUDAL TRUNK, HIP, AND THIGH.
CAREFULLY INCISE THE DEEP FASCIA FROM THE TUBER SACRALE TO THE ISCHIORECTAL
FOSSA AND REFLECT IT VENTRALLY TO THE LEVEL OF THE LARGE BICEPS FEMORIS M.
Figure 6-6. Lateral view of right thigh region. (Photo by Elizabeth Lantz and Elaine Coleman)
The muscle lying most superficially is the flat superficial gluteal m. IDENTIFY AND CLEAN THE
MUSCLE. It arises from the sacrum, first caudal vertebra, and sacrotuberous ligament. AS YOU
ISOLATE THE MUSCLE EDGES, IDENTIFY THE SACROTUBEROUS LIGAMENT EMERGING FROM
UNDER THE CAUDAL EDGE OF THE MUSCLE. It extends from the tuber ischium to the sacrum and
first caudal vertebra. TRANSECT THE SUPERFICIAL GLUTEAL M. CLOSE TO ITS INSERTION,
REFLECT IT DORSALLY AND OBSERVE ITS INNERVATION BY THE CAUDAL GLUTEAL N. Note
that the muscle may have a thin deeper part. Identify the middle gluteal m. TRANSECT ITS
INSERTION ON THE GREATER TROCHANTER AND REFLECT IT DORSALLY.
Figure 6-7. Lateral view of the right hip. Superficial part of the superficial gluteal muscle
has been transected to show the deep part which is sometimes mistaken for the piriformis
muscle. (Drawing by Phil Garrett)
Identify the piriformis m. It may have been reflected with the middle gluteal m. and is now
adhered to the deep surface of the middle gluteal m.; or it may be in place on the outer surface of
the deep gluteal m. Due to text inconsistencies, for the purpose of this course, the piriformis m.
will be considered to be innervated by an untitled branch of the sciatic nerve. The large sciatic n. is
situated between the deep gluteal m. and the more superficially situated middle gluteal and
piriformis muscles. In surgery, the nerve may be used to help distinguish these muscles from the
deep gluteal muscle. Locate the cranial gluteal n. It innervates the middle gluteal m., the deep
gluteal m. (that lies deep to it), and the tensor fasciae latae m.
Figure 6-8. Lateral view of the right hip. The deep part of the superficial gluteal and the
middle gluteal muscles have been transected and reflected to show the piriformis muscle.
(Drawing by Phil Garrett)
Briefly read about the lumbosacral trunk. Inside the pelvis, it gives rise to both of the gluteal
nerves (cranial and caudal) and a nerve trunk which innervates small muscles caudal to the hip
joint. The continuation of the lumbosacral trunk outside of the pelvic cavity is called the sciatic
(ischiatic) nerve. Trace this large nerve as it passes medial to the greater trochanter and continues
beneath the biceps femoris m. into the thigh.
Figure 6-9. Lateral view of the right hip. Notice the innervation of these muscles by the
cranial and caudal gluteal nerves. (Drawing by Phil Garrett)
TRANSECT THE SACROTUBEROUS LIGAMENT CLOSE TO ITS ORIGIN FROM THE SACRUM.
The large artery just ventromedial to the sacrotuberous ligament is the caudal gluteal a. Its first
branch will not be dissected. The second branch is the cranial gluteal a. which may be seen
running with the cranial gluteal n. The next major branch is the lateral caudal a. which runs along
the lateral surface of the tail. The caudal gluteal a. supplies the ischiorectal fossa as well as the
caudal thigh or "hamstring" muscles. Lateral to the coccygeus and levator ani muscles of thinner
dogs, the skin is depressed into the ischiorectal fossa. The sacrotuberous ligament bounds the
fossa laterally while the ischium is its ventral limit.
The "pelvic diaphragm" consists of two muscles that have been seen previously. Laterally, the
coccygeus m. arises from the ischiatic spine and inserts on the first few caudal vertebrae. The
levator ani m. underlies the coccygeus m. and is a broad, thin, flat muscle which covers the floor of
the pelvis. In man, these muscles support the structures of the pelvic cavity.
