HIP ANATOMY
BONY ANATOMY
A. Proximal femur
1. Head, Neck Trochanters
2. Alignment of the femur
a. Angle of Inclination
1. Angle between neck and shaft of femur
2. 125- 130 degrees angle in adults
b. Coxa Vara
1. Angle less than 100degrees
2. Results in shortening of limb on affected side
c. Coxa Valga
1. Angle greater than 130 degrees
2. Results lengthening of limb on affected side sulcus
B. Pelvic / Hip Bone (Os Coxa)
1. Ilium
. Iliac crest
1. L-4
a. Fossa
b. Anterior Superior Iliac Spine (ASIS)
1. Pelvic alignment
2. Measurement of leg length
c. Posterior Superior Iliac Spine
1. S - 2
2. Location of Sacroiliac joint ( dimples)
2. Pubis
. Symphysis
1. strong, slightly moveable joint between right and left
pubic bones
2. supported by fibrocartilage and ligaments
a. Body
b. Rami
1. Superior ramus
2. Inferior ramus
3. Ischium
. Spine
1. Landmark for pudendal vessels and nerve
a. Tuberosity
4. Obturator Foramen
. Opening between ischium and pubis
a. Covered by obturator membrane
5. Acetabulum
. Socket on lateral aspect of pelvic bone
a. Formed by parts of all 3 components of the pelvic bone
b. Forms socket portion of hip joint with the femoral head
6. Notches
. Greater sciatic
1. Between ilium and ischium
a. Lesser sciatic
1. Between ischial spine and tuberosity
7. Ligaments
. Sacrotuberous
1. Sacrum to ischial tuberosity
2. Weight bearing when seated
a. Sacrospinous
1. Sacrum to ischial spine
b. Sacroiliac
1. Bind sacrum to Ilium
2. (2) Support sacroiliac joint
· LINES AND ANGLES AT THE HIP
1.Hilgen Renier Line (HRL) – line connecting the 2 hip joints
2. Perkin’s Line – vertical line passing the outer edge of acetabulum
QUADRANT - formed ny the HRL and the PL
Normal, undislocated femoral head – located in the inferomedial quadrant;
inner lower quadrant
Dislocated head- located in the outer upper quadrant or superolateral
quadrant
3. Sheton’s Line – curve line passing the femoral shaft to the
femoral neck going to the obturator foramen; or obturator
COXOFEMORAL LINE,
* if interrupted, hip is dislocated.
4. Acetabular Index - oblique line passing or intersecting the
HRL from the medial to the outer roof of the acetabulum ( lateral );
measure slope of the acetabulum
- normal value: less than 30 degrees
- if greater than 30 degrees = indicates that the
acetabular roof is inadequate so the femoral head is not covered.
5. Center Edge Angle of Wilsberg - formed by the line passing the
center of the femoral head and by the line passing the the femoral
head to the outer roof of the acetabulum
- measures the coverage of the femoral head of the acetabulum
- normal value: greater than 20 degrees, if less, roof is inadequate
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MUSCLES OF THE HIPS
The thigh is subdivided by the attachments of the fascia lata ( deep
fascia of the thigh) into 3 functional compartments). Each
compartment contains a primary functional group of muscles,
the innervation to theses muscles and a major source of arterial
blood. It is necessary to understand the attachments, innervation
and actions of these muscles in order to appreciate how the hip
functions. The anatomy of the compartments of the thigh are
covered in the text. The attachments, innervation and functions
of the thigh muscles are outlined in Chart 1.
A. A. Anterior Compartment
1. Muscles
a. Sartorius
b. Tensor fascia lata
c. Quadriceps femoris
1. Rectus femoris
2. Vastus lateralis
3. Vastus medialis
4. Vastus intermedius
d. Pectineus
e. Iliopsoas
1. Iliacus
2. Psoas
2. Nerve Supply
. Femoral ( L 2,3,4 )
a. (1) Motor
b. Quadriceps femoris
c. Sartorius
d. Pectineus
e. Sensory
f. Anterior and lateral portion of thigh
g. Medial portion of leg
3. Blood Supply
. Femoral Artery
1. Anterior Abdominal Wall
2. Deep ( profunda ) femoral
3. Muscular to muscles in anterior compartment
4. Descending Genicular
a. Deep ( Profunda ) Femoral
1. Lateral femoral circumflex
2. Medial femoral circumflex
3. Perforating
B. Medial Compartment
1. Muscles
. Pectineus
a. Adductor longus
b. Adductor brevis
c. Adductor magnus
d. Gracilis
2. Nerve Supply
. Obturator ( L 2, 3, 4 )
1. Motor to muscles in medial compartment
2. Sensory to medial portion of thigh
3. Bloody Supply
. Obturator Artery
1. Muscular branches to muscles in medial
compartment of thigh
2. Acetabular branch
3. Head of Femur
0. Important in children
C. Posterior Compartment
1. Muscles
. Hamstrings
1. Biceps femoris
2. Semimembranosus
3. Semitendinosus
2. Nerve Supply
. Sciatic ( L 4 - S 3 )
0. Motor to hamstring muscles
1. Sensory - see unit on The Leg and Foot
2. Motor deficits
3. Blood Supply
. Perforating branches of Deep femoral artery
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JOINTS AND LIGAMENTS
Hip Joint
A. Type
1. A multiaxial ball and socket synovial joint between
the head of the femur and the acetabulum of the coxal
( pelvic ) bone.
