D. J. (Daniel John) Cunningham.

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obturator foramen of the hip bone (Fig. 125). While still
within the foramen it divides into an anterior and a
posterior division.
VOL. i is



274



THE INFERIOR EXTREMITY



The anterior division of the obturator nerve enters the thigh
over the upper border of the obturator externus muscle, and
proceeds, distally, upon the anterior surface of the adductor
brevis. Anterior to it are the pectineus and adductor longus
muscles. It gives branches to three muscles, viz., the adductor
longus, the adductor brevis, and the gracilis. Very rarely



A.B. Adductor brevis.
Ace. Accessory obturator

nerve.

A. L. Adductor longus.
A.M. Adductor magnus.

G. Gracilis.

G.Ma. Glutaeus maximus.
I.C. Medial circumflex
artery of the thigh.
Obt. Obturator nerve.
O.K. Obturator externus.




O.I. Obturator internus
P. Pectineus.
Py. Piriformis muscle,
Q. Quadratus femoris
+. Branch to hip join

1. Cutaneous branch

2. Twig to walls

femoral artery.

3. Branch to kni

joint.



FIG. 124. Diagram to illustrate the distribution of the Obturator Nerve and
the general disposition of the Adductor Muscles of the Thigh (Paterson).

it supplies a twig to the pectineus. In addition to these
branches it also supplies (i) an articular branch to the hip
joint (Fig. 124. + ); (2) a fine twig, which appears at the
distal border of the adductor longus, to join the sub-sartorial
plexus ; and (3) a terminal twig, which goes to the femoral
artery -(Fig. 124) and breaks up into fine filaments upon
its walls.



MEDIAL SIDE OF THE THIGH



275



The posterior branch of the obturator nerve, as it enters the
thigh, pierces the upper border of the obturator externus. It
extends distally, between the adductor brevis and the
adductor magnus, and is expended chiefly in the supply
of the latter muscle. It gives also, however, a branch to
the obturator externus and an articular branch to the knee
joint. The latter branch pierces the distal part of the

Femoral nerve (O.T. ant. crural)

Lumbo-inguinal nerve
Femoral sheath
Femoral canal
Obturator artery
Obturator nerve
Adductor longus ^in^S&




FIG. 125. Dissection to show the Structures surrounding the Obturator
Foramen of the Hip Bone.

adductor magnus, close to the linea aspera, and may be
seen in the popliteal fossa, lying posterior to the popliteal
artery.

M. Gracilis. The gracilis is a long, strap - like muscle,
which lies along the medial aspect of the thigh and knee. It
springs, by a thin tendon, from the lower half of the body of the
pubis, close to the symphysis, and also from the upper half of
the pubic arch (Fig. 119). It ends in a slender, rounded



276 THE INFERIOR EXTREMITY

tendon which inclines forwards, distal to the knee, and then
expands and is inserted into the proximal part of the medial
surface of the tibia, under cover of the tendon of the sartorius,
and at a higher level than the insertion of the semi-
tendinosus (Fig. 139, p. 322). A mucous bursa separates the
expanded tendon of the gracilis from the tibial collateral liga-
ment of the knee joint, and is prolonged proximally, so as to
intervene between it and the tendon of the sartorius. The
gracilis is supplied by the anterior division of the obturator nerve.
It adducts the thigh, flexes the knee joint and rotates the
leg medially.

M. Adductor Magnus. The adductor magnus is one of
the most powerful muscles of the thigh. It forms a flat, fleshy
mass, which springs from the anterior surface of the entire length
of the pubic arch of the corresponding side, and from the lower
part of the ischial tuberosity (Figs. 128, 129). The fibres
which arise from the pubic arch spread out as they approach the
posterior aspect of the femur ; the more medial in origin are
the more horizontal in direction ; the more lateral in origin
are the more oblique in direction. They are inserted into the
posterior part of the femur, just medial to the gluteal tuberosity,
into the linea aspera, and into a small portion of the proximal
part of the medial supracondylar ridge (Figs. 121, 122). The
fibres which take origin from the ischial tuberosity descend
almost vertically and form the thick medial border of the
muscle. In the distal third of the thigh they end in a strong,
rounded tendon, which is inserted into the adductor tubercle
on the medial condyle of the femur (Figs. 120, 121). This
tendon is further attached to the femur by the medial inter-
muscular septum which stretches between it and the medial
supracondylar line. Close to the linea aspera are the
fibrous arches, formed in connection with the insertion of the
adductor magnus, for the passage of the perforating arteries,
and in series with them is the opening through which
the femoral artery enters the popliteal fossa. The opening
is a gap between two portions of the muscle, and is situated
at the junction of the proximal two-thirds with the distal
third of the thigh (Fig. 120).