The fascias covering the thigh are referred to as superficial and deep femoral fascias. Examine
the medial surface of the thigh and identify the femoral triangle. Identify its cranial and caudal
boundaries. Within this triangular region find the large femoral artery and vein, lymphatics, and
the small saphenous nerve. The triangle is bounded cranially by the caudal belly of the sartorius
m., caudally by the small pectineus m., laterally by the vastus medialis m. and iliopsoas m., and
medially by femoral fascia and skin. The superficial location of major vessels in the femoral
triangle provide a good site for taking the pulse or intravascular injection or catheterization.
In the abdominal cavity, you will see that three muscles lie on the ventral surface of the
lumbar vertebral column. The psoas minor m. is the most superficial. Its broad flat tendon of
insertion attaches to the craniolateral border of the pelvis. The largest muscle is the iliopsoas m.
(combined psoas major and iliacus mm.) It inserts on the minor trochanter of the femur. The
quadratus lumborum m. can be seen dorsolateral to the iliopsoas m.
Verify that the femoral nerve emerges from the substance of the iliopsoas m. and gives rise to
the saphenous nerve which conveys sensation from the medial surface of the thigh and crus. The
femoral nerve terminates by sending large muscular branches into the four heads of the
quadriceps femoris muscle and the sartorius muscle.
Figure 6-10. Lateral view of the right thigh. Notice the innervation of these muscles by the
femoral nerve. (Drawing by Phil Garrett)
In general, the cranial thigh muscles serve to flex the hip and extend the stifle, the latter
action depending on the position of the limb. Identify the cranial and caudal bellies of the sartorius
m. TRANSECT THIS MUSCLE IN THE MID-THIGH REGION AND REFLECT ITS PARTS PROXIMAD
AND DISTAD. On the cranial border of the thigh, the tensor fasciae latae m. appears to be divided
into two parts. Its action is accomplished through the deep femoral fascia (fascia lata) on which it
inserts.
NOTE: Authors differ in listing the innervation of the sartorius muscle (either femoral n. or
saphenous n.). Of the two, we prefer the femoral nerve.
ON THE LATERAL SURFACE OF THE THIGH, INCISE THE FASCIA ALONG THE CRANIAL
EDGE OF THE BICEPS FEMORIS M. DISTALLY TO THE LEVEL OF THE STIFLE JOINT. NOTE
THAT HERE THE FASCIA LATA HAS TWO LAYERS. THE DEEPER ONE COVERS THE LATERAL
SURFACE OF THE VASTUS LATERALIS M. AND ATTACHES CAUDALLY TO THE FEMUR, AND THE
OTHER ATTACHES CAUDALLY TO THE BICEPS FEMORIS M. During a lateral surgical approach to
the shaft of the femur, if you incise the fascia lata more cranially, you encounter only one layer.
This makes it is easier to locate the shaft of the femur at the caudal edge of the vastus lateralis
m. It is by the fibers of the fascia lata that the biceps femoris m. acts as an extensor of the stifle
when the limb bears weight. UNDERMINE THE CAUDAL EDGE OF THE FASCIA LATA AND TENSOR
FASCIAE LATAE M. AND REFLECT THEM CRANIALLY. REFLECT THE BICEPS FEMORIS M.
CAUDALLY.
The principle extensor muscle of the stifle joint is the large quadriceps femoris m. which has
four divisions. Identify the (1) vastus lateralis m. WORK ALONG ITS CAUDAL EDGE AND IDENTIFY
THE SHAFT OF THE FEMUR. Observe the branches of the femoral n. which innervate this muscle
mass. The (2) vastus medialis m. should be examined on the medial surface of the thigh. Observe
its attachments and femoral nerve innervation. AS YOU PULL THE PROXIMAL END OF THE
MUSCLE MEDIALLY, YOU WILL SEE A MUSCLE BELLY THAT ARISES FROM THE PELVIS. This is the
(3) rectus femoris m. which extends across both the stifle and hip joints. TRANSECT THE RECTUS
MUSCLE IN ITS PROXIMAL 1/3 AND REFLECT ITS PARTS. CLEAN AND OBSERVE THE
BRANCHES OF THE FEMORAL N. ENTERING THE QUADRICEPS M. AND ALSO THE SARTORIUS
M. The (4) vastus intermedius m. which lies deep to the rectus femoris m. is the fourth belly. It
contacts the cranial, medial and lateral surfaces of the femoral shaft. Although the quadriceps m.
attaches to the patella, the patellar ligament actually provides a common attachment of the four
heads to the tibial tuberosity. The sartorius and quadriceps group are innervated by the femoral n.