B. Fibrous Capsule
1. Proximal attachment - encircles rim of acetabulum
2. Distal Attachment
a. anterior - greater trochanter,
intertrochanteric line
b. posterior - neck of femur
c. capsule incomplete posteriorly
C. Ligaments
1. Iliofemoral
a. Covers hip joint anteriorly
b. Arises from anterior inferior iliac spine
c. Inserts into intertrochanteric line
2. Pubofemoral
a. Covers hip joint anteriorly
b. Arises from pubic bone and margin of
obturator foramen
c. Inserts into femoral neck deep to
iliofemoral ligament
3. Ischiofemoral
a. Covers hip joint posteriorly
b. Arises from ischium
c. Inserts into greater trochanter of femur
4 Functions
. Limit Motion
1. Pubofemoral ligament limits abduction
2. Lateral band of iliofemoral ligament limits
adduction
3. Medial band of iliofemoral ligament limits
lateral rotation
4. Ischiofemoral ligament limits medial rotation
Stability
1. Iliofemoral Ligament becomes taut in extension
preventing the femur from moving past
vertical position ( resists hyperextension)
2. Maintains hip in locked or stable configuration
D. Intracapsular
1. Ligament of the head of the femur
. Very Weak
a. Conveys branches of obturator artery to head
of femur
E. Retinacula
1. Composed of fibers derived from fibrous capsule
2. Retinacula fibers reflect back along femoral neck
towards the femoral head
3. Convey small arteries to head of femur
. Branches of medial and lateral
femoral circumflex arteries
a. Main blood supply to femoral head
b. Commonly found on anterior surface of
femoral neck
F. Fractures/ Dislocation
1. Fracture of femoral neck
. Could disrupt retinacula and blood
supply to femoral head
a. Avascular necrosis of femoral head
b. Limb outwardly rotated
1. Pull of lateral rotator muscles
2. Dislocation
. Limb is shortened and inwardly
rotated
G. Cruciate anastomosis ( collateral circulation
posterior to hip joint)
1. Deep Femoral
. Transverse branch of lateral femoral
circumflex artery
a. Medial femoral circumflex a.
b. Recurrent branch of 1st. perforating a.
2. Inferior gluteal artery
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KINESIOLOGY
III. LOCKING OF THE HIP JOINT
A. Function
1. Permits standing upright with little expenditure
of energy in the form of muscle contraction
2. Occurs when the head of the femur and the
acetabulum are congruent ( fit tightly together
and the iliofemoral ligament becomes taut. )
B. Mechanism
1. Fibrous Capsule
a. Iliofemoral Ligament
1. Covers hip joint anteriorly and interiorly
2. Tightens during hip extension
3. Prevents femur from moving past vertical
position ( resists hyperextension)
b. Ischiofemoral ligament
1. Winds transversely across posterior aspect
of hip
2. Tightens upon hip extension
3. Much weaker than iliofemoral ligament
C. Process
1. Center of mass of the body falls behind hip joint
2. Gravity forces the hip posteriorly into a position
of extension
3. In the extended position, the hip joint locks
. The femoral head fits tightly into the
acetabulum
. Iliofemoral ligament becomes taut
preventing hyperextension
4. Weight of the body supported by
iliofemoral ligament
IV. MOVEMENTS OF THE HIP
Properties of the Hip Joint
1. Multiaxial ball and socket joint
2. Types of Movement - Movements of the lower
limb can best be understand if one realizes
that different bones will move depending upon
whether the limb is in weight bearing or non
weight bearing. In either case the movement is
the same and the same muscles act. It just that
different bones can move given the different
situations.
