D. J. (Daniel John) Cunningham.

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glutaeus medius splits at the upper border of the maximus into
a superficial layer which covers the maximus and a deep layer
which passes downwards over the lower part of the glutaeus
medius and the muscles which lie more distally at the back of
the hip joint. The dissector on the left side will demonstrate
the same facts when he reaches the upper border of the muscle,
for he will find the deep fascia which he has raised from the
surface of the glutaeus maximus blends with the strong
fascia on the glutaeus medius,and by lifting the upper border of
the maximus he will display the deeper layer of fascia.

The glutaeus maximus is a difficult muscle to clean, as the
fasciculi are exceedingly coarse. It is necessary therefore not
only to remove the fascia which covers the muscle, but at the
same time to follow, for a short distance, the septa which
penetrate between the fasciculi and to remove them also. Do
not remove the thick opaque fascia which covers the insertion
of the muscle.

If the work is to be done well the dissector must keep clearly
before him the rules which have already been laid down regard-
ing the cleaning of a muscle : (i) Render the fibres as tense as
possible by rotating the limb medially ; (2) remove the fascia
in one continuous layer ; (3) always cut in the direction of the
muscular fibres ; (4) define very carefully the borders of the
muscle.

M. Glutaeus Maximus. The glutaeus maximus is a
powerful muscle which arises (i) from a narrow, rough
area on the dorsum ilii, which is included between the posterior
curved line and the outer lip of the crest; (2) from the sides
of the lower two pieces of the sacrum and the upper three
pieces of the coccyx ; (3) from the entire posterior surface of
the sacro-tuberous ligament (O.T. great sciatic); and (4),
slightly, from the posterior layer of the lumbo-dorsal fascia,
at the attachment of that fascia to the crest of the ilium.

From this extensive origin the coarse fasciculi of the
muscle proceed obliquely downwards and forwards towards
the proximal portion of the femur ; but only a comparatively



286



THE INFERIOR EXTREMITY



small proportion of them receive direct insertion into that
bone. The greater part of the muscle is inserted into the
fascia lata. To be more precise, it may be said that the deeper
fibres of the lower half of the muscle are directly attached



Latissimus dorsi . . .



M. obliquus externus
abdominis




sartorius
M. tensor fasciae latas

Reflected head
of rectus femoris
Straight head of
rectus femoris



M. gemellus superior
M. gemellus inferior

M. semimembranosus

Mm. biceps and
semitendinosus

M. quadratus femoris



M. pectineus



VT M. rectus abdominis

M. pyramidalis
M. adductor longus
M. gracilis
M. adductor brevis



FIG. 128. External aspect of the Hip Bone, with the Attachments
of the Muscles mapped out.



to the gluteal tuberosity on the back of the femur (i.e. the
ridge which extends from the greater trochanter to the linea
aspera). (Fig. 122, p. 271.) All the remaining fibres of the
muscle are inserted into the fascia lata along the posterior
border of the proximal part of the ilio-tibial tract. The



GLUTEAL REGION 287

glutaeus maximus is supplied by the inferior gluteal nerve. The
glutseus maximus is an extensor of the hip joint and a
lateral rotator of the thigh. Its upper fibres can abduct
the thigh, acting with the tensor fasciae, and the lower fibres
assist in producing adduction.

Dissection. Reflection of the Glutseus Maximus. As the
glutaeus maximus is reflected the dissector must be careful not
to injure the vessels and nerves which lie closely subjacent to
it. The nerves most liable to injury are the posterior cutaneous
nerve of the thigh, which has already been identified and secured
if previous instructions have been followed (see p. 284), and the
perforating cutaneous nerve, which is very liable to injury when
the fibres of the glutseus maximus are being raised from the
sacro-tuberous ligament.