This is the key group of muscles of the hind limb. Damage to the femoral nerve and paralysis of
the quadriceps group results in inability to support weight at the stifle joint.
The medial group of thigh muscles is innervated by the obturator n. and they serve to adduct
the limb. The flat gracilis m. lies superficially on the medial surface of the thigh. Locate its cranial
border adjacent to the sartorius m. and the saphenous a. and n. in the distal half of the thigh.
UNDERMINE AND TRANSECT THE FLAT DISTAL TENDON OF THE GRACILIS M. AND REFLECT IT
PROXIMALLY. NOTE THAT THIS FLAT TENDON EXTENDS INTO THE CRUS. ON THE DEEP
SURFACE OF THE MUSCLE, NOTICE ITS INNERVATION BY THE OBTURATOR N. Identify the
fusiform pectineus m. which creates the caudal boundary of the femoral triangle. Notice its long
flat tendon of termination. TRANSECT THE PECTINEUS M. (This has sometimes done to relieve
the pain associated with hip dysplasia.) IN ITS MIDREGION AND REFLECT THE PROXIMAL
HALF. The large muscle caudal to the pectineus m. and deep to the gracilis m. is the adductor m.
(it has two parts called adductor magnus et brevis & adductor longus). Observe its origin from the
ventral surface of the ischium and the symphyseal tendon. The obturator n. should be observed
innervating the medial group of muscles. This nerve has no cutaneous branches. BLUNTLY
SEPARATE MUSCLE FIBERS TO TRACE THE OBTURATOR N. AND FOLLOW ITS COURSE
PROXIMALLY INTO AND THROUGH THE PELVIC CANAL.
Figure 6-11. Lateral view of the right thigh. Notice the innervation of these muscles by the
obturator nerve. (Drawing by Phil Garrett)
Locate the deep femoral artery as it branches from the external iliac artery. In most dogs, it
gives rise to the pudendoepigastric trunk and then passes through the femoral ring where it
becomes known as the medial circumflex femoral artery. Trace it into the adductor muscle and
observe its several large terminal branches. Also note that this artery lies just medial to the hip
joint and must be considered in medial surgical approaches to this joint. Occasionally, the
pudendoepigastric trunk does not form. Then, the external pudendal a. and the caudal epigastric a.
each arise directly from the deep femoral a.
The femoral artery extends from the femoral ring to the stifle region. Along its course it gives
rise to the superficial circumflex iliac a. (which will not be dissected). Next, the large lateral
circumflex femoral a. is seen as the large arterial supply to the quadriceps group. It arises from the
femoral a. and plunges laterally into this muscle mass. Identify the proximal caudal femoral a.
REMOVE THE SKIN DISTAL TO THE STIFLE JOINT. In the mid-femoral region, notice that
multiple branches of the femoral artery arise to supply the muscles. Identify the prominent
saphenous artery which runs distally on the medial surface of the limb in the subcutaneous tissue.
It is accompanied by the medial saphenous vein and saphenous n. In the proximal region of the
crus, all three structures divide into cranial and caudal branches.
Distal to the origin of the saphenous artery, the femoral artery gives rise to the middle and
distal caudal femoral arteries which pass caudolateral where they supply the caudal thigh and leg
muscles. The distal caudal femoral a. lies deep and perhaps is best seen in a later dissection. The
femoral artery continues into the caudal region of the stifle joint where it is called the popliteal a.
It will be studied later.