The adductor magnus has a double nerve supply. The
fibres which spring from the pubic arch are supplied by the
posterior branch of the obturator nerve. Those which arise
from the ischial tuberosity are supplied by the sciatic nerve.



MEDIAL SIDE OF THE THIGH 277

The fibres which spring from the rami of the pubis and
ischium act like the fibres of the other adductor muscles, that
is, they adduct the thigh, rotate it laterally, and help to flex
the hip joint, but the fibres which arise from the tuberosity of
the ischium and are inserted, by tendon, into the adductor
tubercle of the femur extend the hip joint.

Dissection. Detach the adductor magnus from its origin
from the pubic and ischial rami, in order that the obturator
externus muscle and the obturator artery may be more fully
examined.

M. Obturator Externus. The obturator externus is
a flat, fan-shaped muscle, which is placed over the anterior
aspect of the obturator foramen of the hip bone. It
springs from the medial half of the membrane which closes
the foramen, and also from the medial and lower part of its
bony margin (Figs. 119, 128). It passes backwards and
laterally, below and behind the neck of the femur and the
capsule of the hip joint, and ends in a stout tendon which
obtains insertion into the trochanteric fossa (Figs. 121, 122).
This tendon will be examined in the dissection of the gluteal
region. The obturator externus is supplied by the posterior
division of the obturator nerve. It is a flexor of the hip joint
and an adductor and lateral rotator of the thigh.

Art. Obturatoria. The obturator artery appears in the
thigh through the upper part of the obturator foramen of
the hip bone. It at once divides into two terminal branches,
which diverge from each other and form an arterial circle
upon the obturator membrane, under cover of the obturator
externus. The muscle must therefore be detached in order
that the vessels may be followed. Both branches give twigs
to the neighbouring muscles, whilst the posterior branch
sends an articular twig through the acetabular notch into
the hip joint. When the joint is opened this twig may be
followed, in a well-injected subject, along the ligamentum
teres into the head of the femur.

Mm. Psoas Major and Iliacus. Both the psoas major and
the iliacus muscles arise within the abdomen, and they enter
the thigh posterior to the inguinal ligament. A tendon
appears on the lateral side of the psoas major, and into this
the fibres of the iliacus are for the most part inserted. The
conjoined tendon of the ilio-psoas is implanted into the lesser
trochanter of the femur, but a certain proportion of the fleshy

i 18 a



278 THE INFERIOR EXTREMITY

fibres of the iliacus obtain direct insertion into the body of
the femur, distal to that prominence (Figs. 121, 122).

The action of the psoas major and the iliacus depend
upon the position of the hip joint when the muscles are in
action. If the hip joint is extended they flex it, and rotate
it medially until it is flexed ; then they rotate it laterally.

Dissection. Divide the femoral vessels and the femoral
nerve, about an inch distal to the inguinal ligament, and having
tied them together with twine throw them distally. Now cut
through the sartorius and the rectus femoris, about two inches
from their origins, and turn them aside. The tendon of the
ilio-psoas must next be detached from its insertion and, with
the muscle, turned upwards. This will expose the anterior
surface of the capsule of the hip joint. An intervening mucous
bursa also will be displayed. Open this and ascertain its extent
by introducing the finger. It facilitates the play of the ilio-
psoas upon the front of the hip joint, and in some cases its cavity
will be found to be directly continuous with the cavity of the
joint, through an aperture in the capsule. The intimate con-
nection which exists between the capsule of the hip joint and
the tendon of the glutseus minimus, the reflected head of the
rectus femoris, and the deep layer of the ilio-tibial tract, should
be noticed. Lastly, turn aside the tensor fasciae latae, and
carefully clean the anterior aspect of the capsule of the hip joint.

At the end of the fifth day the dissector must paint the
various parts of the anterior and medial regions of the thigh
with preservative solution, replace them in position and fix
the skin flaps over them with a few points of suture.