The incision through the muscle should extend from a point
on its superior border 3 cm. above the trochanter major to a point
on the inferior border 2.5 cm. medial to the insertion of the muscle
into the femur. The procedure differs on the two sides. On
the right side the dissector should detach the superior border of
the muscle from the fascia on the glutseus medius at the point
selected, and then pass one or two fingers downwards, on the
deep surface of the muscle, along the line of incision. The part
of the muscle thus freed from the deeper structures must then
be divided with the scalpel, and the process must be repeated
until the lower border of the muscle is reached. On the left
side the dissector must commence at the inferior border, and,
adopting the method above described, divide the muscle from
below upwards. When the muscle is divided, reflect the lateral
part to its insertion, the inferior fibres to their attachment to
the gluteal tuberosity, the upper fibres to their attachment into
the ilio-tibial tract. As the upper fibres of the muscle are
followed to the aponeurotic insertion two bursse will come into
view, one between the aponeurotic insertion of the muscle and
the lateral surface of the trochanter major, and a second, more
distally placed, between the aponeurotic insertion and the
lateral surface of the tendon of origin of the vastus medialis.
Open both bursse and examine their extents with the tip of the
index finger. Then turn to the medial part of the muscle and
reflect it towards its origin. As the reflection proceeds keep
the edge of the scalpel close to the deep surface of the muscle
to avoid injuring the posterior cutaneous nerve of the thigh,
and as soon as the vessels and nerves which enter the deep
surface of the muscle appear clean them and turn them medially
with the muscle. As the upper part of the muscle is followed to-
wards the ilium, branches of the superficial division of the superior
gluteal artery will be met with, accompanied by their voluminous
venae comites. Clear the veins away, but keep the arteries.
As the lower fibres are turned towards the tuberosity of the
ischium branches of the inferior gluteal vessels and nerve will
be found entering the deep surface of the muscle. Clear away
the veins, but clean and keep the arteries and nerves. Between
the muscle and the tuber ischii lies a mucous bursa. If it has
not already been removed by the dissector of the perineum, open
it. It is frequently multilocular, and its walls are closely



288 THE INFERIOR EXTREMITY

attached by fibre strands to the glutaeus maximus and to the
tuberosity. Immediately medial and superior to the ischial
tuberosity the deep fibres of the muscle spring from the super-
ficial surface of the sacro-tuberous ligament; detach them
carefully from the ligament and secure the perforating cutaneous
nerve and the coccygeal branches of the inferior gluteal artery
which pierce the ligament. The arteries must be divided in order
that the reflection of the muscle can be continued, but the nerve
should if possible be preserved. Continue the detachment of
the muscle from the sacro-tuberous ligament until the margins
of the sacrum and coccyx are reached, and as they are approached
look for the posterior branches of the sacral nerves which form
a plexus on the superficial surface of the ligament deep to the
muscle.

The method of dissection suggested above is one best adapted
to avoid injury to the branches of the inferior gluteal nerve
which supplies the muscle ; and it gives a view of the structures
subjacent to the muscle similar to that obtained by the surgeon
operating on the proximal part of the sciatic nerve.

The method of dissection previously adopted in this Manual
was to detach the muscle from its origin from the ilium, the
sacrum, the coccyx, and the sacro-tuberous ligament, and to
throw it towards its insertion. That method also gives an
excellent display of the subjacent structures, from a purely
anatomical point of view, and the student who is dissecting the
buttock for the second time might employ it with advantage,
but it is not a plan which could be adopted by the surgeon. The
dissector who employs that method must commence by clearing
the upper and lower borders of the muscle. When that has
been done the left hand must be insinuated between the muscle
and the deeper structures, on the medial side of the greater
trochanter, either from above or from below according to the
side on which the limb is being dissected. Then, when the
muscle has been gently raised from the deeper structures the
reflection should be commenced, but the plan to be adopted
is different on the two sides. On the left side the muscle must
be detached from its origins from above downwards, commencing
at the posterior part of the ilium. When the surface of the
dorsum ilii from which it springs is cleared the upper margin
of the greater sciatic notch is reached. There the dissector must
proceed with caution, because through the notch pass the
gluteal vessels, and their branches enter the deep surface of the
glutseus maximus muscle. When these are secured the muscle
must be detached from the side of the sacrum ; then the piri-
formis muscle, emerging from under cover of the sacrum, comes
into sight. The muscular fibres may now be raised from the
surface of the sacro-tuberous ligament and separated from the
side of the coccyx. As this is being done, care should be taken
to preserve the three sacral cutaneous nerves intact, in order
that they may be subsequently traced to their origins. As the
surface of the sacro-tuberous ligament is gradually laid bare,
a number of small arteries (the coccygeal branches of the inferior
gluteal artery) will be seen piercing it and immediately sinking
into the substance of the glutaeus maximus. These cannot be
retained. It is necessary to sever them in order that the muscle
may be freed. The perforating cutaneous nerve, which winds



GLUTEAL REGION



289



round the lower border of the glutaeus maximus near the coccyx,
must also be remembered and traced to the sacro-tuberous liga-
ment, which it will be seen to pierce.