Locate the biceps femoris m. on the lateral surface of the thigh. INCISE THE MUSCLE CLOSE
TO ITS ORIGINS FROM THE SACROTUBEROUS LIGAMENT AND TUBER ISCHII. REFLECT IT
DISTAD AS FAR AS THE STIFLE REGION. THIS REFLECTION WILL NECESSITATE TRANSECTING
THE MUSCULAR BRANCHES FROM THE ISCHIATIC N. In the distal half of the femoral region,
the ischiatic n. divides into the cranially positioned common peroneal n. and a larger more caudal
tibial n.
On the deep surface of the biceps femoris m. and in the caudal stifle region, locate the
popliteal lymph node. The large vein running deep to the lymph node is the lateral saphenous
vein). Observe its drainage into the caudal femoral v. In the distal half of the crus(leg), the lateral
saphenous vein divides into cranial and caudal branches. The cranial branch of the lateral
saphenous v. is a common site for intravenous injection. Note that you have now seen lateral and
medial saphenous veins.
ISOLATE THE BICEPS FEMORIS FROM THE SEMITENDINOSUS M. Note that distally, the biceps
femoris lies on the lateral surface of the caudal muscles of the crus. This will help distinguish it
from the semitendinosus m. which passes to the medial aspect of the crus. SEPARATE THE
SEMITENDINOSUS M. FROM THE UNDERLYING SEMIMEMBRANOSUS M. AND NOTICE THAT
BOTH HAVE THEIR NERVE SUPPLY FROM MUSCULAR BRANCHES OF THE ISCHIATIC N. Notice
that the caudal gluteal a. supplies the proximal regions of the hamstring muscles
(semimembranosus, semitendinosus and biceps femoris mm.).
Figure 6-12. Lateral view of the right thigh. Notice the innervation of these muscles by the
ischiatic nerve. (Drawing by Phil Garrett)
Observe the deep gluteal m. which lies on the body of the ilium and is supplied by the cranial
gluteal a., v. and n. CLEAN THE MUSCLE AND VERIFY ITS ATTACHMENTS. The middle and deep
gluteal mm. extend the hip. Three muscles are collectively called the inner pelvic muscles. They
insert in the region of the trochanteric fossa of the femur and rotate the hip outward. GENTLY
LIFT ISCHIATIC N. AND THE CAUDAL GLUTEAL A. CRANIAL TO THE GREATER TROCHANTER. Clean
and examine the internal obturator and gemelli muscles. Notice their innervation from small
nerves leaving the ischiatic nerve. The quadratus femoris m., is located lateral to the external
obturator m. and is innervated by branches of the ischiatic n.
Notice that the levator ani muscle lies within the osseous pelvic canal. Verify again that the
obturator nerve passes through the pelvic canal to exit at the obturator foramen. The nerve may
be injured in difficult births or in fractures of the ilium. Reflect the proximal portion of the
adductor m. and observe the underlying external obturator m. which covers the ventral surface of
the pelvic floor. The external obturator m. is innervated by the obturator n.
Deep in the femoral triangle, the hip joint is covered by the iliopsoas m.
INCISE THE DEEP FASCIA ALONG THE LATERAL SURFACE OF THE CRUS FROM THE
STIFLE TO THE TARSUS. REFLECT THE FASCIA CRANIAD AND CAUDAD. THE CRANIAL BRANCH
OF THE LATERAL SAPHENOUS V. MAY BE TRANSECTED AFTER REVIEWING ITS POSITION.
IDENTIFY AND PRESERVE THE COMMON PERONEAL NERVE LYING ON THE SURFACE OF THE
MUSCULATURE IN THE PROXIMAL REGION OF THE CRUS. Trace the common peroneal n. as it
emerges from beneath the biceps femoris m. and then penetrates between the muscles of the
crus. SEPARATE AND ISOLATE THESE MUSCLES and observe the ramifications of the common
peroneal n. One branch, the superficial peroneal n., runs distally between the lateral digital
extensor m. and the peroneus longus m. It eventually continues onto the dorsum of the pes.
Another branch, the deep peroneal n., can be seen on the deep surface of the long digital extensor
m., in company with the cranial tibial artery, as they run distally toward the pes. The common
peroneal n. supplies all of the muscles lying on the craniolateral surface of the crus. These muscles
act to flex the hock and some extend the digits.