On the morning of the sixth day, after the dissection of
the lower limb has been begun, the subject is placed upon
the table with its face downwards and its thorax and pelvis
supported by blocks. In that position it is allowed to
remain for five days, and during that time the dissector
of the lower extremity has a very extensive dissection to
perform. He has to dissect (i) the gluteal region; (2) the
popliteal fossa ; and (3) the posterior region of the thigh.
With so much work before him, and being limited as to the
time in which it must be done, it is necessary that he should
apportion the five days at his disposal so as to complete the
dissection before the body is turned again. The first two
days he should devote to the study of the gluteal region ; the
third and fourth days may be given to the popliteal fossa ;
and on the fifth day he should undertake the dissection of
the back of the thigh, and revise the work of the preceding
four days.



GLUTEAL REGION 279



GLUTEAL REGION.

In the gluteal region the following parts will be displayed
in the course of the dissection :

1. Superficial fascia.

2. Cutaneous nerves and blood-vessels.

3. Deep fascia.

'Glutseus maximus (and after this has been reflected),
Three mucous bursse.
The glutseus medius and minimus.

The two gemelli muscles and the tendon of the obturator internus.
Tendon of the obturator externus.
Proximal border of the adductor magnus.
The origin of the hamstrings from the ischial tuberosity.
^The proximal part of the vastus lateralis.
5. The sacro-tuberous ligament. (O.T. great sciatic lig.)

f Superior gluteal.

f- A . Inferior gluteal (O.T. sciatic).

es ' ' 1 1nternal pudenda!.

V Medial femoral circumflex.
Superior gluteal.
Sciatic.
Posterior cutaneous of the thigh.



7. Nerves



Pudendal.
Nerve to obturator internus.
Nerve to quadratus femoris.
Inferior gluteal.



Supposing that two days are allowed for the above dissection, the first
day's work should consist of (i) the dissection of the parts superficial to
the glutseus maximus ; (2) the cleaning and reflecting of that muscle ; (3)
the tracing and defining of the various nerves and blood-vessels which enter
its deep surface. On the second day the parts which are exposed by the
reflection of the glutseus maximus should be dissected.

Surface Anatomy. Before the skin is reflected the surface
markings of the gluteal region must be examined. On each
side the prominence of the nates forms a round, smooth
elevation. Inferiorly the nates are separated, in the middle
line, by a deep fissure the natal cleft. The cleft can be
traced upwards over the coccyx to the level of the lower
part of the sacrum where it disappears. The crest of
the ilium can be felt along its whole length, and in the
well -formed male its position is indicated by a groove
the iliac furrow. The anterior end of the crest terminates
in the anterior superior spine of the ilium; the posterior
end is the posterior superior spine of the ilium. The
position of the latter is indicated by a faint depression or
dimple which lies on a level with the second spine of the
1186



280 THE INFERIOR EXTREMITY

sacrum, and it corresponds with the middle of the sacro-
iliac articulation. The prominence of the nates is formed
chiefly by the glutaeus maximus muscle, covered by a thick
layer of fat. A deep transverse groove, produced by a fold of
skin and fascia, limits the gluteal elevation below. The groove
is called the gluteal sulcus^ and is sometimes said to correspond
with the distal border of the glutaeus maximus muscle. It can
easily be shown that this is not the case. Its medial end lies
distal to the inferior margin of the muscle, but as the sulcus
proceeds transversely it crosses the border of the muscle, and
finally comes to lie on the surface of the muscle. In disease
of the hip joint, the buttock loses its prominence, whilst
the gluteal sulcus becomes faint. The tuberosity of the
ischium may be felt, deep to the lower border of the glutaeus
maximus, if the fingers are placed in the medial part of the
gluteal sulcus and pressed upwards. A line drawn from the
most prominent part of this tuberosity to the anterior superior
spine of the ilium is called Nelatorfs line \ it passes over
the top of the greater trochanter and crosses the centre of
the acetabulum; and it is used by the surgeon in the diagnosis
of dislocations and other injuries of the hip joint. The greater
trochanter of the femur may be felt at a point about six inches
below the highest part of the crest of the ilium. It can be
seen in thin subjects, but it does not form so projecting a
feature of this region as might be expected from an in-
spection of the skeleton, because the thick tendon of the
glutaeus medius is inserted into its lateral surface, and it is
covered also by the aponeurotic insertion of the glutaeus
maximus.

Dissection. Reflection of Skin. Incisions. (i) From the
posterior superior spine of the ilium in a curved direction along
the crest of the ilium, as far forwards as the position of the body
will permit ; (2) from the posterior extremity of this curved
incision obliquely downwards and medially to the middle line
of the sacral region, and then perpendicularly to the tip of the
coccyx ; (3) from the tip of the coccyx obliquely distally and
laterally over the back of the thigh, to the junction of the proximal
and distal halves of the posterior border of the lateral area of
the thigh.