On the right side commence the reflection in the reverse
manner. Raise the muscle from the ischial tuberosity and

Nerve to quadratus femoris
Inferior gluteal nerve Pudendal nerve
Posterior cutaneous nerve of thigh Inferior glutea , artery

iperficial part of superior gluteal artery Internal pudendal artery

Superior gluteal nerve Nerve tQ obturator intrnus



Deep part of sup. f



gluteal artery



M. gemellus superior

M. obturator internus
M. gemellus inferior

Sacro-tuberous ligament
M. obturator externus

M. quadratus femoris

(cut)

Tuber ischiadicum
(ischial
tuberosity)




M. glutaeus medius

Ferve to tensor fasciae latae
d lateral circumflex artery



Greater trochanter
VI. quadratus femoris (cut)

Medial circumflex artery



M. adductor magnus



M. adductor magnus

LM(. semimembranosus
. semitendinosus
M. biceps femoris



FIG. 129. Dissection of the Gluteal Region. The Glutaeus Maximus and
the Glutaeus Medius have been removed, and the Quadratus Femoris has
been reflected.

separate it first from the coccyx, then from the sacro-tuberous
ligament and the side of the sacrum, and finally from the ilium.
Even when the muscle is completely separated from the parts
from which it arises it still cannot be thrown towards its insertion,
for it is tied to its place by blood-vessels and nerves which enter
its deep surface. These are (i) the branches of the superficial
division of the superior gluteal artery, which appear at the upper

VOL. I 19



2 9 o THE INFERIOR EXTREMITY

border of the piriformis ; (2) branches of the inferior gluteal
artery and the inferior gluteal nerve below the level of the piri-
formis. The venae comites of the arteries may at once be removed,
but the arteries and nerves must be cleaned as they come into
view and followed into the substance of the glutaeus maximus.
Finally, in order to allow the complete reflection of the muscle,
the arteries and nerves must be cut, but a small portion of the
muscle should be left in connection with their cut ends so that
they may be readily recognisable during the further stages of
the dissection. The whole muscle can now be thrown distally
and laterally, and, after a little dissection, an excellent view of
its insertion can be obtained.

When the reflection of the muscle is completed note
carefully the positions of the following parts: (i) the
posterior border of the trochanter major; (2) the gluteal
tuberosity which lies immediately distal to (i); (3) the
tuberosity of the ischium ; (4) the sacro-tuberous ligament.

The trochanter major is situated in the lower and lateral
part of the area exposed by the reflection of the glutaeus
maximus. Immediately distal to it is the gluteal tuberosity
into which the lower deep fibres of the glutaeus maximus are
inserted. The ischial tuberosity lies about 7 or 8 cm. medial
to the distal part of the trochanter major. If the thigh is
rotated laterally the trochanter is approximated to the
tuberosity, and it recedes from the tuberosity when the thigh
is rotated medially. 1 The sacro-tuberous ligament extends
upwards and medially, from the tuberosity of the ischium
to the margins of the sacrum and coccyx, and to the posterior
inferior and superior spines of the ilium. The inferior
border of the ligament is relatively straight It forms the
posterior boundary of the ischio-rectal fossa of the perineum,
which has already been explored by the dissector of the
abdomen. Its upper margin is curved, with the concavity
directed forwards and upwards, and immediately in front of
it are the greater and lesser sciatic foramina, which are
separated from one another by the sacro-spinous ligament
The sacro-spinous ligament can be felt where it is attached
to the spine of the ischium, 2.5 cm. above the upper border
of the tuberosity of the ischium. Note also a group of
muscles which are attached to the tuberosity and descend
from it into the posterior region of the thigh. They are the
hamstring muscles ; do not clean them at present

1 The thigh is said to be rotated medially when its anterior surface is
turned towards the median plane, and laterally when the anterior surface is
turned away from the median plane.



GLUTEAL REGION 291

Bursae Mucosse under cover of the Glutseus Maximus.
Three bursae lie under cover of the glutaeus maximus : one
between its inferior margin and the ischial tuberosity, and
two under cover of the aponeurotic part of its insertion, one
between the aponeurosis and the trochanter major, and the
other between the aponeurosis and the proximal part of the
vastus lateralis.

The bursa between the ischial tuberosity and the glutaeus
maximus is frequently multilocular, being divided into several
compartments by fibrous septa which pass from the bone to
the deep surface of the muscle. The other two bursae are
unilocular, and not infrequently they communicate with one
another.