Figure 6-13. Lateral view of the right crus. Notice the innervation of these muscles by the
common peroneal nerve. (Drawing by Phil Garrett)
The most cranial muscle of the crus is the flat cranial tibial muscle. Sparing the adjacent
vessels and nerves, trace the cranial tibial tendon to its insertion. Deep and lateral to the cranial
tibial muscle is the long digital extensor m. Note that it takes origin from the femur. Identify and
preserve the proximal and distal extensor retinacula that bind the long digital extensor tendon in
place as it crosses the tarsus. Trace the muscle tendon across the tarsus and identify its branches
to each digit. Caudal to the above muscle and cranial to the common peroneal n. is the peroneus
longus m. Trace its tendon to the lateral side of the hock. The common peroneal n. passes
between the peroneus longus m. and the slender lateral digital extensor m. Identify the lateral
digital extensor m. and trace its tendon distally into the metatarsus.
On the medial surface of the crus, locate the saphenous artery accompanied by the medial
saphenous vein and saphenous n. Trace the artery and vein to their origin from the femoral a. and
v. The saphenous vessels divide into cranial and caudal branches in the proximal crural region.
Find these branches. Note again, that there is one saphenous artery (situated on the medial
aspect of the hindlimb) but there are two (medial and lateral) saphenous veins (one on each side
of the limb).
On the medial surface of the thigh, reflect the gracilis muscle cranially and examine the
terminations of the semimembranosus m. and the semitendinosus muscle. ISOLATE THE
TENDON OF THE SEMITENDINOSUS M. AND TRANSECT IT. ISOLATE THE TERMINATION OF THE
SEMIMEMBRANOSUS M. AND TRANSECT IT 2 CM FROM ITS ATTACHMENT. The muscle lying
deep to the insertions of these two muscles is the medial head of the gastrocnemius m. Observe
that the tibial n. passes between the medial and lateral heads of the gastrocnemius m. Notice that
the tibial n. has branches which innervate the caudal muscles of the crus. USING THE TIBIAL
NERVE AS A GUIDE, ISOLATE THE TWO HEADS OF THE GASTROCNEMIUS M. AND THE
SUPERFICIAL DIGITAL FLEXOR M.
Figure 6-14. Lateral view of the right crus. Notice the innervation of these muscles by the
tibial nerve. (Drawing by Phil Garrett)
Locate the femoral artery in the distal region of the thigh. Notice that it passes between the
semimembranosus m. and adductor m., caudal to the femur. It gives off a large caudally directed
distal caudal femoral a. which has been seen, and then continues as the popliteal a. which passes
deep to the medial head of the gastrocnemius m. as does the tibial n. The distal caudal femoral a.
supplies muscles in this general area including the hamstring muscles. These arteries are
accompanied by satellite veins.
TRANSECT THE MEDIAL HEAD OF THE GASTROCNEMIUS M. 3 CM FROM ITS ORIGIN AND
REFLECT ITS PARTS. Notice that the medial and lateral heads of the gastrocnemius m. share a
common tendon of insertion on the calcaneus. The short tendons of origin of the two heads each
contain a sesamoid bone termed a fabella. Observe the fabellae on radiographs. CUT INTO THE
ORIGIN AND NOTE THE EXACT LOCATION OF THESE SMALL BONES. They are often used to
anchor suture material for stabilization of the stifle joint. Examine the two heads of the
gastrocnemius m., and separate them from the superficial digital flexor muscle which lies between
them.
The common calcanean tendon contains the combined tendons of the gastrocnemius m. and
superficial digital flexor m. and some connective tissue fibers from the biceps femoris m., gracilis
m. and semitendinosus m. Notice how the gastrocnemius tendon (which, in the proximal crus, lies
superficial to the superficial digital flexor tendon) twists laterally and finally lies deep to the
superficial digital flexor tendon before terminating on the tuber calcanei. Observe that the
superficial digital flexor tendon continues through the metatarsal region and branches into a
tendon for each digit. At the tuber calcanei, it is protected from the bony process by a bursa.