A large flap of skin is thus marked out, and this must be
raised from the subjacent superficial fascia and thrown laterally.
On the right side of the body the dissector begins at the crest of
the ilium and works downwards and forwards ; whilst on the left
side he commences over the coccyx and works upwards and
forwards.



GLUTEAL REGION 281

Superficial Fascia (Panniculus Adiposus). After the skin



Mastoid pro(

Spine of scapula
Acromion

Inferior angle of scapula t



Superior nuchal line
External occipital protuberance

Spine of seventh cervical vertebra



Posterior superior
spine of ilium'



Tip of coccyx

Greater trochanter
Tuberosity of ischium



Medial condyle of femur 4|2
Lateral condyle of femur ^
Lateral condyle-of tibia i
Head of fibula '




Medial epicondyle
Olecranon

Head of radius



Styloid process of ulna
Styloid process of radius



Medial malleolus
~~~WC Lateral malleolus



FIG. 126. Surface view, showing incisions and bony points.

is reflected the superficial fascia which is exposed, is seen to



282



THE INFERIOR EXTREMITY



partake of the same characters as the corresponding layer of

fascia in other parts of
the body. It presents,
however, certain special
peculiarities. It is much
more heavily laden with
fat more particularly so
in the female ; it thickens
over the upper and lower
margins of the glutaeus
maximus, and it becomes
tough and stringy over
the ischial tuberosity,
where it forms a most
efficient cushion upon
which this bony promin-
ence rests while the body
is in the sitting posture.

Nervi Cutanei (Fig.
127). The cutaneous
nerves of the gluteal
region are numerous.
Some of them are difficult
to find and, if the sub-
ject is obese, many of
them are so embedded
in the fat, at different
levels, that a satisfactory
display of the whole series
is not easily obtained.
Therefore the dissector,
working upon the buttock
for the first time, mnst
not be disappointed if the
final result of his work
does not quite realise his
hopes and expectations.

The nerve twigs dis-

riG. 127. Cutaneous Nerves on the .

posterior aspect of the Inferior Extremity, tnbuted to the skin of

the gluteal region are

derived from the anterior ramus of the last thoracic and
from the anterior and posterior rami of the lumbar and



Lumbar nerves-
Cutaneous branches
of the 1 2th thoracic
and ilio-hypogastric
nerves

Sacral nerves"

Perforating

cutaneous

Branches from

posterior cutaneous

nerve of the thigh

Lateral cutaneous

nerve of the thigh"

Long peririeal

Posterior cutaneous
nerve of the thigh
Medial cutaneous
nerve of the thigh

Lateral cutaneous,
nerve of the thigh



Medial cutaneous
nerve of the thigh"



Anastomotic peroneal
nerve '

Posterior cutaneous nerve
of the thigh



Medial cutaneous nerve of

the calf (O.T. ramus com-

municans tibialis)



Nervus suralis (O.T. short
saphenous)



Medial calcanean nerve



GLUTEAL REGION 283

sacral nerves, and they ramify, as in other regions, in the
superficial fascia on their way towards their terminations.
The nerves which must be sought for are

Lateral branch of last thoracic.
Lateral branch of the ilio-hypogastric.
Twigs from the posterior branch of
the lateral cutaneous nerve of the



Branches of anterior rami of
spinal nerves.



thigh.
Twigs from the posterior cutaneous

nerve of the thigh.
.The perforating cutaneous nerve.

Branches of posterior rami of f Br ches from the three upper lumbar

spinal nerves. 1 Ti^T'

[Three branches from the sacral nerves.

The branches of the sacral nerves supply the skin of the
lower and medial area of the buttock. The lumbar nerves
are distributed to the upper part of the medial area and to
the upper two-thirds of the intermediate area. The lateral
branches of the ilio-hypogastric, the last thoracic nerve, and
the lateral cutaneous nerve of the thigh supply the lateral
area, and the lower area along the fold of the buttock receives
the perforating cutaneous nerve and twigs from the posterior
cutaneous nerve of the thigh (Fig. 127).

Dissection. Seek first for the branches of the posterior rami
of the sacral nerves. Make an incision through the superficial
fascia along a line, commencing 2 cm. medial to the posterior
superior spine of the ilium and terminating at the tip of the
coccyx. Then reflect the lateral part of the superficial fascia
away from the median plane and secure the nerves as they
pierce the deep fascia superficial to the sacral and coccygeal
origins of the glutaeus maximus muscle. They are usually three
in number ; all are small, but the middle of the three is usually
the largest of the series, and as a rule they are situated about
25 mm. from one another.

The branches of the posterior rami of the lumbar nerves
should next be sought. Make an incision into but not through
the superficial fascia along the line of the crest of the ilium.
The object of the incision is to enable the dissector to raise a