a. Weight bearing (fixed) -foot in contact with
ground and the limb is supporting weight
of body
1. Pelvis moves on a fixed femur
2. Bending down to touch toes
b. Non Weight bearing (free) - foot free of
ground and the limb is up to support
weight of body
1. Femur free to move on a fixed pelvis
2. Kicking a ball
A. Movements at the Hip
1. Flexion / Extension
. Occurs in sagittal plane
a. Transverse ( side to side) axis through
head of femur
2. Adduction / Abduction
. Occurs in frontal plane
a. Anterior / posterior axis through head
of femur
3. Inward / Outward Rotation
. Occurs in transverse plane
a. Vertical axis through head of femur
and lateral femoral condyle
B. Muscle Actions
1. Muscles acting to move the hip include the
gluteal muscles, the iliopsoas , and muscles
of the thigh. The Chart lists the movement
that can occur at the hip joint and the
muscles acting as prime movers for
each motion
V. CLINICAL CONSIDERATIONS
A. Actions of the Hip Joint During Gait
1. Acceleration and Heel Strike
a. Restraining the forward movement of
the lower limb occurs during this
interval through the eccentric
contractions of hamstring and gluteus
maximum muscles acting on the hip joint.
This restraining action leaves the hip in a
flexed position.
b. The gluteus medius and gluteus
minimus contract concentricly abducting
the reference limb from a weight bearing
position. This involves moving the iliac
crest of the reference limb away from
the midline (abduction). The iliac crest
moves instead of the femur because
at heel strike, the foot of the reference
limb is in contact with the ground and
in a weight bearing position. The femur
can not move so the muscles act on
the iliac crest which can move.
Concomitantly, the non weight
bearing hip is "hiked" upward
counterbalancing the effect that gravity
wants to exert on the non reference
limb which is about to attain a non
weight bearing position .Without the
concentric contraction of the hip
abductors on the weight bearing reference
limb, the opposite hip would tilt downward
making it very difficult to swing the
limb forward in order to take a step.
This type of gait is called "Trendelenburg
Gait"
2. Heel Strike to Midstance
. The torso is being pulled over the center
of the reference limb as the non
reference limb swings forward. This
puts the hip in a neutral position
without any direct actions of muscles
acting on the hip.
3. Midstance to Toe Off
. The non reference limb is in a non
weight bearing stage and is swinging
forward as a step is taken. This process
"drags" the torso in front of the reference
limb forcing the hip joint of the weight
bearing reference limb into an extended
position. Once again, this occurs without
the direct action of the muscles acting
on the reference limb.
4. Toe Off to Acceleration
. During this interval, the reference
limb goes from a weight bearing to a
non weight bearing position as the
reference limb begins to swing forward
ahead of the torso as a step is being taken.
Powerful concentric contractions of the hip
flexors, mainly the iliopsoas muscle
with help from the adductor muscles bring
the hip into a position of flexion.
a. The hip adductors also helps the swinging
limb move in an inward direction. This
enables the foot to be placed under the
pelvis rather than in a position that would
be parallel with the shoulder.
B. The Effect of Nerve Lesions on the Hip Joint
During Gait
1. Superior gluteal nerve
. Trendelenburg Gait
1. Marked downward tilting of the
hip on the non weight bearing
side due to inability of the gluteus
medius and minimus to actively
abduct the hip on the weight
bearing side during walking
a. Trendelenburg Sign
1. Clinical test to determine the
integrity of the superior gluteal
nerve
2. Patient's hip tilts down when the
limb is non weight bearing
because of superior gluteal nerve
is damaged on weight bearing
side.
2. Obturator nerve
. "Waddling gait"
1. Hip is in a marked abducted
position due to paralysis of hip
adductor muscles.
2. When walking, the foot on the
affected side, can not be placed
under pelvis. Patient has to
"throw" their weight laterally
when taking a step thus,
waddling to the affected side.
C. Lumbar and Lumbosacral Nerve Root I
nvolvement
1. L 1,2
. These roots are mainly involved
with innervating the iliopsoas muscle.
Damage to these roots would result in
very weak hip flexion
a. To test for the integrity of these roots,
ask the patient to sit. Then have them
try and flex the hip from a sitting position.
Weak hip flexion indicates a problem with
the L 1,2 nerve roots
2. L 2,3
. These roots are concerned with the
innervation of the hip abductors. Damage
to these roots can lead to a waddling type
of gait.
a. To test for the integrity of these roots,
have the patient lie on the side with their
body in a straight line. Place the upper hip
into abduction and place each hand on the
inside of each thigh. Have the patient try
and bring the hips into adduction.
Weakness could indicate a lesion of the
L 2,3 nerve roots
3. L 5
. This is the main root innervating the
gluteus medius and minimus muscles. A
positive. Trendelenburg Sign could
indicate damage to this root.
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