ALONG ITS LENGTH, SEVER THE TISSUE BINDING THE TENDON TO THE CALCANEAL TUBER
AND REFLECT THE TENDON TO THE SIDE. Examine the entire superficial digital flexor m.
After supplying branches to all of the muscles lying on the caudal surface of the crus, the tibial
n. continues distally where it is joined by the caudal branches of the saphenous artery and medial
saphenous v. Trace these structures through the tarsal canal to the middle of the metatarsus.
Notice that the tibial n. divides into medial and lateral plantar nerves just proximal to the tarsus.
The other muscles to be dissected on the caudal surface of the crus are the popliteus m. and
the deep digital flexor m. ON THE MEDIAL ASPECT OF THE CRUS, IDENTIFY THE POPLITEUS M.
AND TWO TENDONS OF THE DEEP DIGITAL FLEXOR M. FOLLOW THE TENDONS PROXIMALLY
AND ISOLATE THE TWO HEADS OF THE DEEP DIGITAL FLEXOR M. The popliteus m. is the
triangular muscle mass occupying the most proximomedial position on the caudal surface of the
tibia. Lateral to the popliteus m. is the deep digital flexor m. It has a medial portion and a lateral
portion. The tendons of the two portions unite slightly below the tarsus to form the single tendon
of the deep digital flexor m. Locate this junction. By tracing the tendons proximally, identify the
two portions of the muscle.
Figure 6-13. Lateral view of right crus. CT=cranial tibial m., LDE=long digital extensor m., LDF=lateral digital flexor m. (part of
deep digital flexor m.), SDF=superficial digital flexor m., LG=lateral head of gastrocnemius m., LS= lateral saphenous vein, cbls=cranial
branch of lateral saphenous vein. (Photo by Elizabeth Lantz and Elaine Coleman)
Over the years, different nomenclatures have been used to describe the parts of the deep
digital flexor muscle of the hind limb. Unfortunately, your text carelessly alternates among several
terms when referring to the two heads of the muscle. They are:
Medial head = long digital flexor = m. flexor digitorum longus = medial digital flexor m.
(NAV)
Lateral head = flexor hallucis longus = m. flexor digit I (hallucis) longus = lateral digital
flexor m. (NAV)
We prefer the system indicated by the underlined names above. You will find these terms
used in describing the muscle in veterinary literature. You need to recognize them all.
Locate the popliteal artery. DO NOT DISSECT IT INTO THE POPLITEUS MUSCLE. Notice the
small branches it supplies to the stifle region. Just distal to the popliteus m. the artery terminates
by bifurcating into caudal and cranial tibial arteries. DO NOT ATTEMPT TO FIND the caudal tibial a.
which is very small and terminates in the caudal musculature of the crus. The cranial tibial a.
passes between the tibia and fibula. Turn the limb over, locate and follow the artery where it
accompanies the deep peroneal n., as they course distally in the cranial musculature of the crus.
IN GENERAL, MANY OF THE STRUCTURES OF THE PES HAVE AN ARRANGEMENT
SIMILAR TO THOSE SEEN IN THE MANUS. THEREFORE, THE MUSCLES, NERVES AND ARTERIES
WILL NOT BE DISSECTED.
STUDY THE GENERIC PATTERN OF ARTERY AND NERVE DISTRIBUTION IN THE PES. DO
NOT ATTEMPT TO DISSECT THEM BUT UNDERSTAND THEIR ORIGIN AND DISTRIBUTION AS
OUTLINED IN THE FOLLOWING PARAGRAPHS.
The dorsal common digital nerves arise from the superficial peroneal nerve, and the dorsal
metatarsal nerves arise from the deep peroneal nerve. These nerves are sensory to the dorsal
structures of the digits. Recall that the dorsum of the manus had only one set of nerves. On the
plantar surface of the pes, the medial plantar n. forms the plantar common digital nn. while the
lateral plantar n. forms the plantar metatarsal nerves . These supply the muscles, digital pads,
metatarsal pad and skin.