superficial layer of the superficial fascia, and its depth must
vary with the obesity of the subject. In a very fat subject it
may be 3 or 4 mm. deep, but in a thin subject it must not be
more than 2 mm. deep. After the incision is made, raise a
superficial layer of the lower part of the superficial fascia, throw
it towards the trochanter major, and secure twigs of the lumbar
nerves as they pass from the deeper to the more superficial layers
of the fascia. As soon as a twig is found, follow it towards the
iliac crest ; it will lead to the trunk from which the twig issues.
As soon as the trunk is secured, trace it and its branches towards
their terminations. As the branches are being cleaned twigs
from the adjacent lumbar nerves are certain to be exposed, for



284 THE INFERIOR EXTREMITY

the twigs from adjacent nerves cross one another and sometimes
unite with one another. Trace such twigs to their sources of
origin ; when the trunk from which they arise is found, follow
it and its branches to their peripheral distribution. If the plan
outlined is followed the dissector will demonstrate the branches
of the lumbar nerves without any great difficulty. He should
then attempt to find the lateral branches of the ilio-hypogastric
and last thoracic nerves, following the same plan of search.
The trunks of the two branches cross the iliac crest anterior to
the lumbar nerves, the lateral branch of the last thoracic about
5 cm. posterior to the anterior superior spine of the ilium and
the lateral branch of the ilio-hypogastric a centimetre or more
further back. If the branches of the posterior division of the
lateral cutaneous nerve of the thigh were found and left in
position when the anterior part of the thigh was dissected, they
may be revised now, otherwise the dissector need waste no time
in looking for them, for they will have been already removed.
No time need be lost in looking for the perforating cutaneous
nerve. It pierces the deep fascia and enters the superficial fascia
near the medial part of the lower border of the glutseus maximus
about 2 or 3 cm. from the tip of the coccyx and medial to the
ischial tuberosity, and it has either been displayed and left in
situ by the dissector of the perineum, or it has been removed.
To display the gluteal branches of the posterior cutaneous nerve
of the thigh, cut through the superficial fascia along the lower
border of the glutaeus maximus till the deep fascia is exposed,
then reflect the superficial fascia upwards and secure the branches
sought for as they pierce the deep fascia about midway between
the trochanter major and the tuber ischii.

In well-injected subjects many of the nerves mentioned are
accompanied by small injected arteries which serve as guides
to the nerves, but such arteries cannot be depended upon, and
the dissector should rely upon his senses of sight and touch to
enable him to distinguish the firmer nerve fibres from the strands
of connective tissue which permeate the fat.

After the cutaneous nerves have been demonstrated the
remains of the superficial must be removed both from the
region of the glutaeus maximus and the region anterior to it in
order that the deep fascia may be examined.

Deep Fascia. The deep fascia now exposed differs in
character in the anterior and posterior pans of its extent.
In front of the glutaeus maximus, where the fascia lies over the
anterior part of the glutaeus medius, it is dense in texture
and opaque and pearly white in colour. That part stands
in marked contrast with the deep fascia over the glutaeus
maximus itself, which is thin and transparent. Subsequent dis-
section will show that the dense fascia over the anterior part
of the glutaeus medius, when it reaches the anterior border
of the glutaeus maximus, splits into two lamellae which
enclose the glutaeus maximus between them.

Dissection. Follow the branches of the posterior cutaneous



GLUTEAL REGION 285

nerve of the thigh to the trunk of that nerve at the lower border
of the glutaeus maximus, and after the trunk of the nerve is
secured, proceed to clean the glutaeus maximus. The dissector
of the right inferior extremity should begin at the upper border
of the muscle and work downwards, the dissector of the left
limb should work upwards from the inferior border. On the
right side the dissector should cut through the deep fascia a
little below the upper border of the muscle, then he should
raise the upper portion of the divided fascia until the upper border
of the muscle is exposed, and the fascia superficial to it is
found to blend with the strong fascia covering the glutaeus
medius. The upper border of the muscle should now be raised
and drawn downwards to display the layer of deep fascia sub-
jacent to it. When this has been done the dissector will readily
realise that the strong fascia on the more anterior part of the



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