On the second day after the body is turned on its face
the dissector must examine the muscles, vessels, and nerves
which lie directly subjacent to the glutaeus maximus, as well
as other structures situated in a deeper plane.

Before the work is commenced a pelvis with the ligaments
in situ should be obtained and the skeletal peculiarities of
the region should be studied. The interval between the
posterior part of the hip bone and the margins of the sacrum
and coccyx is divided into two foramina, the greater and
lesser sciatic foramina, by two ligaments, the sacro-tuberous
and the sacro-spinous. The sacro-tuberous ligament is the
more superficial. It extends from the posterior part of the
ilium and the margins of the lower part of the sacrum and
the coccyx to the tuberosity of the ischium. The sacro-
spinous ligament is partly covered by the sacro-tuberous
ligament. It passes from the margin of the lower part of
the sacrum and the margin of the coccyx to the spine of the
ischium. The large foramen above the sacro-spinous ligament
is the greater sciatic foramen. It lies below and behind
the lower part of the ilium, and behind the upper part of
the ischium. The foramen bounded above by the sacro-spinous
and below by the sacro-tuberous ligament is the small sciatic
foramen. It lies behind the lower part of the ischium.
Through both foramina important structures pass to or from
the gluteal region.

Emerging through the greater sciatic, foramen are the

piriformis muscle, the superior gluteal vessels and nerves,

the inferior gluteal vessels and nerve, the posterior cutaneous

nerve of the thigh, the sciatic nerve, the internal pudendal

i 19 a



292 THE INFERIOR EXTREMITY

vessels, the pudendal nerve, the nerve to the obturator
interims and superior gemellus, and the nerve to the
quadratus femoris and inferior gemellus. Through the lesser
sciatic foramen pass the obturator internus muscle, the
pudendal nerve, the nerve to the obturator internus and
the internal pudendal vessels (Fig. 129). All the structures
mentioned, as well as other muscles, vessels, and nerves, have
to be cleaned and examined. Therefore the second day's
dissection is extensive and complicated, and unless it is
proceeded with in a regular and definite manner it will not
be successfully completed.

Dissection. Commence with the superficial branches of the
superior gluteal artery, which enter the upper part of the deep
surface of the glutasus maximus, and follow them to the point
where they emerge through the cleft between the border of the
glutaeus medius and the upper border of the adjacent piriformis
muscle. Then clean the piriformis, from the great sciatic
foramen, through which it emerges, to the greater trochanter,
where its tendon disappears under cover of the glutseus medius.
After the piriformis is defined, clean the posterior cutaneous
nerve of the thigh, following it upward to its exit from the
greater sciatic foramen at the lower border of the piriformis.
Secure its perineal branch, which springs from its medial
border and passes forwards and medially towards the perineum,
anterior to the tuber ischii, and note the cutaneous branches
which were seen on the lower part of the glutaeus maximus.
The posterior cutaneous nerve is sometimes accompanied by a
branch of the inferior gluteal artery. If the inferior gluteal
vessels and nerve, which lie medial to the posterior cutaneous
nerve, were not displayed as the glutaeus maximus was reflected,
clean them now, and follow them to the lower border of the
piriformis. When the inferior gluteal artery and its branches
have been cleaned, place the leg on a large block to flex the
knee, so that the structures in the buttock and the back of the
thigh may be relaxed, then proceed to secure and clean the
sciatic nerve. It is the large white firm cord which lies immedi-
ately deep to the posterior cutaneous nerve. Therefore pull the
latter nerve medially with hooks, then at the level of the top of
the trochanter major cut longitudinally through the fascia on
the sciatic nerve till the nerve is exposed. Insert the handle
of the scalpel into the incision in the fascia and run it upwards,
along the lateral border of the nerve, to the greater sciatic foramen
and downwards to the point where the nerve passes anterior to
the biceps femoris and leaves the area of the present dissection.
Clean the fascia from the back of the nerve from the lateral to
the medial border, and secure the branches to the hamstring
muscles, which spring from the medial border, at or a little
distal to the level of the tuber ischii. Follow the branches to
the muscles and preserve the branches of the medial femoral
circumflex artery which join the nerves as they approach their
terminations.