The continuation of the cranial tibial artery in the pes is termed the dorsal pedal artery. It,
and the cranial branch of the saphenous a., supply the dorsal surface of the pes by ramifying as
dorsal common digital and dorsal metatarsal arteries. The source of blood to the plantar surface is
provided by the caudal branch of the saphenous a. and a perforating metatarsal artery. These
ramify in the pes as plantar common digital and plantar metatarsal arteries.
The veins of the dorsum of the pes are drained by the dorsal branches of the medial and
lateral saphenous veins. The veins draining the plantar surface of the pes are collected by the
plantar branch of the lateral saphenous vein.
The canine stifle joint is a clinically important area. The design of the joint (ie round femoral
condyles on relatively flat tibial condyles) make it intrinsically unstable. Many ligaments and
tendons help stabilize the joint and are subject to trauma.
THE STIFLE JOINT MAY BE DEMONSTRATED TO YOU ON PROSECTION OR ON VIDEOTAPE.
CLEAN THE SUPERFICIAL FASCIA FROM THE JOINT SURFACE AND PALPATE THE PATELLA,
PATELLAR LIGAMENT, AND THE TIBIAL TUBEROSITY. INCISE THE DEEP FASCIA ALONG EACH
SIDE OF THE PATELLAR LIGAMENT. TRANSECT THE QUADRICEPS FEMORIS M. 4 CM
PROXIMAL TO THE PATELLA AND REFLECT THE DISTAL SEGMENT TOWARD THE STIFLE. Notice the
fat pad lying between the patellar ligament and the joint capsule. REMOVE THE FAT PAD.
Observe the tendon of the long digital extensor m. originating from the extensor fossa of the
femur.
Figure 6=14. Left=cranial view of right stifle. Right=caudal view of right stifle. P=patella, TF=femoral trochlea, LDE= tendon
of origin of long digital extensor m., LM=lateral meniscus, MM=medial meniscus, TT=tibial tuberosity, crcl=cranial cruciate
ligament, cdcl=caudal cruciate ligament, LCL=lateral collateral ligament, TP= cut tendon of popliteus m., smg=sesamoid in
tendon of medial head of gastrocnemius m., slg- sesamoid in tendon of lateral head of gastrocnemius m., fllm=femoral ligament
of lateral meniscus.
(Photo by Elizabeth Lantz and Elaine Coleman)
Flex the stifle joint as much as possible and observe the two ligaments located between the
femoral condyles. These two ligaments extend from the femur to the tibia. In doing so, they cross
each another in a craniocaudal and also a mediolateral direction. Hence, they are called cruciate
ligaments. The cranial cruciate ligament arises from the medial surface of the lateral femoral
condyle and inserts on the cranial intercondyloid area of the tibia. Study the origin and insertion
of the caudal cruciate ligament. These prevent "drawer" movements of the tibia. Rupture of the
cranial cruciate ligament is often encountered in small animal practice. Surgical correction may
involve replacement of the ligament with other tissues and or stabilizing the joint by fixation and
tightening of other tissues.
As with many joints, the stifle is provided with two collateral ligaments. USING LIMITED
DISSECTION, ISOLATE THE MEDIAL AND LATERAL COLLATERAL LIGAMENTS.
Two fibrocartilage plates (menisci) are inserted between the femoral and tibial condyles.
These form a more congruous contact surface for the condyles. Examine the menisci; they are
occasionally injured. Ligaments attach the menisci to one another and to the tibia and femur.
Examine these attachments. Examine the femoral ligament of the lateral meniscus.
REFLECT THE SKIN FROM THE TAIL AND, PRESERVING THE ACCOMPANYING VESSELS
AND NERVES, EXAMINE THE MUSCLES. The tail muscles are arranged in symmetrical quadrants.
The naming system of the muscles need not be learned.
The rectococcygeus m. is found on the ventral surface of the base of the tail. It is a
continuation of the smooth muscle fibers which form the longitudinal muscle coat of the rectum.
It aids in defecation.
The three major arteries to the tail are the two lateral caudal aa. and the median caudal a.
They have satellite veins. In dogs older than a few days, these vessels must be ligated when the
tail is amputated.