GLUTEAL REGION 293

After the branches of the sciatic nerve to the hamstrings
have been cleaned, pull the proximal part of the sciatic nerve
laterally, to expose the nerve to the quadratus femoris, which
lies between the sciatic nerve and the posterior surface of the
ischium. The nerve to the quadratus femoris is frequently
accompanied by a small branch of the inferior gluteal artery.
On the medial side of the nerve to the quadratus femoris, lying
on the spine of the ischium, find the nerve to the obturator
internus, the internal pudendal vessels, and the pudendal nerve
in that order from the lateral to the medial side. Clean away
the venae comites of the artery, but carefully preserve the artery
itself and the nerves.

After the nerves and vessels mentioned have been identified
and cleaned, proceed to the examination of the muscles which
lie deep (anterior) to the sciatic nerve. They are, from above
downwards, the superior gemellus, the obturator internus, the
inferior gemellus, the quadratus femoris, and the proximal
part of the adductor magnus. Emerging between the adjacent
borders of the quadratus femoris and the adductor magnus the
transverse terminal branch of the medial femoral circumflex
artery will be found, and, piercing the adductor magnus at the
medial border of the gluteal tuberosity of the femur, in a well-
injected subject, the first perforating branch of the profunda
artery may be seen. Clean the arteries, and then clean the
muscles from above downwards. Note that the obturator
internus emerges from the small sciatic foramen and that as it
emerges it overlaps both the gemelli, whilst near the trochanter
major, toward which all three muscles converge, the gemelli
overlap the tendon of the obturator internus.

After the muscles are cleaned, divide the tendon of the
obturator internus about 15 mm. from the lesser sciatic
foramen. When the medial part of the tendon is raised and
turned backwards the dissector will note that its deep surface
is cleft into four or five strands, and that the margin of the
lesser sciatic foramen, on which the tendon glides, is covered
with smooth cartilage which is raised into ridges corresponding
with the grooves on the deep surface of the tendon. A large
bursa intervenes between the tendon and the bone.

Turn next to the hamstring muscles, which spring from the
tuberosity of the ischium, and separate the common tendon of
the biceps femoris and the semitendinosus from the flattened
tendon of the semimembranosus, which lies immediately sub-
jacent. Then pull the hamstrings laterally and display the
origin of the adductor magnus from the inferior part of the
tuber ischii.

Parts under Cover of the Glutseus Maximus. Four
groups of structures lie under cover of the glutaeus maximus,
viz., bursae, muscles, vessels and nerves.

The bursae, which have already been examined (see p. 291),
are three in number; (i) a bursa between the middle of the
inferior border of the glutaeus maximus and the tuber ischii,
(2) the bursa between the tendinous insertion of the glutseus
maximus and the trochanter major, and (3), immediately

1196



294



THE INFERIOR EXTREMITY



distal to the last, the bursa between the tendinous insertion
of the glutaeus maximus and the vastus lateralis.

The muscles met with between the dorsum ilii above
and the tuber ischii and the posterior area of the thigh



Nerve to quadratus femons
Inferior gluteal nerve \ Pudendal nerve
Posterior cutaneous nerve of thigh
Superficial part of superior gluteal artery
Superior gluteal nerve V



Deep part of sup.
gluteal artery



Inferior gluteal artery

Internal pudendal artery

erve to obturator internus
gemellus superior
M. obturator internus
/M. gemellus inferior
/ Sacro-tuberous ligamer
M. obturator externus

M. quadratus femoris

(cut)

Tuber ischiadicun
(ischial
tuberosity)




M. glutaeus mediu

Nerve to tensor fasciae l
and lateral circumflex artery



Greater trochanter
M. quadratus femoris (cut)

Medial circumflex arter



M. adductor magnus



\ \ M. adductor magnu
\ M. semimembranosus
M. semitendinosus
. biceps femoris



FIG. 130. Dissection of the Gluteal Region. The Glutaeus Maximus and
the Glutaeus Medius have been removed, and the Quadratus Femoris
has been reflected.

below are: (i) The posterior part of the glutaeus medius;
(2) the piriformis, issuing from the pelvis through the greater
sciatic foramen ; (3) the tendon of the obturator internus,
passing through the lesser sciatic foramen ; (4) the gemellus
superior, attached to the upper border of the obturator



GLUTEAL REGION 295

interims; (5) the gemellus inferior, attached to the inferior
border of the obturator internus ; (6) the quadratus femoris,
attached medially to the ischial tuberosity and laterally to



Online LibraryD. J. (Daniel John) CunninghamCunningham's manual of practical anatomy (Volume 1) → online text (page 29 of